Effect of tetrazole derivatives on apoptosis and ergosterol biosynthesis pathway in candida albicans

Abstract

Despite the availability of a large number of antifungal drugs used to treat C. albicans infections, successful treatment continues to be a challenge due to development of drug resistance and side effects. To combat this problem, a number of strategies are being explored as possible solutions. Ergosterol is an important sterol in fungi and a number of antifungal drugs in clinical use target different enzymes in ergosterol biosynthesis pathway. Despite this, ergosterol still remains a rich source of antifungal drug targets because it is synthesized in a multi-step pathway that involves a large number of enzymes. Synthetic compounds with improved pharmacological benefits have received a lot of attention as an alternative treatment. Tetrazole derivatives are aromatic hydrocarbons widely used in medicinal chemistry with a broad spectrum of activity, including antifungal activity. Apoptosis, a form of programmed cell death happens naturally in living organisms, but a number of drugs and compounds have been found to induce the process. Therefore, the aim of this study was to determine the effects of tetrazole derivatives on apoptosis and ergosterol biosynthesis pathway in Candida albicans. The antifungal activity of three tetrazole derivatives (AN1, AN2 and AN3) was established against three C. albicans strains. Inhibitory and subinhibitory concentrations of each tetrazole derivative were selected and used for further studies. Effects of tetrazole derivatives on ergosterol biosynthesis pathway were determined by quantifying ergosterol content. Cell death in C. albicans in response to tetrazole derivatives was evaluated. Apoptotic cell death was studied on the basis of phosphatidylserine externalization, DNA fragmentation and release of cytochrome c oxidase, using FITC annexin V staining, TUNEL assay and cytochrome c oxidase assay, respectively.