Non-Steroidal Triterpenoids

As in the previous Report/ the biosynthesis of steroids and triterpenoids is divided into three sections. This section considers the biosynthesis of cholesterol and related steroids, such as ergosterol. Further metabolism of cholesterol is reviewed in Section 8, whereas non-steroidal triterpenoids are considered in Section 9. The biosynthesis of steroids in lower organisms and arthropod steroid metabolism are discussed in Section 11. 

Biosynthesis of Polyketides Phenolic Compounds derived from Shikimate The Biosynthesis of C5—C20 Terpenoid Compounds Triterpenoids, Steroids, and Carotenoids Non-protein Amino-acids, Cyanogenic Glycosides, and Glucosinolates Biosynthesis of Alkaloids. 

Occurrence in Non-solanaceous Taxa. Steroidal saponins are widespread in the plant kingdom, especially within the monocots (e.g., Agavaceae, Asparagaceae, Dioscoreaceae, Liliaceae). However, they also occur - though much rarer - within the dicots (e.g., Fabaceae, Plantaginaceae, Zygophyllaceae), where triterpenoid saponins are more liequent [occurrence documented in about 60 families (Teuscher and Lindequist 1994)]. 

Non-nucleotide pol inhibitors have been discovered among different classes of namral and synthetic chemical compounds. The main of them are long-chain fatty acids, fatty acid derivatives, bile acid derivatives, steroid derivatives, triterpenoids, cerebrosides, alkaloids, flavonoids, anthocyanins, glycolipids, catechins, coenzyme Qs, isosteviols, dipeptide alcohols, vitamins, etc. [52, 53]. The most well-studied non-nucleotide inhibitors are presented in Table 4.2. 

Description. This class of surfactants essentially covers ethoxylated derivatives of lanolin (wool fat) and castor oil. Lanolin is the generic name of a wax containing a complex mixture of esters and polyesters of high-molecular-weight alcohols (aliphatic, steroid, and triterpenoid) and fatty acids (saturated, unsaturated, hydroxylated, and non-hydroxylated). The ethoxylation is carried out on fractionation products of lanolin (lower aliphatic alcohols and sterols). 

The individual reviews which constitute this volume cover the same areas and appear under the same titles as previously. Unfortunately it was not possible to include reviews on the biosynthesis of triterpenoids, steroids and carotenoids, and on non-protein amino-acids, cyanogenic principles and glucosinolates we hope to make good these omissions in early issues of Natural Product Reports as well as including new material in the burgeoning area which carries the title "Biosynthesis". 

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