Effects of guaraná (Paullinia cupana) on lipid metabolism and bioacessibility of its polyphenols in genes related to the absorption of cholesterol in Caco-2 cells

Abstract

The risk of cardiovascular diseases, such as atherosclerosis, is associated with hypercholesterolemia, a result of behavioral and metabolic risk factors. Dietary interventions with the use of natural foods such as guaraná (Paullinia cupana) may be useful as it is rich in bioactive compounds such as catechins, which have high antioxidant activity, inhibit oxidation of LDL-c and lipid peroxidation, and are able to lower blood cholesterol levels, by a mechanism not yet fully elucidated. Objectives: To investigate the effects of guarana (Paullinia cupana) on lipid metabolism and to evaluate the bioaccessibility of its polyphenols in genes related to the absorption of cholesterol in Caco-2 cells. Methodology: The aqueous extract of guarana will be submitted to in vitro digestion and the phenolic compounds will be quantified and identified. The antioxidant activity will be determined by ORAC and the inhibition of micellar cholesterol solubilization, interaction with micellar phosphatidylcholine, binding to bile acids and inhibition of pancreatic lipase will be performed. The gene expression and protein content of cholesterol transporters (ABCA1, ABCG1, ABCG5, ABCG8, NPC1L1 and LDL receptors) in Caco-2 intestinal cells will be determined. Expected results: It is expected to find an inverse correlation between the content of guarana phenolic compounds and the micellar solubility of cholesterol and pancreatic lipase activity and to verify a modulation in the gene expression of the membrane transporters and a reduction of cholesterol absorption in the experimental model in vitro. (AU)