Behavioral and toxicological studies of cyclopentanoid monoterpenes from Nepeta cataria.

Two samples of catnip oil were analyzed by tic, gc, and hplc; the results indicated the presence of 23 components. Fractionation of the commercial sample of catnip oil by either distillation or gc yielded 40% nepetalactone and 43% nepetalic acid. Catnip oil, nepetalic acid, and a nepetalactone-enriched fraction were evaluated for toxicological and behavioral effects in mice and rats. The LD50 of catnip oil, the nepetalactone-enriched fraction, and nepetalic acid were found in mice to be: 1300 mg/kg, 1550 mg/kg and 1050 mg/kg, respectively. Catnip oil (500 mg/kg) and nepetalic acid (62.5 mg/kg) were found to significantly increase hexobarbital sleeping time in mice. Rats trained on a Sidman avoidance schedule showed a significant decrease in performance following intraperitoneal injections of catnip oil (500--750 mg/kg), nepetalic acid (125--250 mg/kg), and the nepetalactone-enriched fraction (500--750 mg/kg). Rats trained on the same avoidance schedule developed behavioral tolerance after daily injections of 750 mg/kg catnip oil.