Wheat alkylresorcinols reduce micellar solubility of cholesterol in vitro and increase cholesterol excretion in mice

Abstract

Epidemiological studies have shown that the consumption of whole grains can reduce risk for metabolic disorders. We recently showed that chronic supplementation with wheat alkylresorcinols (ARs) prevents glucose intolerance and insulin resistance with hepatic lipid accumulation induced in mice by a high-fat high-sucrose diet (HFHSD). This study examines the effects of ARs on the micellar solubility of cholesterol in vitro, as well as the effects of transient AR supplementation on faecal lipid excretion and plasma lipid levels in mice. We found that ARs formed bile micelles with taurocholate independently of phospholipids, and dose-dependently decreased the micellar solubility of cholesterol in a biliary micelle model. Transient AR supplementation with HFHSD increased faecal cholesterol and triglyceride contents and decreased plasma cholesterol concentrations. These suggest that one underlying mechanism through which ARs suppress diet-induced obesity is by interfering with the micellar cholesterol solubilisation in the digestive tract, which subsequently decreases cholesterol absorption.

Keywords:

• Wheat alkylresorcinols
• bile acids
• micelle
• cholesterol
• obesity
• hepatic lipid

Abbreviations:

• ANOVA: analyses of variance
• ARs: alkylresorcinols
• HFHSD: high-fat high-sucrose diet
• HFHSD-AR: high-fat high-sucrose diet with 0.4% ARs
• PBS: phosphate-buffered saline
• PC: phosphatidylcholine

Acknowledgements

This project was partly supported by a Grant-in-Aid for Scientific Research (C) KAKENHI (25350179) to K. Oishi from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan.

Funding

This work was supported by the Grant-in-Aid for Scientific Research (C) KAKENHI [grant number 25350179].