Determination of the antimicrobial and antioxidant activities of the leaf extracts of Griffonia simplicifolia

Abstract

Griffonia simplicifolia has ethnomedicinal use in the treatment of depression, fibromyalgia, bladder and kidney problems, insomnia, malaria, obesity, migraine, as an aphrodisiac and a remedy for cough. The aim of this present study is to investigate the biological activities (antimicrobial and antioxidant) and isolate some of the components in the methanol and petroleum ether leaf extracts of Griffonia simplicifolia. Phytochemical screening, antimicrobial (agar and broth dilution method) and antioxidant [total antioxidant capacity (TAC), DPPH and H2O2 scavenging] assays were carried out on extracts. Thin layer and column chromatography were employed to isolate a single component which was analyzed using FTIR analysis. The petroleum ether and methanol extracts showed antimicrobial activity against test organisms with MICs ranging from 12.5 – 62.5 mg/mL. The IC50 values for methanol and petroleum ether extracts in the DPPH and H2O2 assays were 61.85 ± 0.41 and 94.26 ± 0.82 µg/mL; and 524.61 ± 0.68 and 976.75 ± 4.17 µg/mL, respectively. The TACs (gAAE/100 g) for methanol and petroleum ether extracts were 36.42 ± 0.38 and 18.47 ± 0.56 g, respectively. The phytochemical investigation revealed the presence of secondary metabolites such as alkaloids, triterpenoids, flavonoids, steroids, saponins, glycosides, phenols, tannins and coumarins. The findings of this study suggest that Griffonia simplicifolia leaves could be exploited as potential therapeutic candidate for the treatment of bacterial infections and diseases associated with oxidative-stress.