Antioxidant Activity of Nocardiopsis sp., a Marine Actinobacterium, Isolated from the Gulf of Mannar Biosphere Reserve, India

Six actinobacterial strains (PU1, PU2, PU3, PU4, PU5 and PU6) were isolated from the sediment samples of the coral reef environment of the Pullivasal Island, Gulf of Mannar Biosphere Reserve, India using Kuster’s agar. Ethyl acetate extracts of these six strains were screened for antioxidant activity viz. total antioxidant activity, total reducing power, DPPH (α,α-diphenyl-α-picrylhydrazyl) radical scavenging, Scavenging of hydrogen peroxide (H 2 O 2 ) and nitric oxide radical scavenging activity (NO). Among the six strains, PU3 showed strong antioxidant activity and PU1 had a week antioxidant activity. PU3 recorded the following: total antioxidant activity, 0.662; total reducing power, 0.181; DPPH, 53.6 %; scavenging of hydrogen peroxide (H 2 O 2 ), 74.2 % and nitric oxide radical scavenging activity (NO), (56 %) in 100 μg/ml concentration. Hence, this strain was further studied and identified as Nocardiopsis sp. based on chemotaxanomical, micromorphological and molecular characters.