Hydrogen peroxide-induced modulation of intracellular oxidized states in cultured macrophage J774A.1 and neuroactive PC-12 cells, and protection by anovel grape seed proanthocyanidin extract

We have previously compared selected antioxidants including vitamins C and E, beta-carotene and a novel IH636 grape seed proanthocyanidin extract (GSP E) with respect to their scavenging abilities against biochemically generat ed free radicals in both in vitro and in viva models, The results demonstra ted that GSPE is a significantly more potent oxygen free radical scavenger compared with vitamins C and E and P-carotene, GSPE has been reported to ex hibit a wide range of biological and pharmacological activities including f ree radical scavenging, antibacterial, antiviral, antiinflammatory, antiall ergic and vasodilator actions, In this study hydrogen peroxide-induced oxidative damage was assessed in ma crophage J774A.1 and neuroactive adrenal pheochromocytoma PC-12 cells, and the concentration-dependent ability of GSPE to protect these cells, Laser s canning confocal microscopy was used to determine intracellular oxidized st ates, Approximately 5.8- and 4.5-fold increases in fluorescence intensity w ere. observed following incubation of macrophage J774A.1 and PC-12 cells wi th 0.50 mM H2O2 for 24 h, respectively, Pretreatment of the J774A.1 cells w ith 50 mg/L and 100 mg/L GSPE decreased H2O2-induced fluorescence intensity by 36% and 70%, respectively, while under these same conditions approximat ely 50% and 70% decreases in fluorescence intensities were observed in PC-1 2 cells. The results indicate that hydrogen peroxide significantly increase s oxidative stress in these cells as demonstrated by the increase in intrac ellular oxidized states, Furthermore, GSPE can significantly protect agains t hydrogen peroxide-induced oxidative stress in cultured J774A.1 macrophage and neuronal PC-12 cells. (C) 1998 John Whey & Sons, Ltd.