HDL particles are protein-rich particles that act as a vehicle for reverse cholesterol transport from tissues to the liver. The purpose of this study was to investigate age-dependent changes in the functional activity of HDL and the effect of high-energy diet on this index, as well as to correct it under the influence of grape polyphenols from “Enoant” obtained from Vitis vinifera grapes. We observed the age-dependent composition changes in HDL particle. It was shown that total lipids and triacylglycerol (TG) levels were higher in 24-month-old animals. In obese rats, HDL total lipids and TG levels were higher in 24-month-old than in the 3-month-old and 12-month-old groups but did not differ from 24-month-old group. The plasma HDL paraoxonase (PON) and lecithin:cholesterol acyltransferase (LCAT) activity levels were decreased in old-aged rats, and cholesteryl ester transfer protein (CETP) activity was higher in old rats. Keeping 12-month-old animals on high-fructose diet completely leveled the age differences in the data that have been measured between 12-month-old and 24-month-old rats. After “Enoant” administration, an increase of HDL PON and LCAT activity levels and a reduction of CETP activity were found in 24-month-old and obese rats.

Growing blueberry (Vaccinium corymbosum L., Highbush blueberry) as a berry crop is developing dynamically, especially in warm temperate, subtropical, and tropical regions of the world. When blueberry is cultivated on plantations, the bushes are pruned annually, and tons of leaves become waste. Thus, the aim of the present study was to create a preparation from blueberry leaves, study their chemical composition and determine their potential as a dietary supplement for the prophylactic and correction of the metabolic syndrome. Several schemes for obtaining extracts from blueberry leaves have been developed, including one with addition of arginine. A total of 18 phenolic substances were identified and quantified in the extracts by TLC and HPLC methods. Chlorogenic acid, hyperoside, and rutin were shown to be dominating constituents. Quantitative determination of hydroxycinnamic acid derivatives, flavonoids and other phenolics in the extracts was performed by spectrophotometric method. The extracts administration led to a significant decrease in the level of glucose, insulin and triacylglycerols in blood serum of adult mature inbred rats with insulin resistance induced by the fructose-enriched diet. The most promising one was the extract modified with arginine. The determined hypoglycemic and hypolipidemic activity of chemically standardized extracts from highbush blueberry leaves indicate the potential of this crop residue in utilization as a dietary supplement recommended in prevention of ailments associated with metabolic syndrome.

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Background Vaccinium myrtillus leaves are known to be rich in phenols and have been used in traditional medicine as an antidiabetic remedy. This study evaluated the powder extract of V. myrtillus leaves obtained with the use of L-arginine and myo-inositol for anti-obesity and lipid-lowering potential in hamsters. Methods Standard phytochemical methods were used to determine the total phenolic and total flavonoid contents of the extract. The obesity condition was induced in Syrian hamsters by feeding them with highly palatable fat- and sugar-rich diet (40.3 kcal% fat) for 12 weeks. From the 10th week of diet feeding, the obese hamsters were treated with the powder extract of V. myrtillus leaves (15, 25 and 35 mg/kg/day, respectively) and "Styfimol" (6.2 mg/kg/day of hydroxycitric acid) as a positive control drug. At the end of the treatment period, the biochemical parameters as well as visceral fat mass were determined. Results Vaccinium myrtillus leaves powder extract at 25 and 35 mg/kg/day caused a significant reduction in body weight gain and visceral fat mass in obese hamsters. Serum triacylglycerols, free fatty acids, total cholesterol and low-density lipoprotein cholesterol (LDL-C) levels were also significantly lower. Besides, the hamsters treated with powder extract at 25 and 35 mg/kg/day had the closest intact value ratio of high-density lipoprotein cholesterol and LDL-C compared with positive control animals. Conclusions The results showed that V. myrtillus leaves powder extract is a promising therapeutic agent for the treatment of obesity and obesity-induced diseases.

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