Constituents of the Cotton Bud. IX. Further Studies on a Polar Boll Weevil Feeding Stimulant Complex124

Abstract

Techniques were used to concentrate and fractionate the polar feeding stimulant for the boll weevil, Anthonomus grandis Boheman, that is found in the buds of cotton, Gossypiun hirsutum L., Delta Pine Smooth Leaf. An active fraction could be extracted from freeze-dehydrated bud powder with water after successive extractions with several less polar solvents and, consequently, after removal of hydrocarbons, carotenoids, terpenoids, and flavonoids. The major active polar principle extractable with water was not absorbed on a weak cation exchange resin and was precipitated with lead ions. Studies by gel permeation suggested a moderate molecular weight <2000) for the active constituent (s) and eliminated proteins, large peptides, and polysaccharides with high molecular weights. Moderate feeding activity was found in methanol extracts of cotton buds in a fraction containing acidic components, but no active phenolic or carboxylic acid was isolated. Strong feeding activity was retained after fractions from methanol extracts were treated to remove or degrade flavonoid glycosides (and other glycosides), although 2 flavonoids with modest activity were isolated.