Monoterpenoids limonene

Raman circular intensity differentials (c.i.d.), which are observed in methyl asymmetric deformations and methyl torsions, may be valuable in probing chirality in monoterpenoids (—)-limonene and (+)-carvone each show a broad, weak depolarized Raman band at 250 cm-1 with a large c.i.d. The origin of these bands is not yet certain.23... 

Figure 27.10 Mechanism of the formation of the monoterpenoid limonene from geranyl diphosphate.

The third paper in this set Zavarin and Snajberk (1976) described their efforts to detect chemical races within big cone Douglas fir. Analysis of the cortical monoterpenoid fraction of 33 trees revealed that the major component was a-pinene, with P-pinene, 3-carene, and limonene present in lesser amounts. The monoterpene profiles of different populations varied somewhat from each other, but the overall profile of big cone Douglas fir was clearly different from that of Douglas fir. There was no evidence for gene flow between the southernmost population of Douglas fir at Lompoc and the closest population of big cone Douglas fir at Figueroa, sites separated by only 34 km. 

Although most consumers appreciate the fieriness of chile, capsaicinoids are not perceived through odor or taste receptors but through the nociceptive pain receptors described earlier. The compounds in chile fruit that create the flavor and aroma are produced in the fruit wall. Buttery et al. [90] generated vacuum steam distilled oil from green bell pepper macerate, with well over 40 peaks on subsequent GC/MS analysis. Of these peaks, the major flavor compound associated with bell pepper aroma was 2-methoxy-3-isobutylpyrazine (Fig. 8.1). They also reported several monoterpenoids in abundance, limonene, trans- 3-ocimene, and linalool as well as other aliphatic aldehydes and ketones. The flavor composition of dried red bell pepper powder (sweet paprika) extracted with ether identified 44 key peaks by GC/MS [91]. In these dried samples the key compounds were P-ionone and several furanones. The post-harvest processing and the different fruit maturities as well as possible varietal differences are all causes for the different aromatic profiles. 

The discussion of a series displacement index for classifying mass spectra and for correlation with structural stability includes some monoterpenoids e.g. myrcene limonene, santene). ... 

With this equation the actual membrane concentration of a hydrophobic compound can be estimated if its concentration in the water phase is known. For instance, limonene, a hydrophobic precursor in many biotransformations to produce monoterpenoid flavour compounds (logPoctanoi/water=4.5), would accumulate within membranes in concentrations of up to 530 mM if it is present in the water phase at saturation concentration of only 0.1 mM [19]. This concentration would clearly not allow conventional microorganisms to survive. 

Finally the biotransformation of limonene was carried out with the same microorganism in the same fashion as with geraniol and nerol. The details of this research will be discussed in the chapter of cyclic monoterpenoids (1.2.1). 

Allylic alcohols [e.g. citronellol, geraniol (8), and nerol (18)] exhibit strong shielding at the y-carbon and deshielding at the 5-carbon in the 13C n.m.r. upon acylation.127 Cationic exchange resins separate acyclic [e.g. myrcene (12)] from cyclic (e.g. limonene) monoterpenoids.128... 

Cyclohexane monoterpenes are a chemically diverse group of monoterpenoids that occur in the plant kingdom mainly as hydrocarbons, alcohols, ketones, aromatic hydrocarbons, and phenols (Fig. 5). The saturated hydrocarbon trans-p-menthme (El) is a constituent of the oil of turpentine and the resin of pine (Pinaceae) trees. Its unsaturated analogs, namely (i )-(- -)-limonene (E2) [present in oil of orange (Citrus aurantium) and mandarin (Citrus reticulata, Rutaceae) peel oil] a-terpinene (E3) and terpinolene (E4) in some Citrus, Juniperus, Mentha and Pinus species (i )-(-)-a-phellandrene (E5) in Eucalyptus phellandra (Myrtaceae) and (5)-(- -)-3-phellandrene (E6) in water feimel (Phel-landrium aquaticum, Umbelliferae), are components of many plant volatile oils. The rich chemical diversity of cyclohexane monoterpene alcohols is apparent from the natural occurrence of all four pairs of / -menthan-3-ol enantiomers, for... 

Previous studies provided data demonstrating that monoterpenoids such as limonene represented a novel class of anticancer drugs with the potential to cause... 

Analytical work on the natural occurrence of monoterpenoids takes three forms. Chemotaxonomy requires a study of proportions of compounds occurring in similar species in different geographical locations. Thus Zavarin s work on Abies balsamea and A. fraseri shows that A. fraseri evolved from eastern A. halsamea by gene-loss during the xerothermic period, by following the content of the pinenes, carene, limonene, and phellandrene. This continues from earlier work on the statistical relationships of monoterpenoids (see Vol. 1, p. 7, and ref. 34). In this context the monoterpenoid composition of the cortical oleoresin of red spruce (Picea rubens) in different populations has been examined. ... 

Green plants also release substantial quantities of isoprene (2) as well as monoterpenoid hydrocarbons such as a-pinene (3), myrcene (4), and limonene (5). These compounds contribute significantly to atmospheric organic concentrations in remote or forested areas (Altshuller, 1983 Hutte et al., 1984). It has been estimated that the global output of these substances may equal about 28% of the annual output of methane (Rasmussen and Went, 1965). 

Topical Exposure. Dosing of female house fly females with five monoterpenoids yielded toxic effects when applied alone at high doses. d-Limonene was the most active of the five (Table I). Use of the synergist piperonyl butoxide enhanced the activity of d-limonene, pulegone, and linalool considerably, by 17, 21, and >14 fold, respectively. These results indicate that those three terpenoids insecticidal activity is expressed more fully when the oxidative detoxification process is inhibited. It is not surprising that flies can detoxify them rapidly, considering the relatively simple hydrocarbon structures of the monoterpenoids. 

Citrus oils and several individual components of them were tested against larvae of the Caribbean fruit fly, Anaatrepha suapenaa (6). Citral was the most efficaceous monoterpenoid, followed by limonene, then a-pinene and a-terpineol. One-hour immersion in a 40% (a.i.) solution of the most potent compound resulted in 50% mortality during the larval development period ... 

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