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Keywords = flash chromatography fractionation

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22 pages, 1698 KB  
Article
Cytotoxic Activity of the Baltic Cyanobacterium Pseudanabaena galeata CCNP1313
by Marta Cegłowska, Robert Konkel and Hanna Mazur-Marzec
Toxins 2025, 17(12), 586; https://doi.org/10.3390/toxins17120586 - 6 Dec 2025
Viewed by 463
Abstract
While tropical regions have traditionally been the focus of studies on natural bioactive products, works published within the last decade demonstrate that cyanobacteria from the Baltic Sea also possess significant biotechnological and pharmaceutical potential. The Baltic Pseudanabaena galeata CCNP1313 previously demonstrated activity against [...] Read more.
While tropical regions have traditionally been the focus of studies on natural bioactive products, works published within the last decade demonstrate that cyanobacteria from the Baltic Sea also possess significant biotechnological and pharmaceutical potential. The Baltic Pseudanabaena galeata CCNP1313 previously demonstrated activity against breast cancer cell lines (MCF7 and T47D) and several viruses. In the present study, the cytotoxicity of cellular extract and flash chromatography fractions from the strain were evaluated against a wider panel of cancer cells (A549, C-33A, CaSki, DoTC2, HeLa, PC3, SiHa, and T47D). To gain better insight into the compounds potentially responsible for the observed effects, high-resolution mass spectrometry was combined with bioactivity-based molecular networking. Both the extract and hydrophobic fractions showed strong cytotoxicity, particularly against breast cancer cells and selected cervical cancer cells. While HRMS analyses confirmed the production of previously characterised peptides by CCNP1313 (Pseudanabaena galeata peptides and galeapeptins), neither of them was found to be responsible for the activity. Instead, the molecular networking approach linked the cytotoxicity to specific lipid classes, including diacylglycerols (DAGs) and monogalactosyldiacylglycerols (MGDGs). This study highlights the necessity of integrating traditional methods with advanced bioinformatics for the successful discovery of bioactive natural products, especially when complex samples, such as extract or chromatographically separated fractions, are analysed. Full article
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11 pages, 1808 KB  
Article
Ultrasound-Assisted Extraction Optimization and Flash Chromatography Fractionation of Punicalagin from Pomegranate Peel (Punica granatum L.)
by Erick M. Raya-Morquecho, Pedro Aguilar-Zarate, Leonardo Sepúlveda, Mariela R. Michel, Anna Iliná, Cristóbal N. Aguilar and Juan A. Ascacio-Valdés
Separations 2025, 12(10), 279; https://doi.org/10.3390/separations12100279 - 11 Oct 2025
Viewed by 1168
Abstract
Background: Pomegranate peel (Punica granatum L.) is a rich source of phenols, particularly ellagitannins, highlighting punicalagin, a bioactive compound with recognized antioxidant potential. However, efficient recovery and purification methods are required to enable its application in food and health-related products. This study [...] Read more.
Background: Pomegranate peel (Punica granatum L.) is a rich source of phenols, particularly ellagitannins, highlighting punicalagin, a bioactive compound with recognized antioxidant potential. However, efficient recovery and purification methods are required to enable its application in food and health-related products. This study aimed to obtain a partially purified fraction of punicalagin from pomegranate peel using optimized extraction and purification strategies. Methods: A Taguchi L9 (3)3 experimental design was employed to optimize ultrasound-assisted extraction, evaluating extraction time (10, 20, 30 min), ethanol concentration (20, 40, 80%), and solid-to-solvent ratio (1:12, 1:14, 1:16). Total polyphenol content was quantified using the Folin–Ciocalteu method. Extracts obtained under optimized conditions were concentrated by rotary evaporation and subjected to semipurification using flash chromatography with Amberlite XAD-16 resin. Subsequently, the fractions were lyophilized and analyzed by HPLC/ESI/MS. Results: The Statistica software determined the optimal conditions for polyphenol extraction (20 min, 40% ethanol, 1:12), with the signal-to-noise (S/N) ratio reaching 88.43 ± 0.66, surpassing the predicted value of 77.42. Flash chromatography yielded four fractions, and HPLC/ESI/MS analysis revealed the presence of ellagitannins in all of them, with fraction number 2 showing the highest relative abundance of punicalagin (89.25%). Conclusions: The combination of ultrasound-assisted extraction and flash chromatography proved effective for obtaining punicalagin-rich fractions from pomegranate peel, supporting its potential for nutraceutical applications. Full article
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16 pages, 3047 KB  
Article
Two-Dimensional Chromatographic Isolation of High Purity Erinacine A from Hericium erinaceus
by Katerina Naumoska, Andrej Gregori and Alen Albreht
J. Fungi 2025, 11(2), 150; https://doi.org/10.3390/jof11020150 - 15 Feb 2025
Cited by 3 | Viewed by 3510
Abstract
A simple and robust two-dimensional chromatographic fractionation protocol for the isolation of the neuroprotective compound erinacine A from Hericium erinaceus is proposed. This production platform yielded 19.4 mg of erinacine A from approximately 130 g of mushroom material, with a chromatographic purity of [...] Read more.
A simple and robust two-dimensional chromatographic fractionation protocol for the isolation of the neuroprotective compound erinacine A from Hericium erinaceus is proposed. This production platform yielded 19.4 mg of erinacine A from approximately 130 g of mushroom material, with a chromatographic purity of 97.4%. The procedure includes extraction, concentration, fractionation, purification, and characterisation of the bioactive compound. The crude H. erinaceus extract was fractionated in the first dimension by normal-phase flash chromatography, and the fraction containing erinacine A was further purified in the second dimension by semi-preparative reversed-phase chromatography. This strategy utilises the orthogonality of the two chromatographic modes to effectively eliminate difficult impurities, including structural isomers and analogues of erinacine A. Complementary analytical approaches such as high-performance thin-layer chromatography (HPTLC) and high-performance liquid chromatography with ultraviolet and tandem mass spectrometric detection (HPLC–UV–MS/MS) were employed to unambiguously confirm erinacine A in the isolated fractions, while HPLC with a charged aerosol detector (CAD) was used to determine its purity. Given the limited commercial availability and the high price of erinacine A, the described method offers a straightforward and cost-effective alternative to obtain this valuable compound for further research and applications. Full article
(This article belongs to the Section Fungi in Agriculture and Biotechnology)
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24 pages, 1100 KB  
Article
Eco-Friendly Extraction of Phlorotannins from Padina pavonica: Identification Related to Purification Methods Towards Innovative Cosmetic Applications
by Moustapha Nour, Valérie Stiger-Pouvreau, Alain Guenneguez, Laurence Meslet-Cladière, Stéphane Cérantola, Ahmed Ali, Gaelle Simon, Abdourahman Daher and Sylvain Petek
Mar. Drugs 2025, 23(1), 15; https://doi.org/10.3390/md23010015 - 28 Dec 2024
Cited by 4 | Viewed by 2614
Abstract
This study focuses on developing innovative and eco-friendly purification methods for the isolation of bioactive compounds derived from Padina pavonica, a brown abundant macroalga in Djibouti. Three distinct fractions, obtained via liquid-liquid extraction (LLE_FAE), solid-phase extraction (SPE_WE50), and flash chromatography (FC_EtOH20), were [...] Read more.
This study focuses on developing innovative and eco-friendly purification methods for the isolation of bioactive compounds derived from Padina pavonica, a brown abundant macroalga in Djibouti. Three distinct fractions, obtained via liquid-liquid extraction (LLE_FAE), solid-phase extraction (SPE_WE50), and flash chromatography (FC_EtOH20), were selected based on their high phenolic content and antioxidant activities. All fractions were also evaluated for their anti-ageing potential by assessing their ability to inhibit two vital skin-ageing enzymes, tyrosinase and elastase. Structural analysis by 1H-13C HMBC NMR and LC-MS revealed a selectivity of phlorotannins depending on the purification methods. The LLE_FAE fraction exhibited greater structural complexity, including compounds such as phloroglucinol, diphlorethol/difucol, fucophlorethol and bifuhalol, which likely contribute to its enhanced bioactivity compared to the fractions obtained by FC_EtOH20 and SPE_WE50, which were also active and enriched only in phloroglucinol and fucophlorethol. These findings highlight the impact of purification techniques on the selective enrichment of specific bioactive compounds and demonstrated the interest of FC or SPE in producing active phlorotannin-enriched fractions. These two purification methods hold strong potential for innovative cosmeceutical applications. Results are discussed regarding the use of P. pavonica as a promising marine resource in Djibouti to be used for the development of cosmetic industry. Full article
(This article belongs to the Special Issue Marine Cosmeceuticals)
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17 pages, 4435 KB  
Article
Bioassay-Guided Isolation and Identification of Antibacterial Compounds from Invasive Tree of Heaven Stem and Trunk Bark
by Anna Cselőtey, Márton Baglyas, Nóra Király, Péter G. Ott, Vesna Glavnik, Irena Vovk and Ágnes M. Móricz
Molecules 2024, 29(24), 5846; https://doi.org/10.3390/molecules29245846 - 11 Dec 2024
Cited by 4 | Viewed by 1772
Abstract
Flash column chromatographic fractionation of tree of heaven (Ailanthus altissima) stem and trunk bark extracts, guided by thin-layer chromatography (TLC)–Bacillus subtilis assay and TLC–heated electrospray high-resolution tandem mass spectrometry (HESI-HRMS/MS), lead to the isolation of six known compounds: (9Z [...] Read more.
Flash column chromatographic fractionation of tree of heaven (Ailanthus altissima) stem and trunk bark extracts, guided by thin-layer chromatography (TLC)–Bacillus subtilis assay and TLC–heated electrospray high-resolution tandem mass spectrometry (HESI-HRMS/MS), lead to the isolation of six known compounds: (9Z,11E)-13-hydroxy-9,11-octadecadienoic acid (13-HODE, A1), (10E,12Z)-9-hydroxy-10,12-octadecadienoic acid (9-HODE, A2), hexadecanedioic acid (thapsic acid, A3), 16-hydroxyhexadecanoic acid (juniperic acid, A4), 16-feruloyloxypalmitic acid (alpinagalanate, A5), and canthin-6-one (A6). Their structures were elucidated by HESI-HRMS/MS and one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. This is the first study identifying A1A5 in A. altissima tree. Except for A5, all isolated compounds exhibited antibacterial activity against B. subtilis in microdilution assays. A6 showed the strongest effect with a minimum inhibitory concentration (MIC) value of 8.3 µg/mL. The antibacterial activity of A3 and A4 is newly described. Full article
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12 pages, 4961 KB  
Article
Identification of 2,4-Di-tert-Butylphenol as an Antimicrobial Agent Against Cutibacterium acnes Bacteria from Rwandan Propolis
by Florent Rouvier, Lydia Abou, Emmanuel Wafo, Perrine Andre, Julien Cheyrol, Mohamed-Mohsen Khacef, Claude Nappez, Hubert Lepidi and Jean Michel Brunel
Antibiotics 2024, 13(11), 1080; https://doi.org/10.3390/antibiotics13111080 - 13 Nov 2024
Cited by 5 | Viewed by 3191
Abstract
Background/Objectives: Acne is the most prevalent dermatological condition among humans, affecting approximately 80% of adolescents during puberty. To date, numerous compounds have been used for acne treatment, including erythromycin ointments and antiseptics, with varying degrees of success. The emergence of erythromycin-resistant C. acnes [...] Read more.
Background/Objectives: Acne is the most prevalent dermatological condition among humans, affecting approximately 80% of adolescents during puberty. To date, numerous compounds have been used for acne treatment, including erythromycin ointments and antiseptics, with varying degrees of success. The emergence of erythromycin-resistant C. acnes strains has spurred the search for new antimicrobial agents, particularly from natural sources. Methods: Propolis collected in Rwanda was extracted and fractionated by flash chromatography and tested against C. acnes growth by using NCLSI recommendations. Results: In our research, we identified a molecule, 2,4-Di-tert-butylphenol (2,4-DTBP) which inhivbited the C. acnes growth at a concentration of 16 µg/mL. Based on these results, we formulated an ointment (1%) using OFAP18 and petroleum jelly for the potential treatment of acne using a mouse model. Conclusions: In vitro and in vivo evidence suggests that 2,4-DTBP has anti-inflammatory properties and could effectively manage the overgrowth of C. acnes as well as serve as a potent alternative for the formulation of an active propolis ointment for acne treatment. Full article
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21 pages, 2593 KB  
Article
Influence of Major Polyphenols on the Anti-Candida Activity of Eugenia uniflora Leaves: Isolation, LC-ESI-HRMS/MS Characterization and In Vitro Evaluation
by Camylla Janiele Lucas Tenório, Thainá dos Santos Dantas, Lucas Silva Abreu, Magda Rhayanny Assunção Ferreira and Luiz Alberto Lira Soares
Molecules 2024, 29(12), 2761; https://doi.org/10.3390/molecules29122761 - 10 Jun 2024
Cited by 5 | Viewed by 2479
Abstract
The content of chemical constituents in Eugenia uniflora leaf extracts correlates positively with biological activities. The experimental objective was to carry out the phytochemical screening and purification of the major polyphenols from the leaves of E. uniflora. In addition, the anti-Candida [...] Read more.
The content of chemical constituents in Eugenia uniflora leaf extracts correlates positively with biological activities. The experimental objective was to carry out the phytochemical screening and purification of the major polyphenols from the leaves of E. uniflora. In addition, the anti-Candida activity of the hydroalcoholic extract, fraction, subfractions and polyphenols purified were evaluated. After partitioning of the extract with ethyl acetate, the fractions were chromatographed on Sephadex® LH-20 gel followed by RP-flash chromatography and monitored by TLC and RP-HPLC. The samples were characterized by mass spectrometry (LC-ESI-QTOF-MS2) and subjected to the microdilution method in 96-well plates against strains of C. albicans, C. auris, and C. glabrata. Myricitrin (93.89%; w/w; m/z 463.0876), gallic acid (99.9%; w/w; m/z 169.0142), and ellagic acid (94.2%; w/w; m/z 300.9988) were recovered. The polyphenolic fraction (62.67% (w/w) myricitrin) and the ellagic fraction (67.86% (w/w) ellagic acid) showed the best antifungal performance (MIC between 62.50 and 500 μg/mL), suggesting an association between the majority constituents and the antifungal response of E. uniflora derivatives. However, there is a clear dependence on the presence of the complex chemical mixture. In conclusion, chromatographic strategies were effectively employed to recover the major polyphenols from the leaves of the species. Full article
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13 pages, 5334 KB  
Article
Isolation of Cardanol Fractions from Cashew Nutshell Liquid (CNSL): A Sustainable Approach
by Bhavika Bhatia, Nagarjuna Amarnath, Sumit K. Rastogi and Bimlesh Lochab
Sustain. Chem. 2024, 5(2), 68-80; https://doi.org/10.3390/suschem5020006 - 1 Apr 2024
Cited by 11 | Viewed by 7390
Abstract
Exploring sustainable approaches to replace petroleum-based chemicals is an ongoing challenge in reducing the carbon footprint. Due to the complexity and percentage variation in nature-generated molecules, which further varies based on geographical origin and the purification protocol adopted, a better isolation strategy for [...] Read more.
Exploring sustainable approaches to replace petroleum-based chemicals is an ongoing challenge in reducing the carbon footprint. Due to the complexity and percentage variation in nature-generated molecules, which further varies based on geographical origin and the purification protocol adopted, a better isolation strategy for individual components is required. Agrowaste from the cashew industry generates phenolic lipid (cardanol)-rich cashew nutshell liquid (CNSL) and has recently shown extensive commercial utility. Cardanol naturally exists as a mixture of three structurally different components with C15-alkylene chains: monoene, diene, and triene. The separation of these three fractions has been a bottleneck and is crucial for certain structural designs and reproducibility. Herein, we describe the gram-scale purification of cardanol into each component using flash column chromatography within the sustainability framework. The solvent used for elution is recovered and reused after each stage (up to 82%), making it a cost-effective and sustainable purification strategy. This simple purification technique replaces the alternative high-temperature vacuum distillation, which requires substantial energy consumption and poses vacuum fluctuation and maintenance challenges. Three components (monoene 42%, diene 22%, and triene 36%) were isolated with good purity and were fully characterized by 1H and 13C NMR, GC-MS, HPLC, and FTIR spectroscopy. The present work demonstrates that greener and simpler strategies pave the way for the isolation of constituents from nature-sourced biochemicals and unleash the potential of CNSL-derived fractions for high-end applications. Full article
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21 pages, 6587 KB  
Article
Lupenone-Rich Fraction Derived from Cissus quadrangularis L. Suppresses Lipid Accumulation in 3T3-L1 Adipocytes
by Thitiporn Lakthan, Panupun Limpachayaporn, Kanok-on Rayanil, Pornsri Charoenpanich, Pornwipa Phuangbubpha and Adisri Charoenpanich
Life 2023, 13(8), 1724; https://doi.org/10.3390/life13081724 - 11 Aug 2023
Cited by 3 | Viewed by 3341
Abstract
Cissus quadrangularis L. (CQ) has potential as a therapeutic for managing obesity and balancing metabolic activity, but the main bioactive compound and regulatory mechanism remain unknown. Herein, the CQ hexane extract was fractionated into 30 fractions (CQ-H) using flash column chromatography and analyzed [...] Read more.
Cissus quadrangularis L. (CQ) has potential as a therapeutic for managing obesity and balancing metabolic activity, but the main bioactive compound and regulatory mechanism remain unknown. Herein, the CQ hexane extract was fractionated into 30 fractions (CQ-H) using flash column chromatography and analyzed using thin-layer chromatography. The direct antiadipogenesis effect of CQ-H fractions was tested on 3T3-L1 preadipocytes. Lupenone-rich fractions 2H and 3H were identified as containing potent antiadipogenesis agents that reduced differentiated cell numbers and intracellular lipid droplet size. Although the overall mitochondrial density remained unchanged, differentiated cells exhibited a higher mitochondrial density than that in non-differentiated cells. Additionally, 2H increased mitochondrial activity in both cell types as shown by their differentiation and lipid formation stages. Lupenone was isolated from 2H (Lu-CQ) and shown to dose-dependently inhibit adipogenesis, with 2H being more potent than Lu-CQ. Lu-CQ and 2H downregulated the expression of Pparg2 mRNA and upregulated that of glucose transporter genes, Slc2a1 and Slc2a4. Lu-CQ and 2H induced increased glucose uptake by 3T3-L1 cells. These findings suggest that lupenone-rich fractions in CQ contribute to balancing metabolic activity and reducing adipose tissue formation. Further exploration of CQ and its components may prompt innovative strategies for managing obesity and metabolic disorders. Full article
(This article belongs to the Section Plant Science)
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13 pages, 1807 KB  
Article
Antioxidant Guided Fractionation of Blackberry Polyphenols Show Synergistic Role of Catechins and Ellagitannins
by Katerina Tzima, Gontorn Putsakum and Dilip K. Rai
Molecules 2023, 28(4), 1933; https://doi.org/10.3390/molecules28041933 - 17 Feb 2023
Cited by 5 | Viewed by 2647
Abstract
In the present study, blackberry extract was prepared using a previously optimized solid–liquid extraction method in 70% aqueous acetone aimed at the recovery of its principal phenolics. Subsequently, 0.5 g of freeze-dried extract was subjected to flash chromatography fractionation, which was conducted on [...] Read more.
In the present study, blackberry extract was prepared using a previously optimized solid–liquid extraction method in 70% aqueous acetone aimed at the recovery of its principal phenolics. Subsequently, 0.5 g of freeze-dried extract was subjected to flash chromatography fractionation, which was conducted on a C18 column using a binary solvent system of water and methanol at 10 mL/min. The total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) activities of the obtained 42 flash fractions were determined, and a strong positive correlation (r ≥ 0.986) was exhibited among them. Furthermore, the graph of the antioxidant indices of the flash fractions resembled the flash chromatogram, suggesting a good correlation among the compounds within the chromatographic peaks and the antioxidant indices. LC-MS/MS identified as many 28 phenolics, including cinnamtannin A2 reported for the first time in blackberries. This study further established the role of dominant anthocyanins (cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside), but uniquely those of ellagitannins and catechins on the antioxidant capacity of blackberries. Full article
(This article belongs to the Special Issue Natural Polyphenols: Isolation, Characterization and Health Benefits)
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30 pages, 5097 KB  
Article
Upcycling Discarded Shoe Polish into High Value-Added Asphalt Fluxing Agent for Use in Hot Mix Paving Applications
by Nader Nciri and Namho Kim
Materials 2022, 15(18), 6454; https://doi.org/10.3390/ma15186454 - 17 Sep 2022
Cited by 1 | Viewed by 4012
Abstract
This research effort is geared towards revealing the latent potential of discarded shoe polish that might be repurposed as an asphalt fluxing agent for the construction of durable and sustainable road surfaces. To drive this creative invention, the effect of various proportions of [...] Read more.
This research effort is geared towards revealing the latent potential of discarded shoe polish that might be repurposed as an asphalt fluxing agent for the construction of durable and sustainable road surfaces. To drive this creative invention, the effect of various proportions of waste shoe polish (e.g., 5, 10 and 15 wt. % WSP) on the performance of base AP-5 bitumen was inspected in great detail. A meticulous investigation of the chemical, physical, and rheological properties of the resultant combinations was carried out using a variety of state-of-the-art laboratory techniques, specifically: thin-layer chromatography-flame ionization detection (TLC-FID), Fourier transform-infrared spectroscopy (FT-IR), needle penetration, ring-and-ball softening point, Brookfield viscometer, ductility, flash/fire points, dynamic shear rheometer (DSR), multiple stress-creep recovery (MSCR), and bending beam rheometer (BBR) tests. The Iatroscan data disclosed that the continuous feeding of binder with WSP had a minor impact on SARA fractional distribution, regardless of aging. According to the FT-IR scan, the stepwise addition of WSP to the binder did not result in any significant chemical alterations in the blends. The combined outcomes of the DSR/BBR/empirical test methods forecasted that the partly bio-sourced additive would greatly improve the mixing–compaction temperatures, workability, and coating–adhesion properties of bituminous mixtures while imparting them with outstanding anti-aging/cracking attributes. In short, the utilization of waste shoe polish as a fluxing agent for hot asphalt mix production and application is not only safe, feasible, and affordable, but it has the potential to abate the pollution caused by the shoe-care market while simultaneously enhancing the overall performance of the pavement and extending its service lifespan. Full article
(This article belongs to the Special Issue Effect of Additives and Binders on Asphalt Pavement Properties)
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13 pages, 2237 KB  
Article
Characterization of the Compounds Released in the Gaseous Waste Stream during the Slow Pyrolysis of Hemp (Cannabis sativa L.)
by Laetitia Marrot, Kristine Meile, Mariem Zouari, David DeVallance, Anna Sandak and Rene Herrera
Molecules 2022, 27(9), 2794; https://doi.org/10.3390/molecules27092794 - 27 Apr 2022
Cited by 8 | Viewed by 3379
Abstract
This study aims to characterize and valorize hemp residual biomass by a slow pyrolysis process. The volatile by-products of hemp carbonization were characterized by several methods (TGA, UV-VIS, TLC, Flash Prep-LC, UHPLC, QTOF-MS) to understand the pyrolysis reaction mechanisms and to identify the [...] Read more.
This study aims to characterize and valorize hemp residual biomass by a slow pyrolysis process. The volatile by-products of hemp carbonization were characterized by several methods (TGA, UV-VIS, TLC, Flash Prep-LC, UHPLC, QTOF-MS) to understand the pyrolysis reaction mechanisms and to identify the chemical products produced during the process. The obtained carbon yield was 29%, generating a gaseous stream composed of phenols and furans which was collected in four temperature ranges (F1 at 20–150 °C, F2 at 150–250 °C, F3 at 250–400 °C and F4 at 400–1000 °C). The obtained liquid fractions were separated into subfractions by flash chromatography. The total phenolic content (TPC) varied depending on the fraction but did not correlate with an increase in temperature or with a decrease in pH value. Compounds present in fractions F1, F3 and F4, being mainly phenolic molecules such as guaiacyl or syringyl derivatives issued from the lignin degradation, exhibit antioxidant capacity. The temperature of the pyrolysis process was positively correlated with detectable phenolic content, which can be explained by the decomposition order of the hemp chemical constituents. A detailed understanding of the chemical composition of pyrolysis products of hemp residuals allows for an assessment of their potential valorization routes and the future economic potential of underutilized biomass. Full article
(This article belongs to the Special Issue Industrial Hemp Chemistry and Nutraceutical Perspectives)
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22 pages, 1612 KB  
Article
Extraction of Phenolic Compounds from Populus Salicaceae Bark
by Elsa Autor, Alfonso Cornejo, Fernando Bimbela, Maitane Maisterra, Luis M. Gandía and Víctor Martínez-Merino
Biomolecules 2022, 12(4), 539; https://doi.org/10.3390/biom12040539 - 2 Apr 2022
Cited by 33 | Viewed by 5256
Abstract
Lignocellulosic residues have the potential for obtaining high value-added products that could be better valorized if biorefinery strategies are adopted. The debarking of short-rotation crops yields important amounts of residues that are currently underexploited as low-grade fuel and could be a renewable source [...] Read more.
Lignocellulosic residues have the potential for obtaining high value-added products that could be better valorized if biorefinery strategies are adopted. The debarking of short-rotation crops yields important amounts of residues that are currently underexploited as low-grade fuel and could be a renewable source of phenolic compounds and other important phytochemicals. The isolation of these compounds can be carried out by different methods, but for attaining an integral valorization of barks, a preliminary extraction step for phytochemicals should be included. Using optimized extraction methods based on Soxhlet extraction can be effective for the isolation of phenolic compounds with antioxidant properties. In this study, poplar bark (Populus Salicaceae) was used to obtain a series of extracts using five different solvents in a sequential extraction of 24 h each in a Soxhlet extractor. Selected solvents were put in contact with the bark sample raffinate following an increasing order of polarity: n-hexane, dichloromethane, ethyl acetate, methanol, and water. The oily residues of the extracts obtained after each extraction were further subjected to flash chromatography, and the fractions obtained were characterized by gas chromatography coupled with mass spectrometry (GC–MS). The total phenolic content (TPC) was determined using the Folin–Ciocalteu method, and the antioxidant activity (AOA) of the samples was evaluated in their reaction with the free radical 2,2-Diphenyl-picrylhydrazyl (DPPH method). Polar solvents allowed for higher individual extraction yields, with overall extraction yields at around 23% (dry, ash-free basis). Different compounds were identified, including hydrolyzable tannins, phenolic monomers such as catechol and vanillin, pentoses and hexoses, and other organic compounds such as long-chain alkanes, alcohols, and carboxylic acids, among others. An excellent correlation was found between TPC and antioxidant activity for the samples analyzed. The fractions obtained using methanol showed the highest phenolic content (608 μg of gallic acid equivalent (GAE)/mg) and the greatest antioxidant activity. Full article
(This article belongs to the Special Issue Biomolecules from Plant Residues, 2nd Version)
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12 pages, 3127 KB  
Article
Isolation of Bioactive Pentacyclic Triterpenoid Acids from Olive Tree Leaves with Flash Chromatography
by Snezana Agatonovic-Kustrin, Vladimir Gegechkori, Ehtesham U. R. Mohammed, Heng Ku and David W. Morton
Appl. Sci. 2022, 12(3), 996; https://doi.org/10.3390/app12030996 - 19 Jan 2022
Cited by 18 | Viewed by 4623
Abstract
The present study reports on the use of the flash chromatography for the isolation and purification of oleanolic and maslinic acids from olive leaf extracts. Although the separation and identification of these acids is considered challenging due to the similarity in their structure, [...] Read more.
The present study reports on the use of the flash chromatography for the isolation and purification of oleanolic and maslinic acids from olive leaf extracts. Although the separation and identification of these acids is considered challenging due to the similarity in their structure, oleanolic and maslinic acids were detected, identified, and separated. Solubility prediction was used to help to match compatibility of extraction solvent with targeted triterpenoid acids. Aqueous washing was used, to first selectively remove unwanted interferents from the extraction solvent. The extracts obtained with different solvents and solvent mixtures were fractionated using flash chromatography and then analyzed. HPTLC chromatography was used to assess collected fractions as either semi-pure or pure, and to identify the fractions containing oleanolic and maslinic acids. The yields of oleanolic and maslinic acids reported here are significantly higher than yields obtained in previously reported isolations. The presence and purity of oleanolic and maslinic acid in collected fractions was confirmed by ATR-FTIR and NMR spectrometry. Full article
(This article belongs to the Topic Applied Sciences in Functional Foods)
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19 pages, 6467 KB  
Article
Resolution of P-Sterogenic 1-Phenylphosphin-2-en-4-one 1-Oxide into Two Enantiomers by (R,R)-TADDOL and Conformational Diversity of the Phosphinenone Ring and TADDOL in the Crystal State
by Elżbieta Łastawiecka, Adam Włodarczyk, Anna E. Kozioł, Hanna Małuszyńska and K. Michał Pietrusiewicz
Molecules 2021, 26(22), 6873; https://doi.org/10.3390/molecules26226873 - 15 Nov 2021
Cited by 2 | Viewed by 2872
Abstract
The resolution of racemic 1-phenylphosphin-2-en-4-one 1-oxide (2), was achieved through the fractional crystallization of its diastereomeric complexes with (4R,5R)-(−)-2,2-dimethyl -α,α,α′,α′-tetraphenyl-dioxolan-4,5-dimethanol (R,R-TADDOL) followed by the liberation of the individual enantiomers of 2 by flash chromatography on [...] Read more.
The resolution of racemic 1-phenylphosphin-2-en-4-one 1-oxide (2), was achieved through the fractional crystallization of its diastereomeric complexes with (4R,5R)-(−)-2,2-dimethyl -α,α,α′,α′-tetraphenyl-dioxolan-4,5-dimethanol (R,R-TADDOL) followed by the liberation of the individual enantiomers of 2 by flash chromatography on silica gel columns. The resolution process furnished the two enantiomers of 2 of 99.1 and 99.9% e.e. at isolated yields of 62 and 59% (counted for the single enantiomer), respectively. The absolute configurations of the two enantiomers were established by means of X-ray crystallography of their diastereomerically pure complexes, i.e., (R)-2R,R)-TADDOL and (S)-2•(R,R)-TADDOL. The structural analysis revealed that in the (R)-2•(R,R)-TADDOL complex, the P-phenyl substituent occupied a pseudoequatorial position, whereas in (S)-2•(R,R)-TADDOL, it appeared in both the pseudoequatorial and the pseudoaxial positions in four symmetrically independent molecules. Concurrent conformational changes of the TADDOL molecules were best described by the observed changes of a pseudo-torsional CO...OC angle that could be considered as a possible measure of TADDOL conformation in its receptor–ligand complexes. The structural analysis of the (R,R)-TADDOL molecule revealed that efficiency of this compound for use as an effective resolving factor comes from its ability to flexibly fit its structure to both enantiomers of a ligand molecule, producing a rare case of resolution for both pure enantiomers with one chiral separating agent. The resolved (R)-2 was used to assign the absolute configuration of a recently described (−)-1-phenylphosphin-2-en-4-one 1-sulfide by chemical correlation. In addition, an attempted stereoretentive reduction of (R)-2 by PhSiH3 at 60 °C revealed an unexpectedly low barrier for P-inversion in 1-phenylphosphin-2-en-4-one. Full article
(This article belongs to the Special Issue Advances in Enantioselective Syntheses and Chiral Separations)
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