Abstract

In this study, resinous exudate from Madia sativa was analyzed by GC-MS. The major bioactive compounds 13,14,15-trihydroxylabd-7-ene (14) and 3,14,15-trihydroxylabd-8-ene (15) were isolated and their structures were determined by NMR. The antifungal activity of the resinous exudate and the labdanes compounds was evaluated using the inhibitory effects on the mycelial growth of plant pathogen Phytophthora cinnamomi causing root rot of various crops. The evaluation of the resinous exudate showed no inhibition over 50% at 75 mg/L, while compound 15 had the stronger effect on the myceliar growth of P. cinnamomi, with a 94.6% inhibition at 175 mg/L. The same way, the mixture of both compounds in equal parts did not show a synergistic effect but showed similar percentages of mycelial growth inhibition from 25 mg/L with respect to the compounds separately.