Terpenoid occurrence

Fig. 3.13 Compounds 286-298, terpenoids from Fitzroya cupressoides. The horizontal lines at ca. 40°S and 43°30 S represent the range of occurrence of Fitzroya...

Sesquiterpenoids possessing the drimane skeleton (22) exhibit an impressive series of biological properties. Recently, all aspects relative to occurrence [76], biological activity [76], insect antifeedant properties [77] and synthesis [78] of these terpenoids have been exhaustively reviewed. 

Alkalization, 19 761-762 Alkaloids, 2 71-113 in coffee, 7 253 economic aspects, 2 107-109 lysine-derived, 2 80-82 major orders bearing, 2 75 miscellaneous types, 2 106-107 nitrogen introduction into terpenoid skeleton, 2 100-105 occurrence, detection, and isolation, 2 75-77... 

Schultz G, Simbro E, Belden J, ZhuJ, Coats J, Catmp, Nepeta catariaiharoiaAes Lamiaceae) — a closer look Seasonal occurrence of nepetalactone isomers and comparative repellency of three terpenoids to insects. Environ Entomol AA 5(>2— 1569,2004. 

G.l.c. papers of interest include the classification of 22 acyclic monoterpenoid alcohols according to retention indexes, resolution of cyclic ketones [e.g. ( )-menthone, ( )-isomenthone] as diethyl (+)-tartrate acetals, and the use of lanthanide shift reagents to resolve non-terpenoid racemic epoxides.The occurrence and prevention of monoterpenoid hydrocarbon isomerization during silica gel chromatography has been examined and the separation of monoterpenoids and sesquiterpenoids by gel permeation chromatography is reported. Monoterpenoid hydrocarbons have been selectively extracted from essential oils using dimethylsilicone. ... 

The remarkable occurrence of narcotine in this plant is recorded. A second base (C11H17ON3) appears to be a terpenoid (138). 

Table 5. Retinoids (Re), Sesterterpenoids (St), and Miscellaneous Terpenoids from Natural Sources and the Bioassay Systems in which the Compounds Exhibited Inhibitory Activities Code Compound Source Occurrence Assay System References...

Radioactive carbon dioxide was detected in the breath of rats and men almost immediately after the administration, either orally or by injection, of (RS)-[5-14C]MVA,36 and up to 6.5% of the administered dose was exhaled within 100 minutes. Since the carbon dioxide was not derived from the unnatural S-enantiometer of MVA, or from degradation of cholesterol biosynthesized from the additive MVA, the observations support the hypothesis that there exists a metabolic shunt of intermediates of sterol biosynthesis which, although derived from MVA, do not lead to sterol formation. The significance of this shunt is that its occurrence could explain some of the human hypercholesterolaemias. The authors claim that MVA has no metabolic fate (hitherto known) except the biosynthesis of terpenoids is quite... 

Other Components of the Unsaponifiable Matter The unsaponifiable matter in a cmde regular sunflower oil is usually in the range of 0.5-1.5% (9, 17), or lower than 15 g/kg according to the Codex-Stan 210-1999. In addition to sterols (around 2.4. 6 g/kg) and tocopherols and tocotrienols (0.4-1.5 g/kg), there are minor components of sunflower oil. Aliphatic compounds and terpenoids occur naturally in oils. Of the terpenoid family, squalene is the most widely occurring compound. The occurrence of squalene in regular sunflower oil is fairly low 0.008-0.019% (5) or 15-20 mg/100 g (9). The aliphatic alcohol content is 100-mg/lOO-g oil (9). 

Tobacco leaf has a complicated chemical composition including a variety of polymers and small molecules. The small molecules from tobacco belong to numerous classes of compounds such as hydrocarbons, terpenes, alcohols, phenols, acids, aldehydes, ketones, quinones, esters, nitriles, sulfur compounds, carbohydrates, amino acids, alkaloids, sterols, isoprenoids [48], Amadori compounds, etc. Some of these compounds were studied by pyrolysis techniques. One example of pyrolytic study is that of cuticular wax of tobacco leaf (green and aged), which was studied by Py-GC/MS [49]. By pyrolysis, some portion of cuticular wax may remain undecomposed. The undecomposed waxes consist of eicosyl tetradecanoate, docosyl octadecanoate, etc. The molecules detected in the wax pyrolysates include hydrocarbons (Cz to C34 with a maximum of occurrence of iso-Czi, normal C31 and anti-iso-C32), alcohols (docosanol, eicosanol), acids (hexadecanoic, hexadecenoic, octadecanoic, etc ). The cuticular wax also contains terpenoids such as a- and p-8,13-duvatriene-1,3-diols. By pyrolysis, some of these compounds are not decomposed and others generate closely related products such as seco-cembranoids (5-isopropyl-8,12-dimethyl-3E,8E,12E,14-pentadecatrien-2-one, 3,7,13-trimethyl-10-isopropyl-2,6,11,13-tetradecatrien-1al) and manols. By pyrolysis, c/s-abienol, (12-Z)- -12,14-dien-8a-ol, generates mainly frans-neo-abienol. 

Reports are available on the discovery of insect anti-feeding substances and anti-juvenile hormones, on the homology of biosynthetic routes and its basis in chemotaxonomy, and on the role of terpenoids in chemical ecology. Further speculations have been made about the biosynthesis of various classes of sesquiterpenoid based on the results of a study of the quantitative co-occurrence of these in the genus Hymenaea. 

Glycosides. Finally, it should be mentioned that in our studies on papaya fruit volatiles and their precursors, glycosidic forms of several volatiles were detected. At this time, we have identified the B-D-glucosides of benzyl alcohol and 2-phenylethanol. There are also indications for the occurrence of glycosidic forms of terpenoids, but from the data available exact structures of the sugar moieties cannot be elucidated as yet. 

The transformation of naturally occurring terpenes has already been referred to in Section 2.4.2.2, and the occurrence of aromatized compounds and plausible mechanisms for their formation from terpenoids and steroids have been presented (Neilson and Hynning 1998). 

In their studies on the biosynthesis of terpenoid indole alkaloids, De Silva and co-workers have carried out a screening of some indole alkaloid producing plants of Sri Lanka for the occurrence of the first nitrogenous monoterpenoid precursor (70,71). In this survey, Rauvolfia serpentina, Strychnos nux-vomica, Cinchona ledgeriana, and a number of Mitragyna and Vinca species were tested for the presence of vincoside and 5a-carboxyvincoside. Although these two proposed bio-intermediates (at the time) were not detected, macroisolation techniques revealed the occurrence of 5a-carboxystrictosidine (78), an isomer of 5a-carboxyvincoside, in all plants tested, and strictosidine (79), an isomer of vincoside, only in... 

The occurrence of a,P-unsaturated carbonyl structures in comparison with other terpenoid classes, is rather high. A very high percentage, 63 % of all sesquiterpenes in the DNP and 81 % of all sesquiterpenoid lactones, contain at least one a,P-unsaturated carbonyl structure element, while these numbers are lower in case of the mono-, di- and triterpenes (10/75%, 14/59% and 7/51%, respectively (numbers based on DNP [4]). However, it becomes evident from these figures that lactone groups tend to be associated with a,P-unsaturated carbonyls throughout all classes of terpenoids. 

Terpenoid Indole Alkaloids.—Enormous strides have been made in understanding the biosynthesis of this large group of alkaloids " and yet much detail remains to be uncovered. One particular problem concerns the natural occurrence of enantiomeric forms of akuammicine (106) and the diastereoisomers (— )-lochneridine (107) and (+ )-20-epilochneridine (108). 

The biochemistry of cyanates and thiocyanates has been reviewed In contrast to the isothiocyanates, the occurrence of thiocyanates is rare in terrestrial organisms " although they are gradually being discovered in marine species, e.g. the cadinane sesqui terpenoid (145) from sponges. ... 

The structures and occurrence of terpenoids and steroids in plants have been reviewed by Bonner, (1950, 1%5), Karrer (1958), Haagen-Smit and Nimmo (1963), Devon and Scott (1972), Newman (1972), Nicholas (1973), and Robinson (1980). Several general reviews and symposia have been published, which deal wholly or in part with the biochemistry of steroids and terpenoids in plants (Pridham, 1%7 Nicholas, 1%7, 1973 Goodwin, 1970, 1971 Runeckles and Mabry, 1973 Nes and McKean, 1977). Recent work on terpenoid biosynthesis has been reviewed by Hanson (1977), Mulheim (1977), and Banthorpe and Charlwood (1977). These last three citations are found in two extremely valuable series of reports published annually by the Chemical Society, London, each covering the literature for a year s period. They are designated Specialist Periodical Reports, and the two series are entitled, respectively, Biosynthesis and Terpenoids and Steroids. The... 

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