In vitro Antimicrobial Activity of Fruit Pulp Extracts of Azanza garckeana (F. Hoffm.) Exell & Hillc. and Isolation of One of its Active Principles, Betulinic Acid

Abstract

Aims: To perform anti-microbial activity guided isolation and to characterize compound(s) from fruit pulp (extracts) of Azanza garckeana. Place and Duration of Study: Department of chemistry, University of Agriculture, Makurdi, Nigeria, and University of Strathclyde in Scotland, United kingdom, from October 2015 to September 2016. Methodology: Crude extracts were screened for phytochemical components. In vitro Anti-microbial assay was performed using Agar Diffusion Method and Broth Dilution Method. Vacuum Liquid Chromatography and gel filtration (Sephadex LH20) were used for the isolation of medicinal principles. Characterization of the isolated compound was carried out using proton Nuclear Magnetic Resonance Spectroscopy. Results: Extracts contained steroids, flavonoids, terpenoids, saponins, alkaloids, reducing sugars and tannins. Ethyl acetate extract had the highest diameter of zones of inhibition (27 mm). Ethyl acetate and methanol extracts had the same Minimum inhibitory concentrations of 1.25 mg/ml against MethicillinResistant Staphylococcus aureus, Staphylococcus aureus, Pseudomonas aeruginosa and Candida krusei but for Escherichia coli which had Minimum inhibitory concentration of 0.625 mg/ml for ethyl acetate extract. Ethyl acetate extract had the best minimum bactericidal/fungicidal concentration (2.5 mg/ml) on pathogens. It was determined from Proton Nuclear Magnetic Resonance Spectrum that the isolated compound contained features conclusively characteristic of Betulinic acid. Conclusion: Fruit extracts of Azanza garckeana show promising in vitro anti-microbial activity. This is the first report of isolation and characterization of betulinic acid from fruits of this species.