Antimicrobial activity of the ethyl acetate extracts of Chrysophyllum albidum (African Star Apple) cotyledons.

Abstract

The challenge of increasing number of antibiotic-resistant nosocomial bacteria pathogens have led to a renewed focus on plants for possible discovery of lead molecule that could pave the way for new generation antimicrobial agent. This study evaluated the antimicrobial activity of the ethyl acetate extract of the cotyledons of Chrysophyllum albidum, with a view to exploring the antimicrobial properties of its chemical constituents. Powdered C. albidum cotyledons were screened for phytochemical constituents using standard methods and the extract obtained by maceration in ethyl acetate. The crude extract was evaluated for antimicrobial activity against Escherichia coli, Staphylococcus aureus, Klebsiella aerogenes, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans and Aspergillus niger using standard agar-well diffusion method. Gas Chromatography-Mass Spectroscopy (GC-MS) was used to determine the chemical constituents of the extract. Alkaloids, phenolics, tannins, terpenoids and flavoniods were the major constituents present in the powdered cotyledons. A deep brown oily extract with a pleasant-sweet odour and a yield of 2.53% was obtained. The extract showed a high antimicrobial activity with inhibition zone diameter (IZD) range of 20.50 - 25.00 mm. Antimicrobial activity of the extract was bacteriostatic at minimum inhibitory concentration (MIC) value of 25.00 mg/mL and bactericidal at a concentration of 50.00 mg/mL (minimum bactericidal concentration (MBC)). Data obtained from GC-MS analysis showed presence of seventeen (17) components with 6 major spectral peaks; oleic acid (54.65%), n-hexadecanoic acid (13.27%), cis-9-hexadecenal (8.68%), betulin (7.23%), 2-pentanone (6.00%) and octamethyl (5.12%). The abundance of fatty acids in the cotyledons of C. albidum coupled with the observed inhibitory activities would present a potential candidate to be explored for the production of bioactive agents.