Acute and subacute toxicity and genotoxicity of schizonepetin, a naturally occurring monoterpene with antiviral activity.

In the present study, the acute, subacute and genetic toxicity of schizonepetin was assessed. The median lethal dose (LD(50)) of schizonepetin after oral administration was 478 mg/kg body weight in mice. Studies on dose toxicity were repeatedly conducted at 0, 60, 120, and 240 mg/kg bw/day in rats for 35 days after oral administration. Based on the results of this study, a dose level of 120 mg/kg bw/day is considered the no-observed-adverse-effect-level (NOAEL) in rats. Schizonepetin was negative in Salmonella typhimurium tester strains TA97, TA98, TA100, TA102 and TA1535, nonclastogenic in Chinese hamster lung (CHL) cells in the mammalian chromosome aberration test, and micronucleus formation were observed and no clinical signs or adverse effects were detected, and our results illustrated that schizonepetin is not genotoxic.