Phytochemical Analysis and Antioxidant Evaluation of Crude Extracts from the Roots, Stem and Leaves of Dictyandraarborescens (Welw.)

Abstract

Antioxidants are compounds which play important roles in the prevention of many diseases by removing free radical intermediates and inhibit other oxidation reactions by being oxidized themselves. Dictyandra arborescens, a tropical plant, is locally used by natives of Mbaise, Imo State, Nigeria for the treatment of various ailments. Phytochemical analysis and in vitro antioxidant activities of parts of the plant were evaluated. Gas chromatography flame-ionization detector (GC-FID) was used to determine the phytochemicals present in the leaves and roots while in vitro antioxidant potentials of extracts of the leaves, stem and roots were determined by their abilities to scavenge 2, 2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), and hydrogen peroxide radicals (H2O2). Ferric reducing antioxidant power (FRAP) and total antioxidant capacity were also determined using standard methods. GC-FID analysis of the leaves and roots identified phytochemicals such as; rutin, ribalinidine, naringin, flavan-3-ol, epihedrine, sapogenin, spartein, flavonones, epicatechin, phytate, oxalate, naringenin, resveratol, quinine, catechin, lunamarin, kaempferol etc. Scavenging of the extracts were concentration-dependent. Activities of the extracts for DPPH, nitric oxide and H2O2 differed significantly (p˂0.05) from the standard antioxidant. Methanolic extract of D. arborescens roots showed the best reducing ability while methanolic extract of D. arborescensroot also showed the highest antioxidant activity (2352.94 ±164.87 mg AA/g extract). Findings showed that extracts of the leaves, and roots of D. arborescens were rich in phytoconstituents which could serve as potential sources of natural antioxidants. Antioxidant and therapeutic activities of this plant could therefore be linked to the synergy between the various phytochemicals.