Antioxidant potential and free radical scavenging activity of Parkia roxburghii, G. Don, a lesser known leguminous tree from North East India

Abstract

Total phenolics in extracts of different parts of Parkia roxburghii varied from 80.1 (flowers) to 311.6 mg/ g GAE (Pods) with moderate amounts of flavonoids and high antioxidant activity (50.1 92.4%). The pods of Parkia roxburghii were found to be potent DPPH radical scavengers followed by leaves, seeds and then flowers as evident by their low IC50, EC50 values and reasonably high ARP values (34.5 230.4). The pod and seed extracts exhibited good reducing power expressed as ascorbic acid equivalents (ASE/ ml) and significant protection against DNA damage caused by free radicals too. The extracts of Tree bean studied showed appreciable free radical scavenging activities through inhibition of lipid per oxidation (LPO) measured by ammonium thiocyanate assay, inhibition of hydroxyl radical observed in non-site specific and site specific assays, metal chelating capacity and superoxide radical scavenging activity. In most of the assays, the pod extracts showed higher potency in scavenging of free radicals than quercetin which was used as a standard. The specific phenolic composition of Parkia roxburghii extracts performed through HPLC and LC-MS/MS showed presence of gallic acid, caffeic acid, chlorogenic acid, ellagic acid ferulic acid. Low amounts of flavonoids like kaempferol, quercetin, diadzein and genestein were also observed in some parts of the plant. Such scientific evidences in the present investigation on the functional attributes of Parkia roxburghii, a traditional food plant would hold significant importance in genetic diversity studies and also for disease prevention and management through diets.