SCREENING OF ANTI-OXIDANT ACTIVITY OF METHANOLIC EXTRACT OF GRACILARIA FERGUSONII J.AG. (RED SEAWEED) IN HARE ISLAND, THOOTHUKUDI, TAMIL NADU, INDIA

In the present study, anti-oxidant activity of methanol extract of Gracilaria fergusonii J.Ag. collected from Hare Island, Thoothukudi in the south east coast of Tamil Nadu, India was screened. Free radical scavenging activity was evaluated using 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical and a reducing power by Cupric Reducing Antioxidant Capacity (CUPRAC) assay. The percentage of scavenging activity of DPPH by methanol extract at 100μg, 200μg, 300μg, 400μg and 500μg were 31.35, 45.23, 61.76, 79.54 and 82.93% respectively. At a concentration of 100μg, 200μg, 300μg, 400μg and 500μg of methanol extract, the absorbance were 0.295, 0.302, 0.328, 0.367 and 0.384 respectively. These results similar to those obtained from the DPPH assay in which 500μg showed the highest total anti-oxidant capacity, followed by 400μg, 300μg and 200μg, and lastly 100μg. The results showed that both DPPH scavenging activity and absorbance were increased when the concentration of methanol extract was also increased. Vitamin C, a strong anti-oxidant was also used as control, and the anti-oxidant potential was compared to all tested samples. Keywords: Seaweeds, Gracilaria fergusonii, anti-oxidant, methanolic extract, Hare Island.