http://www.mdpi.com/journal/molecules/special_issues/phenolics/ Submission All manuscripts should be submitted to molecules@mdpi.org with a copy to the Guest Editor. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website. Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed Open Access monthly journal published by MDPI. Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this Open Access journal is 1400 CHF per accepted paper. http://www.mdpi.com/1420-3049/14/10/4136/ This report describes the characterization of a series of commercially available procyanidin standards ranging from dimers DP = 2 to decamers DP = 10 for the determination of procyanidins from cocoa and chocolate. Using a combination of HPLC with fluorescence detection and MALDI-TOF mass spectrometry, the purity of each standard was determined and these data were used to determine relative response factors. These response factors were compared with other response factors obtained from published methods. Data comparing the procyanidin analysis of a commercially available US dark chocolate calculated using each of the calibration methods indicates divergent results and demonstrate that previous methods may significantly underreport the procyanidins in cocoa-containing products. These results have far reaching implications because the previous calibration methods have been used to develop data for a variety of scientific reports, including food databases and clinical studies. http://www.mdpi.com/1420-3049/14/10/4136/ Thu, 15 Oct 2009 00:00:00 CEST Molecules 2009-10-15 14 10 Article 4136 4146 1420-3049 Characterization of Primary Standards for Use in the HPLC Analysis of the Procyanidin Content of Cocoa and Chocolate Containing Products 2009-10-15 doi: 10.3390/molecules14104136 William J. Hurst Bruce Stanley Jan A. Glinski Matthew Davey Mark J. Payne David A. Stuart http://www.mdpi.com/1420-3049/14/6/2202/ In recent years, few classes of natural products have received as much attention as phenolics and polyphenols. This special issue of Molecules, “Phenolics and Polyphenolics”, is a remarkable confirmation of this trend. Several aspects related to phenolics chemistry, comprising the several classes, will be discussed. In addition, the increasing interest in phenolics’ biological activities is covered, and several works addressing this matter are referred. http://www.mdpi.com/1420-3049/14/6/2202/ Wed, 17 Jun 2009 00:00:00 CEST Molecules 2009-06-17 14 6 Editorial 2202 2211 1420-3049 Phenolics: From Chemistry to Biology 2009-06-17 doi: 10.3390/molecules14062202 David M. Pereira Patrícia Valentão José A. Pereira Paula B. Andrade http://www.mdpi.com/1420-3049/14/4/1404/ The ethanolic extract from seed kernels of Thai mango (MSKE) (Mangifera indica L. cv. ‘Fahlun’) (Anacardiaceae) and its major phenolic principle (pentagalloyl glucopyranose) exhibited dose-dependent inhibitory effects on enzymatic activities of phospholipase A2 (PLA2), hyaluronidase and L-amino acid oxidase (LAAO) of Calloselasma rhodostoma (CR) and Naja naja kaouthia (NK)venoms by in vitro tests. The anti-hemorrhagic and anti-dermonecrotic activities of MSKE against both venoms were clearly supported by in vivo tests. Molecular docking studies indicated that the phenolic molecules of the MSKE could selectively bind to the active sites or their proximity, or modify conserved residues that are critical for the catalysis of PLA2, and selectively bind to the LAAO binding pocket of both CR and NK venoms and thereby inhibit their enzymatic activities. The results imply a potential use of MSKE against snake venoms. http://www.mdpi.com/1420-3049/14/4/1404/ Tue, 31 Mar 2009 00:00:00 CEST Molecules 2009-03-31 14 4 Article 1404 1422 1420-3049 Molecular Docking Studies and Anti-enzymatic Activities of Thai Mango Seed Kernel Extract Against Snake Venoms 2009-03-31 doi: 10.3390/molecules14041404 Jiraporn Leanpolchareanchai Pimolpan Pithayanukul Rapepol Bavovada Patchreenart Saparpakorn http://www.mdpi.com/1420-3049/14/3/1098/ This study was designed to determine the gastroprotective effect of a Mangifera indica leaf decoction (AD), on different experimental models in rodents. The administration of AD up to a dose of 5 g/kg (p.o.) did not produce any signs or symptoms of toxicity in the treated animals, while significantly decreasing the severity of gastric damage induced by several gastroprotective models. Oral pre-treatment with AD (250, 500 or 1000 mg/kg) in mice and rats with gastric lesions induced by HCl/ethanol, absolute ethanol, non-steroidal anti-inflammatory drug (NSAID) or stress-induced gastric lesions resulted in a significant decrease of said lesions. Phytochemical analyses of AD composition demonstrated the presence of bioactive phenolic compounds that represent 57.3% of total phenolic content in this extract. Two main phenolic compounds were isolated, specifically mangiferin (C-glucopyranoside of 1,3,6,7-tetrahydroxyxanthone) and C-glucosyl-benzophenone (3-C-β-D-glucopyranosyl-4’,2,4,6-tetrahydroxybenzophenone). These findings indicate the potential gastroprotective properties of aqueous decoction from M. indica leaves. http://www.mdpi.com/1420-3049/14/3/1098/ Tue, 10 Mar 2009 00:00:00 CET Molecules 2009-03-10 14 3 Article 1098 1110 1420-3049 Polyphenols with Antiulcerogenic Action from Aqueous Decoction of Mango Leaves (Mangifera indica L.) 2009-03-10 doi: 10.3390/molecules14031098 Juliana Aparecida Severi Zeila Pinheiro Lima Hélio Kushima Alba Regina Monteiro Souza Brito Lourdes Campaner dos Santos Wagner Vilegas Clélia Akiko Hiruma-Lima http://www.mdpi.com/1420-3049/14/3/1072/ Around 20,000 snakebites are reported annually in Brazil and 90% of them are inflicted by species of the genus Bothrops. Intravenous administration of antibothropic antivenom neutralizes the systemic actions, but it is of little effect on the reversal of local symptoms and often induces adverse reactions, a context that drives the search for complementary treatments for snakebite accidents. Vegetable extracts with a range of antiophidian activities constitute an excellent alternative. In this study, we investigated the anti-hemorrhagic effects of Mouriri pusa Gardn. (Melastomataceae), Byrsonima crassa Niedenzu (Malpighiaceae), Davilla elliptica St. Hill. (Dilleniaceae) and Strychnos pseudoquina St. Hil. (Loganiaceae) against Bothrops jararaca venom. The methanolic extracts from M. pusa (leaves), B. crassa (leaves) and D. elliptica (leaves) showed total neutralization capacity against local hemorrhages. The amenthoflavone and quercetin fractions from B. crassa and the flavonoids fractions (quercetin and myricetin) from M. pusa and D. elliptica also showed total neutralization capacity. We conclude that flavonoids derived from myricetin, quercetin and amenthoflavone play an important role in the anti-hemorrhagic potential of these Brazilian vegetables species against B. jararaca venom. http://www.mdpi.com/1420-3049/14/3/1072/ Mon, 09 Mar 2009 00:00:00 CET Molecules 2009-03-09 14 3 Article 1072 1080 1420-3049 Anti-hemorrhagic Activity of Four Brazilian Vegetable Species Against Bothrops jararaca Venom 2009-03-09 doi: 10.3390/molecules14031072 Catarine Massucato Nishijima Nishijima Clenilson Martins Rodrigues Marcelo Aparecido Silva Mônica Lopes-Ferreira Wagner Vilegas Clélia Akiko Hiruma-Lima http://www.mdpi.com/1420-3049/14/3/959/ The effect of [10]-gingerol on cytosol free Ca2+ concentration ([Ca2+]i) and viability is large unknown. This study examines the early signaling effects of [10]-gingerol on human colorectal cancer cells. It was found that this compound caused a slow and sustained rise of [Ca2+]i in a concentration-dependent manner. [10]-Gingerol also induced a [Ca2+]i rise when extracellular Ca2+ was removed, but the magnitude was reduced by 38%. In a Ca2+-free medium, the [10]-gingerol-induced [Ca2+]i rise was partially abolished by depleting stored Ca2+ with thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor). The elevation of [10]-gingerol-caused [Ca2+]i in a Ca2+-containing medium was not affected by modulation of protein kinase C activity. The [10]-gingerol-induced Ca2+ influx was insensitive to L-type Ca2+ channel blockers. At concentrations of 10-100 mM, [10]-gingerol killed cells in a concentration-dependent manner. These findings suggest that [10]-gingerol induces [Ca2+]i rise by causing Ca2+ release from the endoplasmic reticulum and Ca2+ influx from non-L-type Ca2+ channels in SW480 cancer cells. http://www.mdpi.com/1420-3049/14/3/959/ Mon, 02 Mar 2009 00:00:00 CET Molecules 2009-03-02 14 3 Article 959 969 1420-3049 Effect of [10]-Gingerol on [Ca2+]i and Cell Death in Human Colorectal Cancer Cells 2009-03-02 doi: 10.3390/molecules14030959 Chung-Yi Chen Yi-Wen Li Soong-Yu Kuo http://www.mdpi.com/1420-3049/14/2/827/ To explore the effects of harvest time on phenolic compounds during wine fermentation, grape berries (Vitis vinifera L. cv. Vidal) were harvested at 17.5, 22.8 and 37.2º Brix and were used to make dry wine, semi-sweet wine and icewine with low alcohol levels, respectively. Phenolic acids and flavan-3-ols were assayed during the fermentation of wines by means of reverse phase-high performance liquid chromatography (RP-HPLC). The results showed that concentrations of most of the phenolic acids and flavan-3-ol in musts increased with harvest time delay and higher total levels of these species were detected in all wines, compared with those measured before fermentation (the total phenolic acid content in wines was 1.5-2.0 fold that of in musts). Except for p-coumaric acid and (-)-epicatechin, other phenolic acids and flavan-3-ols had similar variation patterns (wave-like rise) during fermentation in dry wine and semi-sweet wine. However, some detected compounds, including gentisic acid, p-hydroxybenzoic acid, caffeic acid, p-coumaric acid and sinapic acid showed obviously different trends from the other two wines in the icewine making process. It is thus suggested that the harvest time has a decisive effect on phenols in final wines and influences the evolution of phenolic acids and flavan-3-ols during wine fermentation. http://www.mdpi.com/1420-3049/14/2/827/ Wed, 18 Feb 2009 00:00:00 CET Molecules 2009-02-18 14 2 Article 827 838 1420-3049 Comparison of Phenolic Acids and Flavan-3-ols During Wine Fermentation of Grapes with Different Harvest Times 2009-02-18 doi: 10.3390/molecules14020827 Rong-Rong Tian Qiu-Hong Pan Ji-Cheng Zhan Jing-Ming Li Si-Bao Wan Qing-Hua Zhang Wei-Dong Huang http://www.mdpi.com/1420-3049/14/2/807/ Type A procyanidins can be synthesized in good yields from the condensation of benzopyrilium salts 8 and either catechin or phloroglucinol. http://www.mdpi.com/1420-3049/14/2/807/ Tue, 17 Feb 2009 00:00:00 CET Molecules 2009-02-17 14 2 Article 807 815 1420-3049 A Convenient Synthesis of Type A Procyanidins 2009-02-17 doi: 10.3390/molecules14020807 George A. Kraus Yi Yuan Aaron Kempema http://www.mdpi.com/1420-3049/14/2/738/ Ethanolic extract of propolis (EEP) is one of the richest sources of phenolic acids and flavonoids. EEP and its phenolic compounds have been known for various biological activities including immunopotentiation, chemopreventive and antitumor effects. Tumor necrosis factor related apoptosis inducing ligand (TRAIL) is a naturally occurring anticancer agent that preferentially induces apoptosis in cancer cells and is not toxic toward normal cells. We examined the cytotoxic and apoptotic effect of EEP and phenolic compounds identified in propolis in combination with TRAIL on HeLa cancer cells. HeLa cells were resistant to TRAIL-induced apoptosis. Our study demonstrated that EEP and its components significantly sensitize to TRAIL induced death in cancer cells. The percentage of the apoptotic cell after exposure to 50 μg/mL EEP and 100 ng/mL TRAIL increased to 71.10±1.16%. The strongest cytotoxic effect in combination with TRAIL on HeLa cells exhibited apigenin and CAPE at the concentration of 50 μM (58.87±0.75% and 49.59±0.39%, respectively). In this report, we show for the first time that EEP markedly augmented TRAIL mediated apoptosis in cancer cells and confirmed the importance of propolis in chemoprevention of malignant tumors. http://www.mdpi.com/1420-3049/14/2/738/ Fri, 13 Feb 2009 00:00:00 CET Molecules 2009-02-13 14 2 Article 738 754 1420-3049 Ethanolic Extract of Propolis (EEP) Enhances the Apoptosis- Inducing Potential of TRAIL in Cancer Cells 2009-02-13 doi: 10.3390/molecules14020738 Ewelina Szliszka Zenon P. Czuba Maciej Domino Bogdan Mazur Grzegorz Zydowicz Wojciech Krol http://www.mdpi.com/1420-3049/14/2/682/ The increasing diffusion of herbal products is posing new questions: why are products so often different in their composition and efficacy? Which approach is more suitable to increase the biochemical productivity of medicinal plants with large-scale, low-cost solutions? Can the phytochemical profile of a medicinal plant be modulated in order to increase the accumulation of its most valuable constituents? Will polyphenol-rich medicinal crops ever be traded as commodities? Providing a proactive answer to such questions is an extremely hard task, due to the large number of variables involved: intraspecific chemodiversity, plant breeding, ontogenetic stage, post-harvest handling, biotic and abiotic factors, to name but a few. An ideal path in this direction should include the definition of optimum pre-harvesting and post-harvesting conditions and the availability of specific Good Agricultural Practices centered on secondary metabolism enhancement. The first steps to be taken are undoubtedly the evaluation and the organization of scattered data regarding the diverse factors involved in the optimization of medicinal plant cultivation, in order to provide an interdisciplinary overview of main possibilities, weaknesses and drawbacks. This review is intended to be a synopsis of the knowledge on this regard focused on Hypericum perforatum L. (Hypericaceae/Guttiferae) secondary metabolites of phenolic origin, with the aim to provide a reference and suggest an evolution towards the maximization of St. John's Wort bioactive constituents. Factors considered emerged not only from in-field agronomic results, but also from physiological, genetical, biotic, abiotic and phytochemical data that could be scaled up to the application level. To increase quality for final beneficiaries, growers’ profits and ultimately transform phenolic-rich medicinal crops into commodities, the emerging trend suggests an integrated and synergic approach. Agronomy and genetics will need to develop their breeding strategies taking account of the suggestions of phytochemistry, biochemistry, pharmacognosy and pharmacology, without losing sight of the economic balance of the production. http://www.mdpi.com/1420-3049/14/2/682/ Wed, 11 Feb 2009 00:00:00 CET Molecules 2009-02-11 14 2 Review 682 725 1420-3049 Factors Affecting Polyphenol Biosynthesis in Wild and Field Grown St. John’s Wort (Hypericum perforatum L. Hypericaceae/Guttiferae) 2009-02-11 doi: 10.3390/molecules14020682 Renato Bruni Gianni Sacchetti http://www.mdpi.com/1420-3049/14/1/555/ Coniferyl ferulate, which is noted for its multiple pharmacological activities and chemical instability, is abundant in Angelica sinensis. In this paper, five methods, namely sonication extraction (SE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE), hydrodistillation (HD) and decoction (DC) for extraction of coniferyl ferulate, as well as ferulic acid, Z/E-ligustilide and Z/E-butylidenephthalide, from A. sinensis were optimized and compared. The results showed that the order of extraction efficiency was: PLE»SE>SFE>>HD, DC. The compositions of the SE, PLE and SFE extracts, which had a high ratio of coniferyl ferulate, were very similar, while no coniferyl ferulate was obtained by HD and DC, though they had high selectivity for the extraction of ligustilide and ferulic acid, respectively. It was noteworthy that the content of ligustilide and coniferyl ferulate was not detectable in the decoction, the commonly used oral administration form of Traditional Chinese Medicines in clinical practice. http://www.mdpi.com/1420-3049/14/1/555/ Fri, 23 Jan 2009 00:00:00 CET Molecules 2009-01-23 14 1 Article 555 565 1420-3049 Optimization and Comparison of Five Methods for Extraction of Coniferyl Ferulate from Angelica sinensis 2009-01-23 doi: 10.3390/molecules14010555 Jing-Jing Xie Jia Lu Zheng-Ming Qian Yue Yu Jin-Ao Duan Shao-Ping Li http://www.mdpi.com/1420-3049/14/1/509/ Water infusions of Ligustrum delavayanum and Ligustrum vulgare leaves and eight phenolics isolated therefrom have been assayed in vitro on ofloxacin-induced genotoxicity in the unicellular flagellate Euglena gracilis. The tested compounds luteolin, quercetin, luteolin-7-glucoside, luteolin-7-rutinoside, quercetin-3-rutinoside, apigenin-7-rutinoside, tyrosol and esculetin inhibited the mutagenic activity of ofloxacin (43 µM) in E. gracilis. Water infusions from leaves of L. delavayanum and L. vulgare showed higher antimutagenic effect (pt < 0.001). The activity of these samples against ofloxacin (86 µM)-induced genotoxicity was lower, but statistically significant (pt < 0.05), excluding the water infusion of L. delavayanum leaves (pt < 0.01). Efficacy of quercetin, luteolin-7-rutinoside, apigenin-7-rutinoside was insignificant. The antimutagenic effect of most phenolics we studied could be clearly ascribed to their DPPH scavenging activity, substitution patterns and lipophilicity. http://www.mdpi.com/1420-3049/14/1/509/ Thu, 22 Jan 2009 00:00:00 CET Molecules 2009-01-22 14 1 Article 509 518 1420-3049 Antimutagenic Activity and Radical Scavenging Activity of Water Infusions and Phenolics from Ligustrum Plants Leaves 2009-01-22 doi: 10.3390/molecules14010509 Milan Nagy Lívia Križková Pavel Mučaji Zuzana Kontšeková František Šeršeň Juraj Krajčovič http://www.mdpi.com/1420-3049/14/1/439/ Phenolic compounds may be of natural or anthropogenic origin and be present in the environment as well as in food. They comprise a large and diverse group of compounds that may be either beneficial or harmful for consumers. In this review first a non-exhausting overview of interesting phenolics is given, in particular with regards to their presence in environment and food. For some of these compounds, beneficial, toxicological and/or optionally endocrine disrupting activities will be presented. Further, immunochemical detection and/or isolation methods developed will be discussed, including advantages and disadvantages thereof in comparison with conventional analytical methods such as HPLC, GC, MS. A short overview of new sensor-like methods will also be included for present and future application. http://www.mdpi.com/1420-3049/14/1/439/ Mon, 19 Jan 2009 00:00:00 CET Molecules 2009-01-19 14 1 Review 439 473 1420-3049 Phenolics: Occurrence and Immunochemical Detection in Environment and Food 2009-01-19 doi: 10.3390/molecules14010439 Eline P. Meulenberg http://www.mdpi.com/1420-3049/14/1/364/ Synthesis and characterization of resorcinol-acetone copolymer is described. The polymer was prepared by trifluoroacetic acid-catalyzed polymerization of resorcinol with acetone. According to the 1H-NMR, 13C-NMR, and MALDI-TOF Mass spectra data, the obtained polymer had three types of repeating units: isopropylidene bridged-resorcinol, chromane ring, and spiro-shaped double chromane ring, indicating that polymerization proceeded via simultaneous addition-condensation and cyclization of resorcinol with acetone. The obtained polymer can be useful not only for the development of plastic materials such as thermosets, adhesives, and coatings but also for the synthesis of biomaterials such as antimicrobial agents, pesticides, and medicines. http://www.mdpi.com/1420-3049/14/1/364/ Tue, 13 Jan 2009 00:00:00 CET Molecules 2009-01-13 14 1 Article 364 377 1420-3049 Synthesis and Analysis of Resorcinol-Acetone Copolymer 2009-01-13 doi: 10.3390/molecules14010364 Ataru Kobayashi Gen-ichi Konishi http://www.mdpi.com/1420-3049/14/1/298/ Phenolic derivatives are among the most important contaminants present in the environment. These compounds are used in several industrial processes to manufacture chemicals such as pesticides, explosives, drugs and dyes. They also are used in the bleaching process of paper manufacturing. Apart from these sources, phenolic compounds have substantial applications in agriculture as herbicides, insecticides and fungicides. However, phenolic compounds are not only generated by human activity, but they are also formed naturally, e.g., during the decomposition of leaves or wood. As a result of these applications, they are found in soils and sediments and this often leads to wastewater and ground water contamination. Owing to their high toxicity and persistence in the environment, both, the US Environmental Protection Agency (EPA) and the European Union have included some of them in their lists of priority pollutants. Current standard methods of phenolic compounds analysis in water samples are based on liquid–liquid extraction (LLE) while Soxhlet extraction is the most used technique for isolating phenols from solid matrices. However, these techniques require extensive cleanup procedures that are time-intensive and involve expensive and hazardous organic solvents, which are undesirable for health and disposal reasons. In the last years, the use of news methodologies such as solid-phase extraction (SPE) and solid-phase microextraction (SPME) have increased for the extraction of phenolic compounds from liquid samples. In the case of solid samples, microwave assisted extraction (MAE) is demonstrated to be an efficient technique for the extraction of these compounds. In this work we review the developed methods in the extraction and determination of phenolic derivatives in different types of environmental matrices such as water, sediments and soils. Moreover, we present the new approach in the use of micellar media coupled with SPME process for the extraction of phenolic compounds. The advantages of micellar media over conventional extractants are reduction of organic solvent, low cost, easy handling and shorter time procedures. http://www.mdpi.com/1420-3049/14/1/298/ Fri, 09 Jan 2009 00:00:00 CET Molecules 2009-01-09 14 1 Review 298 320 1420-3049 Methodologies for the Extraction of Phenolic Compounds from Environmental Samples: New Approaches 2009-01-09 doi: 10.3390/molecules14010298 Cristina Mahugo Santana Zoraida Sosa Ferrera M. Esther Torres Padrón José Juan Santana Rodríguez http://www.mdpi.com/1420-3049/14/1/289/ In this study, five biologically phenolic antioxidant Turkish red wines from different regions of Turkey were determined using HPLC with PDA detection. The antioxidant capacities (AC) of the investigated wines are also determined and the relationship between the phenol content and antioxidant capacity is discussed. The results show that Kalecik Karası, Merlot and Cabernet Sauvignon AC values ranged between 15.8-18.7 mmol/L, 15.8-17.6 mmol/L and 18.1-22.6 mmol/L, respectively. Generally, Cabernet Sauvignon wines not only had higher levels of phenolic antioxidants, such as catechin, epicatechin and gallic acid, but also higher antioxidant capacities compared to Kalecik Karası and Merlot wines. When the results were compared on the basis of geographical area, Aegean red wines were found to contain generally higher levels of biologically important phenolics and thus to have more antioxidant capacity compared to the wines of the other regions studied. http://www.mdpi.com/1420-3049/14/1/289/ Fri, 09 Jan 2009 00:00:00 CET Molecules 2009-01-09 14 1 Article 289 297 1420-3049 Antioxidant Phenolic Substances of Turkish Red Wines from Different Wine Regions 2009-01-09 doi: 10.3390/molecules14010289 R. Ertan Anli Nilüfer Vural http://www.mdpi.com/1420-3049/14/1/257/ The alcoholic extract from seed kernels of Thai mango (Mangifera indica L. cv. ‘Fahlun’) (Anacardiaceae) and its major phenolic principle (pentagalloylglucopyranose) exhibited potent, dose-dependent inhibitory effects on tyrosinase with respect to L-DOPA. Molecular docking studies revealed that the binding orientations of the phenolic principles were in the tyrosinase binding pocket and their orientations were located in the hydrophobic binding pocket surrounding the binuclear copper active site. The results indicated a possible mechanism for their anti-tyrosinase activity which may involve an ability to chelate the copper atoms which are required for the catalytic activity of tyrosinase. http://www.mdpi.com/1420-3049/14/1/257/ Wed, 07 Jan 2009 00:00:00 CET Molecules 2009-01-07 14 1 Article 257 265 1420-3049 Molecular Docking Studies and Anti-Tyrosinase Activity of Thai Mango Seed Kernel Extract 2009-01-07 doi: 10.3390/molecules14010257 Saruth Nithitanakool Pimolpan Pithayanukul Rapepol Bavovada Patchreenart Saparpakorn http://www.mdpi.com/1420-3049/14/1/200/ Chocolate contains a wide range of antioxidants that includes soluble phenolic compounds (phenolic acids, catechin, epicatechin, and proanthocyanidins), insoluble polymeric phenolics and methylxanthines. The objective of this study was to determine phenolic and theobromine contents in dark (DC), milk (MC), and white (WC) chocolates commonly found in the Malaysian marketplace. Total phenolic and flavonoids were determined by means of a spectrometric assay, while catechin, epicatechin and theobromine were quantified using a reverse-phase HPLC method. Dark chocolates exhibited the highest phenolics and flavonoids contents, followed by milk and white chocolates. Catechin and epicatechin were major flavonoids detected in dark chocolates. Theobromine was detected in dark and milk chocolates, but not in white chocolates. A high correlation (r= 0.93) between total phenolic and flavonoid contents, indicating that the major phenolic compounds in dark chocolates belong to the flavonoid class. When nutrition and health promotion are of concern, dark chocolates would be recommended over milk and white chocolates owing to their higher contents of antioxidant phenolic compounds. http://www.mdpi.com/1420-3049/14/1/200/ Mon, 05 Jan 2009 00:00:00 CET Molecules 2009-01-05 14 1 Article 200 209 1420-3049 Phenolic and Theobromine Contents of Commercial Dark, Milk and White Chocolates on the Malaysian Market 2009-01-05 doi: 10.3390/molecules14010200 Cheng Chia Meng Abbe Maleyki Mhd Jalil Amin Ismail http://www.mdpi.com/1420-3049/13/12/3129/ A mild acidic dioxane extraction method was employed to isolate lignin from hardwood bleached chemimechanical pulp (BCMP). The isolated lignin was then purified and undergone elemental analysis. To study the photodegradation behavior, the lignin samples were impregnated onto the Whatman filter papers and irradiated with UV light for various periods. The photolyzed lignin was then recovered and analyzed by 1H-NMR spectroscopy. Phenylpropane-based formula (C9) of CMP pulp lignin and the photolyzed samples were then established with elemental analysis and 1H-NMR spectroscopy data. The results indicated that the benzaldehyde and benzoic acid type compounds were the main photodegradation products of BCMP lignin. The lignin photodegradation probably involved the degradation of phenylcoumaran units. Irradiation also increased the phenolic hydroxyl group content and decreased that of methoxyl groups, due to demethoxylation. The degrees of aromatic ring condensation were increased upon continuing the irradiation time, which imples the formation of condensed structures in photolyzed lignin. http://www.mdpi.com/1420-3049/13/12/3129/ Mon, 15 Dec 2008 00:00:00 CET Molecules 2008-12-15 13 12 Article 3129 3139 1420-3049 Photodegradation of Acidolysis Lignin from BCMP 2008-12-15 doi: 10.3390/molecules13123129 Mohammad Azadfallah Seyed Ahmad Mirshokraei Ahmad Jahan Latibari http://www.mdpi.com/1420-3049/13/12/3007/ Proanthocyanidins are present in many fruits and plant products like grapes and wine, and contribute to their taste and health benefits. In the past decades of years, substantial progresses has been achieved in the identification of composition and structure of proanthocyanidins, but the debate concerning the existence of an enzymatic or nonenzymatic mechanism for proanthocyanidin condensation still goes on. Substantial attention has been paid to elucidating the potential mechanism of formation by means of biomimetic and chemical synthesis in vitro. The present paper aims at summarizing the research status on chemical synthesis of proanthocyanidins, including non-enzymatic synthesis of proanthocyanidin precursors, chemical synthesis of proanthocyanidins with direct condensation of flavanols and stereoselective synthesis of proanthocyanidins. Proanthocyanidin-involved reactions in aging wines are also reviewed such as direct and indirect reactions among proanthocyanidins, flavanols and anthocyanins. Topics for future research in this field are also put forward in this paper. http://www.mdpi.com/1420-3049/13/12/3007/ Thu, 04 Dec 2008 00:00:00 CET Molecules 2008-12-04 13 12 Review 3007 3032 1420-3049 Chemical Synthesis of Proanthocyanidins in Vitro and Their Reactions in Aging Wines 2008-12-04 doi: 10.3390/molecules13123007 Fei He Qiu-Hong Pan Ying Shi Chang-Qing Duan http://www.mdpi.com/1420-3049/13/12/2998/ As multiple mechanisms account for polyphenol-induced cytotoxicity, the development of structure-activity relationships (SARs) may facilitate research on cancer therapy. We studied SARs of representatives of 10 polyphenol structural types: (+)-catechin (1), (-)-epicatechin (2), (-)-epigallocatechin (3), (-)-epigallocatechin gallate (4), gallic acid (5), procyanidin B2 (6), procyanidin B3 (7), procyanidin B4 (8), procyanidin C1 (9), and procyanidin C2 (10). Amongst them, the polyphenols containing a pyrogallol moiety (3-5) showed the most potent cytotoxicic activity. These compounds evoked a typical DNA-laddering phenomenon in HEK293T, which indicated that the induction of apoptosis at least partly mediates their cytotoxic activity. Anti-oxidative capacity of compounds 3-5 were comparable to those of the trimers 9 and 10, which were not cytotoxic. Therefore, we suggest that pyrogallol moiety is important for fitting of polyphenols to their putative target molecule(s) in non-oxidative mechanism. http://www.mdpi.com/1420-3049/13/12/2998/ Thu, 04 Dec 2008 00:00:00 CET Molecules 2008-12-04 13 12 Article 2998 3006 1420-3049 Pyrogallol Structure in Polyphenols is Involved in Apoptosis-induction on HEK293T and K562 Cells 2008-12-04 doi: 10.3390/molecules13122998 Shinya Mitsuhashi Akiko Saito Noriyuki Nakajima Hiroshi Shima Makoto Ubukata http://www.mdpi.com/1420-3049/13/11/2704/ Catechins, naturally occurring flavonoids derived from wine and green tea, are known to exhibit multiple health benefits. Epigallocatechin gallate (EGCG) is one of the most widely investigated catechins, but its efficacy in cancer therapy is still inconsistent and limited. The poor stability of EGCG has contributed to the disparity in the reported anti-cancer activity and other beneficial properties. Here we report an innovative enzymatic strategy for the oligomerization of catechins (specifically epicatechin) that yields stable, water-soluble oligomerized epicatechins with enhanced and highly specific anti-proliferative activity for human breast cancer cells. This one-pot oxidative oligomerization is carried out in ambient conditions using Horseradish Peroxidase (HRP) as a catalyst yielding water-soluble oligo(epicatechins). The oligomerized epicatechins obtained exhibit excellent growth inhibitory effects against human breast cancer cells with greater specificity towards growth-inhibiting cancer cells as opposed to normal cells, achieving a high therapeutic differential. Our studies indicate that water-soluble oligomeric epicatechins surpass EGCG in stability, selectivity and efficacy at lower doses. http://www.mdpi.com/1420-3049/13/11/2704/ Sat, 01 Nov 2008 00:00:00 CET Molecules 2008-11-01 13 11 Article 2704 2716 1420-3049 Biocatalytically Oligomerized Epicatechin with Potent and Specific Anti-proliferative Activity for Human Breast Cancer Cells 2008-11-01 doi: 10.3390/molecules13112704 Subhalakshmi Nagarajan Ramaswamy Nagarajan Susan J. Braunhut Ferdinando Bruno Donna McIntosh Lynne Samuelson Jayant Kumar http://www.mdpi.com/1420-3049/13/10/2674/ Proanthocyanidins (PAs), also known as condensed tannins, are a group of polyphenolic secondary metabolites synthesized in plants as oligomers or polymers of flavan-3-ol units via the flavonoid pathway. Due to their structural complexity and varied composition, only in the recent years has the study on the biosynthesis and regulation of PAs in plants taken off, although some details of the synthetic mechanism remain unclear. This paper aims to summarize the status of research on the structures of PAs in plants, the genes encoding key enzymes of biosynthetic pathway, the transport factors, the transcriptional regulation of PA biosynthesis and the genetic manipulation of PAs. The problems of this field were also discussed, including the nature of the final “enzyme” which catalyzes the polymerization reaction of PAs and the possible mechanism of how the elementary units of flavanols are assembled in vivo. http://www.mdpi.com/1420-3049/13/10/2674/ Tue, 28 Oct 2008 00:00:00 CET Molecules 2008-10-28 13 10 Review 2674 2703 1420-3049 Biosynthesis and Genetic Regulation of Proanthocyanidins in Plants 2008-10-28 doi: 10.3390/molecules13102674 Fei He Qiu-Hong Pan Ying Shi Chang-Qing Duan http://www.mdpi.com/1420-3049/13/10/2628/ Luteolin is a flavonoid which is part of our daily nutrition in relatively low amounts (less than 1 mg/day). Nevertheless, some epidemiological studies suggest an inverse correlation between luteolin intake and the risk of some cancer types. Luteolin displays specific anti-inflammatory and anti-carcinogenic effects, which can only partly be explained by its anti-oxidant and free radical scavenging capacities. Luteolin can delay or block the development of cancer cells in vitro and in vivo by protection from carcinogenic stimuli, by inhibition of tumor cell proliferation, by induction of cell cycle arrest and by induction of apoptosis via intrinsic and extrinsic signaling pathways. When compared to other flavonoids, luteolin was usually among the most effective ones, inhibiting tumor cell proliferation with IC50 values between 3 and 50 μM in vitro and in vivo by 5 to 10 mg/kg i.p., intragastric application of 0.1–0.3 mg/kg/d, or as food additive in concentrations of 50 to 200 ppm. Luteolin has been shown to penetrate into human skin, making it also a candidate for the prevention and treatment of skin cancer. http://www.mdpi.com/1420-3049/13/10/2628/ Wed, 22 Oct 2008 00:00:00 CEST Molecules 2008-10-22 13 10 Review 2628 2651 1420-3049 Anti-carcinogenic Effects of the Flavonoid Luteolin 2008-10-22 doi: Günter Seelinger Irmgard Merfort Ute Wölfle Christoph M. Schempp http://www.mdpi.com/1420-3049/13/10/2545/ The antioxidant activity of Syzygium cumini leaf extracts was investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging and ferric-reducing antioxidant power (FRAP) assays. The methanolic extract and its four water, ethyl acetate, chloroform, and n-hexane fractions were prepared and subjected to antioxidant evaluation. The results showed that the ethyl acetate fraction had stronger antioxidant activity than the other ones. HPLC data indicated that S. cumini leaf extracts contained phenolic compounds, such as ferulic acid and catechin, responsible for their antioxidant activity. A significant linear relationship between antioxidant potency, free radical-scavenging ability and the content of phenolic compounds of leaf extracts supported this observation. http://www.mdpi.com/1420-3049/13/10/2545/ Thu, 16 Oct 2008 00:00:00 CEST Molecules 2008-10-16 13 10 Article 2545 2556 1420-3049 Evaluation of the Antioxidant Activity of Syzygium cumini Leaves 2008-10-16 doi: 10.3390/molecules13102545 Zhi Ping Ruan Liang Liang Zhang Yi Ming Lin http://www.mdpi.com/1420-3049/13/10/2521/ Flavonoids, one of the largest groups of secondary metabolites, are widespread in vegetable crops such as herbs, fruits, vegetables, grains, seeds and derived foods such as juices, wines, oils, etc. They receive considerable attention due to their biological and physiological importance. Hundreds of publications on the analysis of flavonoids have appeared over the past decade. Traditional and more advanced techniques have come to prominence for sample preparation, separation, detection, and identification. This review intends to provide an updated, concise overview on the recent development and trends of separation, identification and quantification for flavonoids by modern chromatographic and spectrophotometric analytical techniques, including gas chromatography (GC), liquid chromatography (LC), and capillary electrophoresis (CE). The sample preparation before analysis is also briefly summarized. http://www.mdpi.com/1420-3049/13/10/2521/ Thu, 16 Oct 2008 00:00:00 CEST Molecules 2008-10-16 13 10 Review 2521 2544 1420-3049 Advances of Modern Chromatographic and Electrophoretic Methods in Separation and Analysis of Flavonoids 2008-10-16 doi: 10.3390/molecules13102521 E-Hu Liu Lian-Wen Qi Jun Cao Ping Li Chang-Yin Li Yong-Bo Peng http://www.mdpi.com/1420-3049/13/10/2488/ Phenolcarboxylic acid antioxidants do not act in vivo as radical-scavengers in isolation, but rather together with GSH (glutathione), a coantioxidant, they constitute an intricate antioxidant network. Caffeic acid, p-coumaric acid, ferulic acid and chlorogenic acid with or without 2-mercaptoethanol (ME), as a substitute for GSH, was investigated by the induction period (IP) method for polymerization of methyl methacrylate (MMA) initiated by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN, a source of alkyl radicals, R.) and benzoyl peroxide (BPO, a source of peroxy radicals, PhCOO.) using differential scanning calorimetry (DSC). Upon PhCOO. radical scavenging, the stoichiometric factors (n, number of free radical trapped by one mole of antioxidant) for caffeic acid, ferulic acid, p-coumaric acid and chlorogenic acid were 2.4, 1.8, 1.7 and 0.9, whereas upon R. radical scavenging, the corresponding values were 1.3, 1.2, 1.0 and 0.8, respectively. Antioxidants with n values close to 2 suggest the stepwise formation of semiquinone radicals and quinones. By contrast, those with n values close to 1 suggest the formation of dimers after single-electron oxidation, possibly due to recombination of corresponding aryloxy radicals. The ratio of the rate constant of inhibition to that of propagation (kinh/kp) declined in the order chlorogenic acid > p-coumaric acid > ferulic acid > caffeic acid. The ratio of the observed IP for the phenolcarboxylic acid/2-mercapto-ethanol (ME) mixture (1:1 molar ratio) (A) to the calculated IP (the simple sum of phenol acid antioxidant and ME) (B) was investigated. Upon R. scavenging, the caffeic acid or p-coumaric acid/ME mixture was A/B > 1, particularly the former was 1.2, suggesting a synergic effect. By contrast, upon PhCOO. scavenging, the corresponding mixture was A/B < 1, particularly the latter was 0.7, suggesting an antagonistic effect. Upon both radicals scavenging, the A/B for the ferulic acid or chlorogenic acid/ME mixture was approximately 1. The reported beneficial antioxidant, anti-inflammatory and anticancer effects of caffeic acid and p-coumaric acid may be related to their prooxidant-antioxidant balance in the presence of GSH. http://www.mdpi.com/1420-3049/13/10/2488/ Wed, 15 Oct 2008 00:00:00 CEST Molecules 2008-10-15 13 10 Article 2488 2499 1420-3049 A Comparative Study of the Radical-scavenging Activity of the Phenolcarboxylic Acids Caffeic Acid, p-Coumaric Acid, Chlorogenic Acid and Ferulic Acid, With or Without 2-Mercaptoethanol, a Thiol, Using the Induction Period Method 2008-10-15 doi: 10.3390/molecules13102488 Yoshinori Kadoma Seiichiro Fujisawa http://www.mdpi.com/1420-3049/13/9/2220/ Bergamot juice (BJ) contains different classes of flavonoids (e.g. flavanones and flavones) that can exert beneficial effects on human health. The aim of this study was to evaluate the qualitative and quantitative composition of a BJ obtained from fruits harvested in Southern Italy (Calabria) at the end of their maturation period. The identity of several flavonoids and furanocoumarins was assessed by co-chromatography, UV spectra and molecular weight comparison. The unknown compounds were dissociated by induced collision (CID-MS) and their identity established through the characteristic ions product. By this approach a complete profile of about twenty compounds (furano-coumarins, flavonoids C- and O-glycosides) present in BJ was obtained. Furthermore, three acylated flavanones, present in amounts of 20.1±1.1, 89.3±2.2 and 190.1±3.1 mg/L, respectively, and which seem to correspond to di-oxalate derivatives of neoeriocitrin, naringin and neohesperidin, were identified for the first time in BJ. The other main flavanones were naringin, neohesperidin and neoeriocitrin, and their content was 167.5±1.8, 123.9±1.7 and 73.3±1.6 mg/L, respectively. Concerning flavones, the total amount in BJ was about 160 mg/L and the main ones were vicenin-2, stellarin-2, rhoifolin and neodiosmin. Bergapten and bergamottin were the primary furanocoumarins in BJ and their amounts were 9.0±0.4 and 18.2±0.5 mg/L, respectively. http://www.mdpi.com/1420-3049/13/9/2220/ Thu, 18 Sep 2008 00:00:00 CEST Molecules 2008-09-18 13 9 Article 2220 2228 1420-3049 Evaluation of Flavonoids and Furanocoumarins from Citrus bergamia (Bergamot) Juice and Identification of New Compounds 2008-09-18 doi: 10.3390/molecules13092220 Claudio Gardana Federico Nalin Paolo Simonetti http://www.mdpi.com/1420-3049/13/9/2190/ Cocoa and cocoa products have received much attention due to their significant polyphenol contents. Cocoa and cocoa products, namely cocoa liquor, cocoa powder and chocolates (milk and dark chocolates) may present varied polyphenol contents and possess different levels of antioxidant potentials. For the past ten years, at least 28 human studies have been conducted utilizing one of these cocoa products. However, questions arise on which of these products would deliver the best polyphenol contents and antioxidant effects. Moreover, the presence of methylxanthines, peptides, and minerals could synergistically enhance or reduce antioxidant properties of cocoa and cocoa products. To a greater extent, cocoa beans from different countries of origins and the methods of preparation (primary and secondary) could also partially influence the antioxidant polyphenols of cocoa products. Hence, comprehensive studies on the aforementioned factors could provide the understanding of health-promoting activities of cocoa or cocoa products components. http://www.mdpi.com/1420-3049/13/9/2190/ Tue, 16 Sep 2008 00:00:00 CEST Molecules 2008-09-16 13 9 Review 2190 2219 1420-3049 Polyphenols in Cocoa and Cocoa Products: Is There a Link between Antioxidant Properties and Health? 2008-09-16 doi: 10.3390/molecules13092190 Abbe Maleyki Mhd Jalil Amin Ismail http://www.mdpi.com/1420-3049/13/9/2169/ Aloe greatheadii var. davyana (Asphodelaceae) is used among rural South African communities to treat arthritis, skin cancer, burns, eczema, psoriasis, digestive problems, high blood pressure and diabetes, despite very little supporting scientific evidence. Due to increased interest by both the scientific community and industry regarding the medicinal uses of this plant species, we identified, quantified and compared the phytochemical contents and antioxidant capacities of two extracts of A. greatheadii; a leaf gel extract (LGE) and a 95 % aqueous ethanol leaf gel extract (ELGE), using various modified extraction procedures, GC-MS and spectrophotometry. Apart from extensively characterizing this medicinal plant with regards to its organic acid, polyphenols/phenolic acid, alcohol, aldehyde, ketone, alkane, pyrimidine, indole, alkaloid, phytosterol, fatty acid and dicarboxylic acid contents and antioxidant capacities, we describe a modified extraction procedure for the purpose of general phytochemical characterization, and compare this to a 95 % aqueous ethanol extraction technique. From the results it is clear that A. greatheadii contains a variety of compounds with confirmed antioxidant capacity and other putative health benefits (such as blood glucose, cholesterol and cortisol lowering properties) relating to the prevention or treatment of diabetes, cardiovascular disease, cancer and hypertension. The results also indicate that separate ethyl acetate/diethyl ether and hexane extractions of the LGE, better serve for general phytochemical characterization purposes, and 95 % aqueous ethanol extraction for concentrating selective groups of health related compounds, hence justifying its use for biological in vivo efficacy studies. http://www.mdpi.com/1420-3049/13/9/2169/ Fri, 12 Sep 2008 00:00:00 CEST Molecules 2008-09-12 13 9 Article 2169 2180 1420-3049 Phytochemical Contents and Antioxidant Capacities of Two Aloe greatheadii var. davyana Extracts 2008-09-12 doi: 10.3390/molecules13092169 Lisa Botes Francois H. van der Westhuizen Du Toit Loots http://www.mdpi.com/1420-3049/13/8/1931/ Fifteen flavonoids, 1-7 and 9-16, and a polyacetylene, 8, were isolated from the ethanol extract of the dried whole plant of Bidens parviflora Willd. by various chromatographic techniques. Their structures have been elucidated on the basis of spectroscopic analyses and chemical studies. Compound 8 is new and was identified as 3-(R),8(E)-decene-4,6-diyne-1,3,10-triol. All the flavonoid compounds were isolated for the first time from this plant species. http://www.mdpi.com/1420-3049/13/8/1931/ Thu, 28 Aug 2008 00:00:00 CEST Molecules 2008-08-28 13 8 Article 1931 1941 1420-3049 Flavonoids and a New Polyacetylene from Bidens parviflora Willd 2008-08-28 doi: 10.3390/molecules13081931 Yu-Lan Li Jun Li Nai-Li Wang Xin-Sheng Yao http://www.mdpi.com/1420-3049/13/7/1455/ In this paper, the study of antioxidant activity and phenolic composition of three different extracts (EtOAc, n-BuOH and H2O) of field horsetail (Equisetum arvense L.) is presented. The antioxidant activity has been evaluated measuring the total reducing power (expressed by Ascorbate Equivalent Antioxidant Capacity - AEAC), inhibition of lipid peroxidation, and free radical scavenging capacity (RSC) towards 2,2-diphenyl-1- picrylhydrazyl (DPPH radical) and nitric oxide (NO), respectively. In addition, the total flavonoid content (TFC) and phenolic constituents of each extract have been determined. The results obtained show that the highest RSC regarding both DPPH and NO radicals is expressed by EtOAc extract (EC50=2.37 μg/mL and EC50=90.07 μg/mL, respectively), and the lowest by H2O extract (EC50=37.2 μg/mL and EC50>333.33 μg/mL, respectively). n- BuOH extract showed the highest total reducing power (AEAC=13.40 μg/mL). Differences in the phenolic composition of examined extracts are found comparing the HPLC chemical profiles. Although, isoquercitrin is the main flavonoid in both EtOAc and n-BuOH extracts, a considerable amount of di-E-caffeoyl-meso-tartaric acid was presented in the n-BuOH extract. In H2O extract high content of phenolic acids and low percentage of flavonoids were detected. http://www.mdpi.com/1420-3049/13/7/1455/ Thu, 17 Jul 2008 00:00:00 CEST Molecules 2008-07-17 13 7 Article 1455 1464 1420-3049 Phenolic Compounds in Field Horsetail (Equisetum arvense L.) as Natural Antioxidants 2008-07-17 doi: 10.3390/molecules13071455 Neda Mimica-Dukic Natasa Simin Jelena Cvejic Emilija Jovin Dejan Orcic Biljana Bozin http://www.mdpi.com/1420-3049/12/10/2327/ We have investigated the electrochemical oxidation of a number natural phenolics (salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, protocatechuic acid, o-coumaric acid, m-coumaric acid, p-coumaric acid, caffeic acid, quercetin and rutin) using cyclic voltammetry. The antioxidant properties of these compounds were also studied. A structural analysis of the tested phenolics suggests that multiple OH substitution and conjugation are important determinants of the free radical scavenging activity and electrochemical behavior. Compounds with low oxidation potentials (Epa lower than 0.45) showed antioxidant activity, whereas compounds with high Epa values (>0.45) act as prooxidants. http://www.mdpi.com/1420-3049/12/10/2327/ Wed, 24 Oct 2007 00:00:00 CEST Molecules 2007-10-24 12 10 Article 2327 2340 1420-3049 Electrochemical Behavior and Antioxidant and Prooxidant Activity of Natural Phenolics 2007-10-24 doi: 10.3390/12102327 Aleksandra Simić Dragan Manojlović Dejan Šegan Marija Todorović http://www.mdpi.com/1420-3049/12/9/2228/ Phenolic compounds form one of the main classes of secondary metabolites. They display a large range of structures and they are responsible for the major organoleptic characteristics of plant-derived-foods and beverages, particularly color and taste properties and they also contribute to the nutritional qualities of fruits and vegetables. Phenolic compounds are also highly unstable compounds which undergo numerous enzymatic and chemical reactions during postharvest food storage and processing thus adding to the complexity of plant polyphenol composition. Among these compounds flavonoids constitute one of the most ubiquitous groups of all plant phenolics. Owing to their importance in food organoleptic properties and in human health, a better understanding of their structures, their reactivity and chemical properties in addition to the mechanisms generating them appears essential to predict and control food quality. The purpose of this work is an overview of our findings concerning the hemisynthesis, the reactivity and the enzymatic oxidation of some flavonoids and shed light on the mechanisms involved in some of these processes and the structures of the resulting products. The free radical scavenging activity of some of the synthesized compounds is also presented and a structure-activity relationship is discussed. The first part of this review concerns the synthesis and structural characterization of modified monomeric flavanols. The use of these compounds as precursor for the preparation of natural and modified dimeric procyanidin derivatives was then explored through different coupling reactions. The full characterization of the synthesized compounds was achieved by concerted use of NMR and ESI-MS techniques. The free radical scavenging activity of some of the synthesized compounds was investigated. The second part of this review concerns the enzymatic oxidation of several flavonols by Trametes versicolor laccase. Most of the major oxidation products have been isolated as pure compounds and their structures unambiguously established through spectroscopic methods. Correlation between the structure of the oxidation product and the substitution pattern of the starting materials allows mechanistic features of this transformation to be elucidated. http://www.mdpi.com/1420-3049/12/9/2228/ Wed, 26 Sep 2007 00:00:00 CEST Molecules 2007-09-26 12 9 Review 2228 2258 1420-3049 Flavonoids: Hemisynthesis, Reactivity, Characterization and Free Radical Scavenging Activity 2007-09-26 doi: 10.3390/12092228 Nour-Eddine Es-Safi Souhila Ghidouche Paul Henri Ducrot http://www.mdpi.com/1420-3049/12/9/2130/ In a bioassay-guided search for acetylcholinesterase (AChE) inhibitors from 180 medicinal plants, an ethyl acetate extract of whole plants of Agrimonia pilosa ledeb yielded tiliroside (1), 3-methoxy quercetin (2), quercitrin (3) and quercetin (4). We report herein for the first time that all four flavonol compounds showed significant inhibitory effects on AChE, particularly quercetin (4), which showed twice the activity of dehydroevodiamine (DHED). http://www.mdpi.com/1420-3049/12/9/2130/ Mon, 03 Sep 2007 00:00:00 CEST Molecules 2007-09-03 12 9 Article 2130 2139 1420-3049 Acetylcholinesterase Inhibition by Flavonoids from Agrimonia pilosa 2007-09-03 doi: 10.3390/12092130 Mankil Jung Moonso Park http://www.mdpi.com/1420-3049/12/8/1950/ Chemical evaluation of the semi-purified fraction from the seeds of guaraná, Paullinia cupana H.B.K. var. sorbilis (Mart.) Ducke, yielded the following compounds: caffeine, catechin, epicatechin, ent-epicatechin, and procyanidins B1, B2, B3, B4, A2, and C1. Measurement of the antioxidant activity by reduction of the DPPH radical confirmed the anti-radical properties of the aqueous (AqE) and crude (EBPC) extracts and semi-purified (EPA and EPB) fractions. The EPA fraction showed radical-scavenging activity (RSA) and protected DPPH from discoloration at 5.23±0.08 (RSD%=1.49) μg/mL, and for the phosphomolybdenum complex showed a higher Relative Antioxidant Capacity (RAC) at 0.75±0.01 (1.75). The EPA fraction had a total polyphenolics content of 65.80%±0.62 (RSD%=0.93). The plant drug showed 5.47% ± 0.19 (RSD%=3.51) and 6.19% ± 0.08 (RSD%=1.29) for total polyphenolics and methylxanthines, respectively. In vitro assessment of the antibacterial potential of the Paullinia cupana extracts against Streptococcus mutans showed that these could be used in the prevention of bacterial dental plaque. http://www.mdpi.com/1420-3049/12/8/1950/ Mon, 20 Aug 2007 00:00:00 CEST Molecules 2007-08-20 12 8 Article 1950 1963 1420-3049 Antioxidant Capacity and In Vitro Prevention of Dental Plaque Formation by Extracts and Condensed Tannins of Paullinia cupana 2007-08-20 doi: 10.3390/12081950 Elza Yamaguti-Sasaki Lia Akina Ito Vanessa Cristina Dias Canteli Tânia Mara Antonelli Ushirobira Tânia Ueda-Nakamura Benedito Prado Dias Filho Celso Vataru Nakamura João Carlos Palazzo de Mello http://www.mdpi.com/1420-3049/12/8/1845/ (-)-Epicatechin-3-gallate (ECG) is a polyphenolic compound similar to (-)-epigallocatechin-3-gallate (EGCG) which is abundant in green tea. Numerous workers have proposed that EGCG protects epidermal cells against UVB-induced damage. However, little has been known about whether ECG protects keratinocytes against UVB-induced damage. We decided to investigate the protective effects and underlying mechanisms of ECG on UVB-induced damage. Cell viability was determined by the MTT assay. Activation of ERK1/2, p38 and JNK was analyzed by Western blotting. Intracellular H2O2 production and DNA content was analyzed by flow cytometry. Lipid peroxidation was assayed by colorimetry. In our study, we found that ECG dose-dependently attenuated UVB-induced keratinocyte death. Moreover, ECG markedly inhibited UVB-induced cell membrane lipid peroxidation and H2O2 generation in keratinocytes, suggesting that ECG can act as a free radical scavenger when keratinocytes were photodamaged. In parallel, H2O2-induced the activation of ERK1/2, p38 and JNK in keratinocytes could be inhibited by ECG. UVB-induced pre-G1 arrest leading to apoptotic changes of keratinocytes were blocked by ECG. Taken together, we provide here evidence that ECG protects keratinocytes from UVB-induced photodamage and H2O2-induced oxidative stress, possibly through inhibition of the activation of ERK1/2, p38 and JNK and/or scavenging of free radicals. http://www.mdpi.com/1420-3049/12/8/1845/ Tue, 14 Aug 2007 00:00:00 CEST Molecules 2007-08-14 12 8 Article 1845 1858 1420-3049 (-)-Epicatechin-3-gallate, a Green Tea Polyphenol Is a Potent Agent Against UVB-induced Damage in HaCaT Keratinocytes 2007-08-14 doi: 10.3390/12081845 Chieh-Chen Huang Wen-Bin Wu Jia-You Fang Han-Sun Chiang Shao-Kuan Chen Bing-Huei Chen Ying-Ting Chen Chi-Feng Hung http://www.mdpi.com/1420-3049/12/8/1829/ Calculation of the HPLC chromatographic retention times of different carotenoids supported our improved chromatographic separation of β-carotene and lutein in four tomatoes and two tomatillo varieties in fresh form and after three different cooking procedures: pot boiling, cooking in a pressure cooker and microwaving. A good separation was achieved experimentally using an Ultrasphere ODS column and gradient elution with an acetonitrile-tetrahydrofuran-water mobile phase. It was shown that diverse tomato species contained different amounts of β-carotene (6-400 μg/100 mg) and lutein (2-30 μg/100 mg). The concentration in fresh samples was higher than in cooked tomatoes. The β–carotene content in fresh tomatillo varied between 2 and 20 μg/100 mg. Microwaving caused partial destruction of the β-carotene and lutein in tomatillos. http://www.mdpi.com/1420-3049/12/8/1829/ Mon, 13 Aug 2007 00:00:00 CEST Molecules 2007-08-13 12 8 Communication 1829 1835 1420-3049 Effect of Cooking Processes on the Contents of Two Bioactive Carotenoids in Solanum lycopersicum Tomatoes and Physalis ixocarpa and Physalis philadelphica Tomatillos 2007-08-13 doi: 10.3390/12081829 María P. Elizalde-González Socorro G. Hernández-Ogarcía http://www.mdpi.com/1420-3049/12/8/1762/ The new methyl orthoformate of the powerful antioxidant hydroxytyrosol (or 2- (3,4-dihydroxyphenyl)ethanol) has been synthesized by a two-step high yielding procedure. The protection stabilizes hydroxytyrosol against fast oxidation and allows both easy chromatographic purification and long term storage. The protective group is hydrolyzed over pH = 10 and below pH = 5, thus allowing the release of the active principle under physiological conditions. The use of the methyl orthoformate-protected hydroxytyrosol allows the preparation of protected hydroxytyrosyl esters, like the acetate herein reported, by selective esterification of the alcoholic function. The subsequent quantitative deprotection under non-aqueous and mild conditions affords the hydroxytyrosyl acetate in high yields. http://www.mdpi.com/1420-3049/12/8/1762/ Wed, 08 Aug 2007 00:00:00 CEST Molecules 2007-08-08 12 8 Article 1762 1770 1420-3049 High-Yielding Synthesis of Methyl Orthoformate-Protected Hydroxytyrosol and Its Use in Preparation of Hydroxytyrosyl Acetate 2007-08-08 doi: 10.3390/12081762 Augusto Gambacorta Daniela Tofani Antonella Migliorini http://www.mdpi.com/1420-3049/12/8/1679/ Among vegetable oils, virgin olive oil (VOO) has nutritional and sensory characteristics that to make it unique and a basic component of the Mediterranean diet. The importance of VOO is mainly attributed both to its high content of oleic acid a balanced contribution quantity of polyunsaturated fatty acids and its richness in phenolic compounds, which act as natural antioxidants and may contribute to the prevention of several human diseases. The polar phenolic compounds of VOO belong to different classes: phenolic acids, phenyl ethyl alcohols, hydroxy-isochromans, flavonoids, lignans and secoiridoids. This latter family of compounds is characteristic of Oleaceae plants and secoiridoids are the main compounds of the phenolic fraction. Many agronomical and technological factors can affect the presence of phenols in VOO. Its shelf life is higher than other vegetable oils, mainly due to the presence of phenolic molecules having a catechol group, such as hydroxytyrosol and its secoiridoid derivatives. Several assays have been used to establish the antioxidant activity of these isolated phenolic compounds. Typical sensory gustative properties of VOO, such as bitterness and pungency, have been attributed to secoiridoid molecules. Considering the importance of the phenolic fraction of VOO, high performance analytical methods have been developed to characterize its complex phenolic pattern. The aim of this review is to realize a survey on phenolic compounds of virgin olive oils bearing in mind their chemical-analytical, healthy and sensory aspects. In particular, starting from the basic studies, the results of researches developed in the last ten years will be focused. http://www.mdpi.com/1420-3049/12/8/1679/ Mon, 06 Aug 2007 00:00:00 CEST Molecules 2007-08-06 12 8 Review 1679 1719 1420-3049 Phenolic Molecules in Virgin Olive Oils: a Survey of Their Sensory Properties, Health Effects, Antioxidant Activity and Analytical Methods. An Overview of the Last Decade Alessandra 2007-08-06 doi: 10.3390/12081679 Alessandra Bendini Lorenzo Cerretani Alegria Carrasco-Pancorbo Ana Maria Gómez-Caravaca Antonio Segura-Carretero Alberto Fernández-Gutiérrez Giovanni Lercker http://www.mdpi.com/1420-3049/12/8/1641/ In the early nineties the presence of flavonoids in Citrus juices began to attract the attention of a number of researchers, as a result of their biological and physiological importance. This short review will explore two different aspects. The first part will focus on analytical techniques for the characterization of juices from different Citrus fruits regarding their flavonoid content (even if present in only trace amounts), concentrating on the most widely used methods (LC-MS and LC-MS-MS). The second part analyzes data reported in the literature regarding the composition of Citrus juices. The main components that have been detected so far are flavanone-O-glycosides and flavone-O- or -C-glycosides. The presence of such derivatives in various hand-squeezed and industrial juices is discussed, with special emphasis on their correlation to different species. http://www.mdpi.com/1420-3049/12/8/1641/ Fri, 03 Aug 2007 00:00:00 CEST Molecules 2007-08-03 12 8 Review 1641 1673 1420-3049 Flavonoid Composition of Citrus Juices 2007-08-03 doi: 10.3390/12081641 Giuseppe Gattuso Davide Barreca Claudia Gargiulli Ugo Leuzzi Corrado Caristi http://www.mdpi.com/1420-3049/12/8/1614/ Fire is a dominant ecological factor in Mediterranean-type ecosystems. Management strategies include prescribed (controlled) burning, which has been used in the management of several species, such as Pinus nigra ssp laricio var. Corsicana, a pine endemic to Corsica of great ecological and economic importance. The effects of prescribed burning on Pinus laricio have been little studied. The first aim of this study was to characterize total and simple phenolic compounds in Pinus laricio. The second aim was to understand: i) the short term (one to three months) and medium term (three years) effects of prescribed burning, and ii) the effects of periodic prescribed burning on the production of phenolic compounds in Pinus laricio. The first result of this study is the presence of total and simple phenolic compounds in the needles of Pinus laricio. 3-Vanillyl propanol is the major compound. After a prescribed burning, the synthesis of total phenolic compounds increases in Pinus laricio for a period of three months. Total phenolic compounds could be used as bioindicators for the short-term response of Pinus laricio needles to prescribed burning. Simple phenolic compounds do not seem to be good indicators of the impact of prescribed burning because prescribed burnings are low in intensity. http://www.mdpi.com/1420-3049/12/8/1614/ Mon, 30 Jul 2007 00:00:00 CEST Molecules 2007-07-30 12 8 Article 1614 1622 1420-3049 Characterization of Phenolic Compounds in Pinus laricio Needles and Their Responses to Prescribed Burnings 2007-07-30 doi: 10.3390/12081614 Magali Cannac Cannac Vanina Pasqualini Stéphane Greff Catherine Fernandez Lila Ferrat http://www.mdpi.com/1420-3049/12/8/1569/ Polyphenol oxidases (PPOs) catalyze the oxidation of phenolics to quinones, the secondary reactions of which lead to oxidative browning and postharvest losses of many fruits and vegetables. PPOs are ubiquitous in angiosperms, are inducible by both biotic and abiotic stresses, and have been implicated in several physiological processes including plant defense against pathogens and insects, the Mehler reaction, photoreduction of molecular oxygen by PSI, regulation of plastidic oxygen levels, aurone biosynthesis and the phenylpropanoid pathway. Here we review experiments in which the roles of PPO in disease and insect resistance as well as in the Mehler reaction were investigated using transgenic tomato (Lycopersicon esculentum) plants with modified PPO expression levels (suppressed PPO and overexpressing PPO). These transgenic plants showed normal growth, development and reproduction under laboratory, growth chamber and greenhouse conditions. Antisense PPO expression dramatically increased susceptibility while PPO overexpression increased resistance of tomato plants to Pseudomonas syringae. Similarly, PPO-overexpressing transgenic plants showed an increase in resistance to various insects, including common cutworm (Spodoptera litura (F.)), cotton bollworm (Helicoverpa armigera (Hübner)) and beet army worm (Spodoptera exigua (Hübner)), whereas larvae feeding on plants with suppressed PPO activity had higher larval growth rates and consumed more foliage. Similar increases in weight gain, foliage consumption, and survival were also observed with Colorado potato beetles (Leptinotarsa decemlineata (Say)) feeding on antisense PPO transgenic tomatoes. The putative defensive mechanisms conferred by PPO and its interaction with other defense proteins are discussed. In addition, transgenic plants with suppressed PPO exhibited more favorable water relations and decreased photoinhibition compared to nontransformed controls and transgenic plants overexpressing PPO, suggesting that PPO may have a role in the development of plant water stress and potential for photoinhibition and photooxidative damage that may be unrelated to any effects on the Mehler reaction. These results substantiate the defensive role of PPO and suggest that manipulation of PPO activity in specific tissues has the potential to provide broad-spectrum resistance simultaneously to both disease and insect pests, however, effects of PPO on postharvest quality as well as water stress physiology should also be considered. In addition to the functional analysis of tomato PPO, the application of antisense/sense technology to decipher the functions of PPO in other plant species as well as for commercial uses are discussed. http://www.mdpi.com/1420-3049/12/8/1569/ Fri, 27 Jul 2007 00:00:00 CEST Molecules 2007-07-27 12 8 Review 1569 1595 1420-3049 Functional Analysis of Polyphenol Oxidases by Antisense/Sense Technology 2007-07-27 doi: 10.3390/12081569 Piyada Thipyapong Michael J. Stout Jutharat Attajarusit http://www.mdpi.com/1420-3049/12/8/1548/ In a preliminary antiprotozoal screening of several Clusiaceae species, the methanolic extracts of Allanblackia monticola and Symphonia globulifera showed high in vitro leishmanicidal activity. Further bioguided phytochemical investigation led to the isolation of four benzophenones: guttiferone A (1), garcinol (2), cambogin (3) and guttiferone F (4), along with three xanthones: allanxanthone A (5), xanthone V1 (6) and globulixanthone C (7) as active constituents. Compounds 1 and 6 were isolated from S. globulifera leaves, while compounds 2-5 were obtained from A. monticola fruits. Guttiferone A (1) and F (4) showed particulary strong leishmanicidal activity in vitro, with IC50 values (0.2 μM and 0.16 μM, respectively) comparable to that of the reference compound, miltefosine (0.46 μM). Although the leishmanicidal activity is promising, the cytotoxicity profile of these compounds prevent at this state further in vivo biological evaluation. In addition, all the isolated compounds were tested in vitro for their anticholinesterase properties. The four benzophenones showed potent anticholinesterase properties towards acetylcholinesterase (AChE) and butylcholinesterase (AChE). For AChE, the IC50 value (0.66 μM) of garcinol (2) was almost equal to that of the reference compound galanthamine (0.50 μM). Furthermore, guttiferone A (1) and guttiferone F (4) (IC50 = 2.77 and 3.50 μM, respectively) were more active than galanthamine (IC50 = 8.5) against BChE. http://www.mdpi.com/1420-3049/12/8/1548/ Fri, 20 Jul 2007 00:00:00 CEST Molecules 2007-07-20 12 8 Article 1548 1557 1420-3049 Leishmanicidal and Cholinesterase Inhibiting Activities of Phenolic Compounds from Allanblackia monticola and Symphonia globulifera 2007-07-20 doi: 10.3390/12081548 Bruno Ndjakou Lenta Catherine Vonthron-Sénécheau Bernard Weniger Krishna Prasad Devkota Joseph Ngoupayo Marcel Kaiser Qamar Naz Muhammad Iqbal Choudhary Etienne Tsamo Norbert Sewald http://www.mdpi.com/1420-3049/12/7/1496/ It would be desirable to establish and standardize methods that can measure the total antioxidant capacity level directly from vegetable extracts containing phenolics. Antioxidant capacity assays may be broadly classified as electron transfer (ET)− and hydrogen atom transfer (HAT)−based assays. The majority of HAT assays are kinetics-based, and involve a competitive reaction scheme in which antioxidant and substrate compete for peroxyl radicals thermally generated through the decomposition of azo compounds. ET−based assays measure the capacity of an antioxidant in the reduction of an oxidant, which changes colour when reduced. ET assays include the ABTS/TEAC, CUPRAC, DPPH, Folin-Ciocalteu and FRAP methods, each using different chromogenic redox reagents with different standard potentials. This review intends to offer a critical evaluation of existing antioxidant assays applied to phenolics, and reports the development by our research group of a simple and low-cost antioxidant capacity assay for dietary polyphenols, vitamins C and E, and human serum antioxidants, utilizing the copper(II)-neocuproine reagent as the chromogenic oxidizing agent, which we haved named the CUPRAC (cupric ion reducing antioxidant capacity) method. This method offers distinct advantages over other ET−based assays, namely the selection of working pH at physiological pH (as opposed to the Folin and FRAP methods, which work at alkaline and acidic pHs, respectively), applicability to both hydrophilic and lipophilic antioxidants (unlike Folin and DPPH), completion of the redox reactions for most common flavonoids (unlike FRAP), selective oxidation of antioxidant compounds without affecting sugars and citric acid commonly contained in foodstuffs and the capability to assay –SH bearing antioxidants (unlike FRAP). Other similar ET–based antioxidant assays that we have developed or modified for phenolics are the Fe(III)− and Ce(IV)−reducing capacity methods. http://www.mdpi.com/1420-3049/12/7/1496/ Thu, 19 Jul 2007 00:00:00 CEST Molecules 2007-07-19 12 7 Review 1496 1547 1420-3049 Comparative Evaluation of Various Total Antioxidant Capacity Assays Applied to Phenolic Compounds with the CUPRAC Assay 2007-07-19 doi: 10.3390/12071496 Reşat Apak Kubilay Güçlü Birsen Demirata Mustafa Özyürek Saliha Esin Çelik Burcu Bektaşoğlu K. Işıl Berker Dilek Özyurt http://www.mdpi.com/1420-3049/12/7/1455/ The purpose of this study was to explore the neuroprotective effects of daidzein on the apoptotic pathway in the hippocampus and cortex of D-galactose treated mice. For this purpose we have examined the expression of bcl-2 mRNA, bax mRNA and caspase-3 in the hippocampus and cortex of D-galactose-treated mice after fed with 10 or 5 mg/kg of daidzein. The results of in situ hybridization experiments indicate that daidzein could help increase the transcriptions of bcl-2 and decrease the transcriptions of bax in those brain regions of D-galactose-treated mice. Furthermore, immunohistochemical studies showed that daidzein could reduce the expression of caspase-3 in both brain regions. These results suggest that daidzein in soybean can inhibit the D-gal induced apoptosis via Bcl-2/Bax apoptotic pathway and be a potential medical candidate for neurodegeneration therapy. http://www.mdpi.com/1420-3049/12/7/1455/ Thu, 19 Jul 2007 00:00:00 CEST Molecules 2007-07-19 12 7 Article 1455 1470 1420-3049 The Anti-apoptosis Effects of Daidzein in the Brain of D-Galactose Treated Mice 2007-07-19 doi: 10.3390/12071455 Zhen Mao Yuan-lin Zheng Yan-qiu Zhang Bao-ping Han Xiao-wan Zhu Qing Chang Xiang-bin Hu http://www.mdpi.com/1420-3049/12/7/1367/ The chemoenzymatic synthesis of feruloylated arabino-oligosaccharides has been achieved, using a feruloyl esterase type C from Sporotrichum thermophile (StFaeC).The structure of the feruloylated products was confirmed by ESI-MSn. http://www.mdpi.com/1420-3049/12/7/1367/ Mon, 09 Jul 2007 00:00:00 CEST Molecules 2007-07-09 12 7 Article 1367 1375 1420-3049 Structural Characterisation by ESI-MS of Feruloylated Arabino-oligosaccharides Synthesised by Chemoenzymatic Esterification 2007-07-09 doi: 10.3390/12071367 Christina Vafiadi Evangelos Topakas Edwin J Bakx Henk A Schols Paul Christakopoulos http://www.mdpi.com/1420-3049/12/7/1307/ Dried leaves of Catharanthus roseus were extracted with aqueous acidic 0.1 M solution of HCl. Alkaloid-embonate complexes were obtained as precipitates by treating the extract with an alkaline (NaOH) solution of embonic acid (4,4-methylene-bis-3-hydroxynaphtalenecarboxylic acid). The precipitate mainly consisted of catharanthine and vindoline embonates and it was directly used as the starting material for a semi-synthesis of the anti-cancer bisindole alkaloid vinblastine. The coupling reaction involved oxidation of catharanthine in aqueous acidic medium by singlet oxygen (1O2), continuously produced in situ by the reaction between H2O2 with NaClO. An excess of NaBH4 was used for the reduction step. Analysis of the reaction mixture indicated a maximum yield of 20% for vinblastine at pH 8.3, based on the initial amount of catharanthine concentration. Direct-injection electrospray ionization mass spectrometry in positive ion mode was used for the identification of vinblastine. The mass spectra of vinblastine were dominated by the corresponding protonated molecular ion [M+H]+ at m/z 811 and the characteristic fragment ions matched with those of the standard compound. http://www.mdpi.com/1420-3049/12/7/1307/ Thu, 05 Jul 2007 00:00:00 CEST Molecules 2007-07-05 12 7 Article 1307 1315 1420-3049 A Simplified Procedure for Indole Alkaloid Extraction from Catharanthus roseus Combined with a Semi-synthetic Production Process for Vinblastine 2007-07-05 doi: 10.3390/12071307 Arvind Verma Into Laakso Tuulikki Seppänen-Laakso Aarre Huhtikangas Marja-Liisa Riekkola http://www.mdpi.com/1420-3049/12/7/1290/ Secondary plant compounds are important signals in several symbiotic and pathogenic plant-microbe interactions. The present review is limited to two groups of secondary plant compounds, flavonoids and strigolactones, which have been reported in root exudates. Data on flavonoids as signaling compounds are available from several symbiotic and pathogenic plant-microbe interactions, whereas only recently initial data on the role of strigolactones as plant signals in the arbuscular mycorrhizal symbiosis have been reported. Data from other plant-microbe interactions and strigolactones are not available yet. In the present article we are focusing on flavonoids in plant-fungalinteractions such as the arbuscular mycorrhizal (AM) association and the signaling between different Fusarium species and plants. Moreover the role of strigolactones in the AM association is discussed and new data on the effect of strigolactones on fungi, apart from arbuscular mycorrhizal fungi (AMF), are provided. http://www.mdpi.com/1420-3049/12/7/1290/ Thu, 05 Jul 2007 00:00:00 CEST Molecules 2007-07-05 12 7 Review 1290 1306 1420-3049 Flavonoids and Strigolactones in Root Exudates as Signals in Symbiotic and Pathogenic Plant-Fungus Interactions 2007-07-05 doi: 10.3390/12071290 Siegrid Steinkellner Venasius Lendzemo Ingrid Langer Peter Schweiger Thanasan Khaosaad Jean-Patrick Toussaint Horst Vierheilig http://www.mdpi.com/1420-3049/12/7/1274/ Cocoa contains high levels of different flavonoids. In the present study, the enantioseparation of catechin and epicatechin in cocoa and cocoa products by chiral capillary electrophoresis (CCE) was performed. A baseline separation of the catechin and epicatechin enantiomers was achieved by using 0.1 mol·L−1 borate buffer (pH 8.5) with 12 mmol·L-1 (2-hydroxypropyl)-γ-cyclodextrin as chiral selector, a fused-silica capillary with 50 cm effective length (75 μm I.D.), +18 kV applied voltage, a temperature of 20°C and direct UV detection at 280 nm. To avoid comigration or coelution of other similar substances, the flavan-3-ols were isolated and purified using polyamide-solid-phase-extraction and LC-MS analysis. As expected, we found (-)-epicatechin and (+)-catechin inunfermented, dried, unroasted cocoa beans. In contrast, roasted cocoa beans and cocoa products additionally contained the atypical flavan-3-ol (-)-catechin. This is generally formed during the manufacturing process by an epimerization which converts (-)-epicatechin to its epimer (-)-catechin. High temperatures during the cocoa bean roasting process and particularly the alkalization of the cocoa powder are the main factors inducing the epimerization reaction. In addition to the analysis of cocoa and cocoa products, peak ratios were calculated for a better differentiation of the cocoa products. http://www.mdpi.com/1420-3049/12/7/1274/ Wed, 04 Jul 2007 00:00:00 CEST Molecules 2007-07-04 12 7 Article 1274 1288 1420-3049 (-)-Catechin in Cocoa and Chocolate: Occurence and Analysis of an Atypical Flavan-3-ol Enantiomer 2007-07-04 doi: 10.3390/12071274 Michael Kofink Menelaos Papagiannopoulos Rudolf Galensa