2, 2-Diphenyl-1-picrylhydrazyl Radical Effect and Phytochemical Constituents of Combretum platypetalum Welw. ex. M. A. Lawson subsp. oatesii (Rolfe) Exell Leaf

Abstract

Aims: To investigate the phytochemical constituents and antioxidant properties of Combretum platypetalum leaf. Study Design: In vitro assessment of antioxidant properties and determination of the phytochemical constituents of C. platypetalum leaf extracts. Site and Duration of Study: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ibadan, Ibadan; Department of Biochemistry, University of Ibadan, and University of Agriculture, Makurdi (August 2013 –February 2015). Methodology: Phytochemical constituents of the hexane, ethyl acetate, acetone and methanol extracts were determined following established methods. The extracts were investigated for their antioxidant properties using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, total phenolic content and total flavonoid content assay models. Results: Phytochemical screening showed the presence of alkaloids, terpenoids, saponins, flavonoids, and anthraquinones in the leaf extract. The methanol fraction contained the highest amount of polyphenols and flavonoids (1289.76 and 517.97 µg Catechin equivalent /g of extract respectively). The phenolics content of the extracts also correlated with the observed significant in vitro antioxidant effects. The highest DPPH free radical inhibition for catechin, n-hexane, ethyl acetate, acetone extracts and methanol extracts were observed at 90.41±0.05% at 2000 μg/mL, 20.60±12.38% at 750 μg/mL, 6.73±6.32% at 2000 μg/mL, 25.28±1.46% at 2000 μg/mL and 25.98±1.93%  at 250 μg /mL respectively. Conclusion: The results of this study substantiate the high phenolics content and free radical scavenging effect of C. platypetalum leaf extract and validate the claims for its traditional uses.