Flavanols are an important class of natural products occurring in almost all plants, fruits and vegetables; they have a great influence on wine ageing potential, astringency, colour stability and biological activities. In wine, flavanols react with sulfur dioxide (SO 2), the most widely used preservative in oenology, leading to sulfonated products. Here we report a kinetic investigation, through LC-MS quantitative measurements carried out at different pH (3 and 4) and temperature values (23, 30, 40, 50 and 60 • C), of the reaction products obtained by SO 2 addition to both monomeric (epicatechin and catechin) and dimeric flavanols (procyanidin B2 and procyanidin B3). The results proved that: (a) the major sulfonation route that leads quickly and in good yields to monomeric 4 β-sulfonated derivatives passes through the acid-catalysed depolymerisation of proanthocyanidins; (b) monomeric flavanols lead to the same 4 β-sulfonated products, although in a considerably slower manner, and also to other sulfonated regioisomers; (c) the kinetic data in our hands, in particular the temperature dependence of the observed rates, suggest the involvement of two completely different reaction mechanisms for the SO 2 addition to dimeric and monomeric flavanol substrates; (d) direct sulfonation of epicatechin is slightly faster than that of catechin. Flavanols are among the most important groups of secondary metabolites, due to their ubiquity, biological activities, nutritional value and food quality impact. They include the monomeric epicatechin (1), catechin (2), gallocatechin, epigallocatechin gallate, catechin gallate, oligomeric procyanidins (e.g. procyanidin B2 (3) and procyanidin B3 (4)), prodelphinidins, and polymeric proanthocyanins (Fig. 1). Condensed tannins are defined as oligomeric/polymeric flavanols with mass higher than 500 Dalton 1. This group of secondary metabolites is found in most of the plants, fruits, vegetables and beverages, and so every day we intake huge amounts of them by consuming wine, tea, cocoa, coffee, chocolate, berries, apples, nuts, dry fruits, mint, basil, etc. 2-4. The first scientific works about tannins were focused on their utility in the leather industry 1,5,6 , but today they are known and worldwide studied for their role in (a) human health 3,7,8 , (b) plant physiology and defence 2,9 and (c) contribution to sensorial character of food, due to their astringent and bitter taste, or their ability to stabilise wine red colour 10-14. Their properties depend on their chemical structure, such as degree of polymerisation, Bring hydroxylation and C-ring configuration 15-20. Centuries ago, the addition of SO 2 to a tannin extract was a key process in order to obtain better quality material for leather manufacturing 21. Today, SO 2 (E220) addition is permitted and regularly used in a wide range of food including wine, dried fruits and meat products, because of its preservative effects 22. However, SO 2 and sulfites are among the food allergens and the added doses are subject to legal limits 23,24. ...
Among oregano properties, its antioxidant and antibacterial effects are particularly interesting. Oregano is also able to induce a higher glycoconjugate production in gut, creating a physical barrier against microorganisms. This study evaluated the effects of adding an aqueous extract of oregano (OAE) to the diet of two homogenous groups of pigs during the finisher phase. The diets were as follows: control commercial diet (CTR group) and CTR diet supplemented (2 g/kg) with OAE (O group). Samples of ileum and caecum from the two groups were examined by conventional histochemistry to analyze complex carbohydrates and by immunohistochemistry to detect Bcl-2 Associate X protein (BAX), an indicator of oxidative stress. Glyco-histochemistry showed significant differences between the two groups. Immunohistochemistry revealed a lower presence of BAX in O group. The OAE supplementation improved the production of glycoconjugates, able to enhance in pig the protection of intestinal mucosa by means of direct and indirect defense actions. The reduced BAX immunostaining observed in O group may be an indicator of enhanced antioxidant action promoted by oregano. The results of this study can be used in further research to identify ways to improve endogenous defence ability, with the aim of reducing antibiotic use and preventing antimicrobial resistance.
Strain 3P27G6T was isolated from an artesian well connected to the thermal water basin of Comano Terme, Province of Trento, Italy. In phylogenetic analyses based on multilocus sequence analysis, strain 3P27G6T clustered together with Mesorhizobium australicum WSM2073T. Genome sequencing produced a 99.51 % complete genome, with a length of 7 363 057 bp and G+C content of 63.53 mol%, containing 6897 coding sequences, 55 tRNA and three rRNA. Average nucleotide identity analysis revealed that all distances calculated between strain 3P27G6T and the other Mesorhizobium genomes were below 0.9, indicating that strain 3P27G6T represents a new species. Therefore, we propose the name Mesorhizobium comanense sp. nov. with the type strain 3P27G6T (=DSM 110654T=CECT 30067T). Strain 3P27G6T is a Gram-negative, rod-shaped, aerobic bacterium. Growth condition, antibiotic susceptibility, metabolic and fatty acid-methyl esters profiles of the strain were determined. Only few nodulation and nitrogen fixation genes were found in the genome, suggesting that this strain may not be specialized in nodulation or in nitrogen fixation.
Several classes of flavonoids, such as anthocyanins, flavonols, flavanols, and flavones, undergo a slow H/D exchange on aromatic ring A, leading to full deuteration at positions C(6) and C(8). Within the flavanol class, H-C(6) and H-C(8) of catechin and epicatechin are slowly exchanged in D2O to the corresponding deuterated analogues. Even quercetin, a relevant flavonol representative, shows the same behaviour in a D2O/DMSOd6 1:1 solution. Detailed kinetic measurements of these H/D exchange processes are here reported by exploiting the time-dependent changes of their peak areas in the 1H-NMR spectra taken at different temperatures. A unifying reaction mechanism is also proposed based on our detailed kinetic observations, even taking into account pH and solvent effects. Molecular modelling and QM calculations were also carried out to shed more light on several molecular details of the proposed mechanism.
A series of substituted imidazoquinolines, a structurally related chemotype to pyrazoloquinolinones, a well-known class of GABAA ligands, was prepared via two synthetic procedures and the efficiency of these procedures were compared. One method relies on classical heterocyclic synthesis, the other one aims at late-stage decoration of a truncated scaffold via direct C–H functionalization. A pharmacological evaluation disclosed that one of the synthesized derivatives showed interesting activity on a α1β3 containing receptor subtype. Graphical abstract
The study analyzes red deer responses to disturbances during the day and different exposures to tourists, to establish the more appropriate times to carry out activities inside the Paneveggio deer enclosure. The alarm reactions of red deer were observed after presenting different types of visual stimuli inside and outside the fence, in order to answer some questions: Which stimuli produce the strongest reactions from the animals? Do animals differently react to stimuli presented outside and inside the fence? On which days and times are the animals more sensitive to disturbances? Are there different reactions between the males and females? The results suggest that the red deer adversely react to the disturbance at different degrees of intensity in relation to day, sex, tourist and where the stimuli are presented. It was observed that during the days with the highest tourist presence, the animals were particularly alarmed; discomfort accumulation produced the highest number of alarm reactions on Monday. For these reasons, it would be opportune to manage the pasture on Tuesday, Wednesday and Thursday, scheduled at specific times of day, preferably far from the estimated presence of tourists.
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