Cytotoxic Compounds from the Stem Bark of <i>Calophyllum soulattri</i>

Chemical investigation of the stem bark of Calophyllum soulattri resulted in the isolation of a new phloroglucinol, namely calosubellinone (1) along with two known compounds, garsubellin B (2) and soulattrone A (3). The structures of these compounds were established on the basis of spectroscopic methods. Compounds 1 and 2 displayed growth inhibitory activities against HeLa cancer cells comparable to the positive control cisplatin, with IC₅₀ values of 19.3 and 16.5 μM, respectively. In addition, compound 2 also showed antiproliferative activity against a MDA-MB-231 cancer cell line with an IC₅₀ value of 17.7 μM. Compounds 1 and 2 were found to exhibit good cancer-specific cytotoxicity when tested against noncancerous HEK293 cells. These findings have highlighted the therapeutic potential of compounds 1 and 2 as anticancer agents.