test method:hplc. synonyms:anthraquinone, 1,3,8-trihydroxy-6-methyl- (8ci); 1,3,8-trihydroxy-6-methyl-9,10-anthraquinone; 1,3,8-trihydroxy-6-methylanthraquinone; 1,6,8-trihydroxy-3-methylanthraquinone; 3-methyl-1,6,8-trihydroxyanthraquinone; 4,5,7-trihydroxy-2-methylanthraquinone; archin; emodin; emodol; frangula emodin; frangulic acid; nsc 408120; nsc 622947; rheum emodin; schuttgelb . herb source: rheum palmatum l,rhe root . molecular formula: c15h10o5; molecular weight: 270.23 . physics properties:orange needle crystal ,melting point 256-257’c.no soluble in the water ,soluble in the ethanol ,slightly aether,chloroform,benzene . pharmacology function: regarded as a derivative of anthraquinone; so called from a species of rhubarb (rheum emodei). it is used as a laxative.