A method for increasing the expression of SIRT1 mRNA and/or decreasing the expression of SOCS3 mRNA, and especially for regulating blood glucose levels in a subject in need thereof is provided. The method comprises administering to the subject an effective amount of an active component selected from the group consisting of a compound of formula (I), a pharmaceutically acceptable salt of the compound of formula (I), and combinations thereof:wherein X is H or C1-C3 alkyl one of Y and Z isand the other one is H, OH orwherein when Y isZ isR1 to R13 are independently H or OH, and wherein, R1 to R3 are not simultaneously H R8 and R9 are not simultaneously H.
