title: Antifeedant activity of ethanolic extract from Flourensia oolepis and isolation of pinocembrin as its active principle compound.
abstract: The ethanolic extract from Flourensia oolepis aerial parts showed strong antifeedant activity against the pest larvae, Epilachna paenulata, with an antifeedant index (AI%) of 99.1% at 100 microg/cm(2). Based on chromatographic fractionation of the extract, guided by bioassays on E. paenulata, the flavanone pinocembrin (1) was isolated as the most active principle. In a choice assay, compound 1 showed strong antifeedant activity against E. paenulata, Xanthogaleruca luteola and Spodoptera frugiperda with an AI% of 90, 94 and 91% (p<0.01) respectively, at 50 microg/cm(2). The dosages necessary for 50% feeding inhibition of the insects (ED(50)) were 7.98, 6.13 and 8.86 microg/cm(2), respectively. The feeding inhibitory activity of 1 against E. paenulata was compared with the activity of other structurally related flavonoids like naringenin, which was inactive up to 100 microg/cm(2), catechin which was nearly 6 times less active than 1, and quercetin which was equally active as 1. The effect of these on the feeding behavior of E. paenulata was also studied.
authors.affiliation: Laboratory of Fine Chemicals and Natural Products, Faculty of Chemical Sciences, Catholic University of Córdoba, Camino a Alta Gracia Km 10, (5000) Córdoba, Argentina.
authors.forename: Georgina N
authors.initials: GN
authors.lastname: Diaz Napal
authors.forename: María C
authors.initials: MC
authors.lastname: Carpinella
authors.forename: Sara M
authors.initials: SM
authors.lastname: Palacios