Alpinia属植物の成分研究(第9報) : クマタケラン種子の成分 : 1新フラボノイド, Kumatakeninの構造

抄録

Examination was made on the seeds of Alpinia Kumatake MAKINO (A.formosana K.SCHUMANN) and quercetin, kaempferol, rhamnocitrin, and a new flavonoid derivative (kumatakenin), yellow needles of m.p. 246∼247°, were isolated by thinlayer chromatography and column chromatography. Analyses of kumatakenin agreed with C₁₇H₁₄O₆, involving two methoxyl and two hydroxyl groups. It gives 3, 5, 7, 4'-tetrahydroxyflavone (kaempferol) by demethylation and 3, 5, 4'-trihydroxy-7-methoxyflavone (rhamnocitrin) by partial demethylation. UV and NMR spectra of kumatakenin indicated that it is a kaempferol derivative with hydroxyl groups in 5- and 4'-positions, and methoxyl groups in 3- and 7-positions. Thus, the structure of kumatakenin has been established as 5, 4'-dihydroxy-3, 7-dimethoxyflavone.