In vitro ANTICANCER ACTIVITIES OF SELECTED PHILIPPINE SEAWEEDS AGAINST SEVERAL CANCER CELL LINES

This study aimed to investigate and compare the anticancer activities from different crude extracts of three commonly cultivated seaweeds native in the Philippines namely, Eucheuma striatum, Halymenia durvelaei and Kappaphycus alvarezzi against four (4) cancer cell lines including A549, AGS, HT-29 and PC-3. Water extracts from three selected seaweeds were first evaluated against the four cancer cell lines prior to further extraction of seaweed extract with positive effect using organic solvents of increasing polarities. Cytotoxicity screening of the seaweed extracts (100 μg/ml) was evaluated using Sulforhodamine B (SRB) colorimetric assay at 564 nm in a 96-well microtiter plate reader where cells plated at densities of 1000-200,000 cell per well and fixed with TCA were stained with 0.4% (w/v) SRB and dissolved in 1% acetic acid. Anticancer activities of the water extracts of three seaweeds (ES, HM, KA) exhibited minimum to no inhibitions against the cancer cell lines tested. However, the red algae H. durvillei (HM) showed an inhibition against AGS and HT-29 (27.17% and 1.47%, respectively) as compared to K. alvarezzi (KA) and E. striatum (ES). Further extraction of HM with organic solvents of increasing polarities showed that hexane and ethyl acetate (EA) were active in inhibiting the growth of various cancer cells than the other extracts. Similarly, EA extracts of HM is more effective against HT-29 (42.61% growth inhibitions) as compared to the other cancer cell lines tested. Results of SRB colorimetric assay suggest that ethyl acetate (EA) extracts from H. durvillei (HM) inhibits the growth of various cell lines tested efficiently as compared to that of K. alvarezzi (KA) and E. striatum (ES). Although inhibition is just minimal as compared to control, crude extracts from HM still can be considered as potential anticancer agents either because it is a natural product or it contains active compound, which is yet to be identified.