Free radical scavenging potential of extracts of Gracilaria verrucosa (L) (Harvey): An economically important seaweed from Chilika lake, India

Objective: Marine macroalgae or seaweeds are rich sources of several compounds with biological effects including antioxidant activities. The aim of the study was to evaluate the possible free radical scavenging potential of Gracilaria verrucosa, an economically important seaweed from Chilika Lake. Methods: The algal extracts were obtain with acetone and chloroform and their antioxidant activity was determined by evaluation of total antioxidant capacity by Phosphate Molybdenum method, scavenging of DPPH free radical, total phenol content by Folin-Ciocalteau Phenol reagent (FCP) method and scavenging of Metal chelating activity. Results: Strong antioxidant capacity of 9.82±1.64 and 12.13±1.63 mg catechol equivalent/gm dry weight (DW) was observed in both acetone and chloroform extracts of Gracilaria verrucosa respectively. The total phenol content was found out to be 2.011±0.035 and 1.31±0.028 % catechol equivalent/ gm DW respectively in acetone extract and chloroform extract. The DPPH scavenging potential of the organic extracts was found to be more active in comparison to the standard commercial Butylated hydroxyl toluene (BHT). The Metal chelating activity of the algal extracts was found to be concentration dependent that increases with the increase in concentration of the sample. Conclusion: From the result, it was concluded that both the extracts are successful in extracting the active antioxidant compounds from the alga species. The biological activities observed in this study conclude that Gracilaria verrucosa is a potential source of natural antioxidant and offers opportunities for further research aiming to isolate and identify the specific phenolic compounds responsible for their antioxidant activity.