Phytochemical Composition and In vitro Antioxidant Potential of Different Solvent Extracts of Piliostigma thonningii Schum RedH (Fabaceae)

Traditionally, Piliostigma thonningii have been used in the management and treatment of diverse pharmacological conditions. This claimed potency could be attributed to its rich source of important phytochemicals. This study aimed at evaluating and comparing extracts from the different solvents of the plant leaves for its qualitative phytochemical composition, polyphenolic composition and in vitro antioxidant properties using different models. The plant leaves were collected, prepared and Soxhlet extracted using distilled water, methanol, ethanol, acetone, dichloromethane and ethyl acetate. While the phytochemical screening was performed using standard procedures, the antioxidant screening were performed using DPPH free radical scavenging and ferric reducing assay methods respectively. The result revealed the percentage extraction of the investigated solvents to be in the order MET (31.30) > ETH (28.60) > DW (19.70) > ACT (11.50) > DCM (9.40) > EA (5.30). MET was found to exhibit the highest (91.10 and 88.80%) and ACT have the least (27.30 and 31.30%) antioxidant activity among the investigated solvents at the highest investigated concentration of 100 µg/mL. AA however showed a 97.80% activity in the ferric reducing power and DPPH assay respectively. Methanol is a better extracting solvent if maximum extraction of phytochemicals with diverse pharmacological activity is desired from the leaves of P. thonningii when compared with the other solvents investigated.