Fig. 2 in Dhurrin: A naturally occurring phytochemical as a weapon against insect herbivores

Fig. 2. Mechanism of action of Dhurrin as pest deterrent. Before tissue disruption, compartmentalization of dhurrin in epidermal cells and dhurrinase in mesophyll is depicted. But tissue disruption leads to cyanogenesis, leading to release of HCN by the action of dhurrinase on dhurrin. Inside insect body cyanide inhibits aerobic respiration through binding to cytochrome oxidase, block carbohydrate metabolism by binding with glycolysis intermediates, activates proteolytic enzymes while some of cyanide expired as HCN and carbon dioxide and also excrete in the form of amino acids. Insects are also known to have cyanide detoxification mechanisms where cyanoalanine synthase and nitrilase enzymes act on cyanide to form asparagine, aspartic acid and ammonia. Here, purple structure represents dhurrin and orange structure represents dhurrinase; red structure represents cyanide and the green structure represents the cytochrome oxidase enzyme. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)