Two species of marine algae, Gracilaria edulis and Enteromorpha lingulata, from Chennai coast were evaluated for their antioxidant and antiproliferative activities. Both algae were extracted with three solvents: methanol (M), chloroform (C) and ethyl acetate (E). The M, C, E extracts were investigated for 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging, Beta-carotene Bleaching (BCB), total reducing (TRA) and Growth Inhibitory (GI) activities and Total Phenolic Content (TPC). Thin Layer Chromatography (TLC) was used for qualitatively compare DPPH radical-scavenging activity. Except for BCB, E. lingulata extracts showed comparable (TRA) or higher (DPPH radical-scavenging) antioxidant activity, TPC and GI in HCT15 cells than the extracts of G. edulis. E and C extracts of E. lingulata showed greater antioxidant and GI activities in HCT15 cell (no GI in A549) than M extract. Although M extract of G. edulis showed slightly greater DPPH radical-scavenging activity than C and E extracts, M showed lower TRA, TPC, BCB and GI in HCT15 cells than E and C extracts. None of the extracts showed GI in A549 cells but the GI trend in HCT15 cells mirrored the one seen for all extracts of both algae for TPC (E>C>M; E. lingulata>G. edulis). Except for the E extract of G. edulis which showed slight pro-oxidant activity in the BCB assay, its C and M extracts showed greater BCB inhibition than all the E. lingulata extracts. For all extracts of both algae, DPPH radical-scavenging activity in TLC was associated with the more polar compounds in the extracts.
K. Murugan and V.V. Iyer, 2012. Antioxidant and Antiproliferative Activities of Marine Algae, Gracilaria edulis and Enteromorpha lingulata, from Chennai Coast. International Journal of Cancer Research, 8: 15-26.