Antioxidant activity and inhibitory effect of Gamazumi (Viburnum dilatatum THUNB.) on oxidative damage induced by water immersion restraint stress in rats.

The antioxidant activity and antiulcer effects of Gamazumi (Viburnum dilatatum THUNB.) fruit squeezing solution (GSS) were investigated. GSS including no antioxidant additive showed strong antioxidant activity by the XYZ-dish method and the electron spin resonance (ESR) method. GSS showed to have no negative effect on growth of rats for 2 weeks of feeding with free access to GSS. After feeding, the GSS group showed a significant inhibitory effect on gastric ulcer formation by water immersion restraint stress for 6 hours compared with the Water group. Plasma, liver and stomach concentrations of lipid peroxide in the GSS group were reduced rather than the water group. Furthermore, the activities of plasma lactic dehydrogenase, amylase and creatine phosphokinase are ordinarily increased by stress; however these activities in the GSS group decreased to the level in the Control group having no stress. The physiological effects of GSS were similar to, or higher than, those of 0.1% (-)-epigallocatechin gallate (EGCg) solution. These effects of EGCg and GSS were similar to the order of antioxidant activity against hydroxyl radical found by both the XYZ-dish and the ESR methods. It was concluded that after ingestion of GSS, during the period of strong antioxidant activity in the body, it could prevent stress-induced oxidative damage.