In silico approaches to analyse Acanthus ilicifolius leaves extract as α-glucosidase and α-amylase inhibitors

In an effort to design and synthesize a new class of α-glucosidase and α-amylase inhibitors, we have synthesized novel pyrrole based molecules using molecular hybridization approach. These novel analogs were synthesized by the novel methodology developed in our lab which comprises of the multi-component direct synthesis route using hypervalent iodine reagent. The compounds were characterized by infrared, 1H nuclear magnetic resonance (NMR), 13C NMR and Mass Spectroscopy. These compounds were screened for their α-amylase and α- glucosidase activity. They showed a varying degree of inhibition with IC50 values ranging between 0.4 to 4.14 µmol/mL and 0.8 to 4.14 µmol/mL for α-amylase and α-glucosidase respectively. Compounds 3, 7, 12, and 18 showed excellent activity as compared to standard acarbose. This has identified a new class of α-amylase and α-glucosidase inhibitor which can be further developed as antihyperglycemic agents. The molecular docking analysis was carried out to better understand of interaction between α-amylase and α-glucosidase target and inhibitors in this series. We also generated a homology model for human α-glucosidase enzyme and identified the key residues at the binding site. The outcome of the study could be used for the rational design of potent and selective α-amylase and α-glucosidase inhibitors, respectively.

BackgroundAlbizzia Lebbeck Benth. is traditionally important plant and is reported to possess a variety of pharmacological actions. The present research exertion was undertaken to isolate and characterized the flavonoids from the extract of stem bark of Albizzia Lebbeck Benth. and to evaluate the efficacy of the isolated flavonoids on in-vitro models of type-II diabetes. Furthermore, the results of in-vitro experimentation inveterate by the molecular docking studies of the isolated flavonoids on α-glucosidase and α-amylase enzymes.MethodsIsolation of the flavonoids from the methanolic extract of stem bark of A. Lebbeck Benth was executed by the Silica gel (Si) column chromatography to yield different fractions. These fractions were then subjected to purification to obtain three important flavonoids. The isolated flavonoids were then structurally elucidated with the assist of 1H-NMR, 13C-NMR, and Mass spectroscopy. In-vitro experimentation was performed with evaluation of α-glucosidase, α-amylase and DPPH inhibition capacity. Molecular docking study was performed with GLIDE docking software.ResultsThree flavonoids, (1) 5-deoxyflavone (geraldone), (2) luteolin and (3) Isookanin were isolated from the EtOAc fraction of the methanolic extract of Albizzia lebbeck Benth bark. (ALD). All the compounds revealed to inhibit the α-glucosidase and α-amylase enzymes in in-vitro investigation correlating to reduce the plasma glucose level. Molecular docking study radically corroborates the binding affinity and inhibition of α-glucosidase and α-amylase enzymes.ConclusionThe present research exertion demonstrates the anti-diabetic and antioxidant activity of the important isolated flavonoids with inhibition of α-glucosidase, α-amylase and DPPH which is further supported by molecular docking analysis.

The effects of Ficus carica on the activity of enzymes related to metabolic syndrome

Effect directed analysis of bioactive compounds in leaf extracts from two Salvia species by High-performance thin-layer chromatography

Background: The use of medicinal plants as supplemental or alternative medicine is widespread around the world. For the development of new drugs, studies on these medicinal plants that include pharmacological and toxicological assessments are crucial. Objective: This work aimed to find the total phenolic and flavonoid content, antioxidant, antibacterial, and antidiabetic potential of the traditionally used medicinal plant Mimosa rubicaulis Lam. Methods: The in vitro antidiabetic potential of methanolic extract and its fractions of the roots of M. rubicaulis were performed via enzyme (α-glucosidase and α-amylase) inhibition assays. Antioxidant and anti-inflammatory activities were carried out using 2,2 Diphenyl-1-picrylhydrazyl (DPPH), and reactive oxygen species (ROS) inhibiting methods. Well diffusion method is applied for antibacterial activity. Results: The crude extract reported the highest inhibition activity against α-glucosidase with an IC50 value of 10.29 ± 0.35 μg/mL compared to the standard acarbose’s IC50 value of 5.653 ± 0.29 μg/mL. Similarly, the ethyl acetate (EA) fraction disclosed significant inhibition against α-amylase with an IC50 value of 108.7 ± 0.66 μg/mL compared to the standard acarbose’s IC50 value of 6.01 ± 0.14 μg/mL. Likewise, the EA fraction showed the maximum antioxidant activity with an IC50 value of 11.89 ± 1.05 μg/mL among the crude extract and its fractions. Conclusion: Mimosa rubicaulis was found to have α-glucosidase and α-amylase inhibition, antiinflammatory, and antibacterial activity. To the best of our knowledge, this is the first report of α- glucosidase and α-amylase inhibition activity of this plant. Further studies on this plant are required to isolate potent compounds.

Diabetes mellitus (DM), a complicated metabolic disorder, is due to insensitivity to insulin function or reduction in insulin secretion, which results in postprandial hyperglycemia. α-Glucosidase inhibitors (AGIs) and α-amylase inhibitors (AAIs) block the function of digestive enzymes, which delays the carbohydrate hydrolysis process and ultimately helps to control the postprandial hyperglycemia. Diversified 2-(3-(3-methoxybenzoyl)-4-hydroxy-1,1-dioxido-2H-benzo[e][1,2]thiazin-2-yl)-N-arylacetamides were synthesized and evaluated for their in vitro inhibitory potential against α-glucosidase and α-amylase enzymes. The compounds with chloro, bromo and methyl substituents demonstrated good inhibition of α-glucosidase enzymes having IC50 values in the range of 25.88–46.25 μM, which are less than the standard drug, acarbose (IC50 = 58.8 μM). Similarly, some derivatives having chloro, bromo and nitro substituents were observed potent inhibitors of α-amylase enzyme, with IC50 values of 7.52 to 15.06 μM, lower than acarbose (IC50 = 17.0 μM). In addition, the most potent compound, N-(4-bromophenyl)-2-(4-hydroxy-3-(3-methoxybenzoyl)-1,1-dioxido-2H-benzo[e][1,2]thiazin-2-yl)acetamide (12i), was found to be a non-competitive and competitive inhibitor of α-glucosidase and α-amylase enzymes, respectively, during kinetic studies. The molecular docking studies provided the binding modes of active compounds and the molecular dynamics simulation studies of compound 12i in complex with α-amylase also showed that the compound is binding in a fashion similar to that predicted by molecular docking studies.

Purpose: To investigate the anti-diabetic potential of Picralima nitida leaf extracts in vitro. Methods: The current study evaluated the anti-diabetic potential of Picralima nitida leaf via in vitro inhibition of α-amylase and α-glucosidase using the acetone, water and ethanol extracts. Preliminary phytochemical analysis was performed on the acetone, aqueous and ethanol extracts of Picralima nitida leaf. The α-amylase inhibitory potentials of the extracts were investigated by reacting different concentrations of the extracts with α-amylase and starch solution while α-glucosidase inhibition was determined by pre-incubating α-glucosidase with different concentrations of the extracts followed by the addition of p-nitrophenylglucopyranoside (pNPG). The mode(s) of inhibition of both enzymes was determined using Lineweaver-Burke plot. Results: The acetone extract of Picralima nitida displayed the most effective inhibition of both αamylase and α-glucosidase activities with half-maximal inhibitory concentration (IC 50 ) of 6.50 and 3.00 mg/ml, respectively. The results also showed that the extracts contain both non-competitive and competitive inhibitors of α-amylase and α-glucosidase respectively. The results of phytochemical analysis of the extract revealed the presence of saponins, flavonoids, tannins, terpenoids and reducing sugars. Conclusion: The observed inhibitions of α-amylase and α-glucosidase suggest that the leaf extracts of P. nitida may be useful in the management of diabetes mellitus. This buttresses the traditional use of P. nitida for the management of sugar-related disorders in some parts of Nigeria.

Background: Researchers seeking new drug candidates to treat diabetes mellitus have beenexploring bioactive molecules found in nature, particularly tetrahydropyridines (THPs). Methods: A library of THPs (1-31) were synthesized via a one-pot multicomponent reaction and investigated for their inhibition potential against α-glucosidase and α-amylase enzymes. Results: A nitrophenyl-substituted compound 5 with IC50 values of 0.15±0.01 and1.10±0.04μM, and a Km value of 1.30mg/ml was identified as the most significant α-glucosidase and α-amylase inhibitor, respectively. Kinetic studies revealed the competitive mode of inhibition, and docking studies revealed that compound 5 binds to the enzyme by establishing hydrophobic and hydrophilic interactions and a salt bridge interaction with His279. Conclusion: These molecules may be a potential drug candidate for diabetes in the future.

Synthesis, crystal structure, spectroscopic, antidiabetic, antioxidant and computational investigations of Ethyl 5-hydroxy-1-isonicotinoyl-3-methyl-4,5-dihydro-1H-pyrazole-5-carboxylate

α-amylase and α-glucosidase in the gastrointestinal tract have an important role in the hydrolysis α-1,4 and α-1,6 glycosidic chain of starch, respectively. Inhibition of both enzyme activities becomes one of the strategies to control diabetes. However, commercial drugs such as antidiabetics have adverse effects such as gastrointestinal problems. Therefore, exploring functional food, especially from marine natural products as antidiabetic agents, is potential. In particular, Ceriops sp. was reported to contain bioactive compounds with antidiabetic properties, but its mechanism to treat diabetes has not been proved. The potency of phenolic compounds of C. decandra leaves as α-amylase and α-glucosidase inhibitors were examined in this research by implementing the molecular docking analysis in silico. Three steps of analysis were carried out in this study, including extraction from C. decandra leaves with different polarity solvents, identification of phenolic compounds using LC-HRMS, and molecular docking analysis of phenolic compounds identified from C. decandra leaves. This study revealed that quercetin, rutin, epicatechin, isorhamnetin, caffeic acid, and ferulic acid were identified from C. decandra leaves. According to the drug-likeness and toxicity analysis, the presented compounds in C. decandra leaves had high potential pharmacological properties. Furthermore, molecular interaction analysis exhibited phenolic compounds extracted with ethyl acetate, such as quercetin and epicatechin, and with methanolic extracts, such as quercetin, rutin, epicatechin, and isorhamnetin, were more effective as α-amylase and α-glucosidase inhibitors than from caffeic acid and ferulic acid. Among the phenolic compounds of C. decandra leaves, rutin and quercetin were predicted to be the potential α-glucosidase inhibitors.

Anthocyanins are components of the flavonoid group with different properties, such as antidiabetic properties. This study aimed to isolate anthocyanin from Berberis integerrima Bunge fruits and evaluate α-amylase and α-glucosidase inhibition by this mentioned anthocyanin. The anthocyanin of Berberis integerrima fruit was isolated using column chromatography, and the antidiabetic properties of the anthocyanin were determined by the levels of α-amylase and α-glucosidase inhibition. Km and Vmax were also evaluated using the GraphPad Prism 7. The results of this study showed that the anthocyanin content of the fruit extract was 14.36 ± 0.33 mg/g, and following purification, this amount increased to 34.51 ± 0.42 mg/g. The highest of α-glucosidase inhibition was observed in the purified anthocyanin with IC50 = 0.71 ± 0.085 mg/ml, compared to acarbose as the baseline with IC50 = 8.8 ± 0.14 mg/ml, p < 0.0001. Purified anthocyanin of the mentioned fruit with IC50 = 1.14 ± 0.003 mg/ml had the greatest α-amylase inhibition, which was similar to acarbose as the standard with IC50 = 1 ± 0.085 mg/ml, p < 0.05. The inhibition of α-glucosidase and α-amylase by purified anthocyanin showed uncompetitive inhibition, and the enzyme inhibition by unpurified anthocyanin showed mixed inhibition. The obtained findings showed that Berberis integerrima fruit can be mentioned as a source of anthocyanin with antidiabetic properties.

Enzyme inhibitory activity of Dioscorea nipponica Makito hydroethanolic extracts of leaves and tubers in relation to their major secondary metabolites

Diabetes mellitus (DM) is a chronic metabolic condition that can lead to significant complications and a high fatality rate worldwide. Efforts are ramping up to find and develop novel α-glucosidase and α-amylase inhibitors that are both effective and potentially safe. Traditional methodologies are being replaced with new techniques that are less complicated and less time demanding; yet, both the experimental and computational strategies are viable and complementary in drug discovery and development. As a result, this study was conducted to investigate the in vitro anti-diabetic potential of aqueous acetone Helichrysum petiolare and B.L Burtt extract (AAHPE) using a 2-NBDG, 2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-2-deoxy-d-glucose uptake assay. In addition, we performed molecular docking of the flavonoid constituents identified and quantified by liquid chromatography-mass spectrometry (LC-MS) from AAHPE with the potential to serve as effective and safe α-amylase and α-glucosidase inhibitors, which are important in drug discovery and development. The results showed that AAHPE is a potential inhibitor of both α-amylase and α-glucosidase, with IC50 values of 46.50 ± 6.17 (µg/mL) and 37.81 ± 5.15 (µg/mL), respectively. This is demonstrated by a significant increase in the glucose uptake activity percentage in a concentration-dependent manner compared to the control, with the highest AAHPE concentration of 75 µg/mL of glucose uptake activity being higher than metformin, a standard anti-diabetic drug, in the insulin-resistant HepG2 cell line. The molecular docking results displayed that the constituents strongly bind α-amylase and α-glucosidase while achieving better binding affinities that ranged from ΔG = −7.2 to −9.6 kcal/mol (compared with acarbose ΔG = −6.1 kcal/mol) for α-amylase, and ΔG = −7.3 to −9.0 kcal/mol (compared with acarbose ΔG = −6.3 kcal/mol) for α-glucosidase. This study revealed the potential use of the H. petiolare plant extract and its phytochemicals, which could be explored to develop potent and safe α-amylase and α-glucosidase inhibitors to treat postprandial glycemic levels in diabetic patients.

The aim of current study was to investigate the inhibitory activities of resveratrol and taxifolin against α-amylase, α-glucosidase, and DPP-IV enzymes via in vitro analysis which was further validated by in silico studies. The analysis of molecular docking was also done to determine the binding capabilities of resveratrol and taxifolin with α-amylase, α-glucosidase, and DPP-IV enzymes. Resveratrol and taxifolin having IC50 values, 47.93 ± 5.21 and 45.86 ± 3.78 , respectively, showed weaker effect than acarbose (4.6 ± 1.26 ) on α-amylase but showed significant effect to inhibit α-glucosidase (32.23 ± .556 and 31.26 ± .556 , respectively). IC50 value of resveratrol and taxifolin (5.638 ± .0016 and 6.691 ± .004 ) in comparison to diprotin A (IC50: 7.21 ± .021 ) showed that they have significant inhibitory effect on DPP-IV enzyme. Our results illustrated that resveratrol and taxifolin have potential to prevent the metabolism of carbohydrates via inhibition of α-amylase and α-glucosidase, and prolongs metabolic function of incretin by inhibiting the enzymatic activity of DPP-IV. The results of molecular docking have also revealed that resveratrol and taxifolin have significant affinity to bind with α-amylase, α-glucosidase, and DPP-IV in comparison with standard drugs such as acarbose, miglitol, and diprotin.

Background: Diabetes Mellitus (DM) can appear due to the absence of insulin (DM1- type 1) or poor response of cells to insulin (DM2-type 2). Even though DM1 cannot be controlled using general treatments, DM2 can be easily controlled or prevented using pharmaceuticals, nutraceuticals, or dietary practices. Ceylon cinnamon (Cinnamomum zeylanicum) is one such natural remedy that has been consumed against elevated blood glucose levels in the past. Cinnamon and different types of cinnamon extracts have been scientifically tested for their activities on the inhibition of α-amylase and α-glucosidase enzymes that are responsible for carbohydrate metabolism and are effective in blood glucose regulation. However, the combined effect of aqueous and ethanol extracts of cinnamon bark on blood glucose regulation is still lacking. In this study, Water Extract of Cinnamon (CWE), Ethanol Extracts of Cinnamon (hot ethanol extract of cinnamon-CHEE, cold ethanol extract of cinnamon-CEE, and 50% ethanol extract of cinnamon- CEE-50) were studied for their sugar-controlling properties. Objectives: This study was performed to identify the efficacy of different cinnamon extracts on the inhibition of α-amylase and α-glucosidase enzymes, followed by animal studies to confirm the use of the extracts in nutraceutical formulations. Methods: Water and ethanol-based extraction method was used to prepare cinnamon extracts. These extracts have been scientifically tested for their activities on the inhibition of α-amylase and α-glucosidase enzymes. Molecular docking studies were used to identify the binding of the active molecules to the substrate binding sites of α-amylase and α-glucosidase. In-vivo time dependence postprandial blood glucose regulation studies have been performed with healthy Wistar male rats. Results: Yields of the CHEE, CEE, and CWE were 14±2%, 12±2%, and 8±1% respectively. According to the LCMS data, the major component in the CEE was cinnamaldehyde. Both CWE and CEE were subjected to the Total Polyphenol assay (TPC) and Total Flavonoids (TFC) assays. The TPC of CWE and CEE were 117±1 mg (Gal)/g and 170±10 mg (Gal)/g, while the TFC of CWE and CEE were 359±1 mg (Qc)/g and 254±4 mg (Qc)/g, respectively. In the α-amylase inhibition assay, Acarbose; a known α-amylase inhibitor, and CEE showed IC50 values of 65.4 ppm and 2.6 ppm, while CWE failed to show inhibition against α-amylase. In the α-glucosidase inhibition assay, Acarbose; a known α-amylase inhibitor, CEE, and CWE showed IC50 values of 312 ppm, 4.5 ppm, and 1.3 ppm, respectively. In-vivo time dependence postprandial blood glucose regulation studies that have been performed with healthy Wistar male rats showed a lowering of blood glucose concentrations by 22%, 11%, and 10% of glucose at 30 min, 60 min, and 90 min compared to the control group. Conclusion: The CEE contains polyphenols and flavonoids and is effective in inhibiting both α- amylase and α-glucosidase. The CWE also contains polyphenols and a comparatively higher level of flavonoids and is effective in inhibiting α-glucosidase while not affecting α-amylase inhibition. Overall, the IC50 data, TPC data, and TFC data proposed that the inhibition of carbohydrate hydrolyzing enzymes by polyphenols may depend on the polarity of particular polyphenols. Based on the rat trials, it can be concluded that the 1:1 combination of CWE and CEE may be useful in formulating postprandial blood glucose level-regulating nutraceuticals.