A pair of unique sesquiterpene-chalcone conjugates isolated from the seeds of Alpinia katsumadai

Sumadains A (1) and B (2), a pair of unique isomeric sesquiterpene-chalcone conjugates with unprecedented skeletons, were isolated from the seeds of Alpinia katsumadai. Their structures and relative configurations were established by NMR spectroscopy and X-ray crystallography.