abstract |
(In the formula, R1, R2, R3, R4, R6, and R7 independently represent a hydrogen atom, a hydroxy group, or a methyl group; either one or both of R6 and R7 is/are a hydroxy group; R5 represents a hydrogen atom, a hydroxy group, a galloyl group, or a saccharide; and X represents >CH2, >C═O, or >CHOH.) |