Assessment of in vitro removal of cholesterol oxidation products by Lactobacillus casei ATCC334

Cholesterol oxidation products (COPs) are a group of compounds formed during processing and storage of foods from animal origin. After ingestion, COPs are absorbed in the intestine and can be distributed to serum and various tissues, potentially promoting a variety of toxic effects. Therefore, inhibition of their intestinal absorption may contribute to reduce the health risks associated with dietary intake of COPs. Some studies have shown that drugs and dietary compounds may inhibit the intestinal absorption of dietary COPs. However, proven cholesterol- and/or food toxins-binding lactic acid bacteria have not been previously evaluated as potential COPs removal agents. The aim of this study was to assess the ability of Lactobacillus casei ATCC334 to remove COPs in aqueous solution. Results showed the ability of both growing and resting cells to remove COPs (ca. 30-60%). All COPs-bacterium interactions were specific and partly reversible, being resting cells the most efficient for COPs removal in a ranking order of 7-KC > 7alfa-OH/7beta-OH > triol > 5,6beta-EP > 5,6alfa-EP > 25-OH. Binding to the cell wall and/or cell membrane incorporation appears to be the most likely mechanisms involved on COPs removal by L. casei ATCC 334.