β-Sitosterol (βSito) is the most abundant phytosterol found in elevated concentrations in vegetable oils, nuts, seeds, cereals, fruits, and in many phytosterol-enriched foods. Although the benefits, there is a concern in terms of food quality and health due to the increasing consumption of phytosterols and the possible adverse side effects of their oxidation products, oxyphytosterols. βSito has a similar structure to cholesterol, with an unsaturated double bond at C5–C6, which is susceptible to oxidation by reactive oxygen species like ozone, generating oxyphytosterols. In this work we propose a mechanism of formation of three oxyphytosterols 2-[(7aR)-5-[(1R,4S)-4-hydroxy-1-methyl-2-oxocyclohexyl]-1,7a-dimethyl-1,2,3,3a,4,5,6,7- octahydroinden-4-yl]acetaldehyde (βSec), (2-[(7aR)-5-[(2R,5S)-5-hydroxy-2-methyl-7-oxo-oxepan- 2-yl]-1,7a-dimethyl-1,2,3,3a,4,5,6,7-octahydroinden-4- yl] acetaldehyde (βLac) and 2-((7aR)-5-((1R,4S)-4-hydroxy-1-methyl-2- oxocyclohexyl)-1,7a-dimethyloctahydro-1Hinden-4-yl) (βCOOH) generated by ozonization of βSito, through their synthesis and molecular characterization. The cytotoxic effect of βSito and its main oxyphytosterol βSec was evaluated and both reduced the HepG2 cell viability.

β-谷甾醇（βSito）是植物油，坚果，种子，谷物，水果和许多富含植物甾醇的食物中浓度最高的植物甾醇。尽管有益，但由于植物甾醇的消费增加以及它们的氧化产物氧植物甾醇可能产生的不利副作用，在食品质量和健康方面仍存在担忧。βSito具有与胆固醇相似的结构，在C5–C6处具有不饱和双键，易受臭氧等活性氧的氧化，生成植物甾醇。在这项工作中，我们提出了三种氧固甾醇2-[（（7aR）-5-[[1R，4S）-4-羟基-1-甲基-2-氧代环己基] -1,7a-二甲基-1,2 ，3,3a，4,5,6,7-八氢茚满-4-基]乙醛（βSec），（2-[（（7aR）-5-[（2R，5S）-5-羟基-2-甲基-7-氧代-氧杂环戊烷-2-基] -1,7a-二甲基-1,2,3， 3a，4,5,6,7-八氢茚满-4-基]乙醛（βLac）和2-（（7aR）-5-（（1R，4S）-4-羟基-1-甲基-2-氧代环己基）-通过βSito的臭氧合成，合成和分子表征，生成了1,7a-二甲基八氢-1Hinden-4-yl）（βCOOH），评估了βSito及其主要的植物甾醇βSec的细胞毒性作用，均降低了HepG2细胞的活力。