Sesquiterpenes from the leaves of Laurus nobilis L.
Ten sesquiterpenes, together with 12 known compounds were isolated from leaves of Laurus nobilis L. Based on spectroscopic analyses, the 10 compounds were determined to be eudesmane lactones and their corresponding methyl esters. Most of these compounds exhibited moderate-to-significant cytotoxicity towards K562 leukemia cells. One compound had a higher cytotoxicity than doxorubicin, while other compounds had moderate to no activity.
Microbial transformation of sesquiterpene lactones by the fungi cunninghamella echinulata and rhizopus oryzae
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.
Eudesmane derivatives from Epaltes brasiliensis
Abstract The first investigation of an Epaltes species afforded two thiophene acetylenes and several eudesmane derivatives, all closely related to cuauhtemone, its esters being typical for Pluchea species. The structures were elucidated by spectroscopic methods.