In vitro binding of bile acids by kidney bean (Phaseolus vulgaris), black gram (Vigna mungo), bengal gram (Cicer arietinum) and moth bean (Phaseolus aconitifolins)*1

Abstract

The in vitro binding of bile acids by kidney bean (Phaseolus vulgaris), black gram (Vigna mungo), bengal gram (Cicer arietinum) and moth bean (Phaseolus aconitifolins) was determined using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted, testing whole mature raw seed as substrates on an equal protein basis. Considering cholestyramine as 100% bound, the relative in vitro bile acid binding for kidney bean, black gram, bengal gram and moth bean on equal protein basis was 12%, 15%, 35% and 13%, respectively. Relative bile acid binding on equal dry matter (DM), total dietary fiber (TDF) and insoluble dietary fiber (IDF) basis was for kidney bean 3%, 11% and 14%, black gram 3%, 29% and 36%, bengal gram 7%, 27% and 29%, and moth bean 3%, 19% and 21%, respectively. Except for bengal gram where values were much higher, bile acid binding by kidney bean, black gram and moth bean appear to be related to their DM and protein content. These results point to bile acid binding by bengal gram > black gram=moth beans=kidney bean as indicative of their health-promoting potential. Data suggest that of all four kinds of beans tested, bile acid binding may be related to the anionic, cationic, physical and chemical structure, composition, metabolites, or their interaction with active binding sites. Animal studies are in progress to validate relationship of in vitro bile acid binding of various beans observed herein to lipid, cholesterol-lowering and atherosclerosis amelioration.