Producción de metabolitos secundarios inducida por quitosano en extractos vegetales de Piper auritum y actividad fungicida in vitro sobre Fusarium oxysporum f. sp. vanillae

The effect of chitosan addition on the production of secondary metabolites of Piper auritum ethanolic extracts was tested, as well as the in vitro fungicidal activity against Fusarium oxysporum f. sp. vanillae . Piper auritum plants were divided into six parcels and commercial chitosan was added to half of them. The concentrations of flavonoids, phenols, terpenes, alkaloids and salicylic acid were measured in P. auritum ethanolic extracts and the antifungal activity was measured with the median effective concentration (EC50). The concentrations of total flavonoids, phenols and terpenes were higher with chitosan treatment (respectively 12.8 vs 12.4 ?g quercetin equivalent per mg, 12.6 vs. 2.3 ?g tannic acid equivalent per 10 mg, and 16.3 vs. 11.6 mg menthol equivalent per 100 mg). However, the alkaloid concentration was reduced by chitosan addition (from 148.2 to 84.5 ?g piperine equivalent per mg). Chitosan addition increased the concentration of salicylic acid (from 1.3 to 2.2 ?g salicylic acid equivalent per mg). A 4 mg mL-1 ethanolic extract of P. auritum treated with chitosan inhibited 100% of mycelial growth. The EC50 of P. auritum against F. oxysporum f. sp. vanillae was lower with chitosan treatment (1.5 mg mL-1) compared to control (5.1 mg mL-1). Chitosan addition increased secondary metabolite production and in vitro antifungal activity in P. auritum extracts.