Early state research on antifungal natural products

Abstract

Nosocomial infections caused by fungi have increased greatly in recent years, mainly due to the rising number of immunocompromised patients. However, the available antifungal therapeutic arsenal is limited, and the development of new drugs has been slow. Therefore, the search for alternative drugs with low resistance rates and fewer side effects remains a major challenge. Plants produce a variety of medicinal components that can inhibit pathogen growth. Studies of plant species have been conducted to evaluate the characteristics of natural drug products, including their sustainability, affordability, and antimicrobial activity. A considerable number of studies of medicinal plants and alternative compounds, such as secondary metabolites, phenolic compounds, essential oils and extracts, have been performed. Thus, this review discusses the history of the antifungal arsenal, surveys natural products with potential antifungal activity, discusses strategies to develop derivatives of natural products, and presents perspectives on the development of novel antifungal drug candidates.

Figure 1

Results obtained by our group for propolis and fluconazole against Candida species isolated from HIV-positive patients.

Figure 2

Isolated saponins of butanolic extract from Phytolacca tetramera. The triterpenoid saponins with one, two or three sugars as the glycon moiety were established as phytolaccosides B, E and F, respectively. Adapted from Escalante et al. [142], for illustrative purposes only.

Figure 3

Two steroid saponins from Tribulus terrestris L. that show in vitro antifungal activity. These saponins are tigogenin-3-O-β-d-xylopyranosyl-(1→2)-[β-d-xylopyranosyl(1→3)]-β-d-glucopyranosyl (1→4)-[β-l-rhamnopyranosyl-(1→2)]-β-d-galactopyranoside (saponin 1), tigogenin-3-O-β-d-glucopyranosyl-(1→2)-[β-d-xylopyranosyl-(1→3)]-β-d-glucopyranosyl-(1→4)-β-d-galactopyranoside (saponin 2). Adapted from Zhang et al., [146], for illustrative purposes only.