Evidence of potent antibacterial effect of fermented papaya leaf against opportunistic skin pathogenic microbes

Abstract

The papaya leaf juice has been long practised as a traditional remedy to cure ailments due to its medicinal properties. The objective of this research is to study the effectiveness of fermented papaya leaf to inhibit the growth of pathogenic bacteria and yeast: Staphylococcus aureus, Pseudomonas aeruginosa, Propionibacterium acnes and Candida albicans. The efficacy of fermented papaya leaf against selected pathogenic microbes was evaluated using agar well diffusion assay, broth microdilution assay and time-kill test. Evidence from data collected confirmed that fermented papaya leaf supernatant showed more pronounced antibacterial and antifungal effect than papaya leaf alone. Generally, fermented papaya leaf supernatant demonstrated potent antimicrobial effect against all bacterial pathogens tested particularly P. aeruginosa followed by P. acne and S. aureus. However, it was found that fermented papaya leaf was less effective against Candida albicans. It needs 4- to 7-folds higher concentration to inhibit 50% C. albicans growth than the bacteria. The antibacterial compounds produced in the supernatant appeared to have some bactericidal effect against P. aeruginosa, P. acne and S. aureus with the minimum inhibitory concentration (MIC>99) of 16%, 50% and 60%, respectively. Particularly, the fermented papaya leaf supernatant at 60% concentration showed 100% inhibition rate within 30 mins against P. aeruginosa. However, it needs a longer time to show the same inhibition effect against S. aureus and P. acne, which was about 2-6 h. The potent killing effect of fermented papaya leaf showed a potential use in skincare application to control pathogenic microbe infection