Myrcene metabolic pathways

FIGURE 19.205 Metabolic pathways of myrcene (302) and citronellene (309) by rat and microorganisms. 

Metabolic pathways of citronellol (258), citronellal (261), geraniol (271), nerol (272), citral [neral (275) and geranial (276)], and myrcene (302) are summarized in Figure 19.203 (Seubert and Fass, 1964 Hayashi et al., 1968 Rama Devi and Bhattacharyya, 1977a,b). Geraniol (271) is formed from citronellol (258), nerol (272), linalool (20, and geranyl acetate (270) and metabolized through... 

Metabolic pathways of myrcene (302) and citronellene (309) by microorganisms and insects are summarized in Figure 19.205. (3-Myrcene (302) was metabolized with D. gossypina ATCC 10936 (Abragam et ah, 1985) to the diol (303) and a side product (304). p Myrcene (302) was metabolized with G. applanatum, P. flabellatus, and P. sajor-caju to myrcenol (30 (2 methyl-6-methylene-7-octen-2-ol) and 306 (Busmann and Berger, 1994). 

Knowledge of the biosynthesis of bark beetle pheromones has been largely conjectural, based on simple metabolic pathways from host terpenes. However, the biosynthetic routes of the pheromone components of 7. paracon-fusus are now known (Fig. 12.3). Both sexes produced m-verbenol when exposed to (-)ff-pinene (Renwick et al., 1976), and tran -verbenol from (+)a-pinene. When exposed to the vapour of myrcene, ipsdienol and ipsenol appeared in the hindguts of male beetles, but not in females (Hughes, 1974 Hughes and Renwick, 1977 Byers et al., 1979), whereas no pheromone was detected in the guts of beetles not exposed to myrcene. Deuterium-labelling techniques have now confirmed that myrcene is converted in male I. para-confusus to ipsdienol and ipsenol (Hendry et al., 1980). Thus, all three known pheromone components are obtained by simple oxidation of host plant chemicals. 

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