大黄素的结构A. R1 =CH3 R2 =HB. R1 =CH2OH R2=HC. R1 =CO

大黄素的结构

A. R1 =CH3，R2 =H

B. R1 =CH2OH, R2=H

C. R1 =COOH, R2=H

D. R1 =CH3 ’ R2 =OH

E. R1 =CH3, R2 =OCH3