Feeding deterrents from Momordica charantia leaves to cucurbitaceous feeding beetle species.

Abstract

Cucurbitaceous feeding beetle species, Aulacophora femoralis, A. nigripennis, Epilachna admirabilis and E. boisduvali seldom attack Momordica charantia. The methanol extract of M. charantia leaves strongly deterred four beetle species from feeding. The methanol extract was partitioned between organic solvent and water, and the chloroform fraction, which showed a strong feeding deterrency, was obtained. The chloroform fraction was chromatographed with a silica gel column, and momordicines I and II were isolated. A. nigripennis was strongly deterred from feeding by momordicines I and II at lower concentrations than contained in M. charantia leaves. A. femoralis was deterred from feeding by momordicine II at a high concentration. The feeding of E. admirabilis and E. boisduvali was not affected by momordicines I and II alone. However, E. admirabilis and E. boisduvali were strongly deterred from feeding by mixtures of momordicines I and II, and momordicine II and other components.