Antidiabetic effects of natural plant extracts via inhibition of carbohydrate hydrolysis enzymes with emphasis on pancreatic alpha amylase

Introduction: The increasing prevalence of type 2 diabetes mellitus and the negative clinical outcomes observed with the commercially available anti-diabetic drugs have led to the investigation of new therapeutic approaches focused on controlling postprandrial glucose levels. The use of carbohydrate digestive enzyme inhibitors from natural resources could be a possible strategy to block dietary carbohydrate absorption with less adverse effects than synthetic drugs. Areas covered: This review covers the latest evidence regarding in vitro and in vivo studies in relation to pancreatic alpha-amylase inhibitors of plant origin, and presents bioactive compounds of phenolic nature that exhibit anti-amylase activity. Expert opinion: Pancreatic alpha-amylase inhibitors from traditional plant extracts are a promising tool for diabetes treatment. Many studies have confirmed the alpha-amylase inhibitory activity of plants and their bioactive compounds in vitro, but few studies corroborate these findings in rodents and very few in humans. Thus, despite some encouraging results, more research is required for developing a valuable anti-diabetic therapy using pancreatic alpha-amylase inhibitors of plant origin

Correlation between serum advanced glycation end products and dietary intake of advanced glycation end products estimated from home cooking and food frequency questionnaires

Abstract Background & aims: To our knowledge the association between dietary advanced glycation end-products (dAGEs) and cardiometabolic disease is limited. Our aim was to examine the association between dAGEs and serum concentration of carboxymethyl-lysine (CML) or soluble receptor advanced glycation end-products (sRAGEs), and to assess the difference on dAGEs and circulating AGEs according to lifestyle and biochemical measures. Methods and results: 52 overweight or obese adults diagnosed with type 2 diabetes were included in this cross-sectional analysis. dAGEs were estimated from a Food Frequency Questionnaire (FFQ) or from a FFQ þ Home Cooking Frequency Questionnaire (HCFQ). Serum concentrations of CML and sRAGEs were measured by ELISA. Correlation tests were used to analyze the association between dAGEs derived from the FFQ or FFQ þ HCFQ and concentrations of CML or sRAGEs. Demographic characteristics, lifestyle factors and biochemical measures were analyzed according to sRAGEs and dAGEs using student t-test and ANCOVA. A significant inverse association was found between serum sRAGEs and dAGEs estimated using the FFQ þ HCFQ (r Z 0.36, p Z 0.010), whereas no association was found for dAGEs derived from the FFQ alone. No association was observed between CML and dAGEs. dAGEs intake estimated from the FFQ þ HCFQ was significantly higher among younger and male participants, and in those with higher BMI, higher Hb1Ac levels, longer time with type 2 diabetes, lower adherence to Mediterranean diet, and higher use of culinary techniques that generate more AGEs (all p values p < 0.05). Conclusions: These results show knowledge on culinary techniques is relevant to derive the association between dAGEs intake and cardiometabolic risk factors

Encapsulated high temperature PCM as active filler material in a thermocline-based thermal storage system

A great concern in Concentrated Solar Power (CSP) is to boost energy harvesting systems, by finding materials with enhanced thermal performance. Phase Change Materials (PCM) have emerged as a promising option, due to their high thermal storage density compared to sensible storage materials currently used in CSP. A thermal storage system for solar power plants is proposed, a thermocline tank with PCM capsules together with filler materials, based on multi-layered solid-PCM (MLSPCM) thermocline-like storage tank concept [1,2]. A detailed selection of the most suitable high temperature PCM, their containment materials and encapsulation methods are shown

Impact of polyphenols and polyphenol-rich dietary sources on gut microbiota composition

Gut microbiota plays a key role in host physiology and metabolism. Indeed, the relevance of a well-balanced gut microbiota composition to an individual´s health status is essential for the person's well-being. Currently, investigations are focused on analyzing the effects of pre- and probiotics as new therapeutic tools to counteract the disruption of intestinal bacterial balance occurring in several diseases. Polyphenols exert a wide range of beneficial health effects. However, although specific attention has been paid in recent years to the function of this “biological entity” in the metabolism of polyphenols, less is known about the modulatory capacity of these bioactive compounds on gut microbiota composition. This review provides an overview of the latest investigations carried out with pure polyphenols, extracts rich in polyphenols and polyphenol-rich dietary sources (such as cocoa, tea, wine, soy products and fruits), and critically discusses the consequences to gut microbiota composition which are produced

Reshaping faecal gut microbiota composition by the intake of trans-resveratrol and quercetin in high-fat sucrose diet-fed rats

Diet‐induced obesity is associated to an imbalance in the normal gut microbiota composition. Resveratrol and quercetin, widely known for their health beneficial properties, have low bioavailability and, when reach the colon, they are targets of the gut microbial ecosystem. Hence, the use of these molecules in obesity might be considered as a potential strategy to modulate intestinal bacterial composition. The purpose of this study was to determine whether trans‐resveratrol and quercetin administration could counteract gut microbiota dysbiosis produced by high‐fat sucrose diet (HFS) and in turn, improve gut health. Wistar rats were randomized into four groups fed a HFS diet supplemented or not with trans‐resveratrol (15 mg/kg BW/day), quercetin (30 mg/kg BW/day) or a combination of both polyphenols at those doses. Administration of both polyphenols together prevented body‐weight gain and reduced serum insulin levels. Moreover, individual supplementation of trans‐resveratrol and quercetin effectively reduced serum insulin levels and insulin resistance. Quercetin supplementation generated a great impact on gut microbiota composition at different taxonomic levels, attenuating Firmicutes/Bacteroidetes ratio and inhibiting the growth of bacterial species previously associated to diet‐induced obesity (Erysipelotrichaceae, Bacillus, Eubacterium 1 cylindroides). Overall, the administration of quercetin was found to be effective in lessening HFS diet‐induced gut microbiota dysbiosis. In contrast, trans‐resveratrol supplementation alone or in combination with quercetin, scarcely modified the profile of gut bacteria, but acted at intestinal level altering the mRNA expression of tight‐junction proteins (TJPs) and inflammation associated genes

Analysis of subcellular metabolite levels of potato tubers (Solanum tuberosum) displaying alterations in cellular or extracellular sucrose metabolism

The expression of a heterologous invertase in potato tubers (Solanum tuberosum) in either the cytosol or apoplast leads to a decrease in total sucrose content and to an increase in glucose. Depending on the targeting of the enzyme different changes in phenotype and metabolism of the tubers occur: the cytosolic invertase expressing tubers show an increase in the glycolytic flux, accumulation of amino acids and organic acids, and the appearance of novel disaccharides; however, these changes are not observed when the enzyme is expressed in the apoplast [Roessner et al. (2001). Plant Cell, 13, 11-29]. The analysis of these lines raised several questions concerning the regulation of compartmentation of metabolites in potato tubers. In the current study we addressed these questions by performing comparative subcellular metabolite profiling. We demonstrate that: (i) hexoses accumulate in the vacuole independently of their site of production, but that the cytosolic invertase expression led to a strong increase in the cytosolic glucose concentration and decrease in cytosolic sucrose, whereas these effects were more moderate in the apoplastic expressors; (ii) three out of four of the novel compounds found in the cytosolic overexpressors accumulate in the same compartment; (iii) despite changes in absolute cellular content the subcellular distribution of amino acids was invariant in the invertase overexpressing tubers. These results are discussed in the context of current models of the compartmentation of primary metabolism in heterotrophic plant tissues

Shifts in microbiota species and fermentation products in a dietary model enriched in fat and sucrose

The gastrointestinal tract harbours a “superorganism” called the gut microbiota, which is known to play a crucial role in the onset and development of diverse diseases. This internal ecosystem, far from being a static environment, could be willingly manipulated by diet and dietary components. Feeding animals with high-fat sucrose diets entails diet-induced obesity, a model which is usually used in research to mimic the obese phenotype of Western societies. The aim of the present study was to identify gut microbiota dysbiosis and associated metabolic changes produced in 5 male Wistar rats fed a high-fat sucrose (HFS) diet for six weeks and to compare it with the basal microbial composition. For this purpose, DNA extracted from faeces at baseline and after the treatment was analysed by amplification of the V4-V6 region of the 16S ribosomal DNA (rDNA) gene using 454 pyrosequencing. Short-chain fatty acids (SCFA), acetate, propionate and butyrate, were also evaluated by gas chromatography-mass spectrometry (GC-MS). At the end of the treatment, gut microbiota composition significantly differed at phylum level (Firmicutes, Bacteroidetes and Proteobacteria) and class level (Erisypelotrichi, Deltaproteobacteria, Bacteroidia and Bacilli). Interestingly, Clostridia class showed a significant decrease after the HFS-diet treatment, which correlated with visceral adipose tissue, and is likely mediated by dietary carbohydrates. Of particular interest, Clostridium cluster XIVa species were significantly reduced and changes were identified in the relative abundance of other specific bacterial species (Mitsuokella jalaludinii, Eubacterium ventriosum, Clostridium sp. FCB90-3, Prevotella nanceiensis, Clostridium fusiformis, Clostridium sp. BNL1100 and Eubacterium cylindroides) that, in some cases, showed opposite trends to their relative families. These results highlight the relevance of characterizing gut microbial population differences at species level and contribute to understand the plausible link between the 1 diet and specific gut bacterial species that are able to influence the inflammatory status, intestinal barrier function and obesity development. Keywords: gut microbiota, pyrosequencing, high-fat sucrose diet, short chain fatty acids, Erysipelotrich

Hierarchy Theory of Evolution and the Extended Evolutionary Synthesis: Some Epistemic Bridges, Some Conceptual Rifts

Contemporary evolutionary biology comprises a plural landscape of multiple co-existent conceptual frameworks and strenuous voices that disagree on the nature and scope of evolutionary theory. Since the mid-eighties, some of these conceptual frameworks have denounced the ontologies of the Modern Synthesis and of the updated Standard Theory of Evolution as unfinished or even flawed. In this paper, we analyze and compare two of those conceptual frameworks, namely Niles Eldredge’s Hierarchy Theory of Evolution (with its extended ontology of evolutionary entities) and the Extended Evolutionary Synthesis (with its proposal of an extended ontology of evolutionary processes), in an attempt to map some epistemic bridges (e.g. compatible views of causation; niche construction) and some conceptual rifts (e.g. extra-genetic inheritance; different perspectives on macroevolution; contrasting standpoints held in the “externalism–internalism” debate) that exist between them. This paper seeks to encourage theoretical, philosophical and historiographical discussions about pluralism or the possible unification of contemporary evolutionary biology

Metabolic faecal fingerprinting of trans-resveratrol and quercetin following a high-fat sucrose dietary model using liquid chromatography coupled to high-resolution mass spectrometry

Faecal non‐targeted metabolomics deciphers metabolic end‐products resulting from the interactions among food, host genetics, and gut microbiota. Faeces from Wistar rats fed a high‐fat sucrose (HFS) diet supplemented with trans‐resveratrol and quercetin (separately or combined) were analysed by liquid chromatography coupled to high‐resolution mass spectrometry (LC‐HRMS). Metabolomics in faeces are categorised into four clusters based on the type of treatment. Tentative identification of significantly differing metabolites highlighted the presence of carbohydrate derivatives or conjugates (3‐phenylpropyl glucosinolate and dTDP‐D‐mycaminose) in quercetin group. The trans‐resveratrol group was differentiated by compounds related to nucleotides (uridine monophosphate and 2,4‐dioxotetrahydropyrimidine D‐ribonucleotide). Marked associations between bacterial species (Clostridium genus) and the amount of some metabolites were identified. Moreover, trans‐resveratrol and resveratrol‐derived microbial metabolites (dihydroresveratrol and lunularin) were also identified. Accordingly, this study confirms the usefulness of omics‐based techniques to discriminate individuals depending on the physiological effect of food constituents and represents an interesting tool to assess the impact of future personalized therapies

Kv7 Channels Can Function without Constitutive Calmodulin Tethering

M-channels are voltage-gated potassium channels composed of Kv7.2-7.5 subunits that serve as important regulators of neuronal excitability. Calmodulin binding is required for Kv7 channel function and mutations in Kv7.2 that disrupt calmodulin binding cause Benign Familial Neonatal Convulsions (BFNC), a dominantly inherited human epilepsy. On the basis that Kv7.2 mutants deficient in calmodulin binding are not functional, calmodulin has been defined as an auxiliary subunit of Kv7 channels. However, we have identified a presumably phosphomimetic mutation S511D that permits calmodulin-independent function. Thus, our data reveal that constitutive tethering of calmodulin is not required for Kv7 channel function