Triterpenoid

Farnesol pyrophosphate is an immediate precursor of squalene, the key intermediate in steroid and triterpenoid biogenesis, which arises from the coupling of two farnesol pyrophosphate molecules or of C,s units derived therefrom. The numerous types of sesquiter-penoid carbon skeletons represent various modes of cyclization of farnesol (sometimes with rearrangement) and it is probable that farnesol pyrophosphate is also the source of these compounds. 

Soybeans and peanuts also contain saponins, which are glucoside derivatives of triterpenoid alcohols (37). Saponins range from 0.09 to 0.32% in 457 soybean varieties (38). 

Sterols, triterpenoids (e.g. lupeol), primary and secondary alcohols... 

Terpenes (and terpenoids) are further classified according to the number of 5-carbon units they contain. Thus, monoterpenes are 10-carbon substances biosynthesized from two isoprene units, sesquiterpenes are 15-carbon molecules from three isoprene units, diterpenes are 20-carbon substances from four isoprene units, and so on. Monoterpenes and sesquiterpenes are found primarily in plants, but the higher terpenoids occur in both plants and animals, and many have important biological roles. The triterpenoid lanosterol, for example, is the precursor from which all steroid hormones are made. 

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,... 

Further combination of GPP with another IPP gives the C15 unit farnesyl diphosphate (FPP), and so on, up to C25. Terpenoids with more than 25 carbons—that is, triterpenoids (C30) and tetraterpenoids (C40)—ate synthesized by dimerization of Cj5 and C2q units, respectively (Figure 27.8). Triterpenoids and... 

Steroids are heavily modified triterpenoids that are biosynthesized in living organisms from farnesyl diphosphate (Cl5) by a reductive dimerization to the acyclic hydrocarbon squalene (C30), which is converted into lanosterol (Figure 27.12). Further rearrangements and degradations then take place to yield various steroids. The conversion of squalene to lanosterol is among the most... 

Triterpenoid, 1071 tRNA, see Transfer RNA Trypsin, peptide cleavage with, 1033 Tryptophan, pKa of, 52... 

The biomimetic approach to total synthesis draws inspiration from the enzyme-catalyzed conversion of squalene oxide (2) to lanosterol (3) (through polyolefinic cyclization and subsequent rearrangement), a biosynthetic precursor of cholesterol, and the related conversion of squalene oxide (2) to the plant triterpenoid dammaradienol (4) (see Scheme la).3 The dramatic productivity of these enzyme-mediated transformations is obvious in one impressive step, squalene oxide (2), a molecule harboring only a single asymmetric carbon atom, is converted into a stereochemically complex polycyclic framework in a manner that is stereospecific. In both cases, four carbocyclic rings are created at the expense of a single oxirane ring. 

Sometimes several of these rearrangements occur in one molecule, either simultaneously or in rapid succession. A spectacular example is found in the triterpene series. Friedelin is a triterpenoid ketone found in cork. Reduction gives 3p-friedelanol (47). When this compound is treated with acid, 13(18)-oleanene (48) is formed. In this case seven 1,2 shifts take place. On removal of H2O from position 3 to leave a positive charge, the following shifts occur hydride from 4 to 3 methyl... 

ATA A, NAZ s, CHOUDHARY M I, ATTA-UR-RAHMAN, SENER B, TURKOZ s (2002) New triterpenoidal alkaloids from Buxus sempervirens. Z Naturforsch [C]. 57 21-8. 

GOODWIN T w and goad l j (1971) Carotenoid and triterpenoids , in Hulme A C, The Biochemistry of Fruits and their Products, London, Academic Press, 305-28. 

Pentacyclic triterpenoids-lantadenes Lantana camara var. aculeate SiOj GF Petroleum + AeOEt + AcOH UV Purification, HPLC 43 ... 

Triterpenoids Picea glehni stem bark SiOj Hx + AcOEt uv Identification 58 ... 

Apart from the use and need as fragrances, the resins are marketed for medicinal use as antiarthritic and antiinflammatory pharmaceutical products. The pharmacological effects are mainly attributed to the presence of the nonvolatile pen-tacyclic triterpenoid boswellic acids. This class of ingredients is not present in the actual valuable B. frereana species hence, B. frereana plays no part in the pharmaceutical area. 

Gunatilaka, A. A. L. Triterpenoid quinonemethide and related compound (celastroloids). In Progress in the Chemistry of Organic Natural Products Hertz, W. Kirby, G. W. Moore, R. E. Steglich, W. Tamm, C., Eds. Springer-Verlag New York, 1996 Vol. 67, 1-123. 

Dirsch, V. M. Kiemer, A. K. Wagner, H. Vollmar, A. M. The triterpenoid quinonemethide pristimerin inhibits induction of inducible nitric oxide synthase in murine macrophages. Eur. J. Pharm. 1997, 336, 211-217. 

Sotanaphun, U. Suttisri, R. Lipipun, V. Bavovada, R. Quinone-methide triterpenoids from Glyptopetalum sclerocarpum. Phytochemistry 1998, 49, 1749-1755. 

Mean-Rejon, G. J. Perez-Espadas, A. R. Moo-Puc, R.E. Cedillo-Rivera, R. Bazzocchi, I. L. Jimenez-Diaz, I. A. Quijano, L. Antigiardial activity of triterpenoids from root bark of Hippocratea excelsa. J. Nat. Prod. 2007, 70, 863-865. 

Murayama, T. Eizuru, Y. Yamada, R. Sadanari, H. Matsubara, K Rukung, G. Tolo,F. M. Mungai, G. M. Kofi-Tsekpo, M. Anticytomegalovirus activity of pristimerin, a triterpenoid quinone methide isolated from Maytenus heterophylla (Eckl. Zeyh.). Antiviral Chem. Chemother. 2007, 18, 133-139. 

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