Anti-oxidant and immunomodulatory properties of seabuckthorn (Hippophae rhamnoides) - an in vitro study

This study was designed to determine the anti-oxidant and immunomodulatory properties of scabuckthorn (Hippophae rhamnoides) using lymphocytes as a model system. Chromium(VI) as potassium dichromate was used to induce oxidative damage. The production of free radicals by chromium and the ability of alcoholic leaf and fruit extracts of scabuckthorn to inhibit the oxidative damage induced by chromium was investigated. Addition of chromium (10 mug/ml) to the cells resulted in enhanced cytotoxicity, apoptosis, free radical production and decreased glutathione (reduced) levels. Chromium also caused a significant inhibition of lymphocyte proliferation induced by both lipopolysaccharide and concanavalin A. Alcoholic extracts of leaves and fruits of seabuckthorn at a concentration of 500 mug/ml were found to inhibit chromium-induced free radical production, apoptosis, DNA fragmentation and restored the anti-oxidant status to that of control cells. In addition, these extracts also were able to arrest the chromium-induced inhibition of lymphocyte proliferation. These observations suggest that the alcoholic extracts of leaves and fruits of scabuckthorn have marked cytoprotective properties, which could be attributed to the anti-oxidant activity. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.