RESUMO
In the current study, a carboxyl-rich polysaccharide purified from Lycium barbarum L. leaves (hereafter, LP) and its degradation with ascorbic acid and hydrogen peroxide were characterized. Degradation decreased the molecular weight of LP from 4.63â¯×â¯104 to 3.45â¯×â¯104â¯Da, and increased its zeta potential from -8.01 to -5.35â¯mV. In vitro experiments showed that degradation significantly increased the anticoagulant activity and, in particular, antiplatelet activity of LP (pâ¯<â¯0.05). The polysaccharide with the highest degree of degradation had higher inhibitory activity than aspirin against arachidonic acid- and thrombin-induced platelet aggregation at 0.5â¯g/mL. A reduction in uronic acids between LP and its degradation products significantly decreased their antiplatelet activity (pâ¯<â¯0.05). Further analysis confirmed that polysaccharides changed from a compact spherical structure to a random coil in aqueous solution following degradation, which facilitated the interaction of polysaccharides and platelets.
Assuntos
Lycium/química , Folhas de Planta/química , Polissacarídeos/química , Polissacarídeos/farmacologia , Anticoagulantes/química , Anticoagulantes/farmacologia , Ácido Ascórbico/química , Configuração de Carboidratos , Frutas/química , Humanos , Peróxido de Hidrogênio/química , Peso Molecular , Inibidores da Agregação Plaquetária/química , Inibidores da Agregação Plaquetária/farmacologiaRESUMO
Penicillium thomii PT95 strain was able to form abundant orange, sand-shaped sclerotia in which carotenoids were accumulated. The aim of this work was to determine the effects of copper-induced oxidative stress on the sclerotial differentiation and antioxidant properties of PT95 strain. The results showed that the time of exudates initiation, sclerotial initiation and sclerotial maturation of PT95 strain were advanced in 1-2 days under the copper-induced oxidative stress growth conditions. The analytical results of sclerotial biomass, carotenoids content in sclerotia showed that copper-induced oxidative stress favored the sclerotial differentiation and biosynthesis of carotenoids. Under the copper-induced oxidative stress growth conditions, the total phenolics content and DPPH free radical scavenging activity of sclerotia of this fungus were decreased as compared with the control. However, the oxidative stress induced by a lower amount of CuSO4 in media could enhance significantly the reducing power of sclerotia.
