Antifungal capacity of major phenolic compounds of Olea europaea L. against Phytophthora megasperma Drechsler and Cylindrocarpon destructans (Zinssm.) Scholten

The phenolic composition of olive roots and stems was studied by high performance liquid chromatography–mass spectrometry. The in vivo levels of the principal phenolic compounds found in olive plants infected by Phytophthora megasperma Drechsler and Cylindrocarpon destructans (Zinssm.) Scholten differed from the levels observed in non-infected plants. When the antifungal activity of these compounds against both fungi was studied in vitro, the most active were quercetin and luteolin aglycons, followed by rutin, oleuropein, p-coumaric acid, luteolin-7-glucoside, tyrosol and catechin. Microscopic study showed that these phenolic compounds affected the growth, morphology and ultrastructure of the fungi. Taken together, these findings suggest that the phenolic compounds present in olive plants play an active role in the protection against pathogen attack.