Identification and Characterization of Edible Cricket Peptides on Hypertensive and Glycemic In Vitro Inhibition and Their Anti-Inflammatory Activity on RAW 264.7 Macrophage Cells.

Recent studies continue to demonstrate the potential of edible insects as a protein base to obtain bioactive peptides applicable for functional food development. This study aimed at identifying antihypertensive, anti-glycemic, and anti-inflammatory peptides derived from the in vitro gastrointestinal digests of cricket protein hydrolysates. After sequential fractionation, the protein digest subfraction containing the lowest molecular weight (<0.5 kDa), hydrophobic (C18) and cationic peptides (IEX) was found responsible for the most bioactivity. The cationic peptide fraction significantly reduced (p < 0.05) α-amylase, α-glucosidase, and angiotensin converting enzyme (ACE) activity in vitro, and also inhibited the expression of NF-κB in RAW 264.7 macrophage cells. A total of 28 peptides were identified with mass spectrometry (LC-MS/MS) and de novo sequencing from the potent fraction. Three novel peptides YKPRP, PHGAP, and VGPPQ were chosen for the molecular docking studies. PHGAP and VGPPQ exhibited a higher degree of non-covalent interactions with the enzyme active site residues and binding energies comparable to captopril. Results from this study demonstrate the bioactive potential of edible cricket peptides, especially as ACE inhibitors.

In vitro inhibitory effects of Chinese bayberry (Myrica rubra Sieb. et Zucc.) leaves proanthocyanidins on pancreatic α-amylase and their interaction.

Chinese bayberry leaves proanthocyanidins (BLPs) belongs to the prodelphinidin category with potent EGCG unit, whose inhibition effect on α-amylase and their interaction were investigated by in vitro digestion and enzyme kinetic analysis, multi fluorescence spectroscopies (fluorescence quenching, synchronous fluorescence, and three-dimensional fluorescence), circular dichroism spectra, Fourier transform infrared spectroscopy and in silico modelling. The results revealed that BLPs was a mixed inhibitor to α-amylase with the IC50 value of 3.075 ± 0.073 µg/mL. BLPs could lead to a static fluorescence quenching of α-amylase, mainly by means of interacting with amino acids (mainly Try and Tyr residues) in one site on α-amylase molecule under the action of hydrogen bonding and/or Van der Waals force. This interaction further induced the change of secondary conformational structure, functional group structure and hydrophobicity of α-amylase, thus resulting in lowering activity. Molecular docking simulated that this binding occurred in a cavity on the surface of the α-amylase molecule, and BLPs trimer showed a relatively high binding energy. The present study provided a new insight of BLPs as an α-amylase inhibitor, which could be considered in anti-diabetic therapy.

The inhibitory effect of the catechin structure on advanced glycation end product formation in alcoholic media.

Advanced glycation end products (AGEs) and their important intermediate products (α-dicarbonyl compounds) that are generated by the Maillard reaction are closely related to diabetes. Our study first investigated the mechanisms of the anti-glycation effects of epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), and (-)-epigallocatechin gallate (EGCG) in an alcoholic environment. The results showed that catechins played an important role in the inhibition of AGE formation, and the effect of EC was the best. Their corresponding mechanisms included total antioxidant capacity (TAOC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, trapping of methylglyoxal (MGO), protection of the protein structure, and inhibition of the activities of α-amylase, α-glucosidase, and ß-glucosidase, which were consistent with the study of molecular docking. This study will offer a theoretical basis for the applications of different types of catechins to alcoholic beverages as natural AGE formation inhibitors.

A new analytical concept based on chemistry and toxicology for herbal extracts analysis: From phenolic composition to bioactivity.

Studies regarding the bioactivity of teas are mainly based on the phenolic composition and in vitro antioxidant activity of the herbal species used in their preparation. The aim of this study was to compare the in vitro and ex vivo antioxidant activity, cytotoxic/antiproliferative activity against cancer cells, the inhibitory activity of α-amylase, α-glucosidase and angiotensin I-converting enzymes, as well as the inhibition of DNA-induced fission of the peroxyl radical, in relation to aqueous extracts of Camellia sinensis var. sinensis (CS), Ilex paraguariensis (IP), Aspalathus linearis (AL) and an optimised extract (OT) containing the three herb species. A bivariate and multivariate statistical approach was employed to associate functional activities with individual phenolic composition. The CS and OT extracts showed the highest levels of hesperidin, quercetin-3-rutinoside, (-)-epigallocatechin-3-gallate and isoquercitrin. The CS and OT extracts showed the highest antioxidant activity, greater ability to inhibit α-amylase and proliferation of HCT8 cells, and greater ability to reduce Folin-Ciocalteu reagent. The AL extract, which is the major source of quercetin-3-rutinoside, hesperidin and isoquercitrin, showed the highest ability to inhibit α-glucosidase, the inhibition of LDL oxidation and protection of human erythrocytes. The IP extract showed the highest inhibition of lipoperoxidation in brain homogenate of Wistar rats, antihypertensive activity, and A549 cell proliferation; chlorogenic acid was its major phenolic compound. In general, the in vitro functionality of each extract was dependent on its chemical composition and the OT extract presented the most varied phenolic composition, and biological activity similar to the CS sample. In conclusion, the mixture of CS, AL, and IP represents a chemical and functional-based strategy to develop functional teas.

Influence of gallic and tannic acid on therapeutic properties of acarbose in vitro and in vivo in Drosophila melanogaster.

BACKGROUND: In this study, gallic acid (GA) and its polymeric form-tannic acid (TA) which are two phenolic acids found abundantly distributed in plant food sources were investigated for their influence on therapeutic properties of acarbose (AC) in vitro and in vivo in Drosophila melanogaster. METHODS: Combinations of AC and GA or TA were assessed for their alpha-glucosidase and alpha-amylase inhibitory effects as markers of anti-hyperglycemic properties, as well as their free radicals scavenging, Fe2+ chelating and malondialdehyde (MDA) inhibitory effects (in vitro). Furthermore, wild type D. melanogaster cultures were raised on diets containing AC, GA, TA and their various combinations for seven days. Thereafter, flies were homogenized and glucose concentrations, alpha-glucosidase and alpha-amylase activities, as well as reactive oxygen species (ROS) and total thiol levels were determined. RESULTS: The results showed that GA and TA up to 5 mg/ml significantly (p < 0.05) increased the enzymes' inhibitory effects and antioxidant properties of AC in vitro. Also, there was significant reduction in glucose concentration, enzyme activities and ROS level in D. melanogaster fed diets supplemented with phenolic acids and acarbose. CONCLUSIONS: These bioactive compounds-drug interactions provide useful information on improving the therapeutic properties of acarbose especially in its use as an antidiabetic drug.

A New Extremely Halophilic, Calcium-Independent and Surfactant-Resistant Alpha-Amylase from Alkalibacterium sp. SL3.

A new α-amylase-encoding gene (amySL3) of glycoside hydrolase (GH) family 13 was identified in soda lake isolate Alkalibacterium sp. SL3. The deduced AmySL3 shares high identities (82-98%) with putative α-amylases from the genus Alkalibacterium, but has low identities (<53%) with functionally characterized counterparts. amySL3 was successfully expressed in Escherichia coli, and the recombinant enzyme (rAmySL3) was purified to electrophoretic homogeneity. The optimal temperature and pH of the activity of the purified rAmySL3 were determined to be 45°C and pH 7.5, respectively. rAmySL3 was found to be extremely halophilic, showing maximal enzyme activity at a nearly saturated concentration of NaCl. Its thermostability was greatly enhanced in the presence of 4 M NaCl, and it was highly stable in 5 M NaCl. Moreover, the enzyme did not require calcium ions for activity, and was strongly resistant to a range of surfactants and hydrophobic organic solvents. The major hydrolysis products of rAmySL3 from soluble starch were maltobiose and maltotriose. The high ratio of acidic amino acids and highly negative electrostatic potential surface might account for the halophilic nature of AmySL3. The extremely halophilic, calcium-independent, and surfactant-resistant properties make AmySL3 a promising candidate enzyme for both basic research and industrial applications.

Different Temperature Treatments of Millet Grains Affect the Biological Activity of Protein Hydrolyzates and Peptide Fractions.

The objective of this study was to analyze millet protein hydrolyzates and peptide fractions with molecular mass under 3.0 kDa obtained from grains treated with different temperature values as inhibitors of angiotensin-converting enzyme (ACE), α-amylase, and α-glucosidase activity. The protein fractions were hydrolyzed in vitro in gastrointestinal conditions and the highest degree of hydrolysis was noted for globulin 7S obtained from control grains (98.33%). All samples were characterized by a high peptide bioaccessibility index, which was 23.89 for peptides obtained from globulin 11S after treatment with 100 °C. The highest peptide bioavailability index was noted for peptides obtained from globulin 11S after the treatment with 65 °C (2.12). The highest potential metabolic syndrome inhibitory effect was determined for peptide fractions obtained from the prolamin control (IC50 for ACE and α-amylase was 0.42 and 0.11 mg/mL, respectively) and after the 100 °C treatment (IC50 for ACE and α-glucosidase was 0.33 and 0.12 mg/mL, respectively) and from globulin 11S after the 65 °C treatment (IC50 0.38 and 0.05 for ACE and α-glucosidase, respectively). The effect of these samples on endothelial cell HECa10 was determined. The sequences of potential inhibitory peptides were identified as GEHGGAGMGGGQFQPV, EQGFLPGPEESGR, RLARAGLAQ, YGNPVGGVGH, and GNPVGGVGHGTTGT.

The involvement of phenolic-rich extracts from Galician autochthonous extra-virgin olive oils against the α-glucosidase and α-amylase inhibition.

'Brava' and 'Mansa de Figueiredo' extra-virgin olive oils (EVOOs) are two varieties identified from north-western Spain. A systematic phenolic characterization of the studied oils was undertaken by LC-ESI-IT-MS. In addition, the role of dietary polyphenols from these EVOOs has been evaluated against the inhibition of key enzymes (α-glucosidase and α-amylase) in the management of diabetes mellitus (DM). Oleuropein and ligstroside derivatives comprised 83% and 67% of the total phenolic compounds in 'Brava' and 'Mansa de Figueiredo' EVOOs, respectively. The main secoiridoids from oleuropein were DOA (3,4-DHPEA-EDA, 59 and 22 mg kg-1, respectively) and the main isomer of OlAgl (3,4-DHPEA-EA, 74 and 23 mg kg-1). The main secoiridoids from ligstroside were D-LigAgl (p-HPEA-EDA or oleocanthal, 23 and 167 mg kg-1) and the main isomer of LigAgl (p-HPEA-EA, 214 and 114 mg kg-1). For α-glucosidase, both EVOO extracts displayed stronger inhibitory activity (IC50 values of 60 ±â€¯8 and 118 ±â€¯9 µg mL-1, respectively) than the commercial inhibitor acarbose (IC50 = 356 ±â€¯21 µg mL-1). Nevertheless, for α-amylase, only 'Brava' extracts showed anti-α-amylase capacity. A daily VOO intake lower than the requirements of EFSA seem to be enough to reach both 50% for α-glucosidase and 25% for α-amylase inhibition. These findings support the potential health benefits derived from Galician EVOOs that might be probably linked to the outstanding high concentration levels of phenolic acids and flavonoids.

Leucine regulates α-amylase and trypsin synthesis in dairy calf pancreatic tissue in vitro via the mammalian target of rapamycin signalling pathway.

Starch digestion in the small intestines of the dairy cow is low, to a large extent, due to a shortage of syntheses of α-amylase. One strategy to improve the situation is to enhance the synthesis of α-amylase. The mammalian target of rapamycin (mTOR) signalling pathway, which acts as a central regulator of protein synthesis, can be activated by leucine. Our objectives were to investigate the effects of leucine on the mTOR signalling pathway and to define the associations between these signalling activities and the synthesis of pancreatic enzymes using an in vitro model of cultured Holstein dairy calf pancreatic tissue. The pancreatic tissue was incubated in culture medium containing l-leucine for 3 h, and samples were collected hourly, with the control being included but not containing l-leucine. The leucine supplementation increased α-amylase and trypsin activities and the messenger RNA expression of their coding genes (P <0.05), and it enhanced the mTOR synthesis and the phosphorylation of mTOR, ribosomal protein S6 kinase 1 and eukaryotic initiation factor 4E-binding protein 1 (P <0.05). In addition, rapamycin inhibited the mTOR signal pathway factors during leucine treatment. In sum, the leucine regulates α-amylase and trypsin synthesis in dairy calves through the regulation of the mTOR signal pathways.

Effects of exogenous gamma-aminobutyric acid on α-amylase activity in the aleurone of barley seeds.

Gamma-aminobutyric acid (GABA), a nonprotein amino acid, often accumulates in plants exposed to certain environmental stimuli. Previous studies indicated that a closed relationship existed between endogenous GABA and seed germination. However, there are few studies on the effect of exogenous GABA on seed germination. The objective of this study was to explore whether exogenous GABA affected α-amylase activity which the activation is an important stage in seed germination. The level of endogenous GABA in barley seeds rose gradually during germination, suggesting that endogenous GABA was involved in germination. We measured starch degradation under application of various concentration GABA and found that GABA promoted seed starch degradation with a dose-responsive effect. The relationship between GABA and α-amylase activity was investigated by treating barley aleurone with exogenous GABA. The result showed that α-amylase activity began to rise after about 24 h and reached a peak at 48 h. Molecular evidence suggested that GABA increased α-amylase gene expression. We explore the possible roles played by GABA in signal transduction.

Inhibitory activity of phenolic-rich pistachio green hull extract-enriched pasta on key type 2 diabetes relevant enzymes and glycemic index.

Phenolic compounds as agro-industrial by-products have been associated with health benefits since they exhibit high antioxidant activity and anti-diabetic properties. In this study, polyphenol-rich extract from pistachio green hull (PGH) was evaluated for antioxidant activity and its ability to inhibit α-amylase and α-glucosidase activity in vitro. The effect of PGH extract powder on in vitro starch digestibility was also evaluated. The results showed that PGH had stronger antioxidant activity than Trolox. The inhibitory effect of PGH extract against α-amylase from porcine pancreas was dose dependent and the IC50 value was ~174µgGAE/mL. The crude PGH extract was eight times more potent on baker yeast α-glucosidase activity (IC50~6µgGAE/mL) when compared to acarbose, whereas the IC50 value of PGH extract against rat intestinal maltase activity obtained ~2.6mgGAE/mL. The non-tannin fraction of PGH extract was more effective against α-glucosidase than tannin fraction whereas the α-amylase inhibitor was concentrated in the tannin fraction. In vitro starch digestibility and glycemic index (GI) of pasta sample supplemented with PGH extract powder (1.5%) was significantly lower than the control pasta. The IC50 value of PGH extract obtained from cooked pasta against α-amylase and α-glucosidase was increased. These results have important implications for the processing of PGH for food industry application and therefore could comply with glucose control diets.

In Vitro Investigation of Potential Anti-Diabetic Activity of the Corm Extract of Hypoxis Argentea Harv. Ex Baker.

The corms of Hypoxis argentea are widely used as a traditional remedy for diabetes mellitus in South Africa. In this study, we investigated the effects of non-toxic concentrations (12.5-100 µg mL-1) of the aqueous extract of H. argentea (HAA) corms on glucose uptake, pancreatic beta cell proliferation, and adipocyte differentiation. HAA stimulated glucose uptake in HepG2 cells up to 19.6 % and 17.0 % in L6 myotubes. Live-cell imaging microscopy revealed significant increases (p < 0.001) in total INS-1 cell numbers exposed to HAA, although no effect was observed on adipogenesis in 3T3-L1 pre-adipocytes. HAA produced weak to moderate inhibition of porcine pancreatic α-amylase, α-glucosidase, porcine pancreatic lipase, dipeptidyl peptidase IV (DPP IV) activities, as well as protein glycation. Our results suggest that the acclaimed anti-diabetic effects of H. argentea could be mediated by its promotion of glucose utilization and preservation of pancreatic beta cell populations while preventing fat accumulation in adipocytes.

Inhibition of α-glucosidase and α-amylase by Spanish extra virgin olive oils: The involvement of bioactive compounds other than oleuropein and hydroxytyrosol.

Despite the wide use of extra virgin olive oil (EVOO) to combat several diseases, the antidiabetic and anti-cholinesterase activity of Spanish EVOO have not been assessed. In order to evaluate which compounds are responsible for these activities of five Spanish EVOOs, in addition to flavonoids, we investigated for the first time the effect of the contents of carotenoids, fatty acids (FAs), and phytoprostanes (PhytoPs) on four enzymes: α-glucosidase, α-amylase, acetylcholinesterase, and butyrylcholinesterase. The extracts of these five Spanish EVOOs were found to contain three flavones, three carotenoids, six FAs, and seven classes of PhytoPs. The samples exhibited no in vitro anti-cholinesterase activity but presented strong antidiabetic activity, in the order: 'Arbequina'≈'Picual'≈'Cuquillo'>'Hojiblanca'>'Cornicabra'. The samples showed a higher in vitro hypoglycemic effect than individual or mixed standards, possibly due to interaction between multiple identified compounds and/or a very complex multivariate interaction between other factors.

Inhibitory effects of Cymodocea nodosa sulphated polysaccharide on α-amylase activity, liver-kidney toxicities and lipid profile disorders in diabetic rats.

This study aimed to evaluate for the first time the effects of Cymodocea nodosa sulphated polysaccharide (CNSP) on the α-amylase activity, hyperglycaemia, liver-kidney functions, and pancreatic architecture of alloxan-induced diabetic rats. Animals were allocated into four groups of seven rats each, the body weight and blood glucose levels were estimated periodically for 2 months of treatment by gastric gavages route. The CNSP effect was confirmed by biochemical procedures and histological study. The inhibition of α-amylase activity and protection of pancreatic ß-cells induced a decrease in the blood glucose levels and regulated the lipid profile in the plasma of the treated diabetic rats, which helped to maintain the homeostasis of blood lipid. Moreover, CNSP administration induced a significant decrease in the levels of lipid peroxidation in the pancreas, liver and kidney of diabetic rats and protects their functions attested by a decrease in the levels of toxicity parameters in blood.

ZnO Nanoparticles-Red Sandalwood Conjugate: A Promising Anti-Diabetic Agent.

With the advances in nanoscience and nanotechnology the interest of researchers has expanded to interdisciplinary domain like bio-medical applications. Among such domains, one of the most important areas explored meticulously is the development of promising solutions in diabetes therapeutics. The disease associated with metabolic disorder, is one of the major challenges, due to its ever-increasing number of patients. The adverse effects of the synthetic enzymes like α-amylase and α-glucosidase inhibitors have invited many scientists to develop promising contender with minimal side-effects. On the other hand, Zinc has strong role in insulin synthesis, storage and secretion and thus its deficiency can be related to diabetes. In this context we have explored natural extract of Red Sandalwood (RSW) as a potent anti-diabetic agent, in conjugation with ZnO nanoparticles. ZnO nanoparticles have been synthesized via soft chemistry routes and duly characterized for their phase formation with the help of X-ray diffraction technique and Field-Emission Scanning Electron Microscopy. These monodispersed nanoparticles, -20 nm in size, were further conjugated to RSW extract. The conjugation chemistry was studied via Fourier transform infrared spectroscopy, UV-visible spectroscopy. Extract loading percentage was found from thermo-gravimetric analysis. 65% of the RSW extract was found conjugated to the ZnO nanoparticles. The anti-diabetic activity was assessed with the help of like α-amylase and α-glucosidase inhibition assay with murine pancreatic and small intestinal extracts. It was observed that the conjugated ZnO-RSW nanoparticles showed excellent activity against the crude murine pancreatic glucosidase as compared to the individual ZnO nanoparticles and the RSW extract. The ZnO-RSW conjugate showed 61.93% of inhibition while the bare ZnO nanoparticles and RSW showed 21.48% and 5.90% respectively.

Acute effect of Ceylon cinnamon extract on postprandial glycemia: alpha-amylase inhibition, starch tolerance test in rats, and randomized crossover clinical trial in healthy volunteers.

BACKGROUND: Postprandial hyperglycemia is a known risk factor for the development of several health disorders including type 2 diabetes, obesity, oxidative stress, and cardiovascular diseases. One encouraging approach for a better control of postprandial glycemia is to reduce carbohydrate digestion. Cinnamon extracts have been known for managing blood glucose. However, their effects on inhibiting digestion of carbohydrate have been poorly analyzed to date. The aim of this study was to investigate the acute effect of a specific Ceylon cinnamon hydro-alcoholic extract (CCE) on carbohydrate digestion and post-meal blood glucose reduction. METHODS: In vitro enzymatic assays and in vivo starch tolerance tests in rats were designed as preclinical assays. Then, a randomized, double-blind, placebo-controlled, cross-over clinical trial was conducted in 18 healthy female and male volunteers. Following the intake of 1 g of CCE, the subjects ate a standardized meal. Blood samples were collected during the 2 hours following the meal to measure glucose and insulin concentrations. Areas under the curves were calculated and statistical differences between the CCE and placebo groups were analyzed using the Mann Whitney-Wilcoxon test. RESULTS: CCE has demonstrated in the in vitro study that it inhibited pancreatic alpha-amylase activity with an IC50 of 25 µg/mL. In the in vivo study, CCE was shown to acutely reduce the glycemic response to starch in a dose-dependent manner in rats. This effect was significant from the dose of 12.5 mg/kg of body weight. In both, the in vitro and in vivo studies, the hydro-alcoholic extract has shown to be more efficacious than the aqueous extract. In the human clinical trial, 1 g of CCE lowered the area under the curve of glycemia between 0 and 120 min by 14.8% (P = 0.15) and between 0 and 60 min by 21.2% (P < 0.05) compared to the placebo. This effect occurred without stimulating insulin secretion. No adverse effects were reported. CONCLUSION: These results suggest that Ceylon cinnamon hydro-alcoholic extract (CCE) may provide a natural and safe solution for the reduction of postprandial hyperglycemia and therefore help to reduce the risks of developing metabolic disorders. TRIAL REGISTRATION: ClinicalTrials.gov NCT02074423 (26/02/2014).

Parmotrema tinctorum exhibits antioxidant, antiglycation and inhibitory activities against aldose reductase and carbohydrate digestive enzymes: an in vitro study.

This study evaluated the inhibitory potential of ethyl acetate extract of Parmotrema tinctorum (PTEE), an edible lichen, against aldose reductase (AR) and carbohydrate digestive enzymes such as α-glucosidase and α-amylase. It was also screened for antioxidant activities by using DPPH, ABTS, superoxide and hydroxyl radical-scavenging assays. PTEE exhibited α-glucosidase, α-amylase and AR inhibition along with significant antiglycation potential with an estimated IC50 value of 58.45 ± 1.24, 587.74 ± 3.27, 139.28 ± 2.6 and 285.78 ± 1.287 µg/mL, respectively. Antioxidant activity of PTEE against DPPH (IC50 396.83 ± 2.98 µg/mL), ABTS (151.34 ± 1.79 µg/mL), superoxide (30.29 ± 1.17 µg/mL) and hydroxyl (35.42 ± 1.22 µg/mL) radicals suggests the antioxidant potential of P. tinctorum. Significant antioxidant activity and inhibitory potential against carbohydrate digestive enzymes and AR suggest that P. tinctorum can be developed as functional food/nutraceuticals for diabetes after detailed study.

Effect of moderate ethanol administration on biochemical indices in streptozotocin-diabetic Wistar rats.

OBJECTIVE: This study was designed to evaluate the effect of moderate ethanol administration on the biochemical indices in streptozotocin (STZ)-diabetic rats. METHODS: Twenty-four male Wistar rats were divided into four groups of six animals each. Groups one and two contained non-diabetic normal rats and normal rats treated with ethanol, respectively. Group three was untreated STZ-diabetic rats and group four was made up of ethanol-treated STZ-diabetic rats. Diabetes was induced by a single intraperitoneal injection of STZ (35 mg/kg), while ethanol (100%v/v) was given at a dose 2 g/kg thrice per week for three weeks. After the last dose of ethanol and an overnight fasting, rats were sacrificed by cervical dislocation. Blood was collected by syringe from the heart into plain centrifuge tubes. RESULTS: Moderate ethanol administration to STZ-diabetic rats caused a significant (p < 0.05) increase in relative weight of liver relative to normal. Ethanol intake in STZ-diabetic rats produced an insignificant (p > 0.05) effect on the levels of fasting blood glucose (FBG) and HbA1c relative to the untreated-diabetic group. Moderately, ethanol administration to STZ-diabetic rats produced a marked and significant (p < 0.05) increase in the levels of serum total cholesterol, triglycerides, low-density lipoprotein (LDL)-cholesterol and the activities of alanine aminotransferase relative to untreated diabetic rats. Ethanol-treated diabetic rats had significantly (p < 0.05) lower high-density lipoprotein (HDL)-cholesterol levels, while the activities of lactate dehydrogenase and alpha-amylase were insignificantly (p > 0.05) affected. There were no significant (p > 0.05) differences in all the biochemical indices in normal rats relative to ethanol-treated normal rats. CONCLUSIONS: Moderate ethanol administration did not affect FBG and HbA1c, but altered the lipid profile of STZ-diabetic rats. Moderate ethanol intake may further increase the risk of complications in diabetes.

Effect of moderate ethanol administration on biochemical indices in streptozotocin-diabetic Wistar rats / Efecto de la administración moderada de etanol sobre los índices bioqumicos en ratas Wistar diabéticas por estreptozotocina

OBJECTIVE: This study was designed to evaluate the effect of moderate ethanol administration on the biochemical indices in streptozotocin (STZ)-diabetic rats. METHODS: Twenty-four male Wistar rats were divided into four groups of six animals each. Groups one and two contained non-diabetic normal rats and normal rats treated with ethanol, respectively. Group three was untreated STZ-diabetic rats and group four was made up of ethanol-treated STZ-diabetic rats. Diabetes was induced by a single intraperitoneal injection of STZ (35 mg/kg), while ethanol (10%v/v) was given at a dose 2 g/kg thrice per week for three weeks. After the last dose of ethanol and an overnight fasting, rats were sacrificed by cervical dislocation. Blood was collected by syringe from the heart into plain centrifuge tubes. RESULTS: Moderate ethanol administration to STZ-diabetic rats caused a significant (p < 0. 05) increase in relative weight of liver relative to normal. Ethanol intake in STZ-diabetic rats produced an insignificant (p > 0. 05) effect on the levels of fasting blood glucose (FBG) and HbA1c rrelative to the untreated-diabetic group. Moderately, ethanol administration to STZ-diabetic rats produced a marked and significant (p < 0. 05) increase in the levels of serum total cholesterol, triglycerides, low-density lipoprotein (LDL)-cholesterol and the activities of alanine aminotransferase relative to untreated diabetic rats. Ethanol-treated diabetic rats had significantly (p < 0. 05) lower high-density lipoprotein (HDL)-cholesterol levels, while the activities of lactate dehydrogenase and α-amylase were insignificantly (p > 0. 05) affected. There were no significant (p > 0. 05) differences in all the biochemical indices in normal rats relative to ethanol-treated normal rats. CONCLUSIONS: Moderate ethanol administration did not affect FBG and HbA1c , but altered the lipid profile of STZ-diabetic rats. Moderate ethanol intake may further increase the risk of complications in diabetes.

OBJETIVO: Este estudio se diseñó con el propósito de evaluar el efecto del uso de etanol moderado sobre los índices bioquímicos en ratas Wistar diabéticas por estreptozotocina (STZ). MÉTODOS: Veinticuatro ratas Wistar machos fueron divididas en cuatro grupos de seis animales cada uno. Dos de los grupos tenían ratas normales no diabéticas y ratas normales tratadas con etanol, respectivamente. El tercer grupo estaba formado por ratas diabéticas por STZ no tratadas, y el cuarto por ratas diabéticas por STZ tratadas con etanol. La diabetes fue inducida mediante una inyección intraperitoneal de STZ (35 mg/kg), mientras que el etanol (10% v/v) fue administrado en dosis de 2 g/kg tres veces por semana durante tres semanas. Tras la última dosis de etanol y un ayuno de una noche, las ratas fueron sacrificadas mediante dislocación cervical. La sangre fue recogida del corazón con jeringuillas e introducida en tubos para centrífuga sin graduación. RESULTADOS: La administración moderada de etanol a ratas diabéticas por STZ, causó un aumento significativo (p < 0.05) en el peso relativo del hígado con relación al normal. La ingestión de etanol en ratas diabéticas por STZ tuvo un efecto insignificante (p > 0.05) en los niveles de glucosa en sangre en ayuno (GSA) y HbA1c en relación con grupos diabéticos no tratados. En medida moderada, la administración de etanol a ratas diabéticas por STZ produjo un aumento marcado y significativo (p < 0.05) en los niveles de colesterol total en suero, triglicéridos, el colesterol asociado con las lipoproteínas de baja densidad, o colesterol LDL, y la actividad de la aminotransferasa alanina en relación con las ratas diabéticas no tratadas. Las ratas diabéticas tratadas con etanol tuvieron niveles significativamente disminuidos de colesterol asociado con las lipoproteínas de alta densidad, o colesterol HDL, en tanto que la actividad del lactato deshidrogenasa y la α-amilasa no fue afectada significativamente (p > 0.05). No hubo diferencias significativas (p > 0.05) en todos los índices bioquímicos en las ratas normales con respecto a las ratas normales tratadas con etanol. CONCLUSIONES: El suministro moderado de etanol no afectó el GSA ni el HbA1c , pero alteró el perfil lípido de las ratas diabéticas por STZ. La ingestión moderada de etanol puede aumentar a un más el riesgo de las complicaciones de la diabetes.

Cloning, expression, purification, and characterization of cold-adapted α-amylase from Pseudoalteromonas arctica GS230.

A cold-adapted α-amylase (ParAmy) gene from Pseudoalteromonas arctica GS230 was cloned, sequenced, and expressed as an N-terminus His-tag fusion protein in E. coli. A recombinant protein was produced and purified with DEAE-sepherose ion exchange chromatography and Ni affinity chromatography. The molecular weight of ParAmy was estimated to be 55 KDa with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). With an optimum temperature for activity 30 °C, ParAmy showed 34.5% of maximum activity at 0 °C and its activity decreased sharply at above 40 °C. ParAmy was stable in the range of pH 7-8.5 at 30 °C for 1 h. ParAmy was activated by Mn(2+), K(+) and Na(+), and inhibited by Hg(2+), Cu(2+), and Fe(3+). N-Bromosuccinimid showed a significant repressive effect on enzyme activity. The K (m) and V (max) values of the α-amylase for soluble starch were 7.28 mg/mL and 13.07 mg/mL min, respectively. This research suggests that Paramy has a good potential to be a cold-stable and alkalitolerant amylase in detergent industry.