Biliary proteins from hepatic bile of rats fed curcumin or capsaicin inhibit cholesterol crystal nucleation in supersaturated model bile.

Following our earlier observations that curcumin and capsaicin are antilithogenic in mice and hamsters, attempts were now made to understand the manner in which these spice principles were acting. For this purpose, the hepatic biles of rats fed a control, lithogenic, and lithogenic diet supplemented with curcumin or capsaicin were subjected to gel filtration chromatography (sepharose-4B-Cl) and the LMW protein fractions were tested for their ability to influence cholesterol crystal growth in model bile. The LMW protein fraction from the lithogenic group bile shortened the nucleation time and increased the crystal growth rate and final crystal concentration. But with the LMW protein fractions from the biles of rats on the lithogenic group supplemented with curcumin or capsaicin, the nucleation times were prolonged and the crystal growth rates and final crystal concentrations were decreased. The LMW fractions were further purified into three different sugar specific proteins by affinity chromatography. A higher proportion of LMW proteins from the lithogenic group bile was bound to Con-A whereas higher proportions of LMW proteins from the groups fed with curcumin and capsaicin were respectively bound to wheat germ agglutinin and Helix pomatia lectin. The Con-A bound fraction obtained from the lithogenic group showed a pro-nucleating effect. In contrast, the WGA-bound fraction obtained from curcumin group or the Helix pomatia lectin bound fraction obtained from capsaicin group showed a potent antinucleating activity.

Effect on curcumin on cholesterol gall-stone induction in mice.

A study was carried out on the efficacy of curcumin in reducing the incidence of cholesterol gall-stones (CGS), induced by feeding a lithogenic diet in young male mice. Feeding a lithogenic diet supplemented with 0.5 per cent curcumin for 10 wk reduced the incidence of gall-stone formation to 26 per cent, as compared to 100 per cent incidence in the group fed with lithogenic diet alone. Biliary cholesterol concentration was also significantly reduced by curcumin feeding. The lithogenic index which was 1.09 in the cholesterol fed group was reduced to 0.43 in the 0.5 per cent curcumin supplemented group. Further, the cholesterol: phospholipid (C/PL) ratio of bile was also reduced significantly when 0.5 per cent curcumin supplemented diet was fed. A dose-response study with 0.2, 0.5 and 1.0 per cent curcumin supplemented lithogenic diets showed that 0.5 per cent curcumin was more effective than a diet with 0.2 or 1 per cent curcumin.

Comparative influence of vanillin & capsaicin on liver & blood lipids in the rat.

The influence of vanillin (0.15 mg %) and capsaicin (0.3 mg %) on liver and blood lipids in growing female Wistar rats was determined, when fed along with a normal diet. Vanillin, like capsaicin, decreased the serum triglycerides and the triglycerides associated with lipoproteins viz., VLDL+LDL and HDL with a tendency to lower liver triglycerides as well. Cholesterol and phospholipids in liver and serum were unaffected. The accumulation of triglycerides in serum after Triton WR-1339 blocking was higher in animals fed a vanillin supplemented normal or hypertriglyceridemic diet than in the corresponding controls. The accumulation of triglycerides in serum with capsaicin supplementation with either diet was much higher than with vanillin supplementation.

Effect of oryzanol on cholesterol absorption & biliary & fecal bile acids in rats.

Effect of oryzanol on biliary secretion of cholesterol, phospholipid and bile acids and fecal excretion of cholesterol and bile acids was examined in male albino rats. Feeding oryzanol at 0.5 per cent level with the control diet did not cause any change in bile flow and composition. On feeding oryzanol with high cholesterol diet, the bile flow and total bile acid output were increased by 12 and 18 per cent respectively, while biliary cholesterol and phospholipids remained unchanged. The increased bile acid secretion was mainly due to taurocholic acid. In rats fed oryzanol along with high cholesterol diet, there was a significant increase in the fecal excretion of cholesterol (28%) and of bile acids (29%), whereas cholesterol absorption was lowered by 20 per cent.