Abstract

In this work, a group of ten sesquiterpene drimanes, including polygodial (1), isopolygodial (2), and drimenol (3) obtained from the bark of Drimys winteri F. and seven synthetic derivatives, were tested in vitro against a unique panel of bacteria, fungi, and oomycetes with standardized procedures against bacterial strains K. pneumoniae, S. tiphy, E. avium, and E. coli. The minimum inhibitory concentrations and bactericidal activities were evaluated using standardized protocols. Polygodial (1) was the most active compound, with MBC 8 mu g/mL and MIC 16 mu g/mL in E. avium; MBC 16 mu g/mL and MIC 32 mu g/mL in K. pneumoniae; MBC 64 mu g/mL and MIC 64 mu g/mL in S. typhi; and MBC 8 mu g/mL and MIC 16 mu g/mL and MBC 32 mu g/mL and MIC 64 mu g/mL in E. coli, respectively. The observed high potency could be attributed to the presence of an aldehyde group at the C8-C9 position. The antifungal activity of 1 from different microbial isolates has been evaluated. The results show that polygodial affects the growth of normal isolates and against filamentous fungi and oomycetes with MFC values ranging from 8 to 64 mu g/mL. Sesquiterpene drimanes isolated from this plant have shown interesting antimicrobial properties.