Highbush Blueberry (Vaccinium corymbosum L.) Leaves Extract and Its Modified Arginine Preparation for the Management of Metabolic Syndrome-Chemical Analysis and Bioactivity in Rat Model.

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.

Evaluation of anti-obesity and lipid-lowering properties of Vaccinium myrtillus leaves powder extract in a hamster model.

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.

Effect of apple polyphenol concentrate on lipid metabolism in rats under experimental insulin resistance.

INTRODUCTION: Obesity is strongly associated with an increased risk of developing insulin resistance as the metabolic indicator of prediabetes and a major risk factor in diabetes mellitus type 2 pathogenesis. Medicinal products obtained from apples can be used as potent prophylactic and therapeutic remedies in treatment of diabetes mellitus. AIM: Experiment was designed to study the effect of total apple polyphenol food concentrate on lipid metabolism under experimental IR. MATERIALS AND METHODS: Male Wistar rats weighting 180-210 g were used in the experiment. IR was induced by high-calorie diet enriched with fructose. The effect of total apple polyphenol food concentrate was compared with the action of epigallocatechin gallate and quercetin. To estimate the alterations in lipid metabolism in liver homogenate were measured triacylglycerols, free fatty acids, total phospholipids, TBA-reactive substance and conjugated dienes contents. In blood serum were measured total lipids, triacylglycerols, cholesterol, total phospholipids and reduced glutathione levels. RESULTS: The obtained results indicated that feeding rats with high-calorie diet enriched with fructose caused the dyslipidemia and oxidative stress development. The administration of quercetin, epigallocatechin gallate and total apple polyphenol food concentrate improved disorders of lipid metabolism and pro-oxidant-antioxidant homeostasis. CONCLUSIONS: Total apple polyphenol food concentrate had a more pronounced effect on studied indices that is probably due to synergism and additive effect of extract numerous components.