Absorption of Dietary Cholesterol Oxidation Products and Their Downstream Metabolic Effects Are Reduced by Dietary Apple Polyphenols

Abstract

Exogenous and endogenous cholesterol oxidation products (COPs) perturb various metabolic processes, and thereby they may induce various homeostasis-related disorders. Here, we observed that procyanidin-rich dietary apple polyphenol (APP) from unripe apples alleviates the perturbation of lipid metabolism by decreasing the exogenous COP levels in rats. Dietary COPs may be the greatest source of COPs found in the human body. Rats (4 weeks of age) were fed AIN-purified diets containing 0.3% COPs supplemented with 0.5 or 2.5% APP for 3 weeks. Dietary APP alleviated the growth inhibition action of the exogenous COPs. The modulations of the liver lipid profile by COPs remained unchanged. However, serum total cholesterol, high-density lipoprotein cholesterol, and triglyceride levels increased following the intake of dietary APP. Further, dietary APP inhibited the increase in lipid peroxide levels in the liver and serum by COPs. The activity of hepatic Delta6 desaturase was lowered by dietary APP in a dose-dependent manner, although exogenous COPs generally increased the activity of this enzyme. In keeping with this observation, Delta6 desaturation indices in the phospholipids and cholesteryl esters of the liver and serum lipids were lower in the APP-fed groups than those in the control group. Dietary APP also promoted the excretion of exogenous COPs, cholesterol, and acidic steroids in feces. Therefore, the inhibition of intestinal absorption of COPs may partly contribute to the alleviation of the perturbation of lipid metabolism and lipid peroxidation levels. Thus, APP may be an important removal agent of exogenous toxic material such as COPs contained in processed or fast foods.

Effect of gala apples (Malus domestica Borkh) on lipidemia of hyperlipidemic rats

“…Some of these compounds may be absorbed from the intestine and their metabolites may influence lipid metabolism (OGINO et al, 2007).…”

“…However, there are not many researches studying the use of apples in this area, and some of them include their antioxidant compounds (APRIKIAN, et al, 2003;BOYER;LIU, 2004;LEJA;MARECZEK;BEN, 2003;LEONTOWICZ et al, 2001;LEONTOWICZ et al, 2003;OGINO et al, 2007;SEMBRIES et al, 2006;VIDAL et al, 2005).…”

Effect of Dietary Polyphenols from Hop (Humulus lupulus L.) Pomace on Adipose Tissue Mass, Fasting Blood Glucose, Hemoglobin A1c, and Plasma Monocyte Chemotactic Protein-1 Levels in OLETF Rats

“…HPs inhibited the activity of a pancreatic lipase in our in vitro experiment the half maximal inhibitory concentration IC 50 of HPs was 2.5 mg/ ml . Dietary apple polyphenols, especially high-molecularweight procyanidins, may inhibit the intestinal absorption of lipids through micellar disruption 38 . The excreted feces level in the H-group was the highest among the 2 study groups NC-group: 2.75 0.11 g/day; C-group: 2.86 0.06 g/ day; H-group: 3.19 0.05 g/day .…”

Evaluation of Safety of Excessive Intake and Efficacy of Long-term Intake of Beverages Containing Apple Polyphenols

“…Additionally, an in vitro test has demonstrated that they have an inhibitory effect on pancreatic lipase activity and on the micellar solubilization of fat 13 . Moreover, several studies involving animal experiments have revealed that the quantity of fatty acids excreted in rat feces increased with the rat s intake of apple polyphenols 14 , that apple polyphenols had an inhibitory effect on triglyceride absorption in mice 15 in a triglyceride loading test conducted on mice, and that apple polyphenols had a reducing effect on abdominal visceral fat 16 .…”