Antifungal Activity of Resveratrol Derivatives against Candida Species

International audience; trans-Resveratrol (1a) is a phytoalexin produced by plants in response to infections by pathogens. Its potential activity against clinically relevant opportunistic fungal pathogens has previously been poorly investigated. Evaluated herein are the candidacidal activities of oligomers (2a, 3−5) of 1a purified from Vitis vinifera grape canes and several analogues (1b−1j) of 1a obtained through semisynthesis using methylation and acetylation. Moreover, trans-ε-viniferin (2a), a dimer of 1a, was also subjected to methylation (2b) and acetylation (2c) under nonselective conditions. Neither the natural oligomers of 1a (2a, 3−5) nor the derivatives of 2a were active against Candida albicans SC5314. However, the dimethoxy resveratrol derivatives 1d and 1e exhibited antifungal activity against C. albicans with minimum inhibitory concentration (MIC) values of 29−37 μg/mL and against 11 other Candida species. Compound 1e inhibited the yeast-to-hyphae morphogenetic transition of C. albicans at 14 μg/mL. trans Resveratrol (1a) is a natural stilbenoid produced by several plants in response to pathogenic infections. Although present in a restricted number of plant families, 1a forms the backbone of a wide range of stilbene biosynthetic products, leading to a spectrum of monomeric and oligomeric compounds with diverse biological activities.1,2 Stilbenes were first described for their fungicidal action against plant fungal diseases by Langcake and Pryce.3 Later, antimicrobial activities of stilbenes were reported against various phytopathogens, with 1a occurring as a major phytoalexin of the family Vitaceae.4,5 Resveratrol fully inhibits conidial germination of the gray mold agent Botrytis cinerea6 and reduces roughly 75% sporangial germination of the causal agent of grapevine downy mildew, Plasmopara viticola.7 Pterostilbene, the 3,5-dimethoxyresveratrol (1e), and trans ε-viniferin (2a) have been found to be 5- fold more active than 1a, indicating the potential of resveratrol derivatives as a source of effective antifungal agents.8,9 In the field of human health, several investigations have been conducted on 1a due to its multiple pharmacological activities including cardioprotective, antiaging, anticarcinogenic, antiinflammatory, estrogenic/antiestrogenic