The extract of Curcuma longa, better known as turmeric, was orally administered to experimental rats that were fed a high-cholesterol diet to investigate whether it could regulate plasma lipids and cholesterol levels and possibly improve hepatic conditions. With turmeric supplements, rats showed a significant decrease in total plasma cholesterol and low-density lipoprotein cholesterol but an increase in high-density lipoprotein cholesterol when compared with rats that were fed a high-cholesterol diet alone. Fatty liver developed in hypercholesterolemic rats with the high-cholesterol diet treatment, and this condition was markedly improved when rats were provided with turmeric supplements at 100 mg/kg or 300 mg/kg of body mass. The turmeric treatment resulted in a significant decrease in the total amount of hepatic lipid. Histological staining of liver tissues with Sudan III and hematoxylin showed that rats fed with a high-cholesterol diet alone had more and larger granular fat bodies than rats having turmeric extract supplementation in their high-cholesterol diet. Reverse-transcription polymerase chain reaction was used to assess the expression levels of enzymes involved in fat metabolism and cellular homeostasis in experimental rat livers. The results showed that rats fed a high-cholesterol diet supplemented with turmeric extract had a significant increase in the expression of cholesterol 7 α-hydroxylase, hemeoxygenase 1, and low-density lipoprotein receptors but a significant decrease in 3-hydroxy-3-methyl-glutaryl-CoA reductase level when compared with rats fed a normal or high-cholesterol diet, showing that turmeric prevents hypercholesterolemia and the formation of fatty liver by the modulation of expressions of enzymes that are important to cholesterol metabolism.
Practical application: Turmeric may be considered a functional food for regulating plasma cholesterol levels and preventing the development of fatty liver in people who frequently consume a high-cholesterol diet.