Citronella sesquiterpene

Semmler and Spornitz have isolated a sesquiterpene from Java citronella oil, which they have named sesquicitronellene. It has the following characters —... 

Ceylon citronella oil contains an olefinic sesquiterpene having the following characters -—... 

Isolation from Essential Oils. Geraniol is isolated from citronella oils and from palmarosa oil. Fractional distillation of, for example, Java citronella oil (if necessary after saponification of the esters present) yields a fraction containing ca. 60% geraniol, as well as citronellol and sesquiterpenes. 

Collection of volatiles from males feeding on pieces of cabbage revealed a blend of six male-specific sesquiterpenes, including hydrocarbons 24-28 and ketone 29, shown in Figure 19.5 (Bartelt et al., 2001). Compound 24 was the most abundant. One or more of these were thought likely to account for the pheromonal activity reported earlier. Hydrocarbon 28 [(+)-v-cadincnc is known from citronella oil (Herout and Sykora, 1958), but structures 24-27 and 29 were new. The opposite enantiomers of hydrocarbons 24 and 25 were previously isolated from the trees Nordmann fir (Abies nordmanniana) and silver fir (Abies alba) (Bartelt et al., 2001 Khan and Pentegova, 1988 Khan et al., 1989), and the opposite enantiomer of 27, known as ar-himachalene, is found in Himalayan cedar (Pandey and Dev, 1968). Neither compound 26 nor its enantiomer were known from nature, but... 

Reaction of geranyl pyrophosphate with isopentenyl pyrophosphate yields the 15-carbon famesyl pyrophosphate, the precursor of all sesquiterpenes. Far-nesol, the corresponding alcohol, is found in citronella oil and lemon oil. 

Famesol is a natural organic compound, which is a sesquiterpene alcohol present in many essential oil such as citronella, neroli, cyclamen, lemon grass, rose, and musk. Interestingly, it is also produced in humans where it acts on numerous nuclear receptors and has received considerable attention due to its apparent anticancer properties. It is used in perfumery to emphasize the odors of sweet floral perfumes (DeBarber et al., 2004). In vitro studies using recombinant drug metabolizing... 

Ceylon citronella oil contains about 10 to 15 per cent, of terpenes, which include camphene, l-limonene, and dipentene. Geraniol, bomeol, citronellal, methyl-eugenol, methyl-heptenone, isoamyl alcohol, isovaleric aldehyde, valeric acid esters, a-terpineol, thujone ( ), nerol, esters of citronellal, famesol, a mixture of at least two sesquiterpenes (one of low and the other of high specific gi-avity), and a terpene of very low specific gravity have all been detected in this oil. ... 

Java citronella oil owes its odour principally to citronellal with geraniol and some citronellal. Traces of methyl-eugenol, about 1 per cent, (as against 7 or 8 per cent, in Ceylon oil), are present, and about 0 2 per cent, of citral. A sesquiterpene, isolated by Semmler and Spornitz, and termed by them sesquidtronellene, is also present. This body has the following characters —... 

Other constituents include esters (acetates, propionates, etc.) of geraniol, citronellol, and linalool monoterpenes (limonene, pinene, camphene, etc.) sesquiterpenes and alcohols (bourbonene, caryophyllene, elemol, famesol, etc.) phenols (eugenol, methyl eugenol, etc.) and free acids, among others. Java citronella oil contains higher amounts of sesquiterpenes, while the Ceylon type contains much larger amounts of monoterpenes (arctander list... 

Catnip oil is typically composed of 70%-90% nepetalactones (Figure 5.2), which are highly repellent monoterpenoids, and also has caryophyllene (Figure 5.3), which is a sesquiterpene hydrocarbon shown to have little repellency. Two main types of oil of citronella have been reported the Java type consists mostly of citronellal, with some geraniol, and the Ceylon type is principally... 

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