Soyasaponins lowered plasma cholesterol and increased fecal bile acids in female golden Syrian hamsters

Exp Biol Med (Maywood). 2005 Jul;230(7):472-8. doi: 10.1177/153537020523000705.

Abstract

A study was conducted in hamsters to determine if group B soyasaponins improve plasma cholesterol status by increasing the excretion of fecal bile acids and neutral sterols, to identify group B soyasaponin metabolites, and to investigate the relationship between a fecal group B soyasaponin metabolite and plasma lipids. Twenty female golden Syrian hamsters, 11-12 weeks old and 85-125 g, were randomly assigned to a control diet or a similar diet containing group B soyasaponins (containing no isoflavones), 2.2 mmol/kg, for 4 weeks. Hamsters fed group B soyasaponins had significantly lower plasma total cholesterol (by 20%), non-high-density lipoprotein (HDL) cholesterol (by 33%), and triglycerides (by 18%) compared with those fed casein (P < 0.05). The ratio of total cholesterol to HDL cholesterol was significantly lower (by 13%) in hamsters fed group B soyasaponins than in those fed casein (P < 0.05). The excretion of fecal bile acids and neutral sterols was significantly greater (by 105% and 85%, respectively) in soyasaponin-fed hamsters compared with those fed casein (P < 0.05). Compared with casein, group B soyasaponins lowered plasma total cholesterol levels and non-HDL cholesterol levels by a mechanism involving greater excretion of fecal bile acids and neutral sterols. Hamsters fed group B soyasaponins statistically clustered into two fecal soyasaponin metabolite-excretion phenotypes: high excreters (n = 3) and low excreters (n = 7). When high and low producers of this soyasaponin metabolite were compared for plasma cholesterol status, the high producers showed a significantly lower total-cholesterol-to-HDL-cholesterol ratio compared with the low producers (1.38 +/- 0.7 vs. 1.59 +/- 0.13; P < 0.03). Greater production of group B soyasaponin metabolite in hamsters was associated with better plasma cholesterol status, suggesting that gut microbial variation in soyasaponin metabolism may influence the health effects of group B soyasaponins.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Anticholesteremic Agents / pharmacology*
  • Bile Acids and Salts / analysis
  • Bile Acids and Salts / metabolism*
  • Cholesterol / blood*
  • Cricetinae
  • Feces / chemistry
  • Female
  • Mesocricetus
  • Oleanolic Acid / analogs & derivatives*
  • Oleanolic Acid / pharmacokinetics
  • Oleanolic Acid / pharmacology*
  • Saponins / pharmacokinetics
  • Saponins / pharmacology*
  • Soybeans / chemistry
  • Sterols / analysis
  • Sterols / metabolism

Substances

  • Anticholesteremic Agents
  • Bile Acids and Salts
  • Saponins
  • Sterols
  • soyasapogenol B
  • Oleanolic Acid
  • Cholesterol