Flavonoids and Saponins Extracted From Black Bean (Phaseolus Vulgaris L.) Seed Coats Modulate Lipid Metabolism and Biliary Cholesterol Secretion in C57BL/6 Mice

Br J Nutr. 2014 Sep 28;112(6):886-99. doi: 10.1017/S0007114514001536.

Abstract

Black bean (Phaseolus vulgaris L.) seed coats are a rich source of natural compounds with potential beneficial effects on human health. Beans exert hypolipidaemic activity; however, this effect has not been attributed to any particular component, and the underlying mechanisms of action and protein targets remain unknown. The aim of the present study was to identify and quantify primary saponins and flavonoids extracted from black bean seed coats, and to study their effects on lipid metabolism in primary rat hepatocytes and C57BL/6 mice. The methanol extract of black bean seed coats, characterised by a HPLC system with a UV-visible detector and an evaporative light-scattering detector and HPLC-time-of-flight/MS, contained quercetin 3-O-glucoside and soyasaponin Af as the primary flavonoid and saponin, respectively. The extract significantly reduced the expression of SREBP1c, FAS and HMGCR, and stimulated the expression of the reverse cholesterol transporters ABCG5/ABCG8 and CYP7A1 in the liver. In addition, there was an increase in the expression of hepatic PPAR-α. Consequently, there was a decrease in hepatic lipid depots and a significant increase in bile acid secretion. Furthermore, the ingestion of this extract modulated the proportion of lipids that was used as a substrate for energy generation. Thus, the results suggest that the extract of black bean seed coats may decrease hepatic lipogenesis and stimulate cholesterol excretion, in part, via bile acid synthesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bile Acids and Salts / metabolism
  • Cells, Cultured
  • Cholagogues and Choleretics / chemistry
  • Cholagogues and Choleretics / isolation & purification
  • Cholagogues and Choleretics / metabolism
  • Cholagogues and Choleretics / therapeutic use*
  • Cholesterol / metabolism
  • Dietary Supplements*
  • Flavonoids / chemistry
  • Flavonoids / isolation & purification
  • Flavonoids / metabolism
  • Flavonoids / therapeutic use*
  • Gene Expression Regulation
  • Hepatocytes / cytology
  • Hepatocytes / enzymology
  • Hepatocytes / metabolism
  • Lipid Metabolism
  • Lipotropic Agents / chemistry
  • Lipotropic Agents / isolation & purification
  • Lipotropic Agents / metabolism
  • Lipotropic Agents / therapeutic use*
  • Liver X Receptors
  • Male
  • Mexico
  • Mice
  • Mice, Inbred C57BL
  • Orphan Nuclear Receptors / agonists
  • Orphan Nuclear Receptors / genetics
  • Orphan Nuclear Receptors / metabolism
  • Phaseolus / chemistry*
  • Plant Extracts / chemistry
  • Plant Extracts / isolation & purification
  • Plant Extracts / metabolism
  • Plant Extracts / therapeutic use
  • Random Allocation
  • Rats
  • Saponins / chemistry
  • Saponins / isolation & purification
  • Saponins / metabolism
  • Saponins / therapeutic use*
  • Seeds / chemistry*

Substances

  • Bile Acids and Salts
  • Cholagogues and Choleretics
  • Flavonoids
  • Lipotropic Agents
  • Liver X Receptors
  • Orphan Nuclear Receptors
  • Plant Extracts
  • Saponins
  • Cholesterol