P. A. Hedin

2-Hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one (N-O-ME-DIMBOA), a possible toxic factor in corn to the southwestern corn borer.

The southwestern corn borer (SWCB),Diatraea grandiosella Dyar, is a major pest of corn,Zea mays L., in the southern United States. The damage to corn is caused primarily by larval feeding on leaf, ear, and stem tissues. In this study, 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one (N-O-Me-DIMBOA) was identified by MS and NMR as present in corn whorl surface waxes. This compound has evidently not been isolated previously, but its glucoside has been reported in corn, wheat, andCoix lachryma. It is present in the waxes in a higher concentration than DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one) and 6-MBOA (6-methoxybenzoxazolinone). It was toxic to the SWCB in a stress diet, but it was less toxic to this insect than 6-MBOA when incorporated in the standard rearing diet. Nevertheless, it may have some role in the resistance of corn to the SWCB because the total surface wax content is higher in resistant lines than in susceptible lines.

Quercetin 3-O-galactosyl-(1 → 6)-glucoside, a compound from narrowleaf vetch with antibacterial activity

Abstract A new flavonol glycoside, quercetin 3- O -galactosyl-(1 → 6)-glucoside, has been isolated from above-ground parts of narrowleaf vetch, Vicia angustifolia . Its antibacterial activity against Pseudomonas maltophilia and Enterobacter cloacae is compared with that of several other flavonol glycosides.

3′-formyl-2′,4′,6′-trihydroxydihydrochalcone from Psidium acutangulum

Abstract Twig and leaf extracts of the Peruvian plant Psidium acutangulum were shown to have antifungal properties against the fungi Rhizoctonia solani, Helminthosporium teres and Pythium ultimum . Chemical investigation of these extracts resulted in the isolation of the new compound, 3′-formyl-2′,4′,6′-trihydroxychalcone, which demonstrated activity against the fungi R. solani and H. teres .

Hydrocarbons from males, females, and larvae of pecan weevil:Curculio caryae (Horn)

As part of a program to identify as many as possible of the components of the pecan weevil,Curculio caryae (Horn), the hydrocarbons from males, females, and larvae were isolated by solvent extraction and column chromatography and subjected to gas liquid chromatographymass spectrometry analysis. n-Alkanes from C14−C32 in the larvae and unsaturated and branched chain hydrocarbons from C20−C32 in males and females were found. There are no significant differences between the hydrocarbons of the male and female pecan weevils.

A biologically-active procyanidin from Machaerium floribundum

Abstract A procyanidin was isolated from Machaerium floribundum and characterized by its 13 C NMR spectrum. The procyanidin consists of an average of four units, M n = 1150, and the stereochemistry of the heterocyclic ring system is cis . The procyanidin inhibited the growth of Pseudomonas maltophilia .

Biologically-active flavonoids from Gossypium arboreum

Abstract A new flavonol glycoside, gossypetin 8- O -rhamnoside, was isolated from flower petals of Gossypium arboreum along with quercetin 7- O -glucoside, quercetin 3- O -glucoside and quercetin 3′- O -glucoside. These compounds showed antibacterial activity against Pseudomonas maltophilia and Enterobacter cloacae .