Terpenoids sesquiterpenoids

Terpenoids Sesquiterpenoids Diterpenoids luterpenoius. Caroteno ds and Polyler penoids Steroids Physical Methods Steroid Reactions find Partial Synthesis. 

GC-MS analysis to study the content and composition of extracts of celery revealed the presence of terpenoids, sesquiterpenoids and phthalides in the essential oils and extracts obtained with organic solvents from two celery cultivars (Wolski et al., 2004). The composition of the essential oil obtained from the fruits of three A. graveolens var. dulce cultivars, i.e. Helios, Orient and Zefir, showed that the main components of the essential oil were isoprenoids, including monoterpenes and sesquiterpenes. Essential oil content ranged from 2.5 to 3.0%. The percentage... 

Terpenoids are classified according to the number of five-carbon multiples they contain. Monoterpenoids contain 10 carbons and are derived from two isopentenyl diphosphates, sesquiterpenoids contain 15 carbons and are derived from three isopentenyl diphosphates, diterpenoids contain 20 carbons and are derived from four isopentenyl diphosphates, and so on, up to triterpenoids (C30) and tetraterpenoids (C40). Monoterpenoids and sesquiterpenoids are found primarily in plants, bacteria, and fungi, but the higher terpenoids occur in both plants and animals. The triterpenoid lanosterol, for example, is the precursor from which steroid hormones are made, and the tetraterpenoid /3-carotene is a dietary source of vitamin A (Figure 27.6). 

The terpenoid precursor isopentenyl diphosphate, formerly called isopentenyl pyrophosphate and abbreviated IPP, is biosynthesized by two different pathways depending on the organism and the structure of the final product. In animals and higher plants, sesquiterpenoids and triterpenoids arise primarily from the mevalonate pathway, whereas monoterpenoids, diterpenoids, and tetraterpenoids are biosynthesized by the 1-deoxyxylulose 5-phosphate (DXP) pathway. In bacteria,... 

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. 

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. ... 

Further investigations on the terpenoid constituents of various species of Eupa-torium have revealed the presence of two new acyclic sesquiterpenoids, (1) and (2). ... 

Sesquiterpenes are formed by the addition of one more isoprene units to a monoterpene molecule, and thus have the molecular formula C15H24 (see also Fig. 4.2). There are linear, branched or cyclic sesquiterpenes. Sesquiterpenes are unsaturated compounds. Cyclic sesquiterpenes may be monocyclic, bicyclic or tricyclic. They are the most diverse group among the volatile terpenoids [2, 3, 7-11, 13,14, 16, 20-24, 37-39, 49]. The DNP treats sesquiterpenoids in 147 different structural types [37]. Various types of sesquiterpenes (69-109) can also be seen in Structure 4.16. 

Angelica root Angelica archangelica L. 15-Pentadecanolide, 13-tridecano-lide as characteristic minor components in addition to terpenoids and sesquiterpenoids (about 90)... 

Terpenoids are structurally based on the isoprenoid (C5) unit and include monoterpenoids, sesquiterpenoids, diterpenoids, triterpenoids, steroids and carotenoids. These compounds can be further modified to generate greater structural complexity. Thus the saponins are surface active amphiphiles deriving from the glycosylation of steroid (C27) or triterpenoid (C30) entities. Plant triterpenoids with very specific biochemical effects include those that mimic the effects of mammalian steroid hormones or of insect developmental hormones. 

A few individual terpenoids, as well as less expensive mixtures of these compounds, find practical applications. Some examples are the tli terpenoid Vitamin A, the sesquiterpenoid santonin (as an anthelmintic), and the pyrcthnns, pyrctholonc esters of the monoterpenoid chrysanthcmic acid (used as an insecticide). A number of sesquiterpenoid lactones of the germacranolide. guaianolide and elemanolide types have shown promise as rumor inhibitors. 

Studies of terpenoid chemistry have also in volved syntheses. Several of the complex sesquiterpenoid structures have been confirmed or. in some cases, correctly established through synthesis. Many elegant new general synthetic methods have been developed asaresult of attempts to synthesize terpenoids. The chemistry of terpenoids present a continually growing area of chemical research, perhaps the equal of any in complexity, subtlety, and variety. 

Tables 2-5 list monoterpenoids (Mo), sesquiterpenoids (Sq), diterpenoids (Di), and retinoids (Re), sesterterpenoids (St), meroterpenoids and miscellaneous terpenoids (Me), respectively, discussed in this review. The bioassay systems in which the compounds exhibited inhibitory effects, together with the major sources of the compounds, are included in the Tables. Most of these terpenoids are isolated from natural sources, and their structures are shown in Figs. (2)-(5). Some terpenoids which exhibit significant and/or a broad range of chemopreventive and anti-inflammatory activities are discussed below.

Several terpenoids have been evaluated for their inhibitory effects on EBV-EA activation induced by TPA. Table 6 shows the inhibitory effects of monoterpenoids [70,71], sesquiterpenoids [20,119-123], diterpenoids [21,123-131], and meroterpenoids [117] against TPA (32 pmol, 20 ng)-induced EBV-EA activation in Raji cells. The inhibitory effects were compared with that of [3-carotene, a vitamin A precursor that has been studied intensively in cancer chemoprevention using animal models [2,4]. All of the terpenoids tested caused higher viability (60-80%) of Raji cells even at mol ratio of compound to TPA = 1000 1 indicating their very low cytotoxicity at that high concentration (refer to Table 6). 

As part of a general investigation of terpenoid synthesis from isoprene units it has been shown that condensation of limonene (46) with senecioyl chloride in the presence of stannic chloride, followed by dehydrochlorination, provides a new simple synthetic route to a mixture of cis- (47) and frans-atlantones (48).23a Using acetyl chloride instead of senecioyl chloride in the synthetic sequence provides a C12 trisnor-sesquiterpenoid (49) which co-occurs with trans-atlantone in the essential oil of Cedrus atlantica.23b... 

Structural elucidation of the terpenoid constituents of marine plants and animals has revealed the presence of several compounds whose novel structures often have chlorine, bromine, or isocyanide substituents (cf. pp. 65 and 89). 9-Isocyano-pupukeanone (273) is a recent example of a marine sesquiterpenoid isolated from a... 

Various studies have also been reported on sesquiterpenoid lactones in Xanthium strumarium and Vemonia species,452,453 diterpenoids of Isodon species,454 and triterpenoids in Lycopodium species.455 Analyses of the carotenoids of Medicago species and of berries from a range of sources reinforce previously held views that the distribution of carotenoids in these sources has no taxonomic significance.456,457 Although most higher plants that have been investigated do not retain the capacity to biosynthesize the normal pattern of terpenoids when in tissue culture, it has been reported that Ruta graveolens did retain this ability.458... 

Which of the following terpenoids might have been formed by a tail-to-tail coupling (a) monoterpenoid (b) sesquiterpenoid (c) diterpenoid (d) triterpenoid... 

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