Luis Baró

Oral administration of a turmeric extract inhibits LDL oxidation and has hypocholesterolemic effects in rabbits with experimental atherosclerosis

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 alpha-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.

Oral administration of a turmeric extract inhibits erythrocyte and liver microsome membrane oxidation in rabbits fed with an atherogenic diet

OBJECTIVES The aim of this study was to evaluate the effects of an oral supplementation with a Curcuma longa ethanol and aqueous extract on the susceptibility to oxidation of cellular and subcellular membranes affected in the atherosclerotic process, such as erythrocyte membranes and liver microsomes, in rabbits fed with a high-fat diet. METHODS Twenty-four male rabbits were randomly assigned to one of two groups: group T was treated with a turmeric hydroalcoholic extract (1.66 mg/kg of body weight) dissolved in a hydroalcoholic mixture vehicle (7:2), and group C (control): received a curcuma-free hydroalcoholic solution (7:2). All rabbits had access ad libitum to 150 g/d of an experimental diet rich in cholesterol and lard to provoke an atherosclerotic process. Erythrocyte membranes and liver microsomes were isolated, and the levels of hydroperoxides and thiobarbituric acid-reactive substances were measured after oxidation induction. RESULTS The oxidation of erythrocyte membranes in group T was significantly lower than that in group C, mainly by 30 d (P < 0.05). Levels of hydroperoxides and thiobarbituric acid-reactive substances in liver microsomes also were significantly lower in group T than in group C (P < 0.05). CONCLUSIONS The results of this study indicated that oral administration of a nutritional dose of C. longa extracts reduces the susceptibility to oxidation of erythrocyte and liver microsome membranes in vitro and may contribute to the prevention of effects caused by a diet high in fat and cholesterol in blood and liver during the development of atherosclerosis.

Influence of Casein and Casein Hydrolysate Diets on Nutritional Recovery of Starved Rats

BACKGROUND The aim of this study was to compare the effects of two diets, which differed in their protein source (casein and casein hydrolysate), on the nutritional recovery and intestinal repair of undernourished rats at weaning after a 3-day fasting period. Profound alterations in gut structure and signs of malnutrition appeared after the starvation period. METHODS The casein hydrolysate was prepared by enzymatic hydrolysis and ultrafiltration. Rats were refed the casein-based or the casein hydrolysate-based diet for 96 hours. Normal-fed male Wistar rats at weaning were given the casein diet for 7 days and were used as controls. Liver acetylcholinesterase, glutamate dehydrogenase activities, serum amino acid profiles, jejunal oligosaccharidases, alkaline phosphatase, and leucine aminopeptidase activities were studied. Intestinal permeability to intact proteins was also tested by using ovalbumin and measuring its concentration in serum. RESULTS Intestinal and liver enzyme activities and serum amino acid profiles reached normal values after 96 hours of refeeding, regardless of the diet used. Glutamate dehydrogenase activity remained higher in both diet groups. Intestinal permeability to ovalbumin remained significantly increased only in the group refed the casein diet. CONCLUSIONS Our results show that 4 days of refeeding are sufficient for complete intestinal recovery after fasting, provided the dietary protein source is a casein hydrolysate. We suggest that patients with malnutrition or malabsorption syndrome should be fed formula composed of enzymatic protein hydrolysates (because of their low antigenicity) rather than enteral formulas composed of intact proteins.

Serum amino acid concentrations in growing rats fed intact protein versus enzymatic protein hydrolysate-based diets.

The aim of this study was to evaluate the effect of the molecular form of dietary protein (native or enzymatically hydrolyzed) on the total serum protein concentrations and the serum amino acid profile of growing rats at weaning. Wistar male rats at weaning were randomly assigned to one of the four isocaloric and isonitrogenous (12% protein equivalent content) diets and fed for 7 days. The protein sources of the diets were: whey protein, casein and their respective hydrolysates. Differences in the serum amino acid profiles exclusively related to the amino acid composition of the protein (casein or whey proteins) were observed, but differences due to their molecular form were not observed. It is concluded that the use of enzymatic hydrolysates of whey proteins and casein has the same effects as their native proteins on nitrogen intake, body weight gain and serum amino acid profile of growing rats at weaning.