AIM/NBO Analysis of the Geminal Coupling Constants in the Stabilization of A-Type Dimeric Proanthocyanidin: Angular Dependence.

The angular dependence of the indirect short-range spin-spin coupling constants (SSCC), the geminal , , and in A-type dimeric proanthocyanidin, was investigated using density functional theory. We studied the rotation of ring B around the bond. Therefore, we calculated hyperconjugative charge transfers and bond polarizations within the natural bond orbital (NBO) approach, performing a topological study based on Bader's theory, AIM (atoms in molecules), and analyzing the angular dependence of AIM/NBO parameters.

Resonance structure contributions, flexibility, and frontier molecular orbitals (HOMO-LUMO) of pelargonidin, cyanidin, and delphinidin throughout the conformational space: application to antioxidant and antimutagenic activities.

This research refers to the study and understanding of the conformational space of the positive-charged anthocyanidin structures in relation with the known chemical reactivities and bioactivities of these compounds. Therefore, the planar (P) and nonplanar (Z) conformers of the three hydroxylated anthocyanidins pelargonidin, cyanidin, and delphinidin were analyzed throughout the conformational space at the B3LYP/6-311 ++ G** level of theory. The outcome displayed eleven new conformers for pelargonidin, fifty-four for cyanidin, and thirty-one for delphinidin.

COVID-19 and Alzheimer's Disease: Neuroinflammation, Oxidative Stress, Ferroptosis, and Mechanisms Involved.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by marked cognitive decline, memory loss, and spatio-temporal troubles and, in severe cases, lack of recognition of family members. Neurological symptoms, cognitive disturbances, and the inflammatory frame due to COVID-19, together with long-term effects, have fueled renewed interest in AD based on similar damage. COVID-19 also caused the acceleration of AD symptom onset.

Dietary anthocyanins balance immune signs in osteoarthritis and obesity - update of human studies and clinical trials.

Anthocyanins are known to change ligand-receptor bindings, cell membrane permeability, and intracellular signaling pathways. The beneficial effects of dietary anthocyanins have been chronologically demonstrated in interventional and observational studies, including fourteen human chondrocyte studies and related cell culture assays, nineteen human clinical trials in osteoarthritis patients, seven obesity assays, nineteen assays in preadipocytes and related cells, and twenty-two clinical trials in overweight/obese subjects, which are critically discussed in this update. Strawberries, cherries, berries, pomegranate, tropical fruits, rosehip, purple rice, purple corn, red beans, and black soybean, together with cyanidin, delphinidin, malvidin, peonidin, some 3--glycosides, metabolites, and acylated anthocyanins from a potato cultivar have shown the best outcomes.

Uncommon Noninvasive Biomarkers for the Evaluation and Monitoring of the Etiopathogenesis of Alzheimer's Disease.

Background: Alzheimer´s disease (AD) is the most widespread dementia in the world, followed by vascular dementia. Since AD is a heterogeneous disease that shows several varied phenotypes, it is not easy to make an accurate diagnosis, so it arises when the symptoms are clear and the disease is already at an advanced stage. Therefore, it is important to find out biomarkers for early AD diagnosis that facilitate treatment or slow down the disease.

Neuroproteomics Chip-Based Mass Spectrometry and Other Techniques for Alzheimer's Disease Biomarkers - Update.

Background: Alzheimer's disease (AD) is a progressive neurodegenerative disease of growing interest given that there is cognitive damage and symptom onset acceleration. Therefore, it is important to find AD biomarkers for early diagnosis, disease progression, and discrimination of AD and other diseases.

Objective: The objective of this study is to update the relevance of mass spectrometry for the identification of peptides and proteins involved in AD useful as discriminating biomarkers.

Resolvin D1 and D2 reduce SARS-CoV-2-induced inflammatory responses in cystic fibrosis macrophages.

An excessive, non-resolving inflammatory response underlies severe COVID-19 that may have fatal outcomes. Therefore, the investigation of endogenous pathways leading to resolution of inflammation is of interest to uncover strategies for mitigating inflammation in people with SARS-CoV-2 infection. This becomes particularly urgent in individuals with preexisting pathologies characterized by chronic respiratory inflammation and prone to bacterial infection, such as cystic fibrosis (CF).

QSAR studies of the antioxidant activity of anthocyanins.

Through experimental information available from antioxidant assays of seventeen anthocyanins, and six common anthocyanidins, quantitative structure-activity relationships (QSAR) have been established in the present work. The antioxidant bioactivity has been predicted in three different lipid environments: emulsified and bulk oil (methyl linoleate) (in vitro tests) at concentrations of 50 and 250 μM, and 50 μM of the inhibitor, respectively, and in human LDL (low-density lipoprotein; "bad cholesterol") (ex vivo test) at concentrations of 2.5, 10, and 25 μM of the inhibitor.

Proresolving Lipid Mediators and Receptors in Stem Cell Biology: Concise Review.

Accumulating evidence indicates that stem cells (SCs) possess immunomodulatory, anti-inflammatory, and prohealing properties. The mechanisms underlying these functions are being investigated with the final goal to set a solid background for the clinical use of SCs and/or their derivatives. Specialized proresolving lipid mediators (SPMs) are small lipids formed by the enzymatic metabolism of polyunsaturated fatty acids.

Z-Isomers of (4α→6″, 2α→O→1″)-phenylflavan substituted with R'=R=OH. Conformational properties, electronic structure and aqueous solvent effects.

Procyanidins are highly hydroxylated polymers known as antioxidant compounds, thereby exhibiting beneficial effects. These compounds are protective agents against oxidative stress and the damage induced by free radicals in membranes and nucleic acids. This paper describes a study of the conformational space of (4α→6″, 2α→O→1″)-phenylflavan substituted with R'=R=OH as part of a larger study of similar structures with different substitutions.

New Insights of the Fenton Reaction Using Glycerol as the Experimental Model. Effect of O2, Inhibition by Mg(2+), and Oxidation State of Fe.

The use of iron ions as catalyst of oxidation with hydrogen peroxide, known as the Fenton reaction, is important for industry and biological systems. It has been widely studied since its discovery in the 19th century, but important aspects of the reaction as which is the oxidant, the role of oxygen, and the oxidation state of Fe still remain unclear. In this work new mechanistic insights of the oxidation of carbohydrates by the Fenton reaction using glycerol as experimental model are described.

Exploratory conformational study of (+)-catechin. Modeling of the polarizability and electric dipole moment.

The extension of the study of the conformational space of the structure of (+)-catechin at the B3LYP/6-31G(d,p) level of theory is presented in this paper. (+)-Catechin belongs to the family of the flavan-3-ols, which is one of the five largest phenolic groups widely distributed in nature, and whose biological activity and pharmaceutical utility are related to the antioxidant activity due to their ability to scavenge free radicals. The effects of free rotation around all C-O bonds of the OH substituents at different rings are taken into account, obtaining as the most stable conformer, one that had not been previously reported.

Structure and electronic properties of (+)-catechin: aqueous solvent effects.

We report a study of the structure of (+)-catechin, which belongs to the family of the flavan-3-ols-one of the five most widely distributed phenolic groups. The biological activities and pharmaceutical utility of these compounds are related to antioxidant activity due to their ability to scavenge free radicals. A breakthrough in the study of the conformational space of this compound, so far absent in the literature, is presented herein.

Naturally-occurring dimers of flavonoids as anticarcinogens.

Biflavonoids are dimers of flavonoid moieties linked by a C-C or C-O-C bond. Simple, complex, rearranged, natural and ketalized Diels-Alder adducts, benzofuran derivatives, and spirobiflavonoids are some of the structural groups of biflavonoids. These compounds are mainly distributed in the Gymnosperms, Angiosperms (monocots and dicots), ferns (Pteridophyta), and mosses (Bryophyta).

Amino acid profiles and quantitative structure-property relationship models as markers for Merlot and Torrontés wines.

Quantitative structure-property relationships (QSPRs) were applied to the aminograms obtained by HPLC in our laboratories for Torrontés and Merlot wines. Dragon theoretical descriptors were derived for a set of optimized amino acid structures with the purpose of establishing QSPR models. The statistical Replacement Method was used for designing the best multi-parametric linear regression models, which included structural features selected from a pool containing 1497 constitutional, topological, geometrical or electronic molecular descriptors.

(Iso)flav(an)ones, chalcones, catechins, and theaflavins as anticarcinogens: mechanisms, anti-multidrug resistance and QSAR studies.

Flavonoids have shown anticarcinogenic activity in cancer cell lines, animal models, and some human studies. Quantitative structure-activity relationship (QSAR) models have become useful tools for identification of promising lead compounds in anticancer drug development. However, epidemiological and clinical studies are still scarce.

Antimicrobial capacity of Aloe vera and propolis dentifrice against Streptococcus mutans strains in toothbrushes: an in vitro study.

Objectives: This study evaluated in vitro the efficiency of Aloe vera and propolis dentifrice on reducing the contamination of toothbrush bristles by a standard strain of Streptococcus mutans (ATCC 25175; SM), after toothbrushing.

Material And Methods: Fifteen sterile toothbrushes were randomly divided into 5 toothbrushing groups: I (negative control): without dentifrice; II: with fluoridated dentifrice; III: with triclosan and gantrez dentifrice; IV (positive control): without dentifrice and irrigation with 10 mL of 0.12% chlorhexidine gluconate; V: with Aloe vera and propolis dentifrice.

Structural and electronic properties of Z isomers of (4α→6´´,2α→O→1´´)-phenylflavans substituted with R = H, OH and OCH₃ calculated in aqueous solution with PCM solvation model.

In the search for new antioxidants, flavan structures called our attention, as substructures of many important natural compounds, including catechins (flavan-3-ols), simple and dimeric proanthocyanidins, and condensed tannins. In this work the conformational space of the Z-isomers of (4α→6´´, 2α→O→1´´)-phenylflavans substituted with R = H, OH and OCH(3) was scanned in aqueous solution, simulating the solvent by the polarizable continuum model (PCM). Geometry optimizations were performed at B3LYP/6-31 G level.

In vivo long-term kinetics of radiolabeled n,n-dimethyltryptamine and tryptamine.

Unlabelled: N,N-dimethyltryptamine (DMT), a strong psychodysleptic drug, has been found in higher plants, shamanic hallucinogenic beverages, and the urine of schizophrenic patients. The aim of this work was to gain better knowledge on the relationship between this drug and hallucinogenic processes by studying DMT behavior in comparison with tryptamine.

Methods: (131)I-labeled DMT and tryptamine were injected into rabbits.

Theoretical study of Z isomers of A-type dimeric proanthocyanidins substituted with R=H, OH and OCH₃: stability and reactivity properties.

The stereochemistry of A-type dimeric proanthocyanidins was studied, focusing on the factors that determine it, and the changes that occur with R = OCH₃, R' = H, and R = OH, R' = H as substituents, starting with the study of the conformational space of each species. Using molecular dynamics at a semiempirical level, and complementing with functional density calculations, two conformers of lowest energy were characterized for R = H, eight conformers for R = OH, and three conformers for R = OCH₃. Electronic distributions were analyzed at a higher calculation level, thus improving the basis set.

QSAR study of flavonoids and biflavonoids as influenza H1N1 virus neuraminidase inhibitors.

We performed a predictive analysis based on Quantitative Structure-Activity Relationships (QSAR) of a very important property of flavonoids which is the inhibition (IC50) of influenza H1N1 virus neuraminidase. The best linear model constructed from 20 molecular structures incorporated four molecular descriptors, selected from more than a thousand geometrical, topological, quantum-mechanical and electronic types of descriptors. The obtained model suggests that the activity depends on the electric charges, masses and polarizabilities of the atoms present in the molecule as well as its conformation.

Conformational and electronic (AIM/NBO) study of unsubstituted A-type dimeric proanthocyanidin.

Unlabelled: The conformational space of the unsubstituted A-type dimeric proanthocyanidin was scanned using molecular dynamics at a semiempirical level, and complemented with functional density calculations. The lowest energy conformers were obtained. Electronic distributions were analysed at a higher calculation level, thus improving the basis set.

Vibrational spectra, NMR and theoretical studies of the enantiomers and rotamers of alpha-cypermethrin.

NMR, infrared and Raman vibrational spectra of alpha-cypermethrin have been measured at room temperature. Infrared spectra were also recorded to low temperature. The spectra were analyzed by means of ab initio calculations.

In vitro anthelmintic activity of Melia azedarach naturalized in Argentina.

The anthelmintic activity of the drupe extracts of Melia azedarach L. (Meliaceae) growing in Argentina was tested against tapeworms, hookworms, nodular worms and earthworms, and was shown to be better than the standards piperazine phosphate and hexylresorcinol against tapeworms and hookworms, respectively.