A process for preparation of novel insecticidal oligosaccharides form the roots of decalepis hamiltonii effective against household and stored grain insect pests
Extracts from the edible roots of Decalepis hamiltonii were found to have insecticidal activity against the stored product insects. The bioactive principles were isolated from the active extracts by column chromatographic fractionation. The molecular structures of the compounds were characterized by NMR and MS. The bioactive molecules were identified as ß-D-xylopyranosyl (1-4) ß-D- galactopyranosyl-(1-4)-ß-D -glucose {Decaleside-I) and ß-D-altropyranosyl (1-4) ß-D-galactopyranosyl-(1-4)-ß-D -glucose [Decaleside-II). The purified compounds showed insecticidal potency against the stored product insects, Rhizopertha dominica, Sitophilus oryzae, Callosobruchus chinensis, Tribolium castaneum, and, the household insect pests, Musca domestica and Blatella germanica by contact bioassay. Grain protection properties of the compounds were evident from treated wheat and green gram treated with125mg/kg (Decaleside-1) and 100mg/kg (Decaleside-II). The compounds were found to protect the grain against infestation during storage. The compounds could also be used for household infestation control and ectoprasitic control on domestic animals and pets. Decaleside-I and Decaleside-ll represent a novel class of bioactive molecules with insecticidal activity from roots of D. hamiltonii and a promising grain protectant of natural origin.
