Y-selinene

The racemic form of a new sesquiterpenoid, voleneol diacetate (394), has been identified as a constituent of the stem bark of Lepidotrichilia volensii Leroy. Several new eudesmane derivatives have been isolated from various species of Verbesina and their structures, (395)—(398), determined by spectroscopic methods.Related investigations have shown that cuauhtemone (399) (Vol. 5, p. 74) and the eudesmane derivative (400) are metabolites of Pluchea foetida while y-selinen-8-one (401) occurs in the roots of Peteravena schultzii ... 

Ginseng herb oil (P. ginseng) has been reported to contain sesquiterpenes, including bicyclogermacrene, a- and P-panasinsenes, caryophyUene, a- and P-humulenes, a- and P-neoclovenes, P-famesene, and a-, P-, and y-selinenes. ... 

Steele C. L., Crock J., Bohlmann J. and Croteau R. (1998) Sesquiterpene synthases from grand fir (Abies grandis) comparison of constitutive and wound-induced activities, and cDNA isolation, characterization and bacterial expression of 8-selinene synthase and y-humulene synthase. J. Biol. Chem. 273, 2078-2089. 

The volatiles showed variation in different environments. The composition of the oil from the fresh aerial parts of A. graveolensvai. secalinum (at the flowering stage) obtained from three locations in Egypt revealed that the main components were a- and /3-pinene, myrcene, limonene, cis-jl- ocimene, y-terpinene, cis-allo-ocimene, frans-farnesene, humulene, apiol, /3-selinene, senkyunolide and neocnidilide (Saleh et al., 1985). The chief component in the essential oils from fruits, and to a lesser extent in the leaves and stems, was limonene, whereas the roots and tubers had more frans-ocimene, 3-methyl-... 

Previous studies (Z) showed evidence for the presence of at least 20 sesquKerpene hydrocarbons in pineapple. These researchers identified 7 sesquiterpenes (1 tentative). We confirmed the presence of 3 of the sesquiterpenes and identified p-copaene, y-muurolene, a- and p-selinene in addition. Mass spectral data indicated the presence of other sesquiterpene hydrocarbons and oxygenated sesquiterpenes which we have been unable to characterize at present. 

Well-known eudesmane derivatives in flavors and fragrances include a- and p-selinene from the oils of Cannabis saliva var. indica (Moraceae), celery (Apium graeveolens, Umbelliferae) and hops (Humulus lupulus, Moraceae), (+)-a- and (+)-P-eudesmol from some oils of eucalyptus (Eucalyplus macarlhuri), (-)-epi-y-eudesmol with its woody odor from the north African oil of geranium (Pelargonium odoralissimum and allied species), and the almost odorless diastereomeric (+)-y-eudesmol from various ethereal oils (+)-p-Costus acid and (+)-p-costol belong to the constituents of the essential oil obtained from the roots of Saussurea... 

Miyazawa, M., Y. Honjo, and H. Kameoka, 1997b. Biotransformation of the sesquiterpenoid P-selinene using the plant pathogenic fungus Glomerella cingulata. l toch iiii , 44 433-436. 

In accord with the high level of sequence similarity between d-selinene synthase and y-humulene synthase, all carbocation deprotonations result by abstraction from a hmited number of common carbon atoms (Scheme 12 and 13). It is Hkely that a single active site base can mediate deprotonations from spatially adjacent carbon atoms of these carbocationic intermediates. In the case of... 

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