Phytochemical analysis, antioxidant, and anticancer activities of three brown algae from the Persian Gulf

Abstract

Marine seaweeds are sources of bioactive compounds such as novel anticancer components. This study investigated the phytochemical composition, antioxidant, and anticancer activities of aqueous and methanolic extracts of three brown algae (Sargassum obtusifolium, Padina gymnospora, and Cystoseira indica) from the Persian Gulf. The contents of total polyphenols, total flavonoids, and total carbohydrates were determined. The antioxidant activity of the extracts was determined by DPPH method. The cytotoxicity of extracts was evaluated using the MTT assay on breast cancer (MCF7) and lung cancer (A549) cell lines. The aqueous extracts had higher levels of polyphenols, flavonoids, and carbohydrates (ranging from 125±11 to 202±19 mg/g) than methanolic extracts (ranging from 43.8±3.4 to 76.6±6.9 mg/g). At 50 µg/mL, the inhibition of DPPH radical ranging from 40.9±0.6 to 62.3±1.4% with an IC50 ranged from 60.9±0.5 to 30.4±0.4 µg/mL. The MTT cell proliferation assay confirmed a significant reduction in MCF7 cell line viability in the methanolic extracts at 390 µg/mL and 190 µg/mL compared to the control group. The methanolic extract of S. obtusifolium showed the highest selectivity index on MCF7 and A549 cells (1.16±0.19 and 1.77±0.16 respectively), despite containing lower levels of phytochemicals than the aqueous extracts. The findings suggest that the methanolic extract of S. obtusifolium exhibits selective cytotoxicity against MCF7 cells. Also, the aqueous extract of C. indica shows an adequate antioxidant index, usable in nutritional science.