Preliminary phytochemical screening and antimicrobial activity of seed extracts of Persea americana (avocado pear)

Abstract

Antimicrobial activity of seed extracts of Persia amerciana against Escherichia coli, Klebsiella pneumoniae, Bacillus subtilis, Streptococcus pyogenes, Pseudomonas aeruginosa, Staphylococcus aureus, Corynebacterium ulcerans, Salmonella typhi, Neisseria gonorrhoea and Candida albicans was carried out using the disc diffusion technique. The methanol, ethyl acetate and chloroform extracts demonstrated promising activity against the test organisms. The activity of methanol extract was more pronounced against C. albicans (42mm) while that of petroleum ether extract was the least against E.coli (6mm). However, S. typhi and E. coli were resistant to chloroform and methanol extracts. The activity of the ethyl acetate, chloroform and methanol extracts compared favourably with that of standard antibiotic streptomycin (30μgdics-1). The minimum inhibitory concentration (MIC) showed that methanol and ethyl acetate extracts had the lowest MIC value (10mg/ml) against C. albicans, indicating higher potency. Preliminary phytochemical screening revealed the presence of flavonoids, saponins, tannins, steroids alkaloids and terpenoids. The spectra of antimicrobial activities displayed by the extracts could be attributed to the presence of these phytochemicals and signifies the potential of Persia amerciana as a source of therapeutic agents. This therefore, supports the traditional medicinal use of Persia amerciana and suggests that further studies should be conducted to isolate and identify the active components of the extract.

Keywords: Phytochemical, antimicrobial screening, Persea americana, seeds, MIC