Celastrus paniculatus seed water soluble extracts protect cultured rat forebrain neuronal cells from hydrogen peroxide-induced oxidative injury

The effects of aqueous extracts of Celastrus paniculatus (CP) seeds were shown to have antioxidant properties in rats. In the study reported here, we have investigated the free radical scavenging capacity of three aqueous extracts (WSEs) obtained from CP seeds: a room temperature extract (WF); a hot water extract (HF); an acid extract (AF). All the WSEs exhibited a dose-dependent free radical scavenging capacity for 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and also for superoxide-generated assays (in vitro assays). in addition, we used enriched forebrain primary neuronal cell (FBNC) cultures to evaluate the neuroprotective effects of the three CP-WSE extracts on H2O2-induced toxicity. FBNC were pre-treated with the CP-WSE and then with H2O2 to evaluate the protection afforded against H2O2-induced toxicity. The criteria for neuroprotection by the WSEs were based on a mitochondrial function test following the H2O2-induced neurotoxicity. All the WSEs significantly attenuated H2O2-induced neuronal death, and AF was the most effective in protecting the neuronal cells against oxidative injury caused by H2O2. In 10 day FBNC, cellular superoxide dismutase activity was not affected by the WSEs or H2O2, but catalase activity was decreased and levels of malondialdehyde were increased by H2O2 treatment. When the neuronal cells were treated with WSEs prior to H2O2 exposure, catalase activity was increased and levels of malondialdehyde were decreased significantly. The data presented here suggest that CP seed WSEs protected neuronal cells in part by their free radical scavenging properties, by reducing lipid peroxidation, and also by their ability to induce the antioxidant enzyme catalase. Our results indicate that WSEs might exert neuroprotective effects against increased oxidative stress resulting from free radical damage that is associated with a number of neurodegenerative diseases. (C) 2003 Elsevier B.V. All rights reserved.