Structures of antifungal diarylheptenones, gingerenones A, B, C and isogingerenone B, isolated from the rhizomes of Zingiber officinale

Four new diarylheptenones, 1,7-bis(4-hydroxy-3-methoxyphenyl)hept-4-en-3-one (gingerenone A), 7-(3,5-dimethoxy-4-hydroxyphenyl)-1-(4-hydroxy-3-methoxyphenyl) hept-4-en-3-one(gingerenone B), 1-(3,5-dimethoxy-4-hydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)hept-4-en-3-one (isogingerenone B) and 1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)hept-4-en-3-one (gingerenone C) have been isolated from the rhizomes of Zingiber officinale, and their structures established by spectral methods and some chemical transformations. The results indicate the similarity in the metabolic fates of the curcuminoid constituents to those of the arylalkanoids (dehydrogingerdione → gingerol → shogaol) of zingiberaceous plants. Gingerenone A exhibited a moderate anticoccidium activity in vitro and a strong antifungal effect to Pyricularia oryzae.