Influence of Podophyllum hexandrum on endogenous antioxidant defence system in mice: possible role in radioprotection.

Podophyllum hexandrum, a Himalayan herb with known radioprotective and anti-tumour properties, was investigated for its mechanism of action. Glutathione S-transferase (GST), catalase, superoxide dismutase (SOD) activities and lipid peroxidation (LPx) were determined in the liver, jejunum and ileum at various time intervals, with and without the aqueous extract of P. hexandrum rhizome (200 mg/kg b.w. i.p.) in unirradiated and whole body irradiated (10 Gy,-2 h) male Swiss albino mice. Pre-irradiation treatment with P. hexandrum enhanced liver GST (P<0.01) and SOD (P<0.05) at 12 h post irradiation, the intestinal SOD (P<0.00005) at 84 h post irradiation was significantly elevated. However, no significant change was manifested in the catalase activity in the liver, at any of the post irradiation intervals (0, 12 and 84 h). The antioxidant defence with Podophyllum sp. treatment in mice can explain to some extent its protective action manifested in terms of survival against whole body lethal irradiation. However, some other possible mechanisms that may strengthen radioprotective action of the Podophyllum sp. extract need to be investigated further.