Phytochemical analysis of the resinous exudate from the Chilean plant Adesmia balsamica using chromatographic and spectroscopic methods led to the identification of five known metabolites: 1-(2',4'-dihydroxy-5'-(3-methylbut-2-en-1-yl)phenyl)-3-phenylpropan-1-one (1), glabranin (2), isocordoin (3), 2',4'-dihydroxychalcone (4), and 7-hydroxyflavanone (5). Their activity was evaluated in vitro against Saprolegnia parasitica and S. australis and complemented by in silico molecular docking against Htp-1 and ATPase. Results identified 2',4'-dihydroxychalcone (4) as the most potent compound, with high efficacy (MIC ≤ 0.02 µM) and achieving 100% inhibition of both mycelial growth and cell membrane lysis, supported by highly favourable binding energies (-7.95 kcal/mol). The prenylated flavanone glabranin (2) also showed significant activity, with MIC values as low as 0.04 µM and causing up to 78% membrane damage. In conclusion, chalcone 4 and flavanone 2 are the primary drivers of the exudate's bioactivity, positioning them as promising candidates for developing new biopesticides to control saprolegniosis.
Trujillo et al. (Thu,) studied this question.