Two novel anti-emetic principles of Alpinia katsumadai.

Two novel diarylheptanoids named katsumadain A (1) and katsumadain B (2) were isolated from the seeds of Alpinia katsumadai, and their structures were determined by spectroscopic analysis. Both katsumadains A (1) and B (2) showed anti-emetic activities on copper sulfate-induced emesis in young chicks.