Alpha-glucosidase Inhibitory Effects Research Articles

Alpha-glucosidase Inhibitory Effects of Flavonoids, Phenolic Acids and Iridoids Isolated From Vinca soneri: In vitro and in silico Perspectives.

Various Vinca species have been traditionally used for their antihypertensive, sedative, and hemostatic properties, as well as for treating diabetes. In this study, some flavonoids, phenolic acids and iridoids were isolated from an endemic Vinca species, Vinca soneri for the first time. α-Glucosidase inhibitory effects of the isolates were tested and kaempferol-3-O-α-rhamnopyranosyl (1→6) β-galactopyranoside (1) was found to be the most active one with an IC50 value of 285.73 ± 7.35 µM. Enzyme kinetic assay revealed that it inhibited α-glucosidase in competitive manner. Molecular geometry of 1 was predicted and Frontier molecular orbital analysis was performed using Density Functional Theory (DFT) calculations. Molecular docking and MM-GBSA calculations predicted good fit for 1 in the enzyme active site and key interactions with the catalytic residues. As a result, current study identifies 1 as a promising competitive α-glucosidase inhibitor to be developed as a potential antidiabetic drug candidate.

Salvia mirzayanii and Salvia hypoleuca Essential Oils: Chemical Composition, Alpha-Glucosidase Inhibitory, and Synergistic Effects of Selected Components

Background: Salvia is one of the most important genera belonging to the Lamiaceae family that has been used in various applications in folk medicine and the pharmaceutical and food industries. Objectives: This study investigated the chemical composition, antioxidant activity, and α-glucosidase inhibitory activity of Salvia mirzayanii Rech. f. and Esfand. and Salvia hypoleuca Benth. essential oils (EOs). Additionally, the enzyme inhibitory activity of the mixture of compounds was evaluated to find whether the synergistic effect is responsible for the desired activity or not. Methods: The constituents of S. mirzayanii and S. hypoleuca EOs collected from Fars and Alborz provinces, Iran, were determined using gas chromatography-mass spectroscopy (GC-MS) analysis. They were evaluated for their α-glucosidase inhibitory activity by the determination of para-nitrophenol (pNP), derived from the enzymatic degradation of para-nitrophenol-D-glucopyranoside (pNPG) as the substrate. The activity of the selected components was also tested. Moreover, the antioxidant activity of EOs was evaluated based on the radical scavenging capability (2,2-Diphenyl-1-picrylhydrazyl [DPPH]) assay, and their total phenolic content (TPC) was determined using the Folin-Ciocalteu method in terms of gallic acid equivalent (GAE). Results: In total, 66 compounds were detected in the S. mirzayanii and S. hypoleuca EOs. The results showed that S. mirzayanii EO had more potent antioxidant activity (half-maximal inhibitory concentration [IC50] = 0.77 ± 0.00 mg/mL), higher TPC (78.26 ± 1.26 mg GAE/g EO), and a greater inhibitory effect toward α-glucosidase (IC50 = 55.15 ± 1.60 mg/mL) than S. hypoleuca EO. Furthermore, caryophyllene oxide (IC50 = 19.94 ± 0.26 mg/mL), α-pinene (IC50 = 17.59 ± 0.19 mg/mL), and linalool (IC50 = 38.00 ± 0.22 mg/mL) showed high levels of α-glucosidase inhibitory activity among the major constituents. In addition, the combination of linalool: 1,8-cineole: α-terpineol (40: 35: 25) inhibited this enzyme synergistically (combination index [CI] < 1). Conclusions: The findings indicated that S. mirzayanii EO had a high potential for developing efficient anti-type 2 diabetes agents.

Alpha-glucosidase inhibitory and hypoglycemic effects of imidazole-bearing thioquinoline derivatives with different substituents: In silico, in vitro, and in vivo evaluations

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by high blood sugar levels. It was shown that modulating the activity of α-glucosidase, an enzyme involved in carbohydrate digestion and absorption, can improve blood sugar control and overall metabolic health in individuals with T2DM. As a result, in the current study, a series of imidazole bearing different substituted thioquinolines were designed and synthesized as α-glucosidase inhibitors. All derivatives exhibited significantly better potency (IC50 = 12.1 ± 0.2 to 102.1 ± 4.9 µM) compared to the standard drug acarbose (IC50 = 750.0 ± 5.0 µM). 8g as the most potent analog, indicating a competitive inhibition with Ki = 9.66 µM. Also, the most potent derivative was subjected to molecular docking and molecular dynamic simulation against α-glucosidase to determine its mode of action in the enzyme and study the complex's behavior over time. In vivo studies showed that 8g did not cause acute toxicity at 2000 mg/kg doses. Additionally, in a diabetic rat model, treatment with 8g significantly reduced fasting blood glucose levels and decreased blood glucose levels following sucrose loading compared to acarbose, a standard drug used for blood sugar control. The findings suggest that the synthesized compound 8g holds promise as an α-glucosidase inhibitor for improving blood sugar control and metabolic health.

PRELIMINARY PHYTOCHEMICAL SCREENING AND BIOACTIVITY INVESTIGATIONS OF AVORRHEA CARAMBOLA L.

Averrhoa carambola L. (A. carambola) is particularly well-known for its distinctive star-shaped fruit (Star fruit), cultivated in Southeast Asia, the Indian subcontinent, and northern and southern America. Historically, it has been used for a long time to cure many ailments, including vomiting, fever, arthralgia, cough, hypertension, hangovers, chronic paroxysmal headache, hyperglycemia, and diabetic nephropathy. This study aimed to examine its preliminary phytochemical and some biological properties. For this, fresh leaves of A. carambola were extracted (hot and cold) with ethanol, which was then fractionated with n-hexane and chloroform. Following a preliminary investigation of phytochemicals, radical scavenging, membrane stabilizing, alpha-glucosidase inhibitory, and clot lysis effects were evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, egg albumin model, alpha-amylase assay, and human blood clot lysis assay, respectively using suitable reference standards. The results suggest that A. carambola contains alkaloids, glycosides, steroids, tannins, flavonoids, saponins, and reducing sugars. All the organic fractions demonstrated significant (p <0.05) radical scavenging, membrane stabilizing, alpha-glucosidase inhibitory, and clot lysis activities in a concentration-dependent approach. Except for DPPH radical scavenging, the ethanol fraction showed better activities than the n-hexane and chloroform fractions. In summary, A. carambola might be a potential source of antioxidant, anti-inflammatory, hypoglycemic, and atherothrombolytic agents. Further studies are required to isolate, characterize, and establish molecular mechanisms for each component’s biological effects.

Evaluation of the Alpha-Glucosidase Inhibitory Activity of Endophytic Bacteria Extracts Isolated from Ludwigia octovalvis (Jacq.) P. H. Raven (Onagraceae)

The study aimed at evaluating the alpha-glucosidase inhibitory potential of extracts of endophytic bacteria isolated from Ludwigia octovalvis (Jacq.) P. H. Raven (Onagraceae). Isolation of endophytic bacteria was done on supplemented and non-supplemented nutrient agar. The extracts of these endophytes were obtained after fermentation in Mueller-Hinton Broth (MHB). The inhibitory effect on the alpha-glucosidase enzyme of the extracts of endophytic bacteria was determined in the presence of starch and sucrose at 6 mg/mL at 37°C and by measuring the absorbance at 517 nm. Nineteen endophytic bacteria were isolated from the leaves, stems, roots, flowers, fruits and twigs of L. octovalvis. The extracts obtained from these endophytic bacteria all showed an alpha-glucosidase inhibitory effect. The S4155 extract showed less than 50% enzyme inhibitory activity with an IC50 of 163.98 μg/mL. Endophyte bacteria associated with L. octovalvis provided a source of bioactive compounds that can prevent or reduce the prevalence of diabetes.

Phytochemical analysis and biological activities of ethanolic extract of Curcuma longa rhizome.

Curcuma longa is an important dietary plant which possess several pharmacological activities, including antioxidant, antimicrobial, anti-inflamatory, anticancer and anti clotting etc. The aim of the present study was to determine the phenolic profile of Curcuma longa and in vitro antioxidant and antidiabetic activities. In HPLC chromatogram of Curcuma longa rhizome extract 15 phenolic compounds were identified namely Digalloyl-hexoside, Caffeic acid hexoside, Curdione, Coumaric, Caffeic acid, Sinapic acid, Qurecetin-3-D-galactoside, Casuarinin, Bisdemethoxycurcumin, Curcuminol, Demethoxycurcumin, and Isorhamnetin, Valoneic acid bilactone, Curcumin, Curcumin-O-glucuronide respectively. The ethanolic extract displayed an IC50 value of 37.1±0.3 µg/ml against alpha glucosidase. The IC50 value of DPPH radical scavenging activity was 27.2 ± 1.1 μg/mL. It is concluded that ethanolic extract of Curcuma long is rich source of curcumin and contain several important phenolics. The in vitro antioxidant and alpha glucosidase inhibitory effect of the plant justifies its popular use in traditional medicine.

Computational study and in vitro alpha-glucosidase inhibitory effects of medicinal plants from a Thai folk remedy

The number of patients with type 2 diabetes mellitus (T2DM) has increased worldwide. Although an instant cure was achieved with the standard treatment acabose, unsatisfactory symptoms associated with cardiovascular disease after acabose administration have been reported. Therefore, it is important to explore new treatments. A Thai folk recipe has long been used for T2DM treatment, and it effectively decreases blood glucose. However, the mechanism of this recipe has never been proven. Therefore, the potential anti-T2DM effect of this recipe, which is used in Thai hospitals, was determined to involve alpha-glucosidase (AG) inhibition with a half maximal inhibitory concentration (IC50). In vitro experiments showed that crude Cinnamomum verum extract (IC50 = 0.35 ± 0.12 mg/mL) offered excellent inhibitory activity, followed by extracts from Tinospora crispa (IC50 = 0.69 ± 0.39 mg/mL), Stephania suberosa (IC50 = 1.50 ± 0.17 mg/mL), Andrographis paniculate (IC50 = 1.78 ± 0.35 mg/mL), and Thunbergia laurifolia (IC50 = 4.66 ± 0.27 mg/mL). However, the potencies of these extracts were lower than that of acabose (IC50 = 0.55 ± 0.11 mg/mL). Therefore, this study investigated and developed a formulation of this recipe using computational docking. Among 61 compounds, 7 effectively inhibited AG, including chlorogenic acid (IC50 = 819.07 pM) through 5 hydrogen bonds (HBs) and 2 hydrophobic interactions (HIs); β-sitosterol (IC50 = 4.46 nM, 6 HIs); ergosterol peroxide (IC50 = 4.18 nM, 6 HIs); borapetoside D (IC50 = 508.63 pM, 7 HBs and 2 HIs); borapetoside A (IC50 = 1.09 nM, 2 HBs and 2 His), stephasubimine (IC50 = 285.37 pM, 6 HIs); and stephasubine (IC50 = 1.09 nM, 3 HBs and 4 HIs). These compounds bind with high affinity to different binding pockets, leading to additive effects. Moreover, the pharmacokinetics of six of these seven compounds (except ergosterol peroxide) showed poor absorption in the gastrointestinal tract, which would allow for competitive binding to AG in the small intestine. These results indicate that the development of these 6 compounds into oral antidiabetic agents is promising.

Phytochemical investigation ofbauhinia winitiibased on alpha-glucosidase inhibitory effect and molecular docking affirmation

Background: Bauhinia winitii (BW) (Fabaceae) plant revealed poor phytochemical investigation and anti-diabetic report. As one of the Bauhinia family which known with abundant flavonoids content, contrary, BW was only used for the treatment of diarrhea in Thai conservative remedy. Objectives: The aim of this study was to investigate the phytochemical constituents and anti-alpha glucosidase activity of BW. Materials and Methods: Phytochemical study was based on the alpha-glucosidase inhibitory effect. Isolated compounds were determined by chromatographic and spectroscopic techniques. The alpha-glucosidase enzymatic inhibitory test was then connected with molecular docking affirmation. Results: The ethyl acetate and ethanol extracts from leaves and woods exhibited the strongest activity with above 60% inhibition. Six compounds were isolated from these extracts, naringenin (1), luteolin (2), isoquercitrin (3), griffonilide (4), lithospermoside (5), and epi-β amyrin (6). The alpha-glucosidase inhibitory test showed that flavonoids performed potential results with naringenin as the highest IC50 on 0.41 mM. The docking ensured the flavonoids activated at the same binding of alpha-glucosidase enzyme active site. Conclusion: This study would be the first report of chemical constituents from BW with its isolated compounds was presented anti-diabetic activity as alpha-glucosidase inhibitors.

Antidiabetic activity, alpha-amylase, and alpha-glucosidase inhibitory effect of Tradescantia spathacea Swartz extract

Tradescantia spathacea Swartz belongs to the genus Commelinaceae, a tropical tree used in many countries as an herbal drug for the care of diabetic patients. The aim of this study was to examine anti-diabetic activity of the Tradescantia spathacea Swartz methanolic extract (METSW) and the in-vitro activity of α-amylase, and α-glucosidase was carried out. METSW compared with acarbose inhibition of the α-amylase and α-glucosidase enzyme, METSW exhibited IC50 less than 100μg/mL would be considered as healthy. The METSW showed IC50 66.22 ± 0.52μg/mL α-amylase activity, acarbose revealed an IC50 of 83.25 ± 1.28μg/mL. METSW demonstrated IC50 levels of 85.37 ± 0.72 μg/mL (y= 0.095x+41.89) inhibition of the α-Glucosidase enzymes. METSW at 400 mg/kg greatly decreased the region under the blood glucose level curve in a typical rat test for oral glucose tolerance. The single dose of the extract decreased dramatically from 211 mg/dl to 89.22 mg/dl at 400 mg/kg METSW in the alloxan induced diabetic model. METSW possesses strong antidiabetic activity in vivo and in vitro. Besides, the extract has also been shown to have a significant inhibitory activity of α-amylase and α-glucosidase which may lead to its anti-hyperglycemic function when used in diabetic patients.

In Vitro Antidiabetic and Antioxidant Effects of Different Extracts of Catharanthus roseus and Its Indole Alkaloid, Vindoline.

The Catharanthus roseus plant has been used traditionally to treat diabetes mellitus. Scientific evidence supporting the antidiabetic effects of this plant’s active ingredient-vindoline has not been fully evaluated. In this study, extracts of C. roseus and vindoline were tested for antioxidant activities, alpha amylase and alpha glucosidase inhibitory activities and insulin secretory effects in pancreatic RIN-5F cell line cultured in the absence of glucose, at low and high glucose concentrations. The methanolic extract of the plant showed the highest antioxidant activities in addition to the high total polyphenolic content (p < 0.05). The HPLC results exhibited increased concentration of vindoline in the dichloromethane and the ethylacetate extracts. Vindoline showed noticeable antioxidant activity when compared to ascorbic acid at p < 0.05 and significantly improved the in vitro insulin secretion. The intracellular reactive oxygen species formation in glucotoxicity-induced cells was significantly reduced following treatment with vindoline, methanolic and the dichloromethane extracts when compared to the high glucose untreated control (p < 0.05). Plant extracts and vindoline showed weaker inhibitory effects on the activities of carbohydrate metabolizing enzymes when compared to acarbose, which inhibited the activities of the enzymes by 80%. The plant extracts also exhibited weak alpha amylase and alpha glucosidase inhibitory effects.

LC-MS analysis, antioxidant and alpha-glucosidase inhibitory activities of Centaurea papposa extracts

This work aimed to ascertain the phenolic compounds and assess the antioxidant capacity and alpha-glucosidase inhibitory activity of Centaurea papposa extracts. Phenolic compounds were appraised using LC-MS technique. Moreover, antioxidant activity was investigated using DPPH, ABTS, CUPRAC and FRAP assays. In vitro alpha-glucosidase inhibitory effect was carried out. LC-MS analysis revealed the presence of 21 compounds among which 13 were phenolic acids, 6 flavonoids, 1 phenolic aldehyde and 1 benzopyrone. The ethyl acetate extract exhibited the highest activity in ferric reducing antioxidant power (FRAP) assay (IC50: 22.9 ± 2.8 µg/mL). Nevertheless the n-butanol extract was the most active in cupric reducing antioxidant capacity assay (IC50: 3.1 ± 0.1 µg/mL). A significant alpha-glucosidase inhibitory activity was displayed by dichloromethane extract (IC50: 227.6 ± 4.4 µg/mL).&#x0D; Video Clip of Methodology:&#x0D; Cupric reduction antioxidant capacity: 1 min 47 sec: Full Screen Alternate

Evaluation of Alpha-Glucosidase Inhibitory Activity of Vinca Rosea

Diabetes mellitus (DM) has developed into serious health problem worldwide. α-glucosidase inhibitors are used in management of Type II Diabetes mellitus. Medicinal plants are known to be effective in treating various diseases and disorders. Catharanthus roseus belonging to family Apocyanaceae is very well known for its anticancer property. The present study was aimed to compare the alpha glucosidase inhibitory effect of leaves and flowers extracts of Vinca rosea by an in-vitro assay. Methanolic extracts were obtained using Soxhlet apparatus. Yeast alpha glucosidase was used as the enzyme source. Acarbose was used as the reference drug. The % inhibition was calculated. The results proved that both leaves and flowers extract of Vinca rosea possess α-glucosidase inhibitor activity. The leaf extract (57.87%) showed a better activity when compared to flower extracts (48.31%). The result supports Vinca rosea as a potential source in treating Diabetes mellitus.

In vitro and in vivo studies on the alpha-glucosidase inhibitory effects of the leaf extract of Carica papaya Linn

The search for novel alpha-glucosidase inhibitory agents is currently an important scientific endeavour to the biopharmaceutical companies due to their potentials to reduce postprandial hyperglycaemia in type 2 diabetic patients. The present research attempted to investigate the alpha-glucosidase inhibitory effects of the leaf extract of Carica papaya. Aqueous, methanol, ethyl acetate and n-hexane extracts of C. papaya leaf were subjected to in vitro alpha-glucosidase inhibitory studies, and methanol extract was the most potent (IC50 = 171.83 ± 26.89 μg/mL). Consequently, the methanol extract was further fractionated by column chromatography which yielded six pooled fractions (A–F) and fraction A (FA) showed the lowest IC50 (78.62 ± 25.23 μg/mL). Subsequently, the FA was subjected to in vivo oral maltose and sucrose tolerance tests which revealed that FA had potent inhibitory effects on maltose and sucrose tolerance in rats. The computed area under the curves (AUC(0–120)) further indicates that FA (200 mg/kg bw) have better inhibitory activity on maltase than sucrase. The GC-MS analysis of FA indicates the presence of phenolics, various fatty acids and their derivatives. This research suggests that the leaf extract of C. papaya possesses alpha-glucosidase inhibitory effects and might be exploited in retarding postprandial hyperglycaemia.

Alpha Glukosidase Inhibitory Test and Total Phenolic Content of Ethanol Extract of Parkia Speciosa Plant

Parkia speciosa (Fabaceae), much grow in South Sumatera. The seed of P. speciosa used as traditional medicine for diabetes mellitus therapy. Another parts of P speciosa is suspected to have the same chemical compounds and potency as the seed. Based on phytochemical screening of leaf and rind of P speciosa have secondary metabolites as flavonoid, phenolic and terpenoid. This research aims to know effectiveness of alpha glucosidase inhibitory effect of ethanol extract of rind, leaf and seed of p. speciosa and its correlation to total phenolic content of the extracts. The inhibitory activity of the alpha glucosidase enzyme was measured at l 405 nm. The result showed that there was correlation between effectiveness of inhibitory and total phenolic content of the extract, that is the higher of the total phenolic content will caused the greater of enzymatic inhibition of extract. The IC50 of alpha glucosidase inhibitory effect of ethanol extract of rind, leaf and seed of P speciosa are 4,596 ppm, 54,341 ppm, dan 67,425 ppm and the total Phenolic content of the extract are 138,15 mgGAE/g, 59,25 mgGAE/g, dan 36,25 mgGAE/g respectively.

Alpha-glucosidase and amylase inhibitory effects of Eruca vesicaria subsp. longirostris essential oils: synthesis of new 1,2,4-triazole-thiol derivatives and 1,3,4-thiadiazole with potential inhibitory activity

Context: The substantial increase in the number of diabetics has encouraged the search for new pharmacological strategies to face this problem. In this regard, triazole and its derivatives have attracted considerable attention for the past few decades due to their pharmacological significance.Objective: Evaluation of the inhibitory activity of α-glucosidase and α-amylase in essential oils extracted from plant Eruca vesicaria (L) Cav. subsp. longirostris (Brassicaceae) (EVL) and to verify whether the triazoles and thiadiazol bearing the lipophilic 4-methylthiobutyl group synthesized from the essential oil contribute to this activity.Materials and methods: The essential oils were extracted by hydrodistillation from leaf, stem, root, and fruit of EVL, and their chemical compositions were analyzed by gas chromatography and gas chromatography-mass spectrometry. We present here the synthesis of three new types of 1,2,4-triazole-thiol and 1,3,4-thiadiazol and the structures were confirmed by NMR, mass spectrometry. The α-glucosidase and α-amylase inhibitory activities were investigated in vitro.Results: The main compound in fruit, stem, and root was erucin (96.6, 85.3, and 83.7%, respectively). The three essential oils of the fruit, stem, and root have strong inhibitory activity on α-glucosidase and α-amylase; IC50 values of roots were 0.81 ± 0.02 μg/mL and 0.13 ± 0.01 μg/mL, respectively. Derivatives 1 b, 2 b, 3 b, and 2c showed remarkable inhibitory activity against α-glucosidase with potencies better than that of acarbose with IC50 values ranging between 0.49 and 1.43 μM.Conclusions: Current results indicate that ECL fruit essential oil can be used as a natural precursor for the synthesis of triazoles as potential hypoglycemic agents.

Alpha amylase and Alpha glucosidase inhibitory effects of aqueous stem extract of Salacia oblonga and its GC-MS analysis

ABSTRACT Our present investigation deals with the phytochemical screening, estimation of total flavonoids, terpenoids and tannin contents to evaluate the anti-diabetic activities of Salacia oblonga stem followed by GC-MS analysis. It explores the natural compounds and the potential α-amylase and α-glucosidase inhibitory actions of stem extracts. The aqueous stem extract was selected from other extracts (ethanol, acetone, petroleum ether and chloroform) for the in vitro study of anti-diabetic activity by alpha amylase and alpha glucosidase inhibitory assays. The stem extract was also analyzed by gas chromatography mass spectrometry to identify the natural chemical components. Phytochemical analysis of aqueous stem extract showed major classes of secondary metabolites such as phenols, flavonoids, alkaloids, terpenoids, tannins, saponins. The total flavonoid, terpenoid, and tannin contents were quantified as 19.82±0.06 mg QE/g, 96.2±0.20 mg/g and 11.25±0.03 mg TAE/g respectively. The percentage inhibition of assays showed maximum inhibitory effects (59.46±0.04% and 68.51±0.01%) at a concentration of 100 mg/mL. The IC50 values of stem extract was found to be 73.56 mg/mL and 80.90 mg/mL for alpha amylase and alpha glucosidase inhibition. Fifteen chemical constituents were found by GC-MS analysis. This study suggest the aqueous stem extract of Salacia oblonga might be considered as potential source of bio active constituents with excellent antidiabetic activity.

Fermentation alters the bioaccessible phenolic compounds and increases the alpha-glucosidase inhibitory effects of aronia juice in a dairy matrix following in vitro digestion.

The prevalence of diabetes reached 415 million worldwide in 2015. Polyphenol-rich food intake can benefit the glycemic control for individuals with diabetes. Fermentation may increase the bioavailability of polyphenols, which is generally low. Aronia (Aronia melanocarpa) is a polyphenol-rich berry that is native to North America. Proanthocyanins and anthocyanins are the major phenolic compounds in aronia. In this study, aronia kefir was made by fermenting cow's milk with added aronia juice. The changes in bioaccessible polyphenols of aronia kefir during digestion were assessed using an in vitro model. The impact of fermentation on the potential bioactivity of aronia polyphenols was evaluated. Results showed that the bioaccessible polyphenols in aronia kefir were elevated during digestion and the antioxidant capacity increased (IC50 of DPPH scavenging decreased from 24.07 mg kefir per mL to 8.97 mg kefir per mL). Digested aronia kefir had less bioaccessible anthocyanins (cyanidin-3-galactoside, cyanidin-3-arabinoside and cyanidin-3-xyloside) but similar antioxidant capacity and stronger inhibitory activity on α-glucosidase (IC50: 152.53 mg kefir per mL) compared to the non-fermented control (IC50: 484.93 mg kefir per mL). These results indicate that fermentation may produce metabolites with higher antioxidant capacity and better α-glucosidase inhibitory activity. Utilizing aronia kefir in the diet is a good strategy to help control blood glucose levels without abdominal side effects. Fermentation may be an effective method to increase the bioavailability of dietary polyphenols in food. More studies about the effects of fermentation on polyphenol-rich food are needed to optimize the potential health-promoting properties.

α-Amylase and α-glucosidase inhibitory activities of the herbs of Artemisia dracunculus L. and its active constituents

A new phenylpropanoid named 4-(1′,1′,2′,2′-tetramethylpropyl)-1,2-benzenediol (1) with a known phenylpropanoid: 3-(p-methoxyphenyl)-1,2-propanediol (2), a coumarin: herniarin (3), and a flavonol glycoside: rutin (4) were isolated from the aerial parts of Artemisia dracunculus L. Their structures were elucidated by detailed analyses of 1D and 2D nuclear magnetic resonance, IR, ESI–MS and HR–ESI–MS data. Methanol extract of aerial parts of the plant, different polarity fractions of methanol extract and the isolated compounds from these fractions were evaluated for their alpha amylase and alpha glucosidase inhibitory effects. Phenylpropanoids containing fraction had a significantly higher α-glucosidase inhibitory activity (90.4%) when compared with the standart compound acarbose (26.0%) at 1 mg/mL. However none of the tested extracts or compounds were found to be active on α-amylase inhibition.

Antihyperglycemic Activity of Caralluma fimbriata: An In vitro Approach.

Background:An increase in prevalence of diabetes mellitus necessitates the need to develop new drugs for its effective management. Plants and their bioactive compounds are found to be an alternative therapeutic approach. Caralluma fimbriata, used in this study, is well known for its various biological effects.Objective:The present study was designed to investigate the antihyperglycemic effect of the ethanolic leaf extract of C. fimbriata.Materials and Methods:Different concentrations (1–1000 mg/mL) of the ethanolic leaf extract of C. fimbriata were subjected to alpha-amylase and alpha-glucosidase inhibitory assay with acarbose as control. Cytotoxicity was assessed by 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Glucose uptake assay was performed on L6 myotubes using the extract in 1 μg–100 μg/mL, using metformin and insulin as control.Results:The C. fimbriata extract showed potent inhibitory activity on enzymes of glucose metabolism in a dose-dependent manner. The maximum alpha-amylase inhibitory effect was 77.37% ± 3.23% at 1000 μg/mL with an IC50 value of 41.75 μg/mL and alpha-glucosidase inhibitory effect was 83.05% ± 1.69% at 1000 μg/mL with an IC50 value of 66.71 μg/mL. The maximum glucose uptake was found to be 66.32% ± 0.29% for the Caralluma extract at 100 μg/mL and that of metformin (10 μg/mL) was 74.44% ± 1.72% and insulin (10 mM) 85.55% ± 1.14%. The extract was found to be safe as the IC50 of extract and metformin was found to be ≥1000 μg/mL and ≥1000 μM, respectively, in the cell line tested.Conclusion:The study concludes that C. fimbriata has promising antihyperglycemic activity.SUMMARY Caralluma fimbriata extract exhibited effective dose dependent inhibitory activity against alpha-amylase and alpha- glucosidaseEnhanced glucose uptake from L6 myotubes was appreciated in the presence of the extract, comparable to Insulin and metforminCaralluma fimbriata has potent antihyperglycemic properties. Abbreviations used: GLUT: Glucose transporter; MTT: 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide.

Antidiabetic potentials of Syzygium guineense methanol leaf extract

This study examines the effects of a methanol extract of Syzygium guineense leaves in streptozotocin (STZ) - induced diabetes, evaluates its effect on alpha glucosidase and 2, 2-diphenyl-1-picrylhydrazyl radical. Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (60 mg/kg). An oral glucose tolerance test was performed after diabetes induction and repeated after 14 days of treatment with the extract. The extract elicited antihyperglycemic action in diabetic rats evidenced by an improved oral glucose tolerance. A dose of 250 mg/kg of extract significantly (P&lt;0.01, 0.001) enhanced glucose clearance at the end of treatment period and was comparable with metformin, the group also showed increase in hepatic glycogen content by 33.9% relative to the diabetic control. Serum biochemical analysis showed that the extract improved indices of renal and hepatic function by reduction in serum albumin, creatinine, liver enzymes, total and direct bilirubin. Similarly, the extract reduced serum cholesterol, triglycerides and high density lipoprotein (HDL) in a non-dose dependent manner; treatment with 250 mg/kg extract caused significant (P&lt;0.05) reduction of HDL. Groups which received 250 and 500 mg/kg of extract showed reversal of glomerular damage compared with the diabetic untreated group. The extract also exhibited concentration-dependent antioxidant activity (EC50= 0.2 mg/ml) and statistically significant (P&lt;0.01, 0.001) alpha glucosidase inhibitory effect (IC50= 6.15 mg/ml). These findings show the antidiabetic potential of S. guineense leaf extract, likely mediated through its ability to inhibit alpha glucosidase, scavenge free radicals and increase intrahepatic glucose uptake and storage.