Sitostanol 3-Sitosterol

The sitosterol-sitostanol mixture is cleaned via adsorption on active carbon before entering the hydrogenation reactor. 

The proportions of delta 8-cholesterol and desmosterol in the serum rose while those of cholestanol, campesterol and sitosterol dropped, implying a decreased absorption of cholesterol and a compensatory increase in its synthesis. High basal precursor sterol proportions were predictive of a large decrement in titer of LDL cholesterol. It appeared that partial substitution of normal dietary lipid consumption with sitostanol was a safe and effective therapeutic measure for children with FH (Lees et al., 1977 Wang and Ng, 1999). The effect of a small amount of sitosterol, sitostanol and sitostanol esters dissolved in rapeseed oil on serum lipids and cholesterol metabolism in patients with primary hypercholesterolemia and various apolipoprotein E phenotypes on a rapeseed oil diet showed a diminution in TC and LDL-cholesterol levels in the serum (Gylling and Miettinen, 1994). 

Oil campesterol stigmasterol p-sitosterol sitostanol A5-avenasterol A7-stigmasterol A7-avenasterol ref... 

The main sterols of olive oU are (40, 43, 45-66) campesterol, stigmasterol, clerosterol, p-sitosterol, sitostanol, and 8-5-avenasterol. 

Oil Campesterol Stigmasterol (j-Sitosterol Sitostanol A5-Avenasterol A7-Stigmasterol A7-Avenasterol Reference... 

The practical development of plant sterol drugs as cholesterol-lowering agents will depend both on structural features of the sterols themselves and on the form of the administered agent. For example, the unsaturated sterol sitosterol is poorly absorbed in the human intestine, whereas sitostanol, the saturated analog, is almost totally unabsorbable. In addition, there is evidence that plant sterols administered in a soluble, micellar form (see page 261 for a description of micelles) are more effective in blocking cholesterol absorption than plant sterols administered in a solid, crystalline form. 

Figure 8.10 Reaction scheme in the hydrogenation of sitosterol to sitostanol.

Figure 8.11 Example of data fitting results - concentrations of sitosterol, campesterol, and the products in the hydrogenation of sitosterol to sitostanol (increasing curve) on Pd/Sibunit. The lower curves represent campesterol and campestanol.

Martin Curvelo, G. (2008) Hydrogenation of sitosterol to sitostanol on Pd catalysts. M.Sc. Thesis, Abo Akademi, Turku/Abo Finland. 

Plant sterols such as sitosterol and camposterol, as by-products from vegetable oils at prices of about 15 kg-1, are also important starting materials for the production of steroid hormones. A new application is the cholesterol lowering property of these sterols esterified with fatty acids (with a production of about 10000 t a 1). They can be found in the margarine Becel pro-active of Unilever. A Finnish equivalent is Benecol, which contains stands such as sitostanol and campostanol, sterols having the 5,6-double bound hydrogenated, also esterified with fatty adds [33]. 

Becker, M., Staab, D., and von Bergmann, K. 1993. Treatment of severe familial hypercholesterolemia in childhood with sitosterol and sitostanol. J. Pediatr. 122, 292-296. 

Heinemann, T., Pietruck, B., Kullak-Ublick, G., and von Bergmann, K. 1988. Comparison of sitosterol and sitostanol on inhibition of intestinal cholesterol absorption. Agents Actions... 

Ikeda, I., Tanabe, Y., and Sugano, M. 1989a. Effects of sitosterol and sitostanol on micellar solubility of cholesterol. J. Nutr. Sci. Vitaminol. 35, 361-369. 

For cholesterol absorption, one can take advantage of the fact that plant sterols (phytosterols) are poorly absorbed by mice and humans despite close structural similarity to cholesterol. Beta sitosterol, for example, differs from cholesterol only by the addition of an ethyl group to carbon 24 of the sterol side chain (see Fig. 10.1). This reduces absorption to 6% (34, 35) as compared to 60-80% for cholesterol. Sitostanol, which has a saturated C5-C6 bond in addition to the ethyl group, is only absorbed at 3% (34, 35) and is widely used as a non-absorbed sterol marker (Fig. 10.1). 

Radiolabeled Sterols (see Note 1) 1. 3H-sitostanol or sH-(3-sitosterol 2. 14C-cholesterol... 

Ethanol solutions of 5a-cholestane, lathosterol, coprostanol, desmosterol, sitosterol, stigmasterol, sitostanol... 

P-Sitosterol and sitostanol Many plants Hypocholesterolemic Gylling and Miettinen (1996)... 

The esterification of either of the sterols enhances its solubility in a hydrophilic environment. This modification makes the phytosterol a more active ingredient when used to fortify edible products that lower serum cholesterol. The cholesterol-lowering action of (3-sitosterol was first reported more than 40 years ago (Farquhar et al., 1956). The differences between the plant sterols and the cholesterol include the addition of an ethyl group to the aliphatic side-chain of both sterols. Saturation of the double bond in the second ring of (3-sitosterol yields sitostanol. The presence of the ethyl group on the side-chain increases the hydrophobicity of both phytosterols such that it is greater than the hydrophobicity of the base molecule, cholesterol. This increase in hydrophobicity is expected to decrease the absorption of... 

The columns used for the GC separation of phytosterols are currently almost exclusively capillary columns with 0.1-0.3 mm internal diameter, and fused-silica capillary columns with chemically bonded stationary phases are commonly used (Abidi, 2001). The best separation of structurally very similar sterols, such as sitosterol and its saturated counterpart sitostanol, is obtained with slightly polar stationary phases like 5% diphenyl-95% dimethylpolysiloxane, and they are currently the most used columns for the separation of phytosterols (Lagarda et al., 2006). For detailed lists of different columns used in sterol analysis, see the papers by Abidi (2001) and Lagarda (2006). 

Phytosterols are partially absorbed in the small intestine. Human absorption efficiency is estimated to be approximately 10% for campesterol and campestanol, 4 to 5% for sitosterol and stigmasterol, and negligible for sitostanol. The absorption of cholesterol ranges from 33 to 60%. Structural features, including the length and configuration of the aliphatic side chain of phytosterols, are thought to contribute to the differences in the absorption efficiency between phytosterols and cholesterol. " Phytosterols apparently displace cholesterol by mass action and... 

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