Antimicrobial activity of Plectranthus amboinicus solvent extracts against Human Pathogenic Bacteria and Fungi

Abstract

Plectranthus amboinicus or locally known as bangun-bangun, is an indigenous vegetable which can be freshly eaten. However, the plant is unpopular among local people and being neglected. It has been reported to be traditionally used for medicine to cure common illnesses such as cough, stomachache, headache and skin infection. Based on the potential, a study was conducted to bioprospect the antimicrobial activity of the essential oil. Plectranthus amboinicus essential oil of methanol and chloroform extract was tested against nine bacteria and four fungi i.e., Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Shigella flexneri, Klebsiella pneumoniae, Enterococcus faecal, Staphylococcus aureus, Salmonella typhi, Bacillus cereus, Candida albicans, Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus. The methanol extract of Plectranthus amboinicus showed the maximum antibacterial activity against the bacteria Klebsiella pneumoniae and fungi Candida albicans. The antimicrobial activity of Plectranthus amboinicus was more at 100 mg/ml concentration when compared to 50 mg/ml concentration. Comparatively, the Methanol extract of Plectranthus amboinicus exhibited maximum antimicrobial activity when compared to Chloroform extract. The Plectranthus amboinicus has showed good antimicrobial activity against most of the bacteria and only one fungal yeast Candida albicans. No zone of inhibition was recorded against other fungal isolates like Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus and Negative DMSO control. Keywords: Plectranthus amboinicus, Bacteria, Fungi, Antimicrobial activity and Well diffusion assay.