| Affiliation: | (1) Department of Food Science, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden;(2) Department of Chemistry, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden |
| Abstract: | Although the structure of phytosterols is closely related to cholesterol, there is a gap in knowledge concerning the formation and occurrence of oxidation products from phytosterols. The main objective of this study was to isolate and characterize some side-chain oxidation products formed after autoxidation of stigmasterol. Another objective was to highlight the difficulties in the analysis of phytosterol and a mixture of their oxidation products by GC. Pure stigmasterol was oxidized at 120°C for 72 h in an air-ventilated oven. Preparative TLC separated the oxidation products, and the products were characterized with GC-MS and NMR. In addition to the common ring-structure oxidation compounds, three semipolar oxidation products—24-ethylcholest-5,22-dien-3β,25-diol, 24-ethylcholest-5,22-dien-3β,24-diol, and 24-ethyl-5,22-choladien-3β-ol-24-one—were characterized for the first time by TLC, GC-MS, and NMR. Moreover, the results of the analysis of a large number of oxidation products from sitosterol, campesterol, and stigmasterol by capillary column GC indicated that further efforts and optimization are required in this area. |
