Terpenoid derivatives

Classical cannabinoids (CCs) are tricyclic terpenoid derivatives bearing a benzopyran moiety. This class includes the natural product (-)-delta-nine-tetrahydrocannabinol (Fig. 8, 1) and the other pharmacologically active constituents of the plant Cannabis sativa. 

Even more complex potential prodrugs of indomethacin were examined, namely its limonenyl, perillyl, bomyl, and menthyl esters, i. e., terpenoid derivatives [21]. These highly lipophilic esters showed rapid enzymatic hydrolysis, and the limonenyl prodrug assayed in humans had an interesting delayed and sustained cutaneous anti-inflammatory activity. 

Carotenoids are lipid-soluble terpenoids derived from the isoprenoid pathway and are located in hydrophobic areas of cells. All have a 40-carbon isoprene backbone with a variety of ring structures at one or both ends (Fig. 8.2) [25]. The carbon skeleton is derived from five-carbon isoprenoid groups and contains alternating conjugated double bonds. There are two kinds of carotenoids (Fig. 8.2) carotenes composed of carbon and hydrogen and xanthophylls composed of carbon, hydrogen, and oxygen. 

Until the mid 1960 s the only plant cannabinoid whose structure was fully elucidated was cannabinol (CBN) — a constituent which actually may represent an oxidation artifact. However, on the basis of CBN, the main cannabinoid structure skeleton became known. Thus, cannabidiol (CBD), which had been independently isolated in pure form by Adams and by Todd, was correctly assumed to be, like CBN, a terpenoid derivative attached to olivetol. But its exact structure was not elucidated. The psychoactive components of cannabis were assumed to be related tricyclic derivatives. On the basis of the tentatively elucidated constituents, Todd suggested that the cannabinoids may be formed initially in the plant by condensation of a menthatriene with olivetol. 

The terpenoids are secondary metabolites that are found in essential oils, resins, tissues of higher plants and micro-organisms, whilst recently some have also been located in liverworts [5,6]. The terpenoids are formed from linear arrangements of isoprene units, Fig. (1), which are derived from acetate metabolism through mevalonic acid (MVA). This pathway was found to be common to the whole range of natural terpenoid derivatives... 

Some of these structures retain the methyl from the isoprenyl substituent, whilst in others this has been removed, e.g. alizarin from madder (Rubia tinctomm Rubiaceae), presumably via an oxidation-decarboxylation sequence. Hydroxylation, particularly in the terpenoid-derived ring, is also a frequent feature. 

This review for 1970—1971 follows the conventions adopted in last year s Report. The hydrogen atoms of mevalonic acid (1) are again represented so that a hydrogen atom of a terpenoid derived from the [2R]hydrogen of mevalonic acid will... 

Waxes, resins, fatty acids, terpenoid derivatives... 

Mevalonate kinase is the first enzyme involved in the biosynthesis of terpenoid derivatives in plants and microorganisms. The terpenoid derivatives are the largest group of natural products which lead to the formation of a huge number of compounds extraordinarily diverse in structure and function, playing important roles in plant growth and development. 

The remainder of this section is divided into 20 sub-sections. The first 9 describe the main approaches to the production of the large-volume terpenoids and the remaining 11 describe individual groups of terpenoids, sometimes classified biogenetically and otherwise, when more appropriate, by odour type. There are so many terpenoid-derived fragrance ingredients that it would be impossible to mention them all in this book. This chapter will, therefore, include only a selection of the more important and interesting ones. 

Previous detailed reports on the composition of tobacco included those issued by Briickner in 1936 (451), Latimer in 1955 (2270), Johnstone and Plimmer in 1959 (1971), Shmuk in 1961 (3657), Stedman in 1968 (3797), Roberts et al. in 1975 (3224), Schmeltz and Hoffmann on nitrogen-containing tobacco components in 1977 (3491), Enzell and colleagues on terpenoid-derived tobacco components between 1976 and the late 1980s (1149, 1150, 1156, 4089, 4090). One thing has become apparent since the mid-1950s No other consumer product that involves a complex mixture has been defined in such detail as tobacco and/or its smoke, for example, the number of components identified to date in tobacco is almost twice that of the number identified in coffee. 

In this review we have only dealt with alkaloid biosynthesis in C. roseus the biochemistry of this plant has also been studied in detail for other aspects, such as anthocyanin production, phosphate metabolism, cell growth, and cell division cycle (e.g., ref. 362). Unfortunately, most of the studies concerning the primary metabolism are not linked with those of secondary metabolism. However, one may expect that in the future the studies on secondary metabolism, such as chorismate-derived products (an-thocyanins, benzoic acid derivatives, and alkaloids) and terpenoid-derived products such as the alkaloids, will be integrated. This will eventually allow us a much better insight into the overall biochemistry of the plant. All of the available information makes C. roseus an outstanding model system for the study of the regulation of plant metabolism. 

Example. Conversion of isodihydrocarvone—a terpenoid derivative, into the corresponding dihydrocarvone analogue—a characteristic flavour in cloves, is accomplished by heating either with an acid or a base as illustrated below ... 

The biosynthesis of the T. proceeds according to the isoprene rule . Acyclic hydrocarbons formed in this way can be converted to a multitude of compounds by substitution, oxidation, cyclization, rearrangement, etc. reactions accordingly a large number of T. (>40000 have been described to date) occurs in nature. Included among the T. are not only the hydrocarbons but also the alcohols, ketones, aldehydes, and esters (alternative name terpenoids) derived from them. For nomenclature and technical use of T., see the individual entries and Lit.. ... 

Daniewski, W.M., M. Gumulka, K. Ptaszynska, P. Skibicki, U. Jacobsson, and T. Norin Synthesis of 5-Hydroxy-lactar-6-en-13-oic-acid y-Lactones, the Sesqui-terpenoid Derivatives of Lactarius Origin. Polish J. Chem., 66, 791 (1992). 

A bacterium has been isolated from the gut of Ips confu-sus that can oxidize a-pinene (14) to verbenol (74), whereas a symbiotic fungus of Dendroctonus has been shown to further oxidize verbenol to verbenone (65) (Fig. 19.19). The male of the insect Ips paraconfusus, which feeds on Pinus ponderosa, produces a frass which contains terpenoid-derived compounds ipsdienol, ipsenol (76), and cfr-verbenol (74) (Wood, 1982). This frass attracts both male and female insects to the tree. It is quite possible that microorganisms play a major role in the survival of the beetle on a successfully colonized tree (Harbome, 1982 Wood, 1982). Produc-... 

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