Antifungal Activity and Mechanism of Action of Different Parts of Myrtus communis Growing in Saudi Arabia against Candida Spp.

Abstract

Discovering new antifungal drugs from natural products is a key target for the treatment of infections, such as candidiasis and other Candida-related infections. As current therapeutic drugs for the treatment of infections, such as candidiasis and other Candida-related infections, have adverse effects on human health, discovering new antifungal drugs from natural products is urgently needed. The objective of this study was to evaluate the antifungal activity of the methanolic and sodium phosphate buffer extracts derived from various parts of Myrtus communis, a plant that is traditionally used in Saudi Arabia, against Candida albicans (ATCC 10213), Candida glabrata (ATCC 2001), Candida kefyr (ATCC 66028), Candida parapsilosis (ATCC 22019), and Candida tropicalis (ATCC 750). A well diffusion assay was performed to assess the antifungal activity through the measurement of the zone of inhibition. Of the extracts, those extracted with methanol from the roots and leaves displayed strong inhibitory activity against Candida glabrata ( $23.5\pm 0.12$ and $20.7\pm 0.22$ , respectively), at 50 mg/ml, with 5 mg/ml fluconazole administered as the standard control. The minimal inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values were 12.5 mg/ml and 25 mg/ml for the M. communis root extract and 25 mg/ml and 50 mg/ml for the M. communis leaf extract against Candida glabrata. The results were confirmed by scanning electron microscopy (SEM) imaging of the control and treated strains of Candida glabrata. Based on SEM, these extracts could alter the morphology and cause loss of cell integrity. The effect of M. communis root and leaf extracts on Candida cells was also determined by measuring the absorbance at 260 nm after treatment for 1 h at 37°C. Interestingly, the 260 nm absorbing material was higher in Candida glabrata than in the resistant strain, Candida parapsilosis (ATCC 22019). Based on our findings, the crude methanolic extract of M. communis roots and leaves exhibited good antifungal activity against the Candida glabrata strain. SEM results and estimation of the 260 nm absorbance material proved that the extract might act on the cell wall and cell membrane of Candida cells, further leading to cell death.