Research of antifungal compounds from the Amazonian biomass by a bio-inspired approach

Our research aims at understanding the chemical resistance mechanisms of durable woods against fungi. Our ultimate goal is to isolate and identify antifungal compounds from these woods that could be used for the treatment of human fungal diseases. We therefore screened highly durable Amazonian wood selected from technical databases [1] and demonstrated that bioactive secondary metabolites responsible of the natural durability of the woods [2] can also be used to treat mycoses. This screening has given a very high percentage of positive hits (30%) for 70 extracts tested, therefore validating the bio-inspiration hypothesis.

Fig.1: Structure of piceatanol (1), isolated from S. longifolia

Fig.2: Structure of bergenin (2), isolated from H. balsamifera

Fig.3: Structure of maslinic acid (3) isolated from H. balsamifera

The bioguided isolation of the substances responsible for the antifungal activity has been pursued for 2 species: Spirotropis longifolia (Fabaceae) from which we isolated 5 active compounds (isoprunetin, piceatanol (1), resveratrol, genistein and 1 triterpen), and Humiria balsamifera (Humiriaceae) from which we isolated bergenin (2) and 3 triterpens including maslinic acid (3). Piceatanol (1) and maslinic acid (3) showed good antifungal activities against 7 human pathogenic fungi (3 dermatophytes and 4 Candida spp) with MIC values between 2 and 32µg/mL, while (2) is active against yeasts only.

References: 1. Scheffer, T. C., and J. J. Morrell. (1998). Natural durability of wood: a worldwide checklist of species. Coordinating ed., T. C. Scheffer and J.J. Morrell. Oregon State University, Corvallis, OR.

2. Schultz, T. P. et al. (1995) Holzforschung 49:29–34.