ANTHRAQUINONES FROM CASSIA FISTULA AND THEIR ANTI-TOBACCO MOSAIC VIRUS ACTIVITY

Two new anthraquinones, 9,11-dihydroxy-2-(hydroxymethyl)-5-methyl-4H-naphtho[2,3-h]chromene-4,7,12-trione (1) and 9,11-dihydroxy-2,5-dimethyl-4H-naphtho[2,3-h]chromene-4,7,12-trione (2), together with five known anthraquinones (3-7) were isolated from the stems of Cassia fistula. Their structures were elucidated by spectroscopic methods, including extensive 1D- and 2D NMR techniques. Compounds 1-7 were tested for their anti-tobacco mosaic virus activity. The results showed that compound 7 exhibited high anti-TMV activity with inhibition rate of 35.2%. The inhibition rate is higher than that of positive control. The other compounds also showed potential anti-TMV activities with inhibition rates in the range of 15.2-24.8%, respectively.