Lipid-Lowering Effects and Intestinal Transport of Polyphenol Extract from Digested Buckwheat in Caco-2/HepG2 Coculture Models.

Polyphenol extracts derived from gastrointestinal digestates of buckwheat (Fagopyrum Mill) were studied for their intestinal transport and lipid-lowering effects in Caco-2/HepG2 coculture models. The relative amounts of all phenolic compounds throughout the digestion and intestinal absorption process were determined by UHPLC-Q-Orbitrap mass spectrometry. The digestible and easily transported phenolic compounds in buckwheat extract were identified. Herein, four main phenolic compounds and their metabolites were found on both the apical and basolateral sides of the Caco-2 cell transwell model. The transepithelial transport rates in the Caco-2 cell monolayer were scoparone (0.97) > hydroxycinnamic acid (0.40) > rutin (0.23) > quercetin (0.20). The main metabolism of hydroxycinnamic acid, quercetin, and scoparone in transepithelial transport was found to be methylation. Furthermore, results indicated that triglyceride, low-density lipoprotein cholesterol, total cholesterol, aspartate aminotransferase, and alanine aminotransferase levels in HepG2 cells on the basolateral side of coculture models can be suppressed by 53.64, 23.44, 36.49, 27.98, and 77.42% compared to the oleic acid-induced group (p < 0.05). In addition, the mRNA expression of Fabp4 relative to the control was found to be significantly upregulated (85.82 ± 10.64 to 355.18 ± 65.83%) by the easily transported buckwheat polyphenol components in HepG2 cells (p < 0.01).