Antimicrobial potential of methanolic extracts of Hibiscus sabdariffa and Ricinus communis

Abstract

Antimicrobial resistance threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, parasites, viruses and fungi. Patients with infections caused by drug-resistant microorganisms are generally at increased risk of worse clinical outcomes and death, and consume more healthcare resources. This study was carried out to evaluate the antimicrobial potential of leaves and seeds methanolic extracts of the medicinal plants Hibiscus sabdariffa and Ricinus communis against standard microbial strains include Gram-positive bacteria, Gram-negative bacteria and fungal strains. The agar well diffusion technique was carried out to perform the antimicrobial activity of the candidate plants. Leaves from methanolic extracts of H. sabdariffa was found to be more active against Gram-positive bacteria (Bacillus subitilis NCTC: 8236 and Staphylococcus aureus ATCC: 25923), as well as Gram-negative bacteria (Escherichia coli ATCC: 25922, Pseudomonas aeruginosa ATCC: 27853, Klebsiella pneumoniae ATCC: 53657 and Proteus vulgaris ATCC: 6380) than leaves methanolic extracts of R. communis. The leaves from methanolic extracts of H. sabdariffa obtained an intermediate antifungal activity against two reference fungal strains (Candida albicans ATCC: 7596 and Aspergillus niger ATCC: 9765). The seeds from methanolic extracts of R. communis and H. sabdariffa did not show any activity against both bacterial and fungal reference strains examined. In the present study, methanolic leaves extracts of H. sabdariffa revealed that the selected plant had a significant potential effect to inhibit the growth of both bacterial and fungal strains.

Keywords: Ricinus communis, Hibiscus sabdariffa, antimicrobial potential, methanolic extracts, Escherichia coli, seeds extract.