Treatment of mice with a herbal preparation (mentat) protects against radiation-induced mortality.

The effect of various doses (0, 5, 10, 20, 40, 80, 100, 120 and 160 mg/kg b. wt.) of 50% ethanolic extract of mentat (a herbal preparation) was studied on the survival of mice exposed to 10 Gy of gamma-radiation. Treatment of mice with different doses of mentat consecutively for fi ve days before irradiation delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non-drug treated irradiated controls. Most of the doses of mentat provided protection against the gastrointestinal (GI) death, however, the highest protection against GI death was observed for 80 mg/kg mentat. This was also true for bone marrow deaths, where the highest number of survivors were observed at 30 days post-irradiation in this group (i.e. 80 mg/kg) when compared with the other doses of mentat. The evaluation of acute toxicity showed that mentat was non-toxic up to a dose of 1.5 g/kg b. wt., where no drug-induced mortality was observed. The LD50 dose of mentat was found to be 1.75 g/kg b. wt. Our study demonstrates that mentat can provide good radioprotection at a dose of 80 mg/kg, which is far below its toxic dose. Copyright 2003 John Wiley & Sons, Ltd.