INDEX sesquiterpenes

The oil contains f-o-pinene, and a sesquiterpene ( ) of specific gravity 0 9340, speciHc rotation - 21 24, and refractive index I 49fi0 at 16°. 

Semmler has detected a small qnaotitv of a sesquiterpene alcohol, and a phenol ether to which he assigned the name elemicin. This body h 3 a specific grariiy 1-063 at 30, refractive index 1 3365, aud boils at 144 to 147 - at lO mm. 

Artemisinin 1, a naturally occurring sesquiterpene peroxy-lactone, has been isolated in up to 0.25% yield from the dry leaves of Artemisia annua L.1 Interest in artemisinin is based on its phytomedicinal properties. In 168 b.c. China, as described in a Treatment of 52 Sicknesses, the leaves of A. annua (Qinghao) were used for the treatment of chills and fever.2 It was not until 1972 that the active antimalarial agent qinghaosu was isolated in pure form. This allowed for the unequivocal elucidation of its structure through the use of x-ray crystallography. This complex tetracyclic peroxide is now referred to as artemisinin in various sources such as Chemical Abstracts or the Merck Index. 

The air-dried leaves gave about 0.5 per cent of a light yellow oil, specific gravity at 15°/15, 0.9181, optical rotation -i-337 , refractive index 1.489, ester value 20, acetyl value 3.5. This oil contained 5 to 10 per cent of ci-pinene, 20 to 25 per cent of h-a-phellandrene, 10 to 15 per cent of cineole, sesquiterpenes 30 to 40 per cent, sesquiterpene alcohols 5 to 10 per with traces of aldehydes, phenols and esters. 

The penetration-enhancing activities of monoterpenes, sesquiterpenes, and diter-penes were evaluated. Terpenes with relatively high lipophilic index exhibited absorption-promoting effects however, extremely high Upophilicity led to lower enhancing activities (Takayama et al., 1991). It was suggested that the difference in percutaneous absorption enhancing efficiency of terpenes arose from the difference in their thermodynamic activities in the vehicle (Obata et al., 1993). 

Key Word Index--/xem denticulata f pimatipariita Kitag. I. sonchifolia Hance Compositae sesquiterpene lactone glucoside guaianolide ixerin X ixerin Z cytotoxicity. 

Contents R. W. FRANCK, The Mitomycin Antibiotics — N. H. FISCHER, E J. OLIVIER, and H. D. FISCHER, The Biogenesis and Chemistry of Sesquiterpene Lactones — Author Index — Subject Index. 

Contents C. R. ENZELL, I. WAHLBERG, and A. J. AASEN, Iso-prenoids and Alkaloids of Tobacco - A. R. PIN DER, The Chemistry of the Eremophilane and Related Sesquiterpenes - D. GROSS, Phyto-alexine und verwandte Pfianzenstoffe - K. H. OVERTON and D. J. PICKEN, Studies in Secondary Metabolism with Plant Tissue Cultures - D. P. CHAKRABORTY, Carbazole Alkaloids - J. JACOB, Burzeldriisenlipide - W. VOELTER, Hypothalamus-Regulationshor-mone - Author Index - Subject Index. 

The leaves of this tree yielded 0 261 per cent, of oil having a specific mvity 0 825. optical rotation h- 10 3, and refractive index 1-4752 at 19. The saponification value was 49-59, equal to 17 35 per cent, ester as bomyl and geranyl acetates. In the cold, with three hours contact, the saponification number was 22 78, equal to 7 97 per cent, estar. On redistilling, practically nothing came over below 155 C. between 155 and 160, 35 per cent, distilled between 160 and 165, 17 per cent. between 165 and 200, 20 per cent. between 200 and 250 12 per cent. The somewhat large percentage of the oil boiling above 250 indicated the presence of a sesquiterpene or allied body, but it was not isolated. 

An oil was also obtained, to the extent of 0 56 per cent., from the timber of this tree. It had a specific gravity 1035 at 18 , optical rotation -t- 1 4 , and refractive index 1-5373 at 23 . Its chief constituent is the methyl ether of eugenol, with a small amount of a sesquiterpene, possibly cadinene. 

A sesquiterpene alcohol, CijHg O, of specific gravity 0 9688 at 20, optical rotation -i- 8, and refractive index 1 5126, was also isolated, but, has not yet been named. 

It does not contain any phenols, hut owes its odour to a ketone, which has been named a-mujone. It also contains a sesquiterpene, not yet identified, having a specific gravity 0 9259, optical rotation + 2-16, and refractive index 1-51615. 

Pinene and limonene are probably present. The high boiling-point of the residual fraction, which has a refractive index of about 1 500, points to the presence of a sesquiterpene. The oil is not soluble in 70 per cent, alcohol (10 volumes), hut dissolves in 2 volumes of 80 per cent, alcohol. 

The oil has been, however, carefully investigated by Semmler. It contains about 15 per cent, of a monocyclic sesquiterpene, Cx5Hj, boiling at IdO at 20 mm., and of specific gravity 0-8733 and refractive index 1-4920. An oxide, termed Carlina oxide, C jO, of specific gravity 1-066 and refractive index 1-5860, forms the principal constituent of the oil. It is a complex furane derivative of the constitution. CH -. C CH. (C HjO). Semmler has also isolated a sesquiterpene which... 

Semmler and Liao have isolated the sesquiterpene alcohol of this oil and find it to boil at 152 to 156 (at 17 mm.) and to have a specific gravity 0 9411 at 20, optical rotation — 5, and refractive index 1 5030. They have termed this body elemol. It yields a sesquiterpene, eletnene, on dehydration. 

The oil contains d-a-pinene, d-limonene, traces of palmitic acid, salicylic add, and a phenol, small quantities of esters of formic and valerianic acids, and a sesquiterpene of specific gravity 0 910, and refractive index 1-5030. 

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