Patricia Matanjun1, Syazana Rusdin1 and Mohd Fadzelly Abu Bakar2
1Faculty of Food Science and Nutrition, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia
2Faculty of Applied Sciences and Technology, Universiti Tun Hussein Onn Malaysia, Campus Pagho, KM 1, Jalan Panchor, 84000 Muar, Johor, Malaysia
Seaweeds are considered very attractive sources for the screening of biologically active compounds due to their huge biodiversity. Seaweeds have long been used in traditional Asian foods and folk medicine. The present study was conducted to determine the antioxidant and anticancer activities of different extracts from Malaysian brown seaweed, Sargassum polycystum against four different cancer cell lines, namely human breast MCF-7, human liver HepG2, human cervical HeLa, and human colorectal HT-29 cancer cell lines. The antioxidant activities were evaluated by Ferric Reducing Antioxidant Power (FRAP), 2,2-diphenyl-picrylhydrazyl (DPPH), and β-carotene bleaching assays. MTT assay was used for the cytotoxicity test. Hexane extract showed higher antioxidant activity in FRAP and higher percentage inhibition of β-carotene bleaching activity. Ethanol extract showed higher antioxidant activity in DPPH and had the highest total phenolic content and flavonoid content with the value of 66.8 ± 2.15 mg GAE/g sample and 42.47 ± 0.24 mg CE/g sample respectively. The proliferation, apoptosis, and cell cycle arrest were determined. The results showed that chloroform extracts were antiproliferative against HepG2 and HT-29 at 50% inhibition concentration (IC50) with values of 151 µg/ml and 408 µg/ml respectively. The alginate water extract was antiproliferative against HeLa with IC50 of 360 µg/ml and acetone extract was antiproliferative against MCF-7 with IC50 of 386 µg/ml. The selected extracts induced cell cycle arrest time-dependently in HepG2 cells at the sub-G1 (apoptosis) phase of the cell cycle. These findings suggested that S. polycystum extract has the potential to be used as an antioxidant and anticancer agent.