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Phytosterols, which encompass plant sterols and stanols, are steroid compounds similar to cholesterol which occur in plants and vary only in carbon side chains and/or presence or absence of a double bond. Stanols are saturated sterols, having no double bonds in the sterol ring structure. More than 200 sterols and related compounds have been identified. Free phytosterols extracted from oils are insoluble in water, relatively insoluble in oil, and soluble in alcohols. Phytosterol-enriched foods and dietary supplements have been marketed for decades. Despite well documented LDL cholesterol lowering effects, no scientifically proven evidence of any beneficial effect on cardiovascular disease (CVD) or overall mortality exists.〔 == Structure == The molecule on the left is β-sitosterol. Nomenclature for steroid skeleton is on the right. *By removing carbon 242, campesterol is obtained. *By removing carbons 241 and 242, cholesterol is obtained. *Removing a hydrogen from carbons 22 and 23 yields stigmasterol (stigmasta-5,22-dien-3β-ol). *By hydrogenating the double bond between carbons 5 and 6, β-sitostanol (Stigmastanol) is obtained. *By hydrogenating the double bond between carbons 5 and 6 and removing carbon 242, campestanol is obtained. *Removing carbon 242 and hydrogens from carbons 22 and 23, and inverting the stereochemistry at C-24 yields brassicasterol (ergosta-5,22-dien-3β-ol). *Further removal of hydrogens from carbons 7 and 8 from brassicasterol yields ergosterol (ergosta-5,7,22-trien-3β-ol). Important: Ergosterol is not a plant sterol. Ergosterol is a component of fungal cell membranes, serving the same function in fungi that cholesterol serves in animal cells. *Esterification of the hydroxyl group at carbon 3 with fatty/organic acids or carbohydrates results in plant sterol esters, i.e. oleates, ferulates and (acyl) glycosides. *Actually, Lupeol is a triterpenoid, not strictly a sterol; it is not a gonane. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Phytosterol」の詳細全文を読む スポンサード リンク
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