[Toxicological approach to evaluation of bioavailability of powdered medicinal herbs].

Neurotoxicity manifestations related to the extraction of active ingredients from "natural" powdered Atropa belladonna (NPB) and Leonurus cardiaca (NPL) in gastrointestinal tract and respectively of their bioavailability were studied in mice. The symptoms were compared with action of approved officinal extracts. In response to orally administered NPB suspension mice displayed well-defined symptoms of typical cholinolytic appearance. On p.o. administration NPB appeared approximately twice as active as officinal concentrated extract. Sequential administration of NPB and of neostigmine eliminated CNS toxicity confirming the bioavailability and notable cholinolytic activity of NPB. Behavioral, neurological and autonomic profiles developed in response to elevated p.o. doses of NPL were typical of sedative - hypnotic drugs, while maximum prolongation of barbiturate- induced sleep was achieved when "no-effect" doses of NPL and powdered valerian root suspensions were administered concurrently, demonstrating mutual potentiation of specific activity of these natural (non-processed) powders, and respectively excellent bioavailability of their active principles.