Stigmasterol occurrence

Tenerife and La Palma, revealed the existence of luteolin and an array of simple phenolic derivatives as well as three known phytosterols, B-amyrin, sitosterol, and stigmasterol. The phenols identified comprised a set of phenylpropanoids myristicin [566] (see Fig. 6.16 for structures 566-573), methyleugenol [567], todadiol [568], todatriol [569], crocatone [570], elemicin [571], apiole [572], and the coumarin scopoletin [573]. The occurrence of these compounds is recorded in Table 6.5. The differences between the two profiles were taken by Gonzalez and his co-workers... 

The sterol composition of both oils is compared in Table 12. Clearly, for HOSO, p-sitosterol is the sterol with the highest occurrence (42-70% of total sterols), followed by A7-stigmasterol (6.5-24%), campesterol (5-13%), and stigmasterol (4.5-13%). Although there are differences in the sterol composition of both oils, they are not large enough to enable easy analysis. 

Table 15 shows the sterol composition of mid-oleic sunflower oil according to the Proposed Draft Amendments to the Standard for Named Vegetable Oils (Report of the Eighteenth Session of the Codex Committee on Fats and Oils, London, 2003). Clearly, p-sitosterol is the sterol with the highest occurrence (56-58% of total sterols), followed by campesterol (9.1-9.6%) and stigmasterol (9.0-9.3%). p-sitosterol is the main sterol in aU three types of sunflower oil (regular, mid-oleic, and high-oleic). 

Research on maize fiber (Moreau et al. 1996) has shown that oil associated with the fiber fraction is different in composition compared to regular oil obtained from the germ. The fiber oil contains important amounts of ferulate phytosterol esters, free phytosterols, and fatty acid phytosterol esters, which lower serum cholesterol in laboratory animals. The most common class is ferulate phytosterol esters dominated by sitostanol, which is considered more efficient in lowering cholesterol. Phytosterols, such as ergosterol, campesterol, P-sitosterol, and stigmasterol, compete for cholesterol absorption, and therefore are considered hypocholesterolemic and preventive against CVD. According to Raicht et al. (1980) and Fiala et al. (1985) the supplementation of 0.2% P-sitosterol decreases the occurrence of chemically induced colon tumors. 

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