Anti-leukemic activity-guided fractionation of Mammea siamensis flowers
Mammea siamensis (Miq.) T. Anderson (local name: sarapi) is a Thai medicinal plant in the family Clusiaceae and used in indigenous medicine as a heart tonic. In a preliminary biological evaluation, the n-hexane, dichloromethane, methanol-water and aqueous fractions from M. siamensis flowers CH2Cl2-CH3OH (1:1) crude extract were tested in an anti-leukemic activity assay against the human T-lymphoblastoid leukemia cell line CCRF-CEM. The strongest anti-leukemic activity was shown by the n-hexane and dichloromethane fractions, which inhibited the growth of the tumor cells by 83.0±3.8% and 75.3±3.0%, respectively, at 10µg/mL. Bioassay-guided fractionation of the n-hexane fraction led to the isolation of seven active subfractions (MS-H-D to MS-H-J) which were assessed for CCRF-CEM cell growth inhibition activity. Four coumarins: mammea A/AA 1, mammea A/AA cyclo D 2, mammea A/AB cyclo D 3, and mammea A/AC cyclo D 4, together with two steroids: stigmasterol and β-sitosterol, were isolated from the active subfractions of the n-hexane extract. Mammea A/AA is reported for the frist time as a constituent of M. siamensis.
Acknowledgements: C.N. is thankful to Rajamangala University of Technology Thanyaburi for a Ph.D. scholarship.