A-Humulene

Humidity control Huminite Humoryl Humphrey spirals Humphrey s spiral a-Humulene [d753-98-d]... 

Sampling time 60 min extraction temperature 80°C. Monoterpenes a-pinene, p-myrcene, a-phellandreneand limonene sesquiterpenes a-cubebene, a-copaene, p-elemene, p-caryophyllene, a-humulene, y-muurolene, p-eudesmene and caryophyllene oxide diterpenes cembrene A and isoincensole acetate. 

The first observation is the similarity between the chemical compositions of both the Boswellia carteri and Boswellia sacra. For these three olibanum samples, a-pinene (2), (3-myrcene (8) and limonene (14) are the predominant monoterpenes. p-Caryophyllene (73) is the major sesquiterpene besides a-copaene (65), a-humulene (also called a-caryophyllene) (78) and caryophyllene oxide (95). The characteristic olibanum compounds isoincensole and isoincensole acetate (128) together with cembrene A (120) are the main diterpenes. 

Boswellia serrata olibanum has a chemical composition close to that of both the B. carteri and of B. sacra, but contains compounds that are absent in those from other Boswellia and could be used as markers methylchavicol (38), p-anisaldehyde (47), methyleugenol (70), isocaryophyllene (82), sesquiterpene 91, elemicin (92) and an unidentified diterpene (124) eluting between cembrene C (123) and verticilla-4(20),7,ll-triene (125). It is devoid of (5-caryophyllene (73), a-humulene (78), caryophyllene oxide (95) and bornyl acetate (50). 

As indicated in Figure 3, the cadlnanes (170 - 187) are formed from the humulane (205) system, which also is the progenitor of the caryophyllanes (206 - 208). Of these last three compounds, caryophyllene (206) itself is of particular Importance, since it can account for 20 - 25% of the essential oil of some samples (lA). Other major constituents in the same sample were copaene (173, another cadinane) and a-humulene (205), each near 15%. It is therefore apparent that the pathway involving initial conversion of Z,E-farnesyl pyrophosphate to the humulane system is dominant in Gossypiwn terpenoid biogenesis. 

Amongst the monocyclic sesquiterpenes, the plant growth hormone (+)-abscisic acid 446 and a-humulene 451 are found which both can be synthesized by Wittig reactions. To synthesize (+)-abscisinic acid 446 D. L. Roberts et al. 239) converted a-ionone 444 into the allylic alcohol 445 by /-butyl chromate oxidation. 445 is reacted with ethoxycarbonylmethylene-triphenylphosphorane 238 and subsequently... 

Kaul et al. (2003) analysed essential oil profiles of various parts of cinnamon. The oil yields of different plant parts were 0.40% in tender twigs 0.36% in the pedicels of buds and flowers 0.04% in buds and flowers 0.33% in the pedicels of fruits and 0.32% in fruits. The tender twig oil was richer in a-phellandrene (3.4%), limonene (1.6%) and (E)-cinnamaldehyde (4%). The volatile oils from pedicels were richer in (EJ-cinnamyl acetate (58.1-64.5%), -caryophyllene (9.6-11.1%) and neryl acetate (1.4—2.0%). Higher amounts of (Z)-cinnamyl acetate (6.1%), a-humulene (2.2%),... 

The neutral fraction of the bud oil from Madagascar contained (3-caryophyllene (75.64%), a-humulene (14.12%) and 8-cadinene (2.34%) as the major components (Muchalal and Crouzet, 1985). 

The main essential oil components of the edible fruits of G. huillensis Welw. ex. Oliv. growing wild in the Gutu and Rusape areas of Zimbabwe are a-humulene (23.0%), valencene (18.2%), caryophyllene (12.6%), caryophyllene oxide (6.3%) and 8-selinene (5.0%) (Chagonda Lameck and Chalchat, 2005). 

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