New Diarylheptanoids and Kavalactone from Alpinia katsumadai Hayata

Two new diarylheptanoids, katsumains A (1) and B (2), and one new kavalactone, katsumadain (3), together with the three known compounds (4E,6E)‐1,7‐diphenylhepta‐4,6‐dien‐3‐one (4), (5R,6E)‐1,7‐diphenyl‐5‐hydroxyhept‐6‐en‐3‐one (5), and cardamonin (6), were isolated from the seeds of Alpinia katsumadai Hayata. Their structures were elucidated mainly by spectroscopic methods (1D‐ and 2D‐NMR) and by mass spectrometry (HR‐ESI‐MS). Besides, the erroneous nomenclatures for (+)‐linderatin and (+)‐neolinderatin as given in [10] [11] were corrected to be 2′,4′,6′‐trihydroxy‐3′‐[(3R,4R)‐4‐isopropyl‐1‐methylcyclohex‐1‐en‐3‐yl]dihydrochalcone for (+)‐linderatin and 2′,4′,6′‐trihydroxy‐3′,5′‐bis[(3R,4R)‐4‐isopropyl‐1‐methylcyclohex‐1‐en‐3‐yl]dihydrochalcone for (+)‐neolinderatin, respectively.