Investigation into the bioavailability of synthesized phytosterol esters in vitro and in vivo using Caco-2 cell model and Wistar rats

Phytosterols are bioactive components capable of reducing the level of cholesterol in serum. In this study, phytosterol acetic ester (PA), phytosterol oleate ester (PO) and phytosterol linoleic ester (PL) were synthesized from phytosterol (PS) and organic acid to improve the solubility of phytosterols in oil. The purities of PA, PO and PL were 98.4, 95.9 and 95.7%, respectively. Caco-2 cell monolayers and Wistar rats were used to research the bioavailability of synthesized esters (PE) in vitro and in vivo. Experiments using the Caco-2 cell monolayer model showed that the transport mechanism of phytosterol esters was passive transport. Experiments in vivo showed that the PS content in rat blood reached the highest level at 3 h, with a value of 21.82 μg/mL. PS content in the liver was the highest at 3 h, with a value of 43.65 μg/g. Bioavailability of PL is the highest, reaching a value as high as 19.57%. Acute study in the rats showed that the PS concentration in blood was at the safe level, and it had no side effects for health. In conclusion, the bioavailability of PL and PO is better than PS, PL and PO have more advantages in application.