摘要：The present study investigated the phytochemical composition and relative antioxidant activity of selected African indigenous leafy vegetables (ILVs): Corchorus olitorius (Jute mallow), Crotalaria ochroleuca (Slender leaf), Solanum scabrum (Black nightshade) and Cleome gynandra (Spider plant). The crude extracts were prepared by methanol extraction. The study revealed the presence of a wide array of phytochemicals including alkaloids, flavonoids, tannins, saponins, steroids and phenols whereas terpenoids, steroids and anthraquinones were absent in most ILVs. The antioxidant activity was achieved by screening the leaf extracts for their free radical scavenging properties using diphenyl picryl hydrazyl (DPPH) and ascorbic acid as standard antioxidant.The ability of the extracts to scavenge DPPH radicals was determined spectrophotometrically at 517nm. The four ILV extracts had significant radical scavenging effects and almost all reported a significantly higher percentage of DPPH inhibition than ascorbic acid (P < 0.05). The extracts of C. olitorius and C. gynandra were most effective since they had higher percentages of radical scavenging activity and lower IC50 values (concentration which scavenged 50% of the DPPH radicals). The results therefore indicated that these vegetables are phytochemical rich and natural antioxidants with potent antioxidative activities. This is of health or nutraceutical significance and thus authenticates their usefulness for medicinal purposes.
