title: Microbial transformation of sesquiterpene lactones by the fungi cunninghamella echinulata and rhizopus oryzae
abstract: Incubations of the fungi Cunninghamella echinulata and Rhizopus oryzae with the sesquiterpene lactones (+)-costunolide (1), (+)-cnicin (2), (+)-salonitenolide (3), (-)-dehydrocostuslactone (4), (-)-lychnopholide (5), and (-)-eremantholide C (6) were perfomed. Incubation of 1 with C. echinulata afforded Delta11(13)-dihydrogenation and Delta1(10)-epoxidation products (7-10). C. echinulata also hydrolyzed the side chain of 2, and transformed 4 into (+)-11alpha,13-dihydrodehydrocostuslactone (12), a new natural product. R. oryzae converted 4 into both Delta11(13)-dihydrogenation and Delta10(14)-epoxidation products (16 and 17). Both fungi transformed 5 into (-)-16-(1-methyl-1-propenyl)eremantholanolide (13), providing experimental evidence for the biosynthesis of the eremantholide hemiketal unit. Compounds 3 and 6 were not metabolized by either fungus under the test conditions.
authors.affiliation: Departamento de Quimica Organica, Instituto de Biotecnologia, Facultad de Ciencias, Universidad de Granada, Campus Fuentenueva s/n, 18071-Granada, Spain, and Departamento de Quimica, Instituto de Ciencias Exatas, Universidade Federal de Mina.
authors.initials: AF
authors.lastname: Barrero
authors.initials: JE
authors.lastname: Oltra
authors.initials: DS
authors.lastname: Raslan
authors.initials: DA
authors.lastname: Saude