ABSTRACT
Structure-activity relationships of eleven xanthones were comparatively predicted for four cancer cell lines after the compounds were subjected to antiproliferative assay against B-lymphocyte cells [Raji], colon carcinoma cells [LS174T], human neuroblastoma cells [IMR-32] and skin carcinoma cells [SK-MEL-28]. The eleven chemical constituents were obtained naturally from the stem bark of Calophyllum inophyllum and Calophyllum soulattri. Inophinnin [1] and inophinone [2] were isolated from Calophyllum inophyllum while soulattrin [3] and phylattrin [4] were found from Calophyllum soulattri. The other xanthones were from both Calophyllum sp. and they are pyranojacareubin [5], rheediaxanthone A [6], macluraxanthone [7], 4-hydroxyxanthone [8], caloxanthone C [9], brasixanthone B [10] and trapezifolixanthone [11]. Compound 3 was found to be the most cytotoxic towards all the cancer cell lines with an IC[50] value of 1.25[micro]g/mL while the simplest xanthone, compound 8 was inactive