SAPONINS AS POSSIBLE FACTORS OF RESISTANCE OF LEGUME SEEDS TO ATTACK OF INSECTS

A general method has been elaborated for preparing saponins from seeds of chickpeas, garden peas, broad beans, haricot beans, lentils, and peanuts. Paper chromatographic analyses revealed three to six fractions per preparation. Upon hydrolysis two to five aglycones per preparation were found. Further fractionation on Amberlite IRA 401 S resulted in isolation of a saponin fraction which upon hydrolysis gives a single aglycone but different sugars. Saponin preparations I (CaO-precipitable) inhibited development of the Azuki bean beetle (Callosobruchus chinensis L), a major pest of stored legume seeds, when incorporated in diets, whereas saponin preparations II (which do not precipitate with CaO) hardly affected development. A mixture of saponin preparations I and II from chickpeas or lentils, seeds normally attacked by the Azuki bean beetle, had no adverse effect, whereas a similar mixture from a variety of garden peas resistant to this insect inhibited development. © 1969, American Chemical Society. All rights reserved.