Isolation and biological evaluation of demethylcassiarin B from Senna siamea Lam.

In search of potential natural products for the amelioration of obesity, phytochemical investigation of leaves of Senna siamea Lam. was carried out. It led to the isolation of demethycassiarin B (1), 6,8-dihydroxy-3-methyl-1H isochromenone (2), and 6-hydroxymellein (3). The structures were elucidated by a detailed analysis of spectral data. Compound 1 was found to possess a similar structural skeleton as that of cassiarin B except for a methoxyl substitution. Detailed HPLC and HPTLC analysis of methanolic extract for the presence of compound 1 and cassiarin B were performed. Cassiarin B was not detected in extract. Compounds 2 and 3 have been reported for the first time from the genus Senna. The isolated compounds were evaluated for their antiadipogenic activity in murine 3T3L1 cells.