Phytosterols sterol glycoside

Keywords Plant sterol phytosterol sterol conjugate steryl ferulate gamma-oryzanol steryl glycoside acylated steryl glycoside steryl ester free sterol. 

Figure 10.1 Examples of structural formulas of phytosterol and sterol conjugates. FS = free sterol alcohol, SE = sterol fatty acid ester, SF = steryl ferulate, SG = steryl glycoside, ASG = acylated steryl glycoside.

Phytosterols The relationship between total dietary phytosterol content and the fatty acid composition of the diet decreases with increasing saturated fatty acids, whereas the total dietary phytosterol content increases with increasing PUFA (86). Phytosterols consist of a mixture of cell membrane constituents that include free sterols, esterified steryls (e.g., esterified to phenolics), steryl glycosides, and acylated steryl glycosides (Table 2). 

Cholesterol (7), the major sterol in most animals, also is found in small amounts in many plants, where it serves as a precursor for other steroid derivatives, such as the progestagens and cardiac glycosides (Heftman, 1984). In plants, algae, and fiingi, a variety of other phytosterols may serve... 

In Chapter 15, the biosynthesis of phytosterols was described. Briefly some of the major sterols found in plants are shown in Fig. 1. Principal differences are in the side chain (C20-CJ7) which has different degrees of substitution and unsaturation. The sterol derivatives, also shown in Fig. 1, are (1) steryl esters (SEs), in which a long-chain fatty acid is esterified at the 3-OH of the sterol, (2) steryl glycosides (SGs) in which the 3-OH of the sterol forms a glycosidic linkage to the 1-position of a monosaccharide, usually glu-... 

Phytosterols (PS) are plant sterols or stands found in plants. Plant sterols belong to the triterpene family and differ from cholesterol by having a methyl or ethyl group in C24. Plant stanols, on the other hand, are the saturated form of the plant sterols (Fig. 113.1). PS are present in free or conjugated form as fatty-acyl esters, hydroxycinnamate steryl esters, steryl glycosides, or acylated steryl glycosides. The main function of plant sterols/stanols is to stabilize plant membranes and serve as precursors in the synthesis of steroidal saponins, alkaloids, and other steroids [1]. 

Phytosterols are another important terpene subclass. Two sterol molecules that are synthesized by plants are p-sitosterol and its glycoside. In animals, these two molecules exhibit anti-inflammatory, antineoplastic, antipyretic, and immune-modulating activity [29]. Ph34osterols were reported to block inflammatory enzymes, for example, by modifying the prostaglandin pathways in a way that protected platelets [30]. 

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