Oral Starch Tolerance Test Research Articles

Combination of plant metabolites hinders starch digestion and glucose absorption while facilitating insulin sensitivity to diabetes.

Diabetes mellitus (DM) is a common endocrine disease resulting from interactions between genetic and environmental factors. Type II DM (T2DM) accounts for approximately 90% of all DM cases. Current medicines used in the treatment of DM have some adverse or undesirable effects on patients, necessitating the use of alternative medications. To overcome the low bioavailability of plant metabolites, all entities were first screened through pharmacokinetic, network pharmacology, and molecular docking predictions. Experiments were further conducted on a combination of antidiabetic phytoactive molecules (rosmarinic acid, RA; luteolin, Lut; resveratrol, RS), along with in vitro evaluation (α-amylase inhibition assay) and diabetic mice tests (oral glucose tolerance test, OGTT; oral starch tolerance test, OSTT) for maximal responses to validate starch digestion and glucose absorption while facilitating insulin sensitivity. The results revealed that the combination of metabolites achieved all required criteria, including ADMET, drug likeness, and Lipinski rule. To determine the mechanisms underlying diabetic hyperglycemia and T2DM treatments, network pharmacology was used for regulatory network, PPI network, GO, and KEGG enrichment analyses. Furthermore, the combined metabolites showed adequate in silico predictions (α-amylase, α-glucosidase, and pancreatic lipase for improving starch digestion; SGLT-2, AMPK, glucokinase, aldose reductase, acetylcholinesterase, and acetylcholine M2 receptor for mediating glucose absorption; GLP-1R, DPP-IV, and PPAR-γ for regulating insulin sensitivity), in vitro α-amylase inhibition, and in vivo efficacy (OSTT versus acarbose; OGTT versus metformin and insulin) as nutraceuticals against T2DM. The results demonstrate that the combination of RA, Lut, and RS could be exploited for multitarget therapy as prospective antihyperglycemic phytopharmaceuticals that hinder starch digestion and glucose absorption while facilitating insulin sensitivity.

Assessment of anti-hyperglycemic and anti-hyperlipidemic effects of thiazolidine-2,4-dione derivatives in HFD-STZ diabetic animal model

Type 2 diabetes mellitus (T2DM) is a chronic endocrine/metabolic disorder characterized by elevated postprandial and fasting glycemic levels that result in disturbances in primary metabolism. In this study, we evaluated the metabolic effects of thiazolidine-2,4-dione derivatives in Wistar rats and Swiss mice that were fed a high-fat diet (HFD) for 4 weeks and received 90 mg/kg of streptozotocin (STZ) intraperitoneally as a T2DM model. The HFD consisted of 17% carbohydrate, 58% fat, and 25% protein, as a percentage of total kcal. The thiazolidine-2,4-dione derivatives treatments reduced fasting blood glucose (FBG) levels by an average of 23.98%–50.84%, which were also improved during the oral starch tolerance test (OSTT). Treatment with thiazolidine-2,4-dione derivatives also improved triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), and total cholesterol levels (P < 0.05). The treatment intake has also shown a significant effect to modulate the altered hepatic and renal biomarkers. Further treatment with thiazolidine-2,4-dione derivatives for 28 days significantly ameliorated changes in appearance and metabolic risk factors, including favorable changes in histopathology of the liver, kidney, and pancreas compared with the HFD/STZ-treated group, suggesting its potential role in the management of diabetes. Thiazolidine-2,4-dione derivatives are a class of drugs that act as insulin sensitizers by activating peroxisome proliferator-activated receptor-gamma (PPAR-γ), a nuclear receptor that regulates glucose and lipid metabolism. The results of this study suggest that thiazolidine-2,4-dione derivatives may be a promising treatment option for T2DM by improving glycemic control, lipid metabolism, and renal and hepatic function.

Comprehensive analysis of bioactive compounds in Crocus sativus stamens extracts by HPLC-DAD: investigating antidiabetic activity via in vitro, in vivo, and molecular docking simulation.

Introduction: Medicinal herbs used in traditional diabetes treatment are a rich source of anti-diabetic compounds. Pancreatic α-amylase inhibitors offer an effective strategy to reduce postprandial hyperglycemic levels via control of starch degradation. In this context, our study for the first time investigates the effect of Crocus sativus stamens extracts on α-amylase inhibition. Material and methods: The hydromethanolic and hydroethanolic extracts were obtained by macerating the dried stamen powder with methanol/water or ethanol/water, respectively. The total phenolic content of the stamen extracts was assessed using the Folin-Ciocalteu reagent method, while the total flavonoid content was determined using the Aluminum Chloride method. Phytochemicals were further quantified and identified using HPLC-DAD. For evaluation of hypoglycemic activity, in vitro α-amylase enzyme inhibition was calculated. The results were confirmed in vivo using an oral starch tolerance test in both normal and diabetic rats. Results: Our findings demonstrated a higher level of polyphenols and flavonoids in the hydroethanolic extract. Important flavonoids found were kaempferol, rutin, and vanillic acid, while prominent carotenoids contained trans- and cis-crocins. The in vitro study showed that both hydromethanolic and hydroethanolic extracts had considerable inhibitory effects, with maximum inhibitions of approximately 83% and 89%, respectively. In vivo tests indicated that both extracts effectively lowered peak blood glucose and area under the curve in both normal and diabetic rats following oral starch treatment. The obtained results are also supported by a docking study. Conclusion: These findings imply that C. sativus stamens possess a distinctive capability to reduce postprandial blood glucose levels. This effect is likely mediated through the inhibition of α-amylase, presenting a novel dietary avenue for managing diabetes.

Inhibitory effects of Buddleja scordioides (salvilla) leaves on digestive enzymes and carbohydrate absorption in vivo

The effects of Buddleja scordioides (BsLI) leaf infusions on digestive enzymes and carbohydrate absorption were evaluated. The BsLI yield was 21.64 %. In addition, a chemical characterization was carried out identifying hydroxybenzoic acids, hydroxycinnamic acids, flavonols, flavanones and flavones. In vitro studies were performed to determine the inhibitory action of BsLI on lipase, α-amylase, and α-glucosidase. Then, in rats, oral starch tolerance tests (OSTT) were carried out using BsLI at a dose of 9.5 mg/kg body weight. Results showed moderate inhibition of lipase and α-glucosidase, but greater inhibition of α-amylase compared to positive controls. During the OSTT trial, the group receiving BsLI showed a significant reduction in glucose levels compared to the negative control group. Bioactive compounds, such as naringenin, luteolin, quercetin, and coumaric acid, were identified after BsLI administration. Furthermore, the consumption of BsLI was safe and showed antioxidant activity like Trolox. In conclusion, BsLI may have an enhanced effect on glucose metabolism by inhibiting carbohydrate absorption.&#x0D; DOI: https://doi.org/10.54167/tch.v17i2.1221

Inhibitory Effects of Nipa Palm Vinegar on the Carbohydrate Hydrolysing Enzymes

Nipa palm vinegar has been traditionally used to manage blood glucose levels by diabetic patients in Southeast Asia. This study was designed to evaluate the efficacy of nipa palm vinegar in inhibiting the activity of carbohydrate hydrolyzing enzymes, α-glucosidase, and α-amylase. In vitro spectrophotometric assays were used to evaluate the inhibitory activity of nipa palm activity against α-glucosidase and α-amylase. To confirm the in vitro findings, an oral starch tolerance test in the normoglycemic Sprague Dawley rat was conducted. Acarbose was used as the positive control for both tests. Nipa palm vinegar at a concentration ranging from 4000 to 62.5 mg/mL inhibited the activity of α-glucosidase and α-amylase in a concentration-dependent manner with the respective IC50 values of 144.50 ± 1.1 mg/mL and 90.30 ± 1.7 mg/mL. It also exerted uncompetitive inhibition against α-glucosidase and competitive inhibition towards α-amylase. In vivo oral starch tolerance test showed a significant (p &lt; 0.05) postprandial glucose-lowering effect of nipa palm vinegar at the doses of 2 mL/kg and 1 mL/kg body weight as compared to the control. In a conclusion, this study demonstrated that nipa palm vinegar suppressed the rise in postprandial glucose levels partly by inhibiting the activity of digestive enzymes.

Synthesis, spectroscopic and DFT studies of 5-methyl-1H-pyrazole-3-carbohydrazide N-glycoside as potential anti-diabetic and antioxidant agent

A novel pyrazole-carbohydrazide N-glycoside derivative (SM1) was prepared by condensation of D-glucose with 1H-pyrazole-3-carbohydrazide. The structure of SM1 was identified by FT-IR, 1H-NMR, 13C-NMR, UV–Vis and mass spectrometry. Structures and properties of SM1 in gas phase, methanol and aqueous solution were predicted by using hybrid B3LYP method with the 6–31G* and 6–311++G** basis sets. Considerable correlations were observed among the experimental spectra and the corresponding theoretical ones. Both levels of calculations evidence that the glucose moiety modify the dihedral angles and that the C=O and the N-NH group of pyrazole ring are in a cis position. A high negative solvation energy of SM1 in water is observed (-196.36 kJ/mol). Both methods show changes in volumes with the size of basis sets and with the permittivity of solvent while the dipole moments follow approximately a same tendency. NBO and AIM studies predict high stabilities of SM1 with both methods supported probably by low separations MK charges on N7 and O13 atoms while the low reactivity of SM1 could be explained by the low electrophilicity index ω. Complete vibrational assignments of all vibration modes of SM1 are reported together with the scaled harmonic force constants. Compound SM1 was tested in vitro for their α-glucosidase and α-amylase inhibitory activity and the postprandial glucose level after administration of this compound was measured by using oral starch tolerance test (OSTT). The in vitro antioxidant activities of SM1 were determined by DPPH, ABTS, and H2O2 radical scavenging methods and the total reducing power Fe3+-Fe2+ transformation (FRAP). The results shown that SM1 exhibited a potent α-glucosidase inhibition with IC50 value of 59.75 ± 0.80 µM, compared to acarbose (IC50 = 72.58 ± 0.68 µM). The result of OSTT showed that SM1 caused the reduction of blood glucose by 42% at 60 min in diabetic mice, which also showed its significant hypoglycemic effect. Moreover, the results of antioxidant activities showed that the title compound has potent antioxidant and radical scavenger.

Antidiabetic Effect of &lt;i&gt;Beta vulgaris&lt;/i&gt; Mixture: Regulation of Glycolytic Enzymes and Pancreatic Beta Cells

Diabetes is a chronic metabolic disease with a high prevalence worldwide. Beet (Beta vulgaris) is a plant that is widely used in many countries and has various biological activities. In this study, we aimed to evaluate the antidiabetic effect of a B. vulgaris mixture (BM). In the in vitro evaluation, we measured the inhibitory activities of α-amylase and α-glucosidase, performed the oral starch tolerance test (OATT) and oral sucrose tolerance test (OSTT) in Sprague Dawley (SD) rats, and evaluated the clinical symptoms, oral glucose tolerance test (OGTT), number of blood cells, and insulin resistance in db/db mice. BM showed an inhibitory effect against α-amylase and α-glucosidase activity and decreased the blood glucose increased in the OATT and OSTT. In the diabetes mouse model, BM alleviated the general symptoms of diabetes and OGTT results showed a decrease in the increased blood sugar level. Regarding diabetes-related tissue weight, BM decreased the reduced pancreatic weight and showed an effect on diabetes-related factors of blood. Histological analysis indicated that BM decreased insulin concentration, insulin resistance, and insulin secretion ability in serum, and increased insulin concentration in the islets of Langerhans. These results demonstrate that BM has an antidiabetic effect through the regulation of glycolytic enzymes and β cell activity in the pancreas.

Bio-Guided Isolation of Two New Hypoglycemic Triterpenoid Saponins from Polygonum capitatum.

PurposeDiabetes is a common disease caused by a combination of genetic and environmental factors, which was the top three diseases threatening human health. Therefore, it is necessary to seek more efficient hypoglycemic drugs. The main objective of this study was to investigate the potential hypoglycemic effects of compounds from Polygonum capitatum.Materials and MethodsOur experiments were divided into three steps: (1) α-amylase test and oral starch tolerance test (OSTT) for screening the biological extract part of P. capitatum; (2) chemical isolation and identification using various separation techniques, and spectrum methods; and (3) evaluation of α-amylase inhibitory activity of isolates and in silico analysis for mechanism investigation.ResultsThe n-butanol fractioned part of P. capitatum was confirmed to be the biological part according to α-amylase test. Then, two new triterpenoid saponins were isolated from the n-butanol part, which were also the first isolated triterpenoid saponins from P. capitatum. The activities of compounds 1 and 2 against α-amylase were 51.9±2.8% and 38.1±2.2%, respectively, which was consistent with the molecular docking analysis. In which, 1 and 2 showed the binding affinity energy for α-amylase was −9.4 kcal/mol and −7.8 kcal/mol, respectively.ConclusionTwo new triterpenoid saponins were firstly isolated from P. capitatum, and displays potency as a hypoglycemic agent through blocking α-amylase.

A nutraceutical combination of cinnamon, purple onion, and tea linked with key enzymes on treatment of type 2 diabetes.

Diabetes mellitus (DM) is concomitant with significant morbidity and mortality and its prevalence is accumulative worldwide. The conventional antidiabetic agents are known to mitigate the symptoms of diabetes; however, they may also cause adverse effects. This study was to explore the efficacy of polyherbal dietary supplement cinnamon, purple onion, and tea on the mediation of postprandial hyperglycemia in the search of combinations with a maximal response. A starch solution (3g/kg Bwt) of oral starch tolerance test (OSTT) and glucose solution (4g/kg Bwt) of oral glucose tolerance test (OGTT) with and without cinnamon, purple onion, tea extract (15mg/kg Bwt), and mixture (each 5mg/kg Bwt, 1:1:1), metformin (14mg/kg Bwt), or acarbose (50mg/kg Bwt) was administered to high fat plus high fructose-induced diabetic mice after an overnight fast. Postprandial plasma glucose levels were measured and changed areas under the response curve were calculated to find out the maximal efficacy of optimal polyherbal combinations. Compared with acarbose, the mixture of extracts (purple onion, cinnamon, and tea) indicated the decreasing blood glucose in OSTT. In OGTT, the mixture of extracts showed greater efficacy for hypoglycemia when compared with metformin. The molecular docking of α-amylase, α-glucosidase, and AMPK was further confirmed the putatively acting molecules from the extracts of purple onion, cinnamon, and tea. Overall, this investigation evidenced a beneficial mediation for the progression of lowering blood glucose with a combinatory extract of cinnamon, dietary onion, and tea, implicating their prospective as nutraceuticals that might ameliorate hyperglycemia in diabetes. PRACTICAL APPLICATIONS: Diabetes mellitus (DM), one of metabolic syndrome, attributes to risk factors like obesity, physical inactivity, ageing, life style, and genetic predisposition even with significant morbidity and mortality. DM is increasing and accounts for an estimated annual medical expenditure of US$ 827 billion worldwide. Therefore, maintaining blood glucose levels within the normal range is critical for preventing diabetes and its co-morbidities. The conventional antidiabetic agents are known to mitigate the symptoms of diabetes; nevertheless, they may also cause adverse or side effects. In an effort to design novel and well-tolerated solutions to halt the progression of DM, however evidence-base is extremely limited regarding the efficacy of polyherbal dietary supplement individual herbs for the management of glycemia. In this investigation evidenced a beneficial mediation for the progression of lowering blood glucose with a combinatory extract of cinnamon, dietary onion, and tea, implicating their prospective as nutraceuticals that might ameliorate hyperglycemia in diabetes.

Syringaldehyde promoting intestinal motility with suppressing α-amylase hinders starch digestion in diabetic mice

The antihyperglycemic potential of syringaldehyde has been previously investigated; however, the underlying mechanism remains unclear. In this study, we performed a postprandial glucose test (in vivo) including oral glucose tolerance test (OGTT) and oral starch tolerance test (OSTT) in fructose-induced diabetic mice on a high-fat diet for mimicking type 2 diabetes to explore the hypoglycemic efficacy of syringaldehyde and the underlined molecular involvement of syringaldehyde in a glucose-lowering effect. The results revealed that syringaldehyde dose-dependently suppressed blood glucose in both the OSTT and OGTT when referenced to acarbose and metformin, respectively. Surprisingly, syringaldehyde triggered jejunum motility (ex vivo) via activation of the muscarinic-type acetylcholine receptor. By performing virtual screening with molecular docking, the data showed that syringaldehyde nicely interacted with glucagon-like peptide 1 receptor (GLP-1R), peroxisome proliferator-activated receptor (PPAR), dipeptidyl peptidase-IV (DPP-4), acetylcholine M2 receptor, and acetylcholinesterase. These results showed that syringaldehyde can potentiate intestinal contractility to abolish the α-amylase reaction when concurrently reducing retention time and glucose absorption to achieve a glucose-lowering effect in diabetic mice, suggesting its potential therapeutic benefits with improvement for use as a prophylactic and treatment.

Dipeptidyl peptidase-IV inhibitory peptides derived from salmon milt and their effects on postprandial blood glucose level

The hydrolysate of Oncorhynchus keta (chum salmon) milt was found to exhibit strong inhibitory activity against dipeptidyl peptidase-IV (DPP-IV), and the hypoglycaemic effect of these salmon milt peptides (SMPs) was confirmed using oral starch tolerance tests in Sprague–Dawley rats. Specifically, the oral administration of SMPs at a dose of 300 mg/kg body weight for 1 week resulted in a significant decrease in the blood glucose level of the rats 60 min after starch consumption compared with the control. The bioassay-guided separation of SMPs, using a combination of column chromatographic techniques, led to the identification of 12 active di-, tri- and tetrapeptides, including four novel DPP-IV inhibitory peptides, namely Phe-Pro-Val-Gly, Leu-Pro-Val-Leu, Val-Pro-Phe-Pro and Ile-Pro-Leu. Among these 12 peptides, Ile-Pro contributed the most (1.3%) to the total DPP-IV inhibitory activity of SMPs. Therefore, SMPs may have the potential to be used as a suppressor of postprandial hyperglycaemia and to be considered a promising functional food material for the prevention of type II diabetes.

Leaf extracts of Glyphaea brevis attenuate high blood glucose and lipids in diabetic rats induced with streptozotocin

Background: Diabetes is a non-communicable disease causing impairment of carbohydrate and lipid metabolisms. Previous ethnobotanical surveys showed that leaves of Glyphaea brevis (G. brevis) are used conventionally in the treatment of diabetes with limited scientific evidence. Objective: We aimed to determine the effects of aqueous (AE) and hydroethanolic extracts (HEE) of G. brevis leaves in attenuating diabetes-linked hyperglycemia and hyperlipidemia in an animal model. Materials and Methods: Thirty streptozotocin-induced diabetic male rats were divided into six groups receiving the following daily treatments for 4 weeks orally: control (distilled water), reference (tolbutamide 80 mg/kg) and 4 tests (AE 250 mg/kg, AE 500 mg/kg, HEE 250 mg/kg, and HEE 500 mg/kg). The effects of each treatment on postprandial hyperglycemia were assessed using oral glucose tolerance and oral starch tolerance tests. Blood was collected to assess the effects of treatments on fasting plasma glucose, glycated hemoglobin (HbA1c), and lipid profile. Liver glycogen and gluconeogenic enzyme activity were also measured. Results: AE- and HEE-treated rats had 36%–64% lower fasting blood glucose levels, 34%–73% lower postprandial glycemia, and 15%–75% lower HbA1c than rats from control group (P

Improvement in serum amylase and glucose levels in diabetic rats on oral administration of bisdemethoxycurcumin from Curcuma longa and limonoids from Azadirachta indica.

Curcuma longa and Azadirachta indica are traditionally used in Indian cuisine and Ayurvedic medicine as nutraceuticals against diabetes. The crude C.longa isopropanol extract, bisdemethoxycurcumin (BDMC), the purified bioactive component from C.longa, and limonoids azadiradione, gedunin from A.indica, are able to inhibit in vitro the antidiabetic target human pancreatic α-amylase independently. However, no reports on their in vivo efficacy in animal models exist. Thus, the antidiabetic effect of these orally administered human pancreatic α-amylase inhibitors was performed on streptozotocin-induced Sprague-Dawley rats. Initially, the normal rats were treated with test compounds (10-100mg/kg of body weight) in corn oil (5ml/kg), and as no lethality was observed in these doses, further studies were carried out with lowest concentration of 10mg/kg of body weight. A reduction in area under curve (AUC) suggested glucose-lowering effect of these compounds in starch fed diabetic rats. The efficacy study showed a significant improvement in body weight, blood glucose levels, serum amylase, and fructosamine levels as well in other serum parameters associated with diabetes with respect to liver and renal functions. Hence, under in vivo conditions, inhibition of α-amylase activity by BDMC and limonoids affirms it as one of the mechanisms of action resulting in reduction of blood glucose levels. PRACTICAL APPLICATIONS: Bisdemethoxycurcumin from C.longa and limonoids, namely, azadiradione and gedunin, from A.indica are potent inhibitors of the antidiabetic target human pancreatic α-amylase. Oral Starch Tolerance Test (OSTT) and 28-day efficacy study to check the effect of these orally administered inhibitors in diabetic rat models showed significant improvements in serum blood glucose and amylase levels as well as in other diabetes related serum parameters, namely, bilirubin, lipids, lactate dehydrogenase, alkaline phosphatase, and urea. The study contributes to understanding the action and efficacy of these pancreatic α-amylase inhibitors and suggests a potential role for them as nutraceuticals/therapeutics in management of post-prandial hyperglycemia.

Hypoglycemic and antioxidant effects of green tomato ( Physalis ixocarpa Brot.) calyxes’ extracts

The aim of this study was to evaluate the hypoglycemic and antioxidant potential of green tomato (Physalis ixocarpa Brot.) calyxes' extracts. Three methods were used to obtain the extracts: maceration (M), ultrasound-assisted (US), and infusion. Regarding in vitro hypoglycemic evaluation, glucose diffusion assay and enzymatic inhibitory action of α-amylase and α-glucosidase were performed. Whereas, for in vivo assessment an oral starch tolerance test (OSTT) was tested with aqueous extracts [infusion (40mg/kg b. wt.), maceration (M) water (98mg/kg b. wt.), and US water (82.24mg/kg b. wt.)] on male Wistar rats. Additionally, in vitro antioxidant activity of P. ixocarpa calyxes' was evaluated through inhibition of scavenging radical assay and lipid peroxidation. Extracts decreased the glucose diffusion in a range of 18%-56% compared with the negative control. Additionally, extracts inhibited α-amylase (above 80%) and α-glucosidase enzymes (above 90%). All groups treated with P. ixocarpa calyxes' significantly reduced the glucose levels at 120min (infusion=13.3%, M Water=12.7%, and US Water=19.4%) in comparison with the negative control, and similar levels to acarbose at 120min (13.1%). Finally, extracts showed IC50 values in a range of 2.5-6.6µg/µl for radical scavenging, and 118-199µg/µl for lipid oxidation. Our results show that P. ixocarpa calyxes' extracts induce hypoglycemia and antioxidant effects in vitro and in vivo. PRACTICAL APPLICATIONS: The green tomato is usually consumed in Mexico, the United States, and Central America. This fruit grows inside a calyx, which is considered an agro-food waste. However, some regions of Latin America have a traditional medicine purpose for diabetes affections. To the best of our knowledge, there are no published data that supports its hypoglycemic action. The information provided will be useful to nutraceutical applications that allow value-added products and sustainable green tomato production.

Polyphenol-rich extract and fractions of Terminalia phaeocarpa Eichler possess hypoglycemic effect, reduce the release of cytokines, and inhibit lipase, α-glucosidase, and α-amilase enzymes

Ethnopharmacological relevancespecies of Terminalia (Combretaceae) are used to treat diabetes and metabolic disorders in Asia, Africa, and America. Terminalia phaeocarpa Eichler is an endemic tree from Brazil, popularly known as capitão. This species is closely related to Terminalia argentea Mart., also vulgarly known as capitão, a native but not endemic tree. Due to their phenotype similarity, these species might eventually prove inseparable and they are indistinctly used by locals to treat diabetes, among other diseases. The potential antidiabetic effect of T. argentea has been previously reported, whereas the biological effects and chemical composition of T. phaeocarpa have never been addressed so far. Aim of the studyinvestigate the hypoglycaemic effect of an ethanol extract (EE) of T. phaeocarpa leaves and its ethyl acetate (FrEtOAc) and hydromethanolic (FrMEOH) fractions, in addition to their activity on the release of pro-inflammatory mediators and inhibition of lipase, α-amylase, and α-glucosidase enzymes. Additionally, it aimed to characterize the chemical composition of the extract and fractions, seeking to identify the compounds related to the biological activities. Materials and methodsThe effect on the release of TNF-α, IL-1β, and CCL-2 was evaluated in LPS-stimulated THP-1 cells (ATCC TIB-202). The inhibition of lipase, α-amylase, and α-glucosidase was tested in vitro, whereas the hypoglycemic effect was assayed in the oral starch tolerance test. The chemical composition was investigated by extensive UHPLC-DAD-ESI-MS/MS analyses. ResultsThe extract and derived fractions reduced TNF-α (EE pIC50 = 4.58 ± 0.01; FrEtOAc pIC50 = 4.69 ± 0.01; FrMeOH pIC50 = 4.54 ± 0.02) and IL-1β (EE pIC50 = 4.86 ± 0.02; FrEtOAc pIC50 = 4.86 ± 0.02; FrMeOH pIC50 = 4.75 ± 0.01) release by LPS-stimulated THP-1 cells in a concentration-dependent manner, whereas the inhibitory effect on CCL-2 release did not reach a clear linear relationship for the tested concentrations. The extract and fractions also inhibited in vitro the activity of lipase (EE pIC50 = 3.97 ± 0.12; FrEtOAc pIC50 = 3.87 ± 0.04; FrMeOH pIC50 = 3.67 ± 0.14), α-amylase (EE pIC50 = 4.46 ± 0.27; FrEtOAc pIC50 = 5.47 ± 0.27; FrMeOH pIC50 = 4.26 ± 0.22), and α-glucosidase (EE pIC50 = 5.46 ± 0.05; FrEtOAc pIC50 = 5.79 ± 0.11; FrMeOH pIC50 = 5.74 ± 0.05). The pIC50 values of the test samples were lower than those obtained with orlistat (7.59 ± 0.08) and acarbose (6.04 ± 0.37 and 7.63 ± 0.04) employed as the positive controls respectively in the lipase, α-amylase, and α-glucosidase assays. When assayed in the oral starch tolerance test, the extract and fractions also reduced animal glycaemia. UHPLC-DAD-ESI-MS/MS analyses of the extract and fractions led to the identification of 38 phenolic compounds, mainly phenolic acids, ellagitannins and flavonoids, among others, all of them first-time described for the species. ConclusionBased on our findings, T. phaeocarpa has hypoglycaemic activity and polyphenols are the probable bioactive compounds, which support the ethnomedical use of the species.

In Vitro and In Vivo Antihyperglycemic Activities of Medicinal Mushrooms (Agaricomycetes) from India.

Recent research focuses on exploring natural resources to improve the management of type 2 diabetes and to reduce the precarious health effects of synthetic drugs. This investigation aimed to appraise the antihyperglycemic potential of hydroalcoholic (70% ethanol) extracts of Inonotus pachyphloeus, Phellinus allardii, Ph. fastuosus, Ph. gilvus, Ph. sanfordii, and Ph. torulosus. Antihyperglycemic potential was screened using an in vitro inhibition of enzymatic starch digestion assay model. The amount of glucose liberation was determined using the 3,5-dinitrosalicylic acid method. Mushroom extracts showed a concentration-dependent inhibition of α-amyalse and α-glucosidase and a consequent decrease in glucose liberation. Extracts of Ph. fastuosus (half-maximal inhibitory concentration [IC50] = 27.33 ± 1.45 mg/mL) and Ph. sanfordii (IC50 = 30.33 ± 0.88 mg/mL) causing comparable inhibition of α-amyalse and α-glucosidase and decreased glucose liberation were evaluated in vivo through oral starch tolerance and oral glucose tolerance tests using Wistar albino rats. Acarbose (10 mg/kg body weight) was used as a positive control. The extracts of Ph. fastuosus and Ph. sanfordii (100, 200, and 400 mg/kg body weight) showed a dose-dependent decrease in blood glucose concentration, and this decrease was greater in starch-fed rats than in glucose-loaded rats. Ph. fastuosus and Ph. sanfordii extracts (200 and 400 mg/kg body weight) significantly reduced postprandial hyperglycemic peaks in rats challenged with excess starch and glucose. This decrease was statistically comparable to acarbose with Ph. fastuosus extract (400 mg/kg body weight). Thus, it may be concluded that the antihyperglycemic effect of Ph. fastuosus and Ph. sanfordii is mediated by inhibition of starch digestion (inhibition of α-amylase and α-glucosidase). Hence, Ph. fastuosus and Ph. sanfordii can be developed as natural antidiabetic drugs after detailed pharmacological studies.

Hypoglycemic and antioxidant properties of konjac (Amorphophallus konjac) in vitro and in vivo.

The aim of this study was to evaluate the hypoglycemic and antioxidant potential of konjac in vitro and in vivo. Glucose diffusion and enzymatic starch digestion of konjac were assayed using α-amylase and α-glucosidase. Oral glucose tolerance test (OGTT) and oral starch tolerance test (OSTT) were performed at dose of 102mg/Kg of body weight (equivalent to 1g/meal in humans). Additionally, the antioxidant activity of konjac was evaluated through inhibition of lipid peroxidation. The konjac decreased glucose diffusion by 36% and 19% compared with the negative and positive controls, respectively. Additionally, konjac inhibited α-amylase and α-glucosidase activities by 14% and 90%, respectively. After OSTT, group treated with konjac showed significant lower glucose levels compared with control group (p=.03). Finally, konjac reduced lipid peroxidation in human plasma (93%) compared with the negative control. Our results suggest that konjac exhibits hypoglycemic and antioxidant activities in vitro and in vivo. PRACTICAL APPLICATIONS: Because the use of herbal products have emerged as an attractive therapeutic option for chronic diseases, konjac administration may be an adjuvant for the treatment of type 2 diabetes.

Hypoglycemic and antioxidant effects of five commercial turmeric ( Curcuma longa ) supplements

We evaluate the hypoglycemic and antioxidant effects of five commercial turmeric (Curcuma longa) supplements: (1) bulk samples, (2) turmeric root from India, (3) curcuma turmeric Pronat® , (4) turmeric & black pepper Swanson® , and (5) C3 complex® turmeric curcumin. Glucose diffusion and enzymatic starch digestion assays, using α-amylase and α-glucosidase, were performed. The antioxidant activity of turmeric supplements was measured through lipid peroxidation inhibition and the scavenging radical assay. A starch dose of 102mg/Kg of body weight (equivalent to 1g/day in humans) was used to perform the oral starch tolerance test (OSTT) in Wistar male rats. All turmeric supplements decreased glucose diffusion and α-glucosidase enzyme activity, and inhibited lipid peroxidation. The rats that received bulk samples and CT showed significantly lower glucose levels than rats receiving acarbose and those of negative control group. Our results show that biological activities of turmeric supplements vary according to the commercial presentation. PRACTICAL APPLICATIONS: The study results suggest that the hypoglycemic and antioxidant effects of five commercial turmeric supplements vary among them. The information provided would be useful to physicians and individuals using these supplements.

Lowering effect of viable Pediococcus pentosaceus QU 19 on the rise in postprandial glucose.

In the present study, we investigated the glucose-decreasing action of lactic acid bacteria (LAB). The finding of this study could be helpful for people in controlling their blood sugar levels. The LAB candidate was isolated from a Japanese fermented food and identified as Pediococcus pentosaceus by an analysis of its genome sequence. Postprandial blood glucose elevation was investigated using oral starch tolerance tests in mice. Normal mice were fed starch and lyophilized cells of P. pentosaceus QU 19 at the same time. Even without pre-administration of P. pentosaceus QU 19, elevation of the blood glucose level was significantly suppressed by the intake of P. pentosaceus QU 19 at the same time as oral administration of starch. According to the results for its survival in simulated digestive juice and the reduction of blood glucose level in mice, P. pentosaceus QU 19 has potential hypoglycemic activity. In vitro measurements revealed that the glucose-decreasing action of P. pentosaceus QU 19 is probably caused by the glucose assimilation of the strain, not the inhibition of carbohydrate-splitting enzymes which has been reported for other LABs previously. These findings indicate that specific strains of LAB, especially P. pentosaceus QU 19, and foods fermented by LAB may be beneficial for people who must manage glucose ingestion.

Analysis of chemical composition in Chinese olive leaf tea by UHPLC-DAD-Q-TOF-MS/MS and GC-MS and its lipid-lowering effects on the obese mice induced by high-fat diet.

In the present study, the chemical constituents and inhibitory effects of Chinese olive leaf tea (OLT) on α-amylase, α-glucosidase, and its lipid-lowering effects on obese mice induced by a high fat diet were evaluated. In total, 17 compounds including hydroxytyrosol, hydroxytyrosol-glucoside were tentatively identified as main compounds of OLT with authentic compounds or referring to published articles and accessible databases. In total 105 volatile compounds were identified, in which hexanal, benzaldehyde and nonanal were the main aroma compounds. The bioassay showed that the IC50 values of the OLT on α-amylase and α-glucosidase were 0.2102g/mL and 2.925mg/mL, respectively. It also indicated that the OLT is effective in improving the glucose homeostasis by oral starch tolerance test (OSTT). The experimental results in vivo also indicated that OLT significantly improved body weight, liver weight, abdominal fat, plasma levels of lipids, hepatic and plasma malondialdehyde (MDA) levels compared with obese mice fed high-fat diet. The OLT can enhance the antioxidant enzymes' activities (SOD and GSH-Px), meanwhile prevent the hepatic inflammation induced by high-fat diet. In summary, OLT has a potential application in preventing metabolic syndromes.