Efficacy of Helicteres isora L. against free radicals, lipid peroxidation, protein oxidation and DNA damage

Abstract

BackgroundFree radicals are implicated with cellular disorders through their detrimental actions on proteins, lipids and DNA and are causative factors for large number of degenerative diseases and aging process. Antioxidants of plant origin hold great significance and have therefore gained utmost importance in recent past. Present investigation was a step in this direction, with an objective to comprehensively evaluate the protective effects of Helicteres isora fruits against free radicals, protein oxidation and DNA damage. MethodsAqueous (AqE), aqueous-methanol (AqME), methanol (ME) and acetone (AE) extracts of mature pods (fruits) were obtained and concentrated in vacuo. Total phenols, flavonoids, ascorbic acid and carotenoids were estimated from extracts using standard methods. Antioxidant activities of extracts with varying concentrations (200–1000 μg/ml) were determined by total antioxidant activity (TAA), ferric reducing antioxidant power, DPPH, and OH radical scavenging assays besides lipid peroxidation inhibition. Extracts were assessed for protection against AAPH (2,2′-Azobis(2-methylpropionamidine) dihydrochloride) induced-protein oxidation using SDS-PAGE and Fenton's reagent induced-DNA damage using DNA nicking assay. ResultsThe results postulated that the plant is a rich source of total phenols, flavonoids and ascorbic acid. Extracts showed concentration-dependent free radical scavenging activities and lipid peroxidation inhibition. Amongst all four extracts, AqME showed highest antioxidant potential in terms of reducing power (360 ± 5.9 gallic acid equivalent: GAE), TAA (150 ± 5.6 GAE), scavenging of free radicals including DPPH (75.6%) and OH (100%) besides maximal (97.4%) lipid peroxidation inhibition at 1000 μg/ml concentration. All the extracts barring ME effectively protected the DNA from hydroxyl radical-induced damage. Similarly, fruit extracts effectively protected the AAPH-induced-protein oxidation. ConclusionsH. isora fruits exhibited broad-spectrum antioxidant potencies against free radicals and significantly ameliorated various impairments associated with free radical formation including lipid peroxidation, protein oxidation and DNA damage.