CHEMICAL CONSTITUENTS FROM THE ROOTS OF Calophyllum calaba L.

Abstract

Phytochemical investigation of the CH2Cl2 extract from the roots of C. calaba let to the isolation of three new xanthone derivatives, namely calaxanthones A-C (1-3), along with twenty nine known xanthones (4-32). The structures of all isolated compounds were fully characterized using spectroscopic data (1D and 2D NMR) as well as comparison with the previous literature data. Moreover, all isolated compounds were assessed for their in vitro cytotoxicity against the KB, HeLa S-3, HT29, MCF-7 and HepG2 human cancer cell lines. The tested compounds mostly showed moderate to inactive against these five cell lines, except compounds 3 showed potent cytotoxicity against KB, HeLa S-3, HT29, MCF-7 and HepG2 cells with IC50 values of 1.72, 0.82, 1.17, 5.04 and 1.65 ?M, respectively. Furthermore, compound 6 showed good cytotoxicity against KB and HeLa S-3 cell with IC50 value of 7.06 and 5.27 ?M, respectively. Moreover, compound 13 showed good cytotoxicity against only KB cell with IC50 value of 4.62 ?M.