THE CYTOTOXIC ACTIVITIES OF PHILIPPINE MARINE SPONGES STELODORYX PROCERA TOPSENT 1904 AND RHABDASTRELLA SP. AGAINST COLORECTAL CANCER CELL LINE HCT116

Marine sponges have become a promising source of secondary metabolites with diverse structures and have been shown to have a wide range of biological activities. In search of bioactive compounds, a preliminary cytotoxic assessment of marine sponge extracts was conducted. The cytotoxic activities of the hexane, dichloromethane (DCM), ethyl acetate, and aqueous extracts of the marine sponges, Stelodoryx procera Topsent 1904 and Rhabdastrella sp., collected off the coast of Zamboanga City, Philippines were tested using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay. The hexane extract, ZP12NPh, from S. procera and DCM extract, ZP07NPd, from Rhabdastrella sp. exhibited moderate toxicity against colorectal cancer (HCT116) cell line at 30 µg/mL. Further purification of the hexane extract from S. procera has afforded two (2) sub-fractions, ZP12NPh4 and ZP12NPh5, which have shown to be highly cytotoxic against HCT116 at 30 mg/mL. While the DCM extract from Rhabdastrella sp., has afforded fourteen (14) highly cytotoxic sub-fractions (ZP07NPd2, ZP07NPd3, ZP07NPd4, ZP07NPd5, ZP07NPd9, ZP07NPd10, ZP07NPd13, ZP07NPd15, ZP07NPd16, ZP07NPd17, ZP07NPd18, ZP07NPd19, ZP07NPd20 and ZP07NPd21) against HCT116 at 30 µg/mL. These results warrant further detailed investigation to determine and characterize the structure of the compounds responsible for their bioactivity.