PHYTOCHEMICALS, ANTIOXIDANT ACTIVITY AND PHENOLIC PROFILING OF DIPLOCYCLOS PALMATUS (L.) C. JEFFERY

Objective: The aim of this study was to analyze phytochemicals, antioxidant potential and phenolic profiling of leaf and fruit extracts of Diplocyclos palmatus.Methods: The leaves and fruits were subjected for sequential extraction with hexane, chloroform, methanol and water. All extracts were subjected to biochemical studies such as phenols, tannins, flavonoids, terpenoids and antioxidant assays such as 1,1-diphenyl-1-picryl hydrazyl (DPPH), 2,2’ Azinobis (3-ethyl-benzothiozoline-6-sulfonic acid (ABTS), ferric reducing antioxidant property (FRAP), metal chelating and phospho- molybdenum reduction assay. Further methanolic extract was used for phenolics characterization by reversed phase-high performance liquid chromatography (RP-HPLC).Results: It was observed that methanol fruit extract showed significantly higher phenolics (9.29±0.01 mg tannic acid equivalent (TAE)/g extract), flavonoids (15.02±0.96 mg catechin equivalent (CE)/g extract) and terpenoids (276.73±0.76 mg ursolic acid equivalent (UAE)/g extract). However, chloroform extracts of leaf and fruit exhibited a high amount of tannins (22.07±0.06, 6.99±0.10 mg CE/g extract) respectively. The extracts were subjected to assess their antioxidant potential using various in vitro systems such as DPPH, ABTS, FRAP, metal chelating and phospho- molybdenum reduction. Among the various extracts, methanol fruit extract had highest DPPH radical scavenging activity (26.73±0.14 mg ascorbic acid equivalent (AAE)/g extract), metal chelating activity (0.80±0.01 mg EDTA equivalent (EE)/g extract) and phospho- molybdenum activity (291.24±2.19 mg AAE/g extract). In ABTS radical scavenging assay, aqueous leaf extract (12.11±0.07 mg trolox equivalent (TE)/g extract) showed the best response. The effective ferric reducing antioxidant property (141.54±10.12 mg Fe (II)/g extract) was exhibited by aqueous fruit extract. Overall, methanol and water were found to be the best solvents for the extraction of antioxidant compounds from fruit and leaf. In the RP-HPLC analysis, the major bioactive phenolic compounds such as catechin (CA) and hydroxybenzoic acid (HBA) were recorded in leaf as compared to fruit. In leaf, CA and chlorogenic acid (CLA) were principal compounds in leaf and fruit respectively. However, gallic acid (GA), HBA, CLA and vanillic acid (VA) were widespread in leaf and fruit. Conclusion: On the basis of the results, it was found that D. palmatus may serve as a novel and rich source of natural antioxidants and it can be further explored for pharmaceutical purposes.