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Molecules, Volume 23, Issue 5 (May 2018)

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Cover Story (view full-size image) The image shows the disproportionation reaction of Sn(I)Cl yields in the presence of LiGe(SiMe3)3; [...] Read more.
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Open AccessArticle Evaluation of Lactic Acid Bacteria on the Inhibition of Vibrio parahaemolyticus Infection and Its Application to Food Systems
Molecules 2018, 23(5), 1238; https://doi.org/10.3390/molecules23051238
Received: 22 March 2018 / Revised: 16 May 2018 / Accepted: 22 May 2018 / Published: 22 May 2018
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Abstract
This study tested the effect of lactic acid bacteria (LAB) inhibition on Vibrio parahaemolyticus BCRC (Bioresource Collection and Research Center) 10806 and BCRC 12865 in a food model. MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays indicated that Caco-2 cells were not damaged after a two-hour treatment
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This study tested the effect of lactic acid bacteria (LAB) inhibition on Vibrio parahaemolyticus BCRC (Bioresource Collection and Research Center) 10806 and BCRC 12865 in a food model. MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays indicated that Caco-2 cells were not damaged after a two-hour treatment with lactic acid bacteria (LAB) and V. parahaemolyticus. The LAB cell culture and supernatant effectively inhibited the growth of V. parahaemolyticus in a food model. ELISA (Enzyme-linked immunosorbent assay) results indicated the significant inhibition of TNF-α; IL-1β; and IL-6; but Lactobacillus plantarum PM 222 and L. plantarum LP 735 did not significantly affect IL-8 levels. Real-time polymerase chain reaction (PCR) results indicated that LAB could inhibit the mRNA expression of proinflammatory cytokines IL-8; IL-6; and TNF-α; which were induced by V. parahaemolyticus. After rat-received LAB; the expression levels of TNF-α; IL-6; and IL-8 in the serum decreased significantly. In intestinal histology; the rat that received L. plantarum PM 222 and L. plantarum LP 010 was able to alleviate the intestinal villi damage caused by V. parahaemolyticus; which also helped reduce cell apoptosis. In conclusion; our results indicate that LAB can inhibit inflammatory responses caused by V. parahaemolyticus and can effectively inhibit the growth of V. parahaemolyticus in food products. Full article
(This article belongs to the Section Metabolites)
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Open AccessArticle MS/MS-Guided Isolation of Clarinoside, a New Anti-Inflammatory Pentalogin Derivative
Molecules 2018, 23(5), 1237; https://doi.org/10.3390/molecules23051237
Received: 30 March 2018 / Revised: 10 May 2018 / Accepted: 19 May 2018 / Published: 22 May 2018
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Abstract
Re-investigation of the chemical composition of the annual plant Mitracarpus scaber Zucc. led to the identification of clarinoside, a new pentalogin derivative containing a rare quinovose moiety, and the known compound harounoside. While the planar structure was fully determined using tandem mass spectrometry
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Re-investigation of the chemical composition of the annual plant Mitracarpus scaber Zucc. led to the identification of clarinoside, a new pentalogin derivative containing a rare quinovose moiety, and the known compound harounoside. While the planar structure was fully determined using tandem mass spectrometry (MS) and quantum mechanics (QM) calculations, the tridimensional structure was unravelled after isolation and NMR analysis. The absolute configuration was assigned by comparison of experimental and theoretical synchrotron radiation circular dichroism spectra. Both compounds were tested for anti-inflammatory activity, and compound 1 showed the ability to inhibit the production of interleukin-8 (Il-8) with an IC 50 value of 9.17 μ M. Full article
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Open AccessArticle Mass Transfer in Osmotic Dehydration of Kiwiberry: Experimental and Mathematical Modelling Studies
Molecules 2018, 23(5), 1236; https://doi.org/10.3390/molecules23051236
Received: 16 April 2018 / Revised: 12 May 2018 / Accepted: 14 May 2018 / Published: 22 May 2018
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Abstract
The aim of this study was to analyze the impact of osmotic solutions and temperature on the osmotic dehydration (OD) of two cultivars of kiwiberry. OD was carried out in sucrose, xylitol and maltitol solutions at 30 °C and 50 °C, respectively. The
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The aim of this study was to analyze the impact of osmotic solutions and temperature on the osmotic dehydration (OD) of two cultivars of kiwiberry. OD was carried out in sucrose, xylitol and maltitol solutions at 30 °C and 50 °C, respectively. The process of osmotic dehydration was described by the means of water loss (WL), solid gain (SG), weight reduction (WR), and water content changes. Moreover, dehydration was described by mathematical models often used in the literature. The highest WL, WR and SG values were observed for samples treated by xylitol and maltitol at 50 °C. The statistical analysis of the mathematical modelling of the process showed that in most cases, the Peleg’s equation exhibits better fitting for the experimental data. Full article
(This article belongs to the collection Preanalytical Methods for Natural Products Production)
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Open AccessArticle Study on the Discrimination between Citri Reticulatae Pericarpium Varieties Based on HS-SPME-GC-MS Combined with Multivariate Statistical Analyses
Molecules 2018, 23(5), 1235; https://doi.org/10.3390/molecules23051235
Received: 19 April 2018 / Revised: 15 May 2018 / Accepted: 20 May 2018 / Published: 22 May 2018
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Abstract
Citri reticulatae pericarpium (CRP), the dried pericarps of Citrus reticulata Blanco and its cultivars, has been widely used in drugs and foods in China for centuries. In this study, an accurate and feasible analytical method based on HS-SPME-GC-MS coupled with multivariate statistical analyses
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Citri reticulatae pericarpium (CRP), the dried pericarps of Citrus reticulata Blanco and its cultivars, has been widely used in drugs and foods in China for centuries. In this study, an accurate and feasible analytical method based on HS-SPME-GC-MS coupled with multivariate statistical analyses was developed to comprehensively compare volatile compounds of pericarps derived from Citrus reticulata “Chachi” (“Guangchenpi” in Chinese, GCP) and other cultivars of Citrus reticulata Blanco (“Chenpi” in Chinese, CP). Principal component analysis, hierarchical cluster analysis, and orthogonal partial least-squares-discrimination analysis were performed to extract meaningful attributes from volatile profiles based on GC-MS data. Results indicated that samples from GCP and CP could easily be differentiated, and seven potential chemical markers were screened for the quality control of CRP. This study illuminated the volatile profile in CRP, and provides a practical method for the authentication of CRP varieties. Full article
(This article belongs to the Section Analytical Chemistry)
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Open AccessFeature PaperArticle Photothermal Effectiveness of Magnetite Nanoparticles: Dependence upon Particle Size Probed by Experiment and Simulation
Molecules 2018, 23(5), 1234; https://doi.org/10.3390/molecules23051234
Received: 23 April 2018 / Revised: 16 May 2018 / Accepted: 16 May 2018 / Published: 22 May 2018
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Abstract
The photothermal effect of nanoparticles has proven efficient for driving diverse physical and chemical processes; however, we know of no study addressing the dependence of efficacy on nanoparticle size. Herein, we report on the photothermal effect of three different sizes (5.5 nm, 10
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The photothermal effect of nanoparticles has proven efficient for driving diverse physical and chemical processes; however, we know of no study addressing the dependence of efficacy on nanoparticle size. Herein, we report on the photothermal effect of three different sizes (5.5 nm, 10 nm and 15 nm in diameter) of magnetite nanoparticles (MNP) driving the decomposition of poly(propylene carbonate) (PPC). We find that the chemical effectiveness of the photothermal effect is positively correlated with particle volume. Numerical simulations of the photothermal heating of PPC supports this observation, showing that larger particles are able to heat larger volumes of PPC for longer periods of time. The increased heating duration is likely due to increased heat capacity, which is why the volume of the particle functions as a ready guide for the photothermal efficacy. Full article
(This article belongs to the Special Issue Photothermal Agents in Therapy)
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Open AccessReview Molecular Docking Studies of HIV-1 Resistance to Reverse Transcriptase Inhibitors: Mini-Review
Molecules 2018, 23(5), 1233; https://doi.org/10.3390/molecules23051233
Received: 21 March 2018 / Revised: 15 May 2018 / Accepted: 15 May 2018 / Published: 21 May 2018
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Abstract
Currently, millions of people are living with human immunodeficiency virus type 1 (HIV-1), which causes acquired immunodeficiency syndrome. However, the spread of the HIV-1 resistance to antiviral agents is the major problem in the antiretroviral therapy and medical management of HIV-infected patients. HIV-1
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Currently, millions of people are living with human immunodeficiency virus type 1 (HIV-1), which causes acquired immunodeficiency syndrome. However, the spread of the HIV-1 resistance to antiviral agents is the major problem in the antiretroviral therapy and medical management of HIV-infected patients. HIV-1 reverse transcriptase (RT) is one of the key viral targets for HIV-1 inhibition. Therefore, the studies on the combatting the HIV resistance that occurs due to the structural changes in RT, are in great demand. This work aims to provide an overview of the state-of-the-art molecular docking approaches applied to the studies of the HIV-1 resistance, associated with RT structure changes. We have reviewed recent studies using molecular docking with mutant forms of RT. The work discusses the modifications of molecular docking, which have been developed to find the novel molecules active against resistance mutants of RT and/or recombinant strains of HIV-1. The perspectives of the existing algorithms of molecular docking to the studies on molecular mechanisms of resistance and selection of the correct binding poses for the reverse transcriptase inhibitors are discussed. Full article
(This article belongs to the Special Issue Recent Trends on Enzymes Inhibitors and Activators in Drug Research)
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Open AccessArticle Evaluation of Transition Metal Complexes of Benzimidazole-Derived Scaffold as Promising Anticancer Chemotherapeutics
Molecules 2018, 23(5), 1232; https://doi.org/10.3390/molecules23051232
Received: 20 March 2018 / Revised: 8 May 2018 / Accepted: 15 May 2018 / Published: 21 May 2018
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Abstract
Three new transition metal complexes, Cu(II) 1, Co(II) 2, and Zn(II) 3 with ligand “bimnap” derived from 1-methyl-2-aminobenzimidazole and 2-hydroxynapthaldehyde were synthesized and characterized. The structure of the ligand was determined by single X-ray crystallography. All the three complexes, 1
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Three new transition metal complexes, Cu(II) 1, Co(II) 2, and Zn(II) 3 with ligand “bimnap” derived from 1-methyl-2-aminobenzimidazole and 2-hydroxynapthaldehyde were synthesized and characterized. The structure of the ligand was determined by single X-ray crystallography. All the three complexes, 13, were examined for the mode of interaction with biomolecule viz., calf thymus-DNA (CT-DNA) using various spectroscopic methods. The nuclease activity was performed against pBR322 DNA that exhibited concentration-dependent degradation of the nucleic acid. The mechanism of DNA cleavage was studied by the electrophoretic pattern in the presence of the radical scavengers. Also, the complexes 13 were analyzed for groove binding affinity. Moreover, in vitro cytotoxicities of the complexes 13 were tested against the five human cancer cell lines, i.e., HeLa, SK-MEL-1, HepG2, HT108, and MDA-MB 231. Also, the cell adhesion and migration properties upon treatment of cell lines with complexes 13, and consequently, their cell death pathway via apoptosis and necrosis were analyzed. Further, complexes 13 were studied in vivo for their toxicities and tolerabilities in mice. In sum, the complexes 13 showed merits of an effective anticancer agent in cell lines–based study while minor side effects were observed in vivo. Full article
(This article belongs to the Section Inorganic Chemistry)
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Open AccessArticle Density Functional Theory Applied to Excited State Intramolecular Proton Transfer in Imidazole-, Oxazole-, and Thiazole-Based Systems
Molecules 2018, 23(5), 1231; https://doi.org/10.3390/molecules23051231
Received: 16 April 2018 / Revised: 15 May 2018 / Accepted: 17 May 2018 / Published: 21 May 2018
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Abstract
Excited state intramolecular proton transfer (ESIPT) is a photoinduced process strongly associated to hydrogen bonding within a molecular framework. In this manuscript, we computed potential energy data using Time Dependent Density Functional Theory (TDDFT) for triphenyl-substituted heterocycles, which evidenced an energetically favorable proton
[...] Read more.
Excited state intramolecular proton transfer (ESIPT) is a photoinduced process strongly associated to hydrogen bonding within a molecular framework. In this manuscript, we computed potential energy data using Time Dependent Density Functional Theory (TDDFT) for triphenyl-substituted heterocycles, which evidenced an energetically favorable proton transfer on the excited state (i.e., ESIPT) but not on the ground state. Moreover, we describe how changes on heterocyclic functionalities, based on imidazole, oxazole, and thiazole systems, affect the ESIPT process that converts an enolic species to a ketonic one through photon-induced proton transfer. Structural and photophysical data were obtained theoretically by means of density functional theory (DFT) calculations and contrasted for the three heterocyclics. Different functionals were used, but B3LYP was the one that adequately predicted absorption data. It was observed that the intramolecular hydrogen bond is strengthened in the excited state, supporting the occurrence of ESIPT. Finally, it was observed that, with the formation of the excited state, there is a decrease in electronic density at the oxygen atom that acts as proton donor, while there is a substantial increase in the corresponding density at the nitrogen atom that serves as proton acceptor, thus, indicating that proton transfer is indeed favored after photon absorption. Full article
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Open AccessArticle Quality Traits of “Cannabidiol Oils”: Cannabinoids Content, Terpene Fingerprint and Oxidation Stability of European Commercially Available Preparations
Molecules 2018, 23(5), 1230; https://doi.org/10.3390/molecules23051230
Received: 21 April 2018 / Revised: 12 May 2018 / Accepted: 15 May 2018 / Published: 20 May 2018
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Abstract
Cannabidiol (CBD)-based oil preparations are becoming extremely popular, as CBD has been shown to have beneficial effects on human health. CBD-based oil preparations are not unambiguously regulated under the European legislation, as CBD is not considered as a controlled substance. This means that
[...] Read more.
Cannabidiol (CBD)-based oil preparations are becoming extremely popular, as CBD has been shown to have beneficial effects on human health. CBD-based oil preparations are not unambiguously regulated under the European legislation, as CBD is not considered as a controlled substance. This means that companies can produce and distribute CBD products derived from non-psychoactive hemp varieties, providing an easy access to this extremely advantageous cannabinoid. This leaves consumers with no legal quality guarantees. The objective of this project was to assess the quality of 14 CBD oils commercially available in European countries. An in-depth chemical profiling of cannabinoids, terpenes and oxidation products was conducted by means of GC-MS and HPLC-Q-Exactive-Orbitrap-MS in order to improve knowledge regarding the characteristics of CBD oils. Nine out of the 14 samples studied had concentrations that differed notably from the declared amount, while the remaining five preserved CBD within optimal limits. Our results highlighted a wide variability in cannabinoids profile that justifies the need for strict and standardized regulations. In addition, the terpenes fingerprint may serve as an indicator of the quality of hemp varieties, while the lipid oxidation products profile could contribute in evaluation of the stability of the oil used as milieu for CBD rich extracts. Full article
(This article belongs to the Special Issue Qualitative and Quantitative Analysis of Bioactive Natural Products)
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Open AccessArticle Plasma Pharmacokinetic Determination of Canagliflozin and Its Metabolites in a Type 2 Diabetic Rat Model by UPLC-MS/MS
Molecules 2018, 23(5), 1229; https://doi.org/10.3390/molecules23051229
Received: 3 May 2018 / Revised: 15 May 2018 / Accepted: 17 May 2018 / Published: 20 May 2018
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Abstract
Canagliflozin is a novel, orally selective inhibitor of sodium-dependent glucose co-transporter-2 (SGLT2) for the treatment of patients with type 2 diabetes mellitus. In this study, a sensitive and efficient UPLC-MS/MS method for the quantification of canagliflozin and its metabolites in rat plasma was
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Canagliflozin is a novel, orally selective inhibitor of sodium-dependent glucose co-transporter-2 (SGLT2) for the treatment of patients with type 2 diabetes mellitus. In this study, a sensitive and efficient UPLC-MS/MS method for the quantification of canagliflozin and its metabolites in rat plasma was established and applied to pharmacokinetics in a type 2 diabetic rat model. We firstly investigated the pharmacokinetic changes of canagliflozin and its metabolites in type 2 diabetic rats in order to use canagliflozin more safely, reasonably and effectively. We identified three types of O-glucuronide metabolites (M5, M7 and M17), two kinds of oxidation metabolites (M8 and M9) and one oxidation and glucuronide metabolite (M16) using API 5600 triple-TOF-MS/MS. Following liquid–liquid extraction by tert-butyl methyl ether, chromatographic separation of canagliflozin and its metabolites were performed on a Waters XBridge BEH C18 column (100 × 2.1 mm, 2.5 μm) using 0.1% acetonitrile–formic acid (75:15, v/v) as the mobile phase at a flow rate of 0.7 mL/min. Selected ion monitoring transitions of m/z 462.00→191.10, 451.20→153.10, 638.10→191.10 and 478.00→267.00 were chosen to quantify canagliflozin, empagliflozin (IS), O-glucuronide metabolites (M5, M7 and M17), and oxidation metabolites (M9) using an API 5500-triple-MS/MS in the positive electrospray ionization mode. The validation of the method was found to be of sufficient specificity, accuracy and precision. The pathological condition of diabetes could result in altered pharmacokinetic behaviors of canagliflozin and its metabolites. The pharmacokinetic parameters (AUC0–t, AUC0–∞, CLz/F, and Vz/F) of canagliflozin were significantly different between the CTRL and DM group rats (p < 0.05 or p < 0.01), which may subsequently cause different therapeutic effects. Full article
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Open AccessArticle Cyclodextrins: Assessing the Impact of Cavity Size, Occupancy, and Substitutions on Cytotoxicity and Cholesterol Homeostasis
Molecules 2018, 23(5), 1228; https://doi.org/10.3390/molecules23051228
Received: 26 April 2018 / Revised: 11 May 2018 / Accepted: 17 May 2018 / Published: 20 May 2018
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Abstract
Cyclodextrins (CDs) are cyclic oligosaccharides; the most common CDs contain six, seven, or eight glucose units called α-CDs, β-CDs, and γ-CDs, respectively. The use of CDs in biomedical research is increasing due to their ability to interact with membrane lipids as well as
[...] Read more.
Cyclodextrins (CDs) are cyclic oligosaccharides; the most common CDs contain six, seven, or eight glucose units called α-CDs, β-CDs, and γ-CDs, respectively. The use of CDs in biomedical research is increasing due to their ability to interact with membrane lipids as well as a wide variety of poorly water-soluble molecules. We assessed the impact of CD cavity size, occupancy, and substitutions on cytotoxicity and cholesterol homeostasis. The potency of CD-mediated cytotoxicity was in the order of β-CDs, α-CDs, and γ-CDs. Substitutions with hydroxypropyl or carboxymethyl group attenuated cytotoxicity compared with the native CDs, whereas CDs substituted with methyl groups exhibited cytotoxicity that was similar to that of the native CDs. The lipid components in blood exerted remarkable hemolysis-alleviating effects in methyl-β-CD-induced hemolysis. Occupancy of the CD cavity with cholesterol or a structurally related lipid molecule abrogated the cytotoxic capacity of the CDs. Interestingly, hydroxypropyl-γ-CD (HPγCD) was able to reduce intracellular cholesterol accumulation in Niemann–Pick disease type C (NPC) patient-derived fibroblasts as efficiently as HPβCD. Proteomic study indicated that HPβCD and HPγCD treatments altered the expression pattern of cellular proteins, suggesting that some of the CD-induced cellular proteins may play an important function in modulating intracellular cholesterol homeostasis. Full article
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Open AccessArticle The Microencapsulation of Maqui (Aristotelia chilensis (Mol.) Stuntz) Juice by Spray-Drying and Freeze-Drying Produces Powders with Similar Anthocyanin Stability and Bioaccessibility
Molecules 2018, 23(5), 1227; https://doi.org/10.3390/molecules23051227
Received: 31 March 2018 / Revised: 16 May 2018 / Accepted: 16 May 2018 / Published: 20 May 2018
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Abstract
The microencapsulation of maqui juice by spray-drying and freeze-drying was studied as a strategy to protect anthocyanins in new food formulations in order to improve the anthocyanin retention before consumption and the bioaccessibility. It is well known that the encapsulation method affects both
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The microencapsulation of maqui juice by spray-drying and freeze-drying was studied as a strategy to protect anthocyanins in new food formulations in order to improve the anthocyanin retention before consumption and the bioaccessibility. It is well known that the encapsulation method affects both the shape and size of powders, being assumed that undefined forms of freeze-drying powders might affect their stability due to the high permeability to oxygen. The objective of this study was to compare the microencapsulation of maqui juice by spray-drying and freeze-drying, evaluating the stability of specific anthocyanins in yogurt and after in vitro digestion. Results indicated that most relevant differences between spray-drying and freeze-drying powders were the morphology and particle size that affect their solubility (70.4–59.5%) when they were reconstituted in water. Nevertheless these differences did not affect the stability of anthocyanins as other research have proposed. Both encapsulation methods generated powders with a high stability of 3-O-monoglycosylated anthocyanins in yogurt (half-life values of 75–69 days for delphinidin-3-sambubioside). Furthermore, no significant differences in the bioaccessibility of anthocyanins between maqui juice powders (44.1–43.8%) were found. In conclusion, the microencapsulation of maqui juice by freeze-drying is as effective as spray-drying to produce new value-added food formulations with stable anthocyanins. Full article
(This article belongs to the Special Issue Advances in Anthocyanin Research 2018)
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Open AccessFeature PaperReview Nutraceuticals in Periodontal Health: A Systematic Review on the Role of Vitamins in Periodontal Health Maintenance
Molecules 2018, 23(5), 1226; https://doi.org/10.3390/molecules23051226
Received: 25 April 2018 / Revised: 16 May 2018 / Accepted: 17 May 2018 / Published: 20 May 2018
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Abstract
Periodontal disease, a relevant public health problem worldwide, is generally considered a common pathology of elderly people. In this respect, there is agreement about that nutritional status may be a modifying factor in the progression and healing of the periodontal tissues. Vitamins have
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Periodontal disease, a relevant public health problem worldwide, is generally considered a common pathology of elderly people. In this respect, there is agreement about that nutritional status may be a modifying factor in the progression and healing of the periodontal tissues. Vitamins have been recommended as nutraceuticals for prevention and treatment of some pathological conditions, such as cardiovascular diseases, obesity or cancer. Thus, a systematic approach to determining how the different vitamin type could ameliorate periodontal risks or improve periodontal health is necessary to further the understanding of the potential benefits and risks of vitamins supplementation use. For this, a systematic review of English-written literature in PubMed until February 2018, which included both human and animal research on the relationship of each vitamin with periodontal disease, was conducted. Among all the analyzed vitamins those with antioxidant capacity and effects on immune system seem to be useful for prevention or improvement of periodontal disease, as well as those implicated in bone metabolism. In the first case, there are quite information in favor of various vitamins, mainly vitamin C, that is the most studied. In the second case, vitamin D seems to have the most relevant role. Full article
(This article belongs to the Special Issue Nutraceuticals and Their Medicinal Importance)
Open AccessArticle Conformational Aspects of the O-acetylation of C-tetra(phenyl)calixpyrogallol[4]arene
Molecules 2018, 23(5), 1225; https://doi.org/10.3390/molecules23051225
Received: 28 April 2018 / Revised: 15 May 2018 / Accepted: 17 May 2018 / Published: 20 May 2018
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Abstract
Reaction between pyrogallol and benzaldehyde results in a conformational mixture of C-tetra(phenyl)pyrogallol[4]arene (crown and chair). The conformer mixture was separated using crystallization procedures and the structures were determined using FTIR, 1H-NMR, and 13C-NMR. O-acetylation of C-tetra(phenyl)pyrogallol[4]arene (chair) with
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Reaction between pyrogallol and benzaldehyde results in a conformational mixture of C-tetra(phenyl)pyrogallol[4]arene (crown and chair). The conformer mixture was separated using crystallization procedures and the structures were determined using FTIR, 1H-NMR, and 13C-NMR. O-acetylation of C-tetra(phenyl)pyrogallol[4]arene (chair) with acetic anhydride, in pyridine results in the formation of dodecaacetyl-tetra(phenyl)pyrogallol[4]arene. The structure was determined using 1H-NMR and 13C-NMR finding that the product maintains the conformation of the starting conformer. On the other hand, the O-acetylation reaction of C-tetra(phenyl)pirogallol[4]arene (crown) under same conditions proceeded efficiently, and its structure was determined using 1H-NMR and 13C-NMR. Dynamic 1H-NMR of acetylated pyrogallolarene was studied by means of variable temperature in DMSO-d6 solution, and it revealed that two conformers are formed in the solution. Boat conformations for acetylated pyrogallolarene showed a slow interconversion at room temperature. Full article
(This article belongs to the Section Organic Chemistry)
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Open AccessArticle Calculation of the Surface Tension of Ordinary Organic and Ionic Liquids by Means of a Generally Applicable Computer Algorithm Based on the Group-Additivity Method
Molecules 2018, 23(5), 1224; https://doi.org/10.3390/molecules23051224
Received: 16 April 2018 / Revised: 16 May 2018 / Accepted: 17 May 2018 / Published: 20 May 2018
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Abstract
The calculation of the surface tension of ordinary organic and ionic liquids, based on a computer algorithm applying a refined group-additivity method, is presented. The refinement consists of the complete breakdown of the molecules into their constituting atoms, further distinguishing them by their
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The calculation of the surface tension of ordinary organic and ionic liquids, based on a computer algorithm applying a refined group-additivity method, is presented. The refinement consists of the complete breakdown of the molecules into their constituting atoms, further distinguishing them by their immediate neighbour atoms and bond constitution. The evaluation of the atom-groups’ contributions was carried out by means of a fast Gauss-Seidel fitting method, founded upon the experimental data of 1893 compounds from literature. The result has been tested for plausibility using a 10-fold cross-validation (cv) procedure. The direct calculation and the cv test proved the applicability of the present method by the close similarity and excellent goodness of fit R2 and Q2 of 0.9039 and 0.8823, respectively. The respective standard deviations are ±1.99 and ±2.16 dyn/cm. Some correlation peculiarities have been observed in a series of ordinary and ionic liquids with homologous alkyl chains, as well as with di- and trihydroxy-groups-containing liquids, which have been discussed in detail, exhibiting the limit of the present method. Full article
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