CASTANOSPERMINE AND OTHER POLYHYDROXY ALKALOIDS AS INHIBITORS OF INSECT GLYCOSIDASES

The inhibition of glycosidase activity by a range of polyhydroxy alkal oids was studied in a number of insect species from the orders Orthopt era, Phasmida, Dictyoptera, Diptera and Coleoptera. Glycosidase activi ty was inhibited by a number of the alkaloids and the pattern of inhib ition of hydrolysis of beta-glucosides and most alpha-glucosides (exce pt trehalose) was different from that in mammals, 2R,5R-dihydroxymethy l-3R,4R-dihydroxypyrrolidine inhibited both alpha-glucosidase, includi ng trehalase, and beta-glucosidase activity strongly in insects while castanospermine was a significant inhibitor only of beta-glucosidase a ctivity, trehalase and in the Tenebrionidae, isomaltase and additional ly, maltase in Zophobas morio. The identification of an isomaltase in the Tenebrionidae illustrates the value of the alkaloids as taxonomic tools.