Antifungal activity against Candida albicans and effect on mitochondrial NADH oxidation of galangin

Galangin is a flavonoid found in the rhizomes of Alpinia officinarum [1]. In Asia, this plant has long been used as traditional medicine for gastrointestinal ailments and infectious diseases. Galangin has been shown to possess several biological and pharmacological properties, including antimicrobial activity [2]. Candida albicans resides in a diversity of organ surfaces of a healthy host, such as oral cavity, digestive tract, skin and vagina. As an opportunistic pathogen, it can cause life-threatening systemic infection in immunocompromised hosts [3], especially in HIV-infected patients. Nowadays, the number of antifungals against candidiasis is quite limited. In the present study, we found that galangin exhibited antifungal activity against Candida albicans. The MIC value was 25µg/ml (92.5µM). Galangin has been reported to strongly interact with rat liver mitochondrial membranes by acting as an uncoupling agent [4]. In mitochondria isolated from Candida albicans, galangin was found to inhibit NADH oxidation and CCCP-stimulated respiration, suggesting that galangin interfered with the electron transport chain in Candida albicans mitochondria. This mitochondrial effect may contribute to the antifungal activity of galangin against Candida albicans.

References: 1. Mutsuda, H. et al. (2006) Bioorg. Med. Chem. 95:138–142.

2. Cushnie, TPT. et al. (2003) Microbiol. Res. 158:281–289.

3. Calderone, RA., Fonzi, WA. (2001) Trends Microbiol. 9:327–335.

4. Dorta, DJ. et al. (2005) Chem. Biol. Interact. 152: 67–78.