Effect of diosgenin on biliary cholesterol transport in the rat

Abstract

Biliary cholesterol output in rats was stimulated over 3-fold by feeding diosgenin for 5 days, whereas biliary outputs of phospholipid and bile salts were not changed by diosgenin feeding. Isolating and perfusing the liver without bile salts resulted in a rapid and substantial decrease in biliary bile salt output; bile salt depletion abolished the diosgenin-induced increment in biliary cholesterol output, showing that the diosgenin-elevated biliary cholesterol output was bile-salt-dependent. Diosgenin treatment also produced a significant decrease in biliary alkaline phosphodiesterase I. Fresh bile obtained from control and diosgenin-fed rats was subjected to gel-permeation chromatography in order to separate different-sized biliary cholesterol carriers. Two major peaks of cholesterol were eluted, with cholesterol also being eluted between the peaks. The cholesterol peak eluted at the lower molecular mass (20-30 kDa) was observed in all bile samples. The higher-molecular-mass peak, which was eluted at the void volume, was not observed in all biles; control biles contained very little high-molecular-mass form of cholesterol, whereas biles from the diosgenin group contained up to 47% of cholesterol in the high-molecular-mass fraction. Diosgenin treatment produced a range of elevated biliary cholesterol values which positively correlated with the proportion of cholesterol contained in the high-molecular-mass fraction (r = 0.98). The results show that diosgenin induced a marked bile-salt-dependent increase in biliary cholesterol output and a shift in biliary cholesterol transport to higher-molecular-mass structures.

Isolation of biliary lipid carrying vesicles, analysis of their biochemical properties and hepatic ABCG5 mRNA expression in diosgenin-fed rats

“…The inhibition effect on PDE is unlikely due to diosgenin and this may suggest a cholesterolrelated change in the normal distribution or function of some membrane constituents destined for biliary excretion. The decrease in this enzyme activity may also be involved in the formation or exocytosis of phospholipid/ cholesterol vesicles from the canalicular membrane to bile; this is in agreement with the observations of Thewles et al [19]. The microsomal fraction which was expected to contain putative biliary type vesicles was subselected for density gradient centrifugation.…”

“…Previous publications have shown that feeding with diosgenin for 7 days leads to cholesterol saturation in bile [12,19,40]. In our study, diosgenin increased biliary cholesterol over 3 fold (Tab.…”

“…The solvent was allowed to evaporate at room temperature for 48 hours in a fume cupboard. Corresponding control groups received standard diet only as previously described [18,19].…”

A review on pharmacological and analytical aspects of diosgenin: a concise report

“…Isolating and perfusing the liver without bile salts resulted in a rapid and substantial decrease in biliary bile salt output; bile salt depletion abolished the diosgenin-induced increment in biliary cholesterol output, showing that the diosgenin-elevated biliary cholesterol output was bile-saltdependent. 66 Diosgenin and beta-sitosterol were administered to CRJ/CD male mice for 15 days, the changes in bile acid metabolism was examined. This resulted with some differences between diosgenin and beta-sitosterol in their effects on diet intake, liver weight, and plasma cholesterol level.…”

The Effect of Crude Diosgenin Extract from Purple and Yellow Greater Yams (Dioscorea alata L.) on the Lipid Profile of Dyslipidemia Rats

“…Greater yam tuber contains viscous mucilage which consists of soluble glycoprotein, dietary fiber, and saponin (diosgenin) (Thewles et al, 1993;Jenkins et al, 2001). Greater yam tuber has different flesh color including purple, yellow, and white.…”