Phytochemical analysis and evaluation of ethanol and aqueous extracts of Piliostigma thonningii leaf for in vitro antioxidant activities

Abstract

Piliostigma thonningii Linn is a leguminous plant belonging to the family fabacea. It is found growing abundantly as a wild uncultivated tree in many parts of Nigeria. Various studies have been done to identify antioxidants from plant sources and efforts have been taken to integrate it in conventional therapy. In our present study, in vitro antioxidant and phytochemical investigation was carried out using solvent extracts such as ethanol and water. The leaves were collected, washed and air-dried for twenty-one (21) days to constant weight. The leaves were pulverized and extracted using distilled water and ethanol respectively. The phytochemical (qualitative and quantitative) analysis was determined using standard procedures. In vitro antioxidant properties were evaluated by assessing DPPH free radical scavenging abilities, α-tocopherol, ascorbic acid and β-carotene by adopting standard methods. The results of the phytochemical depict the presence of carbohydrates, glycosides, cardiac glycosides, saponins, steroids, triterpenes, tannins, flavonoids, alkaloids and anthraquinones, while the antioxidant studies revealed that DPPH activity was higher in the ethanol and aqueous extracts when compared to the reference antioxidant. However, β-carotene, ascorbic acid and α-tocopherol levels were higher in ethanol than aqueous extract. Conclusively, P. thonningii leaf possesses phytochemical constituents and antioxidant effect as seen in this study.