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The aim of this study was to prepare nanoparticles of grape seed procyanidin B2-3′-O-gallate by chitosan-sodium alginate. The encapsulation system was characterized by transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC), and its biological activity was analyzed by cell-level antioxidant capacity. The results showed that the particle size of nano-carrier was 160~201nm, the B2-3′-O-gallate was well embedded, and the encapsulation efficiency of B2-3′-O-gallate was 93.5%. In vitro digestion experiments suggested that the release of B2-3′-O-gallate was significantly controlled by chitosan-sodium alginate nano-system through anomalous diffusion mechanism, and at about 72-78% of B2-3′-O-gallate was retained under gastrointestinal (GI) condition. Besides, the cytotoxicity results expressed that B2-3′-O-gallate chitosan nanoparticles had obvious protective effect on human HepG2 cells induced by hydrogen peroxide. This work provides a promising way to control the delivery and enhances the biological activity of galloylated procyanidins – one of the most important group of bioactive polyphenols of the grape pomace.

Ethyl-linked anthocyanin-flavanol pigments are one of the most important condensation products formed during the red winemaking and ageing period. They have great contribution to the color characteristics and stability of aged red wines. In this study, the color characteristics and stability of ethyl-linked anthocyanin-flavanol pigments and their precursor anthocyanins were evaluated by combined spectrophotometry and 3D molecular simulations. In model wine solutions, the condensation reactions between three anthocyanins and (-)-epicatechin, mediated by acetaldehyde, were conducted to produce ethyl-linked anthocyanin-flavanol pigments. The color was assessed by the CIELab method, and the concentration changes were analyzed by HPLC-DAD. On the other hand, the stability of these pigmented compounds was also calculated by the three 3D molecular simulation methods, that is molecular mechanics, molecular dynamics, and quantum chemistry simulation. The results obtained from CIELab analysis indicated that the formation of ethyl-linked anthocyanin-flavanol pigments resulted in a decrease of L*, a*, b* and C* values, and conversely, a rising of h* value. The 3D molecular simulations revealed that the stability of anthocyanins was as follows: Mv-3-O-glu > Pn-3-O-glu > Cy-3-O-glu. The cis or trans ethyl-linked anthocyanin-flavanol pigments were much more stable than their precursor anthocyanins. Among the pigments, ethyl-linked malvidin-3-O-glucoside-flavanol was more stable than ethyl-linked cyanidin-3-O-glucoside-flavanol and ethyl-linked peonidin-3-O-glucoside-flavanol.

A riqueza do património genético vitícola existente em Portugal leva a considerá-lo como um dos países da Europa com maior densidade de castas autóctones, embora cerca de 85 % dessas castas só ocupem aproximadamente 10 % da área total de vinha. Apesar da preservação destas castas muito pouco cultivadas, que se designa de castas minoritárias, estar praticamente garantida em coleções ampelográficas, torna-se necessário a sua valorização e difusão pelo sector vitivinícola. Este trabalho constitui uma primeira abordagem para a caracterização físico-química e sensorial de vinhos produzidos, em duas vindimas, a partir de quatro castas brancas e de quatro castas tintas. No caso dos vinhos das castas tintas, a caracterização físico-química incluiu também o estudo do perfil de antocianinas, bem como a determinação dos teores de antocianas totais e de polifenóis totais. Os resultados obtidos mostraram uma diferenciação dos vinhos das duas vindimas, verificando-se também, ao nível organolético, apreciações globais superiores para os vinhos brancos das castas ‘Galego Dourado’ e ‘Códega do Larinho’ e para os vinhos tintos das castas ‘Malvasia Preta’ e ‘Cornifesto’. Verificou-se, ainda, que os vinhos que apresentaram teores mais elevados de antocianas foram os das castas ‘Cornifesto’ e ‘Malvasia Preta’, sendo os vinhos das castas ‘Tinta Negra’ e ‘Malvasia Preta’ os que evidenciaram ser mais ricos em polifenóis totais. Um resultado importante de notar é que os teores de polifenóis totais dos vinhos da mesma casta mostraram ser idênticos ou muito similares, nas duas vindimas. Contudo, considera-se que sejam necessários mais estudos para uma caracterização mais robusta dos vinhos destas castas.

Grape pomaces or vinification by-products are abundant and rich in polyphenols, particularly proanthocyanidins. During the last three decades, grape and wine polyphenols, particularly catechins (CATs) and oligomeric proanthocyanidins (OPCs) have attracted considerable attention of the international scientific community, due essentially to their potential health-beneficial effects, related to their protective action towards cardiovascular disease and the oxygen free radical scavenger capacity. Such phenolic compounds have been proved to be the key components responsible for the health-beneficial effects of red wine. Furthermore, although the most widely recognized antioxidants are Vitamins A, C, and E, scientific research has shown that OPCs are likely the most powerful antioxidants known. Although various OPCs have been available in the market, they are generally very expensive due to the high cost of their production. As a consequence, the development of efficient methods for large-scale preparation of these bioactive compounds have still a challenging task for scientists. In this communication, we will present a new and efficient technology for large preparation of bioactive polyphenols from vinification by-products (grape seed and grape skin). On one hand, polymeric proanthocyanidins were transformed into a series of low- molecule-weight bioactive compounds using various degradation methods. On the other hand, High-Speed Countcurrent Chromatography (HSCCC), as a relative new separation technology for natural product preparation, was applied to large and efficient isolation of these bioactive compounds.

The aim of this study was to investigate the antidepressant-like effect of red wine phenolic extracts in mouse model exposed to exogenous corticosterone. The results showed that 3-week corticosterone injections caused depression-like behavior in mice, as indicated by the significant decrease in sucrose consumption and increase immobility time in the forced swimming test (FST). Red wine phenolic extracts treatment significantly reduced serum corticosterone levels. Moreover, it was found that red wine phenolic extract increased the brain-derived neurotrophic factor protein (BNDF) and tropomyosin-related kinase B (TrkB) phosphorylation and cAMP-responsive element binding protein (CREB) phosphorylation levels in the hippocampus and prefrontal cortex. However, K252a, an inhibitor of TrkB, completely abolished those antidepressant-like effects. These results suggested that the red wine phenolic extracts produce an antidepressant-like effect in corticosteronetreated mice, at least in part, which is possibly mediated by modulating hypothalamic-pituitary-adrenal (HPA) axis, BDNF, TrkB and CREB phosphorylation levels in the brain region of mice.

The seismic performance of prefabricated reinforced concrete shear walls is a key point in the safety of the whole assembly structure under earthquake actions. In this study, six specimens of reinforced concrete shear walls were assembled with a cast-in-place vertical joint with a straight, L, or convex shape. The specimens were tested using a low cyclic loading test under an axial compression ratio of 0.2 or 0.3. The stress process, failure pattern, and hysteretic curve of each specimen were measured. Combined with a numerical analysis using the finite element method, the variations in the bearing capacity, stiffness degradation, ductility, and energy dissipation capacity of the tested specimens were analyzed. Results showed that all specimens failed in a shear pattern without an obvious failure phenomenon along the vertical joint. The hysteresis curves exhibited an obvious pinch phenomenon and good deformation ability. The seismic behavior decreased in sequence for the shear walls assembled with a cast-in-place vertical joint with a straight, L, or convex shape, while a higher axial compression ratio improved the bearing capacity of the shear walls. The shear wall with an L-shaped vertical joint had similar seismic behavior to that with a straight vertical joint, but the shear wall with a convex vertical joint exhibited a decrease of 8.5% and 10.9% in bearing capacity, 18.2% and 1.2% in ductility, and 13.1% and 20.6% in energy dissipation, respectively, under an axial compression ratio of 0.2 and 0.3. The bearing mechanisms of shear walls with different vertical joints are explained with the numerical analysis of the stress vector maps of concrete and the stress cloud maps of reinforcements at different stress levels. [ABSTRACT FROM AUTHOR]

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