Curcuminoids, the yellow pigments of curcuma, exhibit anticarcinogenic, antioxidative and hypocholesterolemic activities. To understand the molecular basis for the hypocholesterolemic effects, we examined the effects of curcumin on hepatic gene expression, using the human hepatoma cell line HepG2 as a model system. Curcumin treatment caused an up to sevenfold, concentration-dependent increase in LDL-receptor mRNA, whereas mRNAs of the genes encoding the sterol biosynthetic enzymes HMG CoA reductase and farnesyl diphosphate synthase were only slightly increased at high curcumin concentrations where cell viability was reduced. Expression of the regulatory SREBP genes was moderately increased, whereas mRNAs of the PPARalpha target genes CD36/fatty acid translocase and fatty acid binding protein 1 were down-regulated. LXRalpha expression and accumulation of mRNA of the LXRalpha target gene ABCg1 were increased at low curcumin concentrations. Although curcumin strongly inhibited alkaline phosphatase activity, an activation of a retinoic acid response element reporter employing secreted alkaline phosphatase was observed. These changes in gene expression are consistent with the proposed hypocholesterolemic effect of curcumin.
Link to article here: http://medind.nic.in/ibi/t04/i6/ibit04i6p382.pdf
Not on pubmed: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC37241/
In rats given cholesterol and curcumin, the colouring principle in turmeric, serum and liver cholesterol fell to one-half or one-third of those in rats given cholesterol and no curcumin. Cholesterol was most in liver from rats given cholesterol and least in rats given curcumin at the same time. Curcumin increased bile acids and cholesterol in faeces in normal and hyper-cholesteraemic rats, an explanation for the reduction of tissue cholesterol. The imbalance in a- and ß-lipoproteins brought about by cholesterol was nearly corrected by curcumin. The beneficial effects were about the same with 0 1 or 0 5% curcumin in the diet, suggesting that the effective amount may be even less than 0.1%. Curcumin maintained body and liver weights.
An experiment was conducted in order to study the hypocholesteremic effect of tumeric and its coloring principle namely curcumin both in the presence and absence of dietary cholesterol. Laying hens were used as the experimental animals and they were fed the experimental diets for a duration of 8 weeks. The results of the experiment showed that tumeric or various levels of curcumin had no adverse effect on egg production, egg weight and feed to egg ratio. Moreover tumeric or various levels of curcumin both in the presence and absence of dietary cholesterol did not reduce the fat or cholesterol levels of plasma, liver or the egg yolk. An interesting finding from this experiment was that the egg yolk cholesterol levels of cholesterol fed groups sharply increased at the beginning of the experiment, and thereafter they gradually decreased and tended to approach the normal levels at the termination of the experiment. The possible reasons for variation in egg yolk cholesterol levels of cholesterol-fed groups with time is discussed.
Effect of oral administration of curcumin (diferuloyl methane) on lipid peroxidation in various organs of mice like liver, lung, kidney and brain was studied in control animals as well as those given carbon tetrachloride, paraquat and cyclophosphamide. Oral administration of curcumin significantly lowered the increased peroxidation of lipids in these tissues produced by these chemicals. Administration of curcumin was also found to lower significantly the serum and tissue cholesterol levels in these animals, indicating that the use of curcumin helps in conditions associated with peroxide induced injury such as liver damage and arterial diseases.
Curcumin and its structurally related compounds (curcuminoids), the phenolic yellowish pigments of turmeric, display antioxidative, anticarcinogenic and hypocholesterolemic activities. In this study, we investigated the effects of dietary supplemented curcuminoids [commercial grade curcumin: a mixture of curcumin (73.4%), demethoxycurcumin (16.1%) and bisdemethoxycurcumin (10.5%)] on lipid metabolism in rats. Male Sprague-Dawley rats were assigned to three diet groups (n = 6) and fed a moderately high-fat diet (15 g soybean oil/100 g diet) for 2 wk. One diet group did not receive supplements (CONT), while the others were supplemented with 0.2 g curcuminoids/100 g diet (CUR0.2) or 1.0 g curcuminoids/100 g diet (CUR1.0). Liver triacylglycerol and cholesterol concentrations were significantly lower in CUR1.0 rats than in CONT rats. Plasma triacylglycerols in the VLDL fraction were also lower in CUR1.0 rats than in CONT rats (P < 0.05). Hepatic acyl-CoA oxidase activity of both the CUR0.2 and CUR1.0 rats was significantly higher than that of CONT rats. Furthermore, epididymal adipose tissue weight was significantly reduced with curcuminoid intake in a dose-dependent manner. These results indicate that dietary curcuminoids have lipid-lowering potency in vivo, probably due to alterations in fatty acid metabolism.
The effect of curcumin administration in reducing the serum levels of cholesterol and lipid peroxides was studied in ten healthy human volunteers, receiving 500 mg of curcumin per day for 7 days. A significant decrease in the level of serum lipid peroxides (33%), increase in HDL Cholesterol (29%), and a decrease in total serum cholesterol (11.63%) were noted. As curcumin reduced serum lipid peroxides and serum cholesterol, the study of curcumin as a chemopreventive substance against arterial diseases is suggested.
Curcuminoids, the yellow pigments of curcuma, exhibit anticarcinogenic, antioxidative and hypocholesterolemic activities. To understand the molecular basis for the hypocholesterolemic effects, we examined the effects of curcumin on hepatic gene expression, using the human hepatoma cell line HepG2 as a model system. Curcumin treatment caused an up to sevenfold, concentration-dependent increase in LDL-receptor mRNA, whereas mRNAs of the genes encoding the sterol biosynthetic enzymes HMG CoA reductase and farnesyl diphosphate synthase were only slightly increased at high curcumin concentrations where cell viability was reduced. Expression of the regulatory SREBP genes was moderately increased, whereas mRNAs of the PPARalpha target genes CD36/fatty acid translocase and fatty acid binding protein 1 were down-regulated. LXRalpha expression and accumulation of mRNA of the LXRalpha target gene ABCg1 were increased at low curcumin concentrations. Although curcumin strongly inhibited alkaline phosphatase activity, an activation of a retinoic acid response element reporter employing secreted alkaline phosphatase was observed. These changes in gene expression are consistent with the proposed hypocholesterolemic effect of curcumin.
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.
The oxidation of low-density lipoproteins (LDL) plays an important role in the development of atherosclerosis. Curcumin is a yellow pigment obtained from rhizomes of Curcuma longa and is commonly used as a spice and food colouring. Curcumin and turmeric extracts have several pharmacological effects including antitumour, anti-inflammatory, antioxidant and antiinfectious activities although the precise mechanisms involved remain to be elicited. We evaluated the effect of an ethanol-aqueous extract obtained from rhizomes of C. longa on LDL oxidation susceptibility and plasma lipids in atherosclerotic rabbits. A total of 18 rabbits were fed for 7 weeks on a diet containing 95.7% standard chow, 3% lard and 1.3% cholesterol, to induce atherosclerosis. The rabbits were divided into groups, two of which were also orally treated with turmeric extract at doses of 1.66 (group A) and 3.2 (group B) mg/kg body weight, respectively. A third group (group C) acted as a control. Plasma and LDL lipid composition, plasma a-tocopherol, plasma retinol, LDL TBARS, LDL lipid hydroperoxides and analysis of aortic atherosclerotic lesions were assayed. The low but not the high dosage decreased the susceptibility of LDL to lipid peroxidation. Both doses had lower levels of total plasma cholesterol than the control group. Moreover, the lower dosage had lower levels of cholesterol, phospholipids and triglycerides in LDL than the 3.2-mg dosage. In conclusion, the use of this extract could be useful in the management of cardiovascular disease in which atherosclerosis is important