Anticancer and antioxidant effects of selected Sri Lankan marine algae

For the investigation of bioactive components from Sri Lankan seaweeds, three species of red algae (Chondrophycus ceylanicus, Gelidiella acerosa, Gracilaria corticata), two species of green algae (Chaetomorpha crassa, Caulerpa racemosa) and one species of brown algae (Sargassum cassifolium) were evaluated. For the bioactivity evaluations, total phenol content (TPC), free radical scavenging activity using electron spin resonance (ESR) spectroscopy and anticancer activity against different cancer cell lines including a human promyelocytic leukemia (HL-60), a human lung carcinoma (A549) and a mouse melanoma (B16F10) were assessed in vitro. Among the extracts, C. racemosa showed significantly higher radical scavenging activity against DPPH (34.34 %), alkyl (85.17 %) and hydroxyl radicals (81.16 %), respectively. The MTT assay confirmed that all the extracts were not cytotoxic at 50 and 100 μg/mL concentrations against vero cells in vitro. In addition, a significant cancer cell growth inhibitory effect (IC 50 value 30.17 μg/mL) was observed by C. racemosa methanol extract against HL-60 cells and it was the highest anticancer effect compared to the other extracts. Apoptotic body formation in HL-60 cells and the accumulation of DNA in sub-G 1 phase were determined by C. racemosa extract in a dose-dependent manner. This study is the first report of Sri Lankan seaweeds with the potential of pharmacological effects including antioxidant and anticancer activity in vitro.