Anti-diabetic activity of chemically profiled green tea and black tea extracts in a type 2 diabetes mice model via different mechanisms

Tea is one of the most popular beverages worldwide. The variety of tea and tea extracts in the market has different polyphenol profiles, which are the bioactive chemical entities. In searching for efficacious molecules from tea against hyperglycaemia, we performed a direct comparison between green tea extracts (GTE) and black tea extracts (BTE), which have been chemically well-characterized by HPLC, in a type 2 diabetic mouse model combining low dose streptozotocin (STZ) with high fat (HF) diet. The results revealed that both GTE and BTE in drinking water substantially lowered blood glucose levels and ameliorated glucose intolerance, but GTE was more effective in anti-hyperglycaemic activity and in lowering body weight gain. GTE was also more effective than BTE in reversing histological deterioration of liver in the diabetic mice. Serum insulin levels significantly increased in BTE group but not in GTE group, suggesting that they might exert their hypoglycaemic effects through different pathways. We explored the possible mechanisms by homeostatic model assessment (HOMA), and results showed that the predominant mechanism for the anti-diabetic effect of GTE was through insulin resistance, while for BTE it was through insulin secretion.     

Micronutrient contents in organic and conventional tomatoes (Solanum lycopersicum L.)

Organic food is associated by the general public with improved nutritional properties, and this has led to increasing demand for organic vegetables. The objective of this study was to investigate whether there were any differences in the micronutrient contents in organic and conventional tomatoes (Solanum lycopersicum L.). Two tomato cultivars ‘Lladó’ and ‘Antillas’ grown organically and conventionally were compared regarding their micronutrient in terms of K, Ca, Na, Mg, Fe, Zn, Mn, Cu, lycopene, ß‐carotene, ascorbic, malic and citric acids, and total phenolic compound content. Cultivar ‘Lladó’ had the highest concentration of the nutrient lycopene, ß‐carotene, Fe, Zn, Mn and Cu. Where cultivation method affected the concentration of ascorbic acid and Mn, only one cultivar was affected. For all nutrients examined, cultivar differences were greater than differences because of cultivation method. This study confirms that the most important variable in the micronutrient content of tomatoes is cultivar; organically grown tomato is no more nutritious than conventionally grown tomato when soil fertility is well managed.     

Putative association between a new polymorphism in exon 3 (Arg109Cys) of the pancreatic colipase gene and type 2 diabetes mellitus in two independent Caucasian study populations

The protein encoded by the pancreatic colipase (CLPS) gene is an essential cofactor needed by pancreatic triglyceride lipase (PNLIP) for efficient dietary lipid hydrolysis. Since the inhibition of lipase activity was shown to reduce the incidence of type 2 diabetes mellitus, we tested the hypothesis that genetic variations in the CLPS and PNLIP genes are associated with type 2 diabetes; 47 unrelated subjects were screened for polymorphisms of the CLPS and PNLIP genes. A nested-case control study of 192 incident type 2 diabetes subjects and 384 sex- and age-matched controls taken from the European Prospective Investigation into Cancer and Nutrition Potsdam Cohort (EPIC) was employed for association studies. The Metabolic Intervention Cohort Kiel (MICK) consisting of 716 males was used for verification. A novel putative functional polymorphism (Arg109Cys) was identified in the CLPS gene. The frequencies of the Arg/Cys genotype were 2.6% in EPIC and 2.2% in MICK study subjects. No homozygotes for the Cys/Cys genotype were found in either study population. Logistic regression analysis showed a statistically significant association of the Arg/Cys genotype with an increased risk of type 2 diabetes. The odds ratios estimated by the model were 3.75 (95%CI = 1.13-12.49, p = 0.03) in EPIC and 4.86 (95%CI = 1.13-20.95, p = 0.03) in MICK. No comparable associations were found with other traits of the insulin-resistance syndrome (e. g.; body mass index, waist to hip ratio). In conclusion, we obtained evidence in two German Caucasian study populations that the variant of the rare CLPS Arg109Cys polymorphism might contribute to increased susceptibility of type 2 diabetes.     

Dietary triterpenes in the treatment of type 2 diabetes: To date

At present, the importance of triterpenes in food and pharmaceutical industries is mainly based on their potential application in health food and medicine, particularly those commonly used in the treatment of diabetes and its complications. The purpose of this study is to review potential dietary triterpene in the treatment of diabetes and to identify the relationship of the structure and its activity of these compounds with their effective mechanisms. We summarized the latest developments of natural dietary triterpene and terpene-rich material, and discussed their underlying molecular mechanisms of anti-diabetic potential. We also suggested a better evaluation of the pharmacological profile of triterpenes and their derivate with a clear-cut choice of possible human pathologies.     

Effect of chronic consumption of pistachios (Pistacia vera L.) on glucose metabolism in pre-diabetics and type 2 diabetics: A systematic review

Pistachio is a nut with high polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA), polyphenols and carotenoids content, and the synergism between these compounds appears to affect glucose metabolism. In this systematic review we analyzed studies in which the effect of chronic consumption of pistachio on markers of glucose metabolism was evaluated in pre-diabetic and type 2 diabetics. We used the PubMed, Scopus, Cochrane and Lilacs databases. The research terms used were pistachio, pre-diabetes, type 2 diabetes mellitus, insulin resistance, blood glucose, hyperglycemia and glycated hemoglobin (HbA1c). Four articles were selected, of which three tested the intake of 50 to 57 g of pistachio/day and one 20% of the daily caloric intake, for a period of 1 to 4 months. Studies reported a decrease in fasting blood glucose, insulinemia, HOMA-IR, and fructosamine, but no change in HbA1c. Lower concentrations of miR-192 and miR-375 were also found, which correlated positively with HOMA-IR. The synergism between PUFA, MUFA, polyphenols and carotenoids present in pistachios can modulate specific miRNA, increasing insulin sensitivity through the PI3K-AKT signaling pathway. This modulation can be used as a tool to monitor the response to interventions, favoring the prevention and treatment of complications related to diabetes.     

Association of acyl-CoA-binding protein (ACBP) single nucleotide polymorphisms and type 2 diabetes in two German study populations

The human acyl-CoA-binding protein (ACBP) is a potential candidate gene of type 2 diabetes (T2D), since it plays a central role in determining the intracellular concentration of activated fatty acids which contribute to insulin resistance. The aim of our study was to evaluate whether single nucleotide polymorphisms (SNPs) of the ACBP gene are associated with risk of T2D. Genotyping of eight SNPs (rs2084202, rs3731607, rs8192501, rs8192504, rs2244135, rs2276596, rs8192506, rs2289948) was performed in 192 incident T2D subjects and 384 matched controls of the European Prospective Investigation into Cancer and Nutrition-Potsdam cohort. A putative promoter SNP (rs2084202) of splice variant ACBP 1c showed decreased risk of T2D (odds ratio (OR) 0.63, 95% CI 0.41-0.96). The haplotype, that contained the mutant base of rs2084202 showed similar evidence for the association with disease risk as single SNP rs2084202. In a second population-based study, Cooperative Health Research in the Augsburg Region of 226 individuals with T2D and 863 control subjects a borderline significant association between rs2084202 and T2D (OR 0.72, 95% CI 0.51-1.01) was observed. In summary, we obtained evidence from two Caucasian study populations that the minor allele of ACBP rs2084202 might be associated with reduced risk of T2D.     

Edible coating as postharvest management strategy for shelf-life extension of fresh tomato (Solanum lycopersicum L.): An overview

Tomato is considered as one of the most grown horticultural crops having a short shelf-life due to its climacteric nature of ripening, susceptibility to postharvest microbial decay, and mechanical damage, resulting in huge postharvest losses. Recently, the use of edible coatings has been seen as a promising environment friendly and sustainable technology for preserving the quality attributes and prolonging the shelf-life of tomato during storage. Although a lot of literature is available on the aspects of edible coating for fresh produce, especially stone and tropical fruits, but there is no dedicated comprehensive review that specifically addresses the requirements of edible coatings for whole fresh tomato. This review aims to provide the information about the desirable coating property requirements specific to tomato and summarizes or analyzes the recent studies conducted on the application of edible coating on tomato. The article also deals with recent trends on utilization of bioactive compounds as well as nanotechnological approaches for improving the performance and functionality of coating materials used for tomato. However, the edible coating technology for tomato is still at infancy state, and adoption of technology on a commercial scale requires economic viability and large-scale consumer acceptability.     

Grape seed proanthocyanidin extracts alleviate oxidative stress and ER stress in skeletal muscle of low‐dose streptozotocin‐ and high‐carbohydrate/high‐fat diet‐induced diabetic rats

Although ER stress in pancreas, liver, and adipose tissue was reported to be a novel event linked to the pathogenesis of type 2 diabetes mellitus, there is much less information on this event in skeletal muscle. Some studies indicated that treatment with antioxidants had beneficial effects on ER stress and diabetes. This study focuses on the effects of a strong antioxidant, grape seed proanthocyanidin extracts (GSPE), on skeletal muscle in diabetic rats induced with low dose streptozotocin‐ and a high‐carbohydrate/high‐fat diet. After 16 wk of GSPE treatment, diabetic rats showed decreased plasma glucose levels and insulin resistance. The efficacious effect of GSPE was manifested by the amelioration of muscular damage and dysfunction, as observed by histological examination and periodic acid Schiff staining. Concurrently, calcium overload and the abnormal activities of antioxidant enzymes and ATPases in diabetic muscles were partially reversed by GSPE treatment. GSPE also increased the activity of protein kinase B (a mediator of insulin's metabolic action) and partially alleviated severe ER stress. These findings suggest that GSPE may have auxiliary therapeutic potential for type 2 diabetes mellitus by decreasing oxidative stress and ER stress in skeletal muscle.