OBJECTIVETo compare the antitussive activity of three kinds of Stemonae Radix specified in the Chinese Pharmacopoeia, including roots of Stemona sessilifolia, S. japonica and S. tuberosa.

METHODThe antitussive activity was determined in mouse after cough induction by ammonia aerosol stimulation and the number of cough in 2 min were detected with codeine as positive control.

RESULTAll the decoctions, the total alkaloid fractions and non-alkaloid fractions of S. sessilifolia, S. japonica and three chemical types of S. tuberosa showed significant antitussive effect and exhibited a dose-dependent inhibition of coughing. The ED50 values showed that the antitussive activity strength for both total alkaloid fractions and the decoctions are: S. tuberosa (Type I) > S. sessilifolia > S. japonica. The total alkaloid fractions had more potent atitussive activity than the decoctions and non-alkaloid fractions. The antitussive activity strength for the three chemical types of S. tuberosa is: Type I > Type III > Type II. The samples from different producing areas for the same species of Stemonae Radix had no significant differences in antitussive activity. The result also showed that the honey-processed slice had much stronger antitussive activity than raw slice.

CONCLUSIONThe antitussive efficacies of Stemonae Radix were influenced by chemical diversity both in same species and among different species, different fractions and processed method.