Α-glucosidase Enzyme Activity Research Articles

Effects of Hibiscus sabdariffa Linn. fruit extracts on α-glucosidase enzyme, glucose diffusion and wound healing activities

ObjectiveTo provide in vitro evidence for antidiabetic activity through potential inhibition of α-glucosidase enzyme, glucose diffusion and enhancement in the wound healing using methanolic extract and fractions from Hibiscus sabdariffa Linn. fruit. MethodsThe inhibitory action of methanolic extract and fractions of such fruit on α-glucosidase enzyme and glucose movement through in vitro assay assessment was reported. Their activities on wound healing were tested using the scratch assay. ResultsEthyl acetate fraction at 50 mg/mL concentration exhibited significant α-glucosidase inhibition (95.79 mg/mL) with P < 0.05. At the same concentration, the methanolic extract as well as other fractions revealed lower α-glucosidase inhibition and higher glucose diffusion retardation across the dialysis tube than the control. Ethyl acetate and butanol fractions displayed notably higher glucose diffusion inhibitory activity of 5.21 mmol/L and 5.2 mmol/L, respectively as compared to methanolic extract and n-hexane fraction of 6.58 mmol/L and 6.49 mmol/L, respectively. Conversely, compared to other fractions the methanolic extract and ethyl acetate fraction manifested proliferative effect at the incubation time of 6 h during the wound healing study. ConclusionsIt is established that methanolic extract and fractions from H. sabdariffa Linn. fruit can inhibit the α-glucosidase enzyme and glucose movement as well as influence the wound healing activity positively.

Newborn Screening for Lysosomal Storage Disorders in Belgium

Lysosomal storage disorders (LSDs) are a group of metabolic disorders with various clinical presentations, which complicate diagnosis. A pilot study was performed to test the appropriateness and effectiveness of the newborn screening method for Pompe disease, Fabry disease and mucopolysaccharidosis (MPS) I in dried blood spots using liquid chromatography–tandem mass spectrometry. Around 20 000 newborn samples were analyzed for 3 lysosomal enzyme activities: α-glucosidase (deficient in Pompe disease), α-galactosidase (deficient in Fabry disease) and α-iduronidase (IDUA, deficient in MPS I). Data were used for statistical analysis and to establish sex- and age-dependent reference ranges. Statistically significant higher α-glucosidase, α-galactosidase, and IDUA enzyme activities were observed in female newborns compared to male newborns. Newborns with a higher gestational age have a statistically significant lower α-glucosidase, α-galactosidase, and IDUA enzyme activities compared to newborns with a lower gestational age. For the first time, the data of a large-scale LSD study were used to assess statistical differences in enzyme activity in the newborn population, and these data highlight the importance of using reference intervals for lysosomal enzyme activities in function of sex and gestational age.

Antioxidant, Acetylcholinesterase, Butyrylcholinesterase, and α-glucosidase Inhibitory Activities of Corchorus depressus.

Background:Corchorus depressus (Cd) commonly known as Boa-phalee belonging to the family Tiliaceae having 50 genera and 450 species. Cd is not among the studied medicinal agent despite its potential in ethnopharmacology.Objectives:The present study investigated antioxidant, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α-glucosidase inhibitory activities of Cd. The dichloromethane and methanolic extracts of the Cd were evaluated for biological activities such as antioxidant and enzyme inhibitory activities of AChE, BChE, and α-glucosidase.Materials and Methods:Antioxidant activity was evaluated by measuring free radical scavenging potential of Cd using 1,1-diphenyl-2-picrylhydrazyl. Enzyme inhibition activities were done by measuring optical density.Results:The methanol extract of roots of Cd showed potential free radical scavenging activity 99% at concentration 16.1 μg/ml. AChE was inhibited by aerial part of dichloromethane fraction by 46.07% ± 0.45% while dichloromethane extracts of roots of Cd possessed significant activity against BChE with 86% inhibition compared with standard drug Eserine at concentration 0.5 mg/ml. The dichloromethane extract of roots of Cd showed 79% inhibition against α-glucosidase enzyme activity with IC50 62.8 ± 1.5 μg/ml.Conclusion:These findings suggest Cd as useful therapeutic option as antioxidant and inhibition of AChE, BChE, and α-glucosidase activities.SUMMARY The aerial parts and roots of Corchorus depressus (Cd) were extracted in dichloromethane and methanolThe extract of roots of Cd showed free radical scavenging activity 99% at concentration 16.1 mg/ml, Ach inhibition by aerial parts of dichloromethane fraction by 46.07%, and 79% inhibition against a-glucosidase enzyme activity with IC50 62.8 ± 1.5 mg/mlThe dichloromethane and methanolic extracts of Cd exhibited antioxidant inhibition of acetyl cholinesterase, butyrylcholinesterase, and a-glucosidase activities. Abbreviations used: DPPH: 1,1-diphenyl-2-picrylhydrazyl, Cd: Corchorus depressus, AChE: Acetylcholinesterase, BChE: Butyrylcholinesterase, AD: Alzheimer's disease.

α-Amylase and α-Glucosidase Inhibitory Activities of Phenolic Extracts from Eucalyptus grandis × E. urophylla Bark

This study evaluated the inhibitory effects of different extracts and fractions from Eucalyptus. grandis × urophylla bark (EB) against α-glucosidase and α-amylase enzyme activities. The ethyl acetate extract (EB-E) showed the highest activity among others. Seven fractions were derived from EB-E; among them EB-E-7 showed the highest significant inhibition of both enzymes, with IC50 of 1.40±0.18 and 1.72±0.12 μg/mL, respectively. EB-E and its active fraction EB-E-7 showed highest contents of total phenolics: 178.79±4.68 and 920.4±5.46 mg GAEag−1, respectively. HPLC-MS analysis of EB-E-7 revealed the presence of ellagic acid, quercetin-glucuronide, quercetin-3-α-rhamnopyranoside, and ellagic acid rhamnoside as major compounds, together with smaller concentrations of myricetin-rhamnoside, isorhamnetin-hexoside, myricetin-3-α-arabinofuranoside, and isorhamnetin. Therefore, the phenolic compounds from Eucalyptus grandis × E. urograndis bark potently inhibited α-amylase and α-glucosidase activity, having potential in prevention of hyperglycemia.

Effect of some Tropical Eggplant Fruits (Solanum Spp) Supplemented Diet On Diabetic Neuropathy In Experimental male Wistar Rats In-vivo

Background: Solanum known as eggplant is a popular vegetable crop grown in the subtropics and tropics. Eggplant is a perennial but grown commercially as an annual crop. The fruits of eggplant is primarily used as a cooking vegetable for various dishes. Eggplant comes in various kinds of species, which are highly variable for its fruit colour, as well as shape and size.Content and Purpose of this study: This study focused on comparing the effect of dietary African eggplants (AP) Solanum kumba,(PG) Solanum gilo (PW) and Solanum aethiopicum (PGW) species. Diabetes was induced experimentally by high fat fed/low dose streptozotocin-diabetic rats (35 mg/kg body wt.) and the diabetic rats were fed diets supplemented with 20–40% supplemented eggplant diet for 14 days. The effect of the diets on the blood glucose level, pancreatic α-amylase, intestinal α-glucosidase and Angiotensin-I converting enzyme (ACE) activities, plasma antioxidant status were determined also quantification of the fruits polyphenols using HPLC/DAD .Results: The results revealed that there was no significant (P &lt; 0.05) difference in the average feed intake and weight changes in all the groups. Supplementation with eggplant diet gradually reduced blood glucose level in diabetic rat compared to diabetic rats and metformin-treated (positive control group). African eggplant showed elevated levels of antioxidant status such as (glutathione peroxidase GPX, glutathione transferase GST,reduced glutathione GSH,Catalase and Ascorbic acid).Conclusions:The results suggest that the eggplant may attenuate hyperglycemia, hypertension and oxidative stress in the type 2 diabetic condition with Solanum kumba having the highest activity which could not be far fetched from its polyphenols as revealed in the HPLC/DAD characterization.Keywords: Solanum spp,polyphenols, diabetes,enzymes

Hypothyroidism in late-onset Pompe disease

PurposeIn Pompe disease, a deficiency of acid α-glucosidase enzyme activity leads to pathologic accumulation of glycogen in tissues. Phenotype heterogeneity in Pompe includes an infantile form and late-onset forms (juvenile- and adult-onset forms). Symptoms common to all phenotypes include progressive muscle weakness and worsening respiratory function. Patients with late-onset forms of Pompe disease commonly complain of chronic fatigue and generalized muscle weakness prior to being diagnosed with Pompe disease, and this may lead to consideration of hypothyroidism in the differential diagnosis. This study aimed to evaluate the prevalence of hypothyroidism in the adult-onset form of Pompe disease. MethodsElectronic chart review was performed at the Advanced Therapies Clinic at the University of Minnesota Medical Center (UMMC) to identify patients with late-onset Pompe disease. The identified charts were reviewed for a co-diagnosis of hypothyroidism. A query was made to the clinical data repository at UMMC searching diagnosis ICD9 code 244.9 (hypothyroidism not otherwise specified) and/or presence of levothyroxine from 2011 to 2014 in patients 18years of age and older. ResultsThe clinical data repository found a prevalence of hypothyroidism of 3.15% (56,072 of 1,782,720 patients) in the adult patient population at UMMC. Ten adult patients with Pompe disease were identified, five with the diagnosis of hypothyroidism (50%, 95% CI: 23.7, 76.3, p<0.001 compared with the general UMMC adult population). ConclusionsHypothyroidism was found at a higher prevalence in patients with late-onset Pompe disease compared to the general adult population at UMMC. Studies in larger populations of patients with Pompe disease would be needed to confirm an association of Pompe disease and hypothyroidism. Challenges include finding an adequate sample size, due the rarity of Pompe disease.

Potent Antidiabetic Activity and Metabolite Profiling of Melicope Lunu-ankenda Leaves.

Diabetes mellitus is normally characterized by chronic hyperglycemia associated with disturbances in the fat, carbohydrate, and protein metabolism. There is an increasing trend of using natural products instead of synthetic agents as alternative therapy for disorders due to their fewer side effects. In this study, antidiabetic and antioxidant activities of different Melicope lunu-ankenda (ML) ethanolic extracts were evaluated using inhibition of α-glucosidase and 2,2-diphenyl-l-picrylhydrazyl (DPPH) radicals scavenging activity, respectively; whereas, proton nuclear magnetic resonance ((1) H NMR) and ultra-high performance liquid chromatography-tandem mass spectrometric (UHPLC-MS/MS) techniques were used for metabolite profiling of ML leaf extracts at different concentrations of ethanol and water. Sixty percent of ethanolic ML extract showed highest inhibitory effect against α-glucosidase enzyme (IC50 of 37 μg/mL) and DPPH scavenging activity (IC50 of 48 μg/mL). Antidiabetic effect of ML extracts was also evaluated in vivo and it was found that the high doses (400 mg/Kg BW) of ML extract exhibited high suppression in fasting blood glucose level by 62.75%. The metabolites responsible for variation among ML samples with variable ethanolic levels have been evaluated successfully using (1) H-NMR-based metabolomics. The principal component analysis (PCA) and partial least squares(PLS) analysis scores depicted clear and distinct separations into 4 clusters representing the 4 ethanolic concentrations by PC1 and PC2, with an eigenvalue of 69.9%. Various (1) H-NMR chemical shifts related to the metabolites responsible for sample difference were also ascribed. The main bioactive compounds identified attributing toward the separation included: isorhamnetin, skimmianine, scopoletin, and melicarpinone. Hence, ML may be used as promising medicinal plant for the development of new functional foods, new generation antidiabetic drugs, as a single entity phytomedicine or in combinational therapy.

Analysis of α-glucosidase enzyme activity used in a rapid test for steam sterilization assurance.

This study was to determine the sources, location and identity of α-glucosidases in dormant/germinating/outgrowing spores and growing cells of Geobacillus stearothermophilus ATCC 7953, an enzymatic activity in spores used in rapid tests of steam sterilization. α-Glucosidase activity in spores and cells was determined measuring methylumbelliferyl-α-d-glucoside (α-MUG) or α-MUG-6-phosphate hydrolysis fluorometrically. While α-MUG-6-phosphate was not hydrolysed by cell or spore extracts, assays with α-MUG showed that: (1) the α-glucosidase activity was inside and outside spores, and the activity outside spores was largely removed by buffer washes or heat activation, whereas α-glucosidase activity was only inside vegetative cells; (2) most α-glucosidase activity in cells and spores was soluble; (3) Western blots and enzyme inhibition using an anti-α-glucosidase antiserum identified ≥2 α-glucosidases in spores and growing cells; (4) α-glucosidase-specific activities were similar in dormant, germinated and outgrowing spore and growing cell extracts; and (5) significant α-glucosidase was synthesized during spore germination and outgrowth and cell growth, this synthesis was not repressed by glucose nor induced by α-MUG, but glucose inhibited α-MUG uptake. α-MUG hydrolysis by G.stearothermophilus is by α-MUG uptake and hydrolysis by ≥2 α-glucosidases associated with dormant spores and synthesized by germinating and outgrowing spores. The enzyme activity observed by sterilization assurance assays appears likely to come from heat-stable enzyme in the spore core and enzyme(s) synthesized in spore outgrowth. The results of this work provide new insight into the science behind a rapid test for steam sterilization assurance.

Dihydropyrano [2,3-c] pyrazole: Novel in vitro inhibitors of yeast α-glucosidase

Inhibition of α-glucosidase enzyme activity is a reliable approach towards controlling post-prandial hyperglycemia associated risk factors. During the current study, a series of dihydropyrano[2,3-c] pyrazoles (1–35) were synthesized and evaluated for their α-glucosidase inhibitory activity. Compounds 1, 4, 22, 30, and 33 were found to be the potent inhibitors of the yeast α-glucosidase enzyme. Mechanistic studies on most potent compounds reveled that 1, 4, and 30 were non-competitive inhibitors (Ki=9.75±0.07, 46±0.0001, and 69.16±0.01μM, respectively), compound 22 is a competitive inhibitor (Ki=190±0.016μM), while 33 was an uncompetitive inhibitor (Ki=45±0.0014μM) of the enzyme. Finally, the cytotoxicity of potent compounds (i.e. compounds 1, 4, 22, 30, and 33) was also evaluated against mouse fibroblast 3T3 cell line assay, and no toxicity was observed. This study identifies non-cytotoxic novel inhibitors of α-glucosidase enzyme for further investigation as anti-diabetic agents.

Inhibitory actions of Pseuderanthemum palatiferum (Nees) Radlk. leaf ethanolic extract and its phytochemicals against carbohydrate-digesting enzymes

ObjectiveTo investigate the effects of the leaf ethanolic extract of Pseuderanthemum palatiferum (PPE) and its isolated phytochemicals, stigmasterol and sitosterol-3-O-β-d-glucopyranoside, against α-amylase and α-glucosidase enzyme activities both in vitro and in vivo. MethodsA concentration of maltose, which is a product released in α-amylase-catalyzing reaction, was used as an index of in vitro α-amylase activity. Meanwhile, in vitro α-glucosidase enzyme activity was indicated by the amount of liberated p-nitrophenol in α-glucosidase-catalyzing reaction. In vivo α-amylase and α-glucosidase enzyme activities were evaluated in the normal rats by using oral starch tolerance test and oral sucrose tolerance test, respectively. ResultsPPE exerted a concentration-dependent inhibitory action against both α-amylase and α-glucosidase in vitro with the IC50 values of (11.79 ± 8.10) mg/mL and (1.00 ± 0.11) mg/mL, respectively. Stigmasterol and sitosterol-3-O-β-d-glucopyranoside also exerted an in vitro α-amylase inhibition with the IC50 values of (59.41 ± 8.22) μg/mL and (111.19 ± 9.02) μg/mL, respectively. However, these phytochemicals did not produce a concentration-dependent inhibition against in vitro α-glucosidase activity. PPE and its isolated phytochemicals significantly decreased the blood glucose levels at t = 30 min in the oral starch tolerance test. From the sucrose tolerance test, only PPE but not its isolated phytochemicals significantly caused a depletion in the blood glucose levels at t = 30 min ConclusionsThese results indicate an inhibitory action against carbohydrate-digesting enzymes as the anti-diabetic mechanism of action of PPE. Nonetheless, further clinical study is required to justify its role in the treatment of diabetes.

AKTIVITAS ANTIDIABET SECARA INVITRO AGAR-AGAR, AGAROSA, DAN AGAROPEKTIN DARI RUMPUT LAUT Gracilaria gigas

Some types of seaweed are reported to have antidiabet activity in vivo or in vitro, but the activity antidiabet fractions of polysaccharides from seaweed has not been widely reported. Gracilaria gigas is one type of red seaweed that can produce agar and it has two factions, namely agarose and agaropectin. The aim of this study was to obtain an agar extract, agarose fraction, agaropektin fraction of Gracilaria gigas and to determine the α-glucosidase inhibitory activity of extracts and the fractions. Extraction of agar that used an ethanol solution, and to fractionate agarose and agaropektin used dimetilsulfoxide solution. The results showed that the fraction of the agarose having lower sulfate content (0.28%) compared with agar (5.91%) and agaropektin (6.07%). Types of samples (agar, agarose, and agaropektin) and sample doses significantly in inhibiting α-glucosidase enzyme activity. Agarose fraction has IC50 value against α-glucosidase lowest (96.86 ± 4.61 ppm), followed by the extract agar (116.63 ± 5.61 ppm), then the fraction agaropektin (158.34 ± 1.77 ppm). Keywords: α-glucosidase, extract, fraction, Gracilaria gigas, IC50

Chemical Constituents of Euonymus alatus (Thunb.) Sieb. and Their PTP1B and α-Glucosidase Inhibitory Activities.

Phytochemical study on the corks of Euonymus alatus resulted in the isolation of a novel 3-hydroxycoumarinflavanol (23), along with ten triterpenoids (1-10), ten phenolic derivatives (11-20), and two flavonoid glycosides (21 and 22). Their structures were determined by extensive 1D and 2D-nuclear magnetic resonance spectroscopic and mass spectrometry data analysis. Furthermore, their inhibitory effects against the protein tyrosine phosphatases 1B (PTP1B) and α-glucosidase enzyme activity were evaluated. Compounds 6, 7, 9, 15, 19, and 23 were non-competitive inhibitors, exhibiting most potency with IC50 values ranging from 5.6 ± 0.9 to 18.4 ± 0.3 µm, against PTP1B. Compound 3 (competitive), compounds 5 and 15 (mixed-competitive) displayed potent inhibition with IC50 values of 15.1 ± 0.7, 23.6 ± 0.6 and 14.8 ± 0.9 µm, respectively. Moreover, compounds 15, 20, and 23 exhibited potent inhibition on α-glucosidase with IC50 values of 10.5 ± 0.8, 9.5 ± 0.6, and 9.1 ± 0.5 µm, respectively. Thus, these active ingredients may have value as new lead compounds for the development of new antidiabetic agents.

A New Indole Alkaloid from Cleome droserifolia

AbstractThe phytochemical investigations on Cleome droserifolia resulted in the isolation and characterization of a new indole alkaloid, 5‐hydroxy‐2‐methoxy‐1‐methyl‐1H‐indole‐3‐carbaldehyde (1). The structure elucidation was carried out on the basis of 1D‐ and 2D‐NMR techniques. In addition to 1, two known aromatic derivatives, veratrol (2) and 2‐methoxy‐4‐methylacetophenone (3), were also obtained. All these compounds were purified by repeated column chromatography of the CH2Cl2 fraction obtained from MeOH extract of Cleome droserifolia. The structure of the new compound 1 was finally confirmed by the combined 1D (1H‐ and 13C‐) and 2D (HC correlations; HMBC and HSQC) NMR and IR spectroscopy, mass spectrometry (MS), and UV absorption spectroscopy techniques. The comparison of the physical and spectroscopic data with those in the literature provided evidence for the structure confirmation of known compounds. All the purified compounds were subjected to urease and α‐glucosidase enzymes inhibition. The results showed that compound 1 was more potent with an IC50 value 11.97±2.067 μg/ml towards urease inhibition, while the activity of α‐glucosidase enzyme was marginal.

Contribution of Musa paradisiaca in the inhibition of α-amylase, α-glucosidase and Angiotensin-I converting enzyme in streptozotocin induced rats.

Unripe plantain based-diets are part of folklore remedy for the management of diabetes in tropical Africa; however, with the dearth of information on the rationale behind this practice; this study therefore, sought to investigate the antihyperglycemic effect of traditional unripe plantain products (Amala and Booli) in high fat fed/low dose streptozotocin-induced diabetic rats and to provide a possible rationale for their antidiabetic properties. Diabetes was induced experimentally by high fat fed/low dose streptozotocin-diabetic rats (25mg/kg body wt.) and the diabetic rats were fed diets supplemented with 20-40% Amala and Booli for 14 days. The effect of the diets on the blood glucose level, pancreatic α-amylase, intestinal α-glucosidase and Angiotensin-I converting enzyme (ACE) activities and plasma antioxidant status as well as amylose/amylopectin content of the unripe plantain products were determined. A marked increase in the blood glucose, α-amylase, α-glucosidase and ACE activities with a corresponding decrease in plasma antioxidant status was recorded in diabetic rats. However, these indices were significantly (P < 0.05) reversed after unripe plantain product supplemented diet treatments for 14 days. Also, the amylose/amylopectin ratio of the products is 1:3. This study revealed that unripe plantain products exert antihyperglycemic effects which could be attributed to the inhibition of α-amylase and α-glucosidase activities by their constituent phytochemicals as well as their amylose/amylopectin contents in the diabetic rats, hence, providing the possible rationale behind their antidiabetic properties.

Desmiflavasides A and B: Two new bioactive pregnane glycosides from the sap of Desmidorchis flava

The sap from the succulent, Desmidorchis flava (N.E.Br) Meve & Liede (Apocyanaceae), provided two new pregnane glycosides named desmiflavasides A (1) and B (2) whose structures were established from 1D and 2D NMR spectroscopic techniques and mass spectromentry (ESIMS) measurements. Desmiflavaside B (2) was tested for anticancer activity and induced a 27.4% and 33.1% growth inhibition of the breast cancer cell line (MDA MB231) at a concentration of 75μg/ml and 100μg/ml, respectively. Desmiflavasides A (1) and B (2) were additionally evaluated for: DPPH antioxidant activity, urease enzyme inhibition as well as for xanthine oxidase enzyme, α-glucosidase enzyme and acetylcholinesterase inhibition activities. They displayed weak antioxidant and urease enzyme inhibition activities with 15% inhibition.

Kadar Xanton dalam Jus Kulit Buah Manggis (garcinia mangostana L.) dan Efek Inhibisi Jus Kulit Buah Manggis Terhadap Aktifitas Enzim alfa-Glukosidase

Glucosidase effects. This study aims to determine the effects of mangosteen rind juice inhibition against α-glucosidase enzyme activity and determine the levels of xanton in mangosteen rind juice. Measuring the level of xanton in mangosteen rind juice using High Performance Liquid Chromatography (HPLC). Enzyme inhibition assay against α-glucosidase activity performed in vitro. The research showed that Mangosteen rind juice samples had a retention time of 8.507 and xanton concentration in each mL juice mangosteen rind of 4.238 μg/mL or 385.272 μg/g juice mangosteen rind. The results showed that xanton in mangosteen rind juice can inhibit the activity of α-glucosidase enzyme. Based on the calculation of percent inhibition mangosteen rind juice against α-glucosidase enzyme activity by 64.71 %.

In Vitro Studies on the Antioxidant Property and Inhibition of α-Amylase, α-Glucosidase, and Angiotensin I-Converting Enzyme by Polyphenol-Rich Extracts from Cocoa (Theobroma cacao) Bean.

Background. This study sought to investigate the antidiabetic and antihypertensive mechanisms of cocoa (Theobroma cacao) bean through inhibition of α-amylase, α-glucosidase, angiotensin-1 converting enzyme, and oxidative stress. Methodology. The total phenol and flavonoid contents of the water extractable phytochemicals from the powdered cocoa bean were determined and the effects of the extract on α-amylase, α-glucosidase, and angiotensin-1 converting enzyme activities were investigated in vitro. Furthermore, the radicals [1,1-diphenyl-2 picrylhydrazyl (DPPH), 2,2..-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), hydroxyl (OH), and nitric oxide (NO)] scavenging ability and ferric reducing antioxidant property of the extract were assessed. Results. The results revealed that the extract inhibited α-amylase (1.81 ± 0.22 mg/mL), α-glucosidase (1.84 ± 0.17 mg/mL), and angiotensin-1 converting enzyme (0.674 ± 0.06 mg/mL [lungs], 1.006 ± 0.08 mg/mL [heart]) activities in a dose-dependent manner and also showed dose-dependent radicals [DPPH (16.94 ± 1.34 mg/mL), NO (6.98 ± 0.886 mg/mL), OH (3.72 ± 0.26 mg/mL), and ABTS (15.7 ± 1.06 mmol/TEAC·g] scavenging ability. Conclusion. The inhibition of α-amylase, α-glucosidase, and angiotensin-1 converting enzyme activities by the cocoa bean extract could be part of the possible mechanism by which the extract could manage and/or prevent type-2 diabetes and hypertension.

Anti-diabetic effects of Caulerpa lentillifera: stimulation of insulin secretion in pancreatic β-cells and enhancement of glucose uptake in adipocytes

To evaluate anti-diabetic effect of Caulerpa lentillifera (C. lentillifera). The inhibitory effect of C. lentillifera extract on dipeptidyl peptidase-IV and α-glucosidase enzyme was measured in a cell free system. Then, interleukin-1β and interferon-γ induced cell death and insulin secretion were measured in rat insulinoma (RIN) cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and ELISA kit, respectively. Glucose uptake and glucose transporter expression were measured by fluorometry and western blotting, using 3T3-L1 adipocytes. C. lentillifera extract significantly decreased dipeptidyl peptidase-IV and α-glucosidase enzyme activities, and effectively inhibited cell death and iNOS expression in interleukin-1β and interferon-γ induced RIN cells. Furthermore, C. lentillifera extract significantly enhanced insulin secretion in RIN cells and glucose transporter expression and glucose uptake in 3T3-L1 adipocytes. Thus, our results suggest that C. lentillifera could be used as a potential anti-diabetic agent.

Varicocele decreases epididymal neutral α‐glucosidase and is associated with alteration of nuclear DNA and plasma membrane in spermatozoa

To assess the relationship between a marker of epididymal function and both the fragmentation of the sperm nucleus and the integrity and maturity of the sperm membrane in patients with or without varicocele. Semen samples were obtained from men with varicocele grades II and III (n = 60) and from a control group with zoospermia defined as normal (n = 30). Samples were evaluated by a spermiogram, a hypoosmotic swelling test (HOST), neutral α-glucosidase (NAG) enzyme activity, sperm hyaluronan-binding assay (HBA) and DNA fragmentation using a sperm chromatin dispersion (SCD) test. Seminal plasma NAG levels, percentage of sperm bound to hyaluronic acid, HOST-positive cells and sperm quality were significantly lower in the varicocele compared with the control group. Higher levels of sperm DNA fragmentation, as measured by SCD, were also observed in the varicocele group compared with the control group. Seminal NAG activity levels showed a strong negative correlation with DNA fragmentation and a significant positive correlation with the HBA test and the HOST. Varicocele causes a reduction in NAG activity by the epididymis that is associated with damage to both the membrane and sperm nucleus and a reduction in the seminal parameters. NAG levels were correlated with the quality of the sperm membrane and nucleus. Data suggest that a reduction of fertilization capacity in men during varicocele can result from damage to both the testis and the epididymis.

Helichrysum and Grapefruit Extracts Inhibit Carbohydrate Digestion and Absorption, Improving Postprandial Glucose Levels and Hyperinsulinemia in Rats

Several plant extracts rich in flavonoids have been reported to improve hyperglycemia by inhibiting digestive enzyme activities and SGLT1-mediated glucose uptake. In this study, helichrysum ( Helichrysum italicum ) and grapefruit ( Citrus × paradisi ) extracts inhibited in vitro enzyme activities. The helichrysum extract showed higher inhibitory activity of α-glucosidase (IC50 = 0.19 mg/mL) than α-amylase (IC50 = 0.83 mg/mL), whereas the grapefruit extract presented similar α-amylase and α-glucosidase inhibitory activities (IC50 = 0.42 mg/mL and IC50 = 0.41 mg/mL, respectively). Both extracts reduced maltose digestion in noneverted intestinal sacs (57% with helichrysum and 46% with grapefruit). Likewise, both extracts inhibited SGLT1-mediated methylglucoside uptake in Caco-2 cells in the presence of Na(+) (56% of inhibition with helichrysum and 54% with grapefruit). In vivo studies demonstrated that helichrysum decreased blood glucose levels after an oral maltose tolerance test (OMTT), and both extracts reduced postprandial glucose levels after the oral starch tolerance test (OSTT). Finally, both extracts improved hyperinsulinemia (31% with helichrysum and 50% with grapefruit) and HOMA index (47% with helichrysum and 54% with grapefruit) in a dietary model of insulin resistance in rats. In summary, helichrysum and grapefruit extracts improve postprandial glycemic control in rats, possibly by inhibiting α-glucosidase and α-amylase enzyme activities and decreasing SGLT1-mediated glucose uptake.