Phytochemical Composition and Free Radicals Scavenging Activities of Methanolic Leaf Extract of Napoleona imperialis

摘要

Aims: Napoleona imperialis is a wild plant commonly found in Southeastern part of Nigeria used mostly for the treatment of wounds. The methanolic leaves extract of Napoleona imperialis was qualitatively and quantitatively analyzed for the presence of bioactive secondary metabolites and its ability to scavenge 2,2-diphenyl-1-picrylhydrazine (DPPH) radical, superoxide anion radical (O₂.‐) and nitric oxide radical (NO.) was studied. Methodology: The leaves of N. imperialis was air dried, pulverized and macerated in 80% methanol. Aliquots of the concentrated crude extract was used for qualitative and quantitative phytochemical screening. DPPH, superoxide (O₂-) anion and nitric oxide radical scavenging capacity of varying concentrations of the extract was evaluated and compared with standard antioxidants; ascorbic acid, quercetin and tocopherol. Results: The result showed the presence of saponins, flavonoids, glycosides, tannins, steroids, alkaloids and resins. Quantitative screening showed a high content of flavonoids and anthocyanins. DPPH radical scavenging potential of the extract was observed to be maximum at concentration of 1000 μg/ml similar to the effect of ascorbate. The extract also had a low superoxide (O₂-) anion radical scavenging ability with IC₅₀ of 20.23 μg/mL compared to quercetin (IC50 = 35.81 μg/mL). The NO. scavenging capacity was concentration dependent with 500 μg/ml of the extracts scavenging most efficiently compared to α-tocopherol. Conclusion: The leaves of N. imperialis has been observed to be rich in phytochemicals and have strong free radical scavenging potentials.