Phenolics from Lippia multiflora Moldenke as potential bioactive agents against peanut pathogens

Abstract

International audienceThe phenolic composition of aqueous extract from dried leaves of Lippia multiflora Moldenke was analyzed by liquid chromatography- mass spectrometry (LC-MS) before inverse solid phase fractionation. The crude extract and the different fractions (from FL1 to FL5) obtained after fractionation were then tested in vitro for their effect on two fungi responsible of peanut foliar diseases, Phaeoisariopsispersonata and Pucciniaarachidis. The chemical analysis of the aqueous L. multiflora crude extract indicated the presence of seven phenolic compounds (nuomiosideA, isonuomiside A, samioside, verbascoside, isoverbascoside, alyssonoside and leucoseptoside A) and one monoterpene (geniposide). The antifungal activity, estimated by the efficient rate of the fungal appressorium formation, varied from 33.33% to 58.33% and 5.56% to 38.89% for P. personataand P. arachidis spores, respectively. By spraying the different fractions on artificially contaminated leaves, the best antifungal activity was noticed using FL3 and FL4 fractions, the only one in which the presence of samioside was described. The results of this study suggest that the protecting effect of Lippiaextracts against peanut pathogens may be related to the presence of four phenylethanoid glucosides: verbascoside, nuomoside A, leucoseptoside A and samiosid