Figure 1 Structure and trivial names of a few common sterols and some of the A-and B-ring structure oxidation products of sitosterol and other ∆5-stenols (see Chapters 3, 4, and 7 for structures of other phytosterols). A, Cholesterol; B, sitosterol; C, sitostanol; D, 7α-hydroxysitosterol; E, 7β-hydroxysitosterol; F, 7-ketositosterol; G, sitosterol-5α,6α-epoxide; H, sitosterol-5β,6β-epoxyside; I, 5α,6β-dihydroxysitosterol (sitostanetriol). Table 1 Nomenclature of Some Common Oxidation Products of Sitosterol, Stigmasterol, and Campesterol

doi:10.1201/9780203913413-63

Chapter

Figure 1 Structure and trivial names of a few common sterols and some of the A-and B-ring structure oxidation products of sitosterol and other ∆5-stenols (see Chapters 3, 4, and 7 for structures of other phytosterols). A, Cholesterol; B, sitosterol; C, sitostanol; D, 7α-hydroxysitosterol; E, 7β-hydroxysitosterol; F, 7-ketositosterol; G, sitosterol-5α,6α-epoxide; H, sitosterol-5β,6β-epoxyside; I, 5α,6β-dihydroxysitosterol (sitostanetriol). Table 1 Nomenclature of Some Common Oxidation Products of Sitosterol, Stigmasterol, and Campesterol

Chapter

Figure 1 Structure and trivial names of a few common sterols and some of the A-and B-ring structure oxidation products of sitosterol and other ∆5-stenols (see Chapters 3, 4, and 7 for structures of other phytosterols). A, Cholesterol; B, sitosterol; C, sitostanol; D, 7α-hydroxysitosterol; E, 7β-hydroxysitosterol; F, 7-ketositosterol; G, sitosterol-5α,6α-epoxide; H, sitosterol-5β,6β-epoxyside; I, 5α,6β-dihydroxysitosterol (sitostanetriol). Table 1 Nomenclature of Some Common Oxidation Products of Sitosterol, Stigmasterol, and Campesterol

ABSTRACT

The initial reactions in the cholesterol autoxidation process involve predominantly abstraction of a reactive allylic 7-hydrogen atom forming a free radical followed by reaction with molecular oxygen (3O2), yielding 3β-hy-droxycholest-5-en-7-peroxyl radicals. These products are stabilized in turn by hydrogen abstraction producing more stable products, 7-hydroperoxides. These compounds further decomposed to the 7α-and 7β-hydroxycholesterol. The epimeric 7-hydroperoxides and 7-hydroxycholesterol can be further thermally degraded to 7-ketocholesterol and subsequently can be converted to cholesta-3,5-dien-7-one (7-9).