Unraveling the importance of molecules of natural origin in antifungal drug development through targeting ergosterol biosynthesis pathway

Over the past decades, the incidence of lifethreatening fungal infections has increased dramatically in particular among patients with hampered immune function. Fungal infections cause around 1.5 million deaths annually, superior to malaria and tuberculosis. With respect to high toxicity, narrow spectrum of activity and drug resistance to current antifungals, there is an urgent need to discover novel leads from molecules of natural origin especially those derived from plants and microorganisms for antifungal drug discovery. Among antifungal drugs introduced into the clinic, those affecting ergosterol biosynthesis are still superior to other classes and the vital role of ergosterol in fungal growth and development. This review highlights current knowledge about available antifungal agents and further issues on antifungal drug discovery from compounds of natural origin which affect ergosterol biosynthesis. Special attention is made to the fungal sterol C24-methyltransferase (SMT), a crucial enzyme in ergosterol biosynthesis pathway as a novel target for rational drug design.