In vitro impact of condensed tannins on the caecal metabolites of chickens / Impacto in vitro de taninos condensados nos metabólitos cecais de frangos de corte

Tannins are a diverse group of plant phenolic compounds. Condensed tannins (CTs) represent a major subgroup of tannins and were extracted from tilia (Tilia L.) flowers and black locust (Robinia pseudoacacia) leaves. These extracts were examined for their effects on the metabolic profile of chicken caeca. By using in vitro, a nuclear magnetic resonance (1H-NMR), which was combined with multivariate statistics, the current study was applied for the first time to investigate how three different CT compositions, procyanidins (PC) and/or prodelphinidins (PD) units influenced the metabolic end-products in caecal contents of chickens. In the presence of tannins, glutamate, leucine, lysine, pyroglutamate, phenylalanine, proline, and sarcosine were significantly decreased. CT extracts significantly influenced the fermentation, increasing the concentrations of some fatty acids such as acetate, butyrate, and propionate whereas. In contrast, lactate decreased between the treatments. This study identified the key structural features of CTs that contain either high molar proportions of PD or PC, which might be useful to improve the efficiency of feed utilization in chickens.(AU)

Taninos são um grupo diversificado de compostos fenólicos derivados de plantas. Os taninos condensados (TCs) representam o maior subgrupo de taninos extraídos das flores de tília (Tilia L) e de folhas negras (acácia-bastarda). Estes extratos foram examinados para a avaliação dos seus efeitos no perfil metabólico do ceco de frangos de corte. Com o emprego da ressonância magnética nuclear in vitro (1H-NMR) combinada com estatística multivariada, o presente trabalho foi aplicado pela primeira vez para investigar como três diferentes composições de TCs, unidades de procianidinas (PC) e/ou prodelfinidinas (PD) influenciariam os produtos metabólicos finais dos conteúdos cecais de frangos de corte. Na presença de taninos, houve um significativo decréscimo de glutamato, leucina, lisina, piroglutamato, fenilalanina, prolina e sarcosina. Os extratos de TCs influenciaram significativamente a fermentação, aumentando as concentrações de alguns ácidos graxos, tais como o acetato, butirato e propionato, enquanto em contraste, houve um decréscimo do lactato entre os tratamentos. Este trabalho identificou aspectos estruturais chave que os TCs contêm, tanto as altas proporções molares de PD como as de PC, as quais podem ser úteis para aumentar a utilização de alimentos em frangos de corte.(AU)

Antioxidant properties of a dry product from Vitis vinifera seeds (Leucoselect) in rat liver endoplasmic reticulum / Propiedades antioxidantes de un producto seco de semillas de Vitis vinifera (Leucoselect) en retículo endoplásmico de hígado de rata

Leucoselect is a commercial dry product obtained from grape seeds and enriched in procyanidins, which display antioxidant activity in virtue to their ability to scavenge oxygen free radicals and to chelate transition metal ions. The hypoxanthine/xanthine oxidase and Cu2+/ascorbate systems are capable of generating reactive oxygen species; the latter system can also promote non-specific binding of copper ions to proteins. Therefore, we assessed the ability of Leucoselect to inhibit oxidative phenomena elicited by both oxidative systems on rat liver microsomes: lipid peroxidation, oxidation of protein thiols, and inhibition of the cytochrome P450 system. The antioxidant activity of Leucoselect was a reflection of its ability to scavenge oxygen free radicals, chelate copper ions, and protect microsomal membranes through direct interaction. These mechanisms were displayed in a dependent manner with the type of biomolecule studied and also with the oxidative system employed, which is an interesting phenomenon to consider when evaluating the antioxidant activity of herbal products.

Leucoselect es un producto comercial seco obtenido de semillas de uva y enriquecido en procianidinas, las cuales presentan actividad antioxidante debido a su capacidad para atrapar radicales libres y quelar metales de transición. Los sistemas hipoxantina/xantina oxidasa y Cu2+/ascorbato generan especies reactivas del oxígeno; este último sistema también promueve la unión inespecífica de iones cobre a proteínas. Por lo tanto, evaluamos la capacidad de Leucoselect para inhibir los fenómenos oxidativos producidos por ambos sistemas oxidantes en microsomas hepáticos de rata: lipoperoxidación, oxidación de tioles proteicos e inhibición de la actividad del sistema citocromo P450. La actividad antioxidante de Leucoselect fue un reflejo de su capacidad de atrapar radicales libres del oxígeno, quelar iones cobre y proteger membranas microsómicas por interacción directa. Dichos mecanismos se manifestaron en forma dependiente del tipo de biomolécula estudiada y del sistema oxidante empleado, fenómeno interesante de considerar al evaluar la actividad antioxidante de preparados herbales.