Porcine Pancreatic Α-amylase Research Articles

Validated HPTLC Method for Detection of Kaempferol in <i>Moringa oleifera</i> Leaf Extract and Investigation of its Antidiabetic Potential by <i>In Vitro</i> and <i>In Silico</i> Studies

Background: Exploring traditional treatments offers valuable foundations for the innovation of new pharmaceuticals for the management of diabetes mellitus and its complications. Validation of plant extract by suitable chromatographic techniques is a part of standardization procedures. Moringa oleifera is one such traditionally used plant to be explored. Aim: The study explores the antidiabetic potential of M. oleifera through both in vitro and in silico explorations along with HPTLC method development and validation for estimation of kaempferol in M. oleifera extract. Method: Plant extract was prepared by maceration method using ethanol: water (70:25) and followed by Soxhlet(95% ethanol). Pharmacognostical analysis was conducted. In silico and in vitro antidiabetic and antioxidant studies were conducted, as well as quality control analysis was done using HPTLC method the mobile phase used was toluene: ethyl acetate: formic acid: methanol: (6:3:0.3:1v/v/v/v). Results: HPTLC analysis showed the presence of kaempferol, and the method was validated as per ICH guidelines. According to reports on molecular docking studies, several phytocompounds inhibited when porcine pancreatic α-amylase (PPA) complexed with a carbohydrate inhibitor (PDB ID: 4W93).The hydroalcoholic extract was discovered to have the ability to inhibit α-amylase, with IC50 values of 57.38588±1.92 μg/mL and 32.51564±1.59 μg/mL for standard acarbose, respectively. Conclusion: Overall, this research provides comprehensive data for the estimation of kaempferol in Moringa oleifera by HPTLC and presents valuable evidence on its antidiabetic potential both in vitro and in silico.

Inhibition of starch hydrolysis during in vitro co-digestion of pasta with phenolic compound-rich vegetable foods

The ability of phenolic compounds to inhibit amylolytic enzymes activities has been investigated, suggesting their possible role in type-2 diabetes management. However, these studies have been carried out with purified enzymes and synthetic substrates and are distant from simulating a real physiological situation. The objective of the present research was to evaluate the ability of phenolic-rich vegetable foods to inhibit starch hydrolysis during in vitro co-digestion with pasta resulting in a potential anti-diabetic effect and mimicking as closely as possible a real scenario. Some tested vegetable foods, such as capers, red-skinned onion, red radish, and olives, determined a decrease in starch hydrolysis by 21.5%–31.7% during in vitro co-digestion with pasta. The quali-quantitative phenolic profiles of in vitro co-digested samples were elucidated and selected standard compounds were tested for their ability to inhibit porcine pancreatic α-amylase and mammalian α-glucosidase. The inhibitory potential of these compounds, especially against α-glucosidase, explained the effect observed during co-digestion experiments. The most active phenolic compounds against α-glucosidase were quercetin-4’-O-glucoside, quercetin-3-O-rutinoside, luteolin-7-O-glucoside and quercetin-3-O-glucoside-4’-O-glucoside with IC50 values of 20.67, 52.23, 68.84 and 87.58 μmol/L, respectively. This is the first report suggesting that these compounds are potent inhibitors of mammalian α-glucosidase. This study indicates that consuming starchy foods (i.e., pasta) with phenolic-rich vegetable foods may result in an inhibition of starch digestion possibly reducing the post-prandial glucose levels.

Indole–thiazolidinedione–triazole hybrids: synthesis, molecular docking, absorption, distribution, metabolism and excretion (ADME) profiling, and biological evaluation as α-amylase inhibitors

Abstract A novel series of hybrid indole–thiazolidinedione–triazole derivatives (6a-l) were synthesized and assessed for their in vitro inhibitory activity against porcine pancreatic α-amylase. The synthetic procedure consists of 3 steps. A crucial step in this process involves the generation of novel target molecules using a Cu(I)-catalyzed azide–alkyne cycloaddition reaction. The α-amylase inhibition IC50 value of the targeted compounds ranged from 0.51 ± 0.02 to 7.99 ± 0.28 μM as compared with 0.68 ± 0.02 μM with acarbose as the standard drug. Using the Autodock technique, all the derivatives 6a-l were subjected to molecular docking investigations against porcine pancreatic α-amylase (PDB ID: 1OSE). Moreover, it was discovered that the docked compounds had excellent binding affinities that ranged from −10.1 to −10.8 kcal/mol as compared with the standard −7.9 kcal/mol. Additionally, a comprehensive analysis of the physicochemical and pharmacokinetic properties associated with absorption, distribution, metabolism and excretion (ADME) was conducted for all the synthesized compounds.

Digestion inhibition of potato starch-botanical proteolytic polypeptides complexes subjected to heat moisture treatment based on steric hindrance and enzymatic inhibition

The effects of food components on starch digestibility is a prominent topic within the realms of food and nutritional science. In this study, complexes of potato starch (PS) and botanical proteolytic polypeptides (BPPs), including wheat peptides, maize peptides, rice peptides, and soybean peptides, were subjected to heat-moisture treatment (HMT). The physicochemical, structural, and digestibility variations of the PS-BPPs complexes were analyzed using polarized light microscopy, DSC, X-ray, FT-IR, SAXS, and in vitro simulated digestion. Additionally, we evaluated the inhibitory effects of BPPs on porcine pancreatic α-amylase (PPA). The results showed that the polarization cross of PS-BPPs complexes was weakened after HMT. The gelatinization temperatures (To, Tp, Tc) of the PS-BPPs complexes increased significantly. The starch in the PS-BPPs complexes transitioned from B-type structure to A-type structure after HMT, accompanied by an increase in short-range ordering and semicrystalline lamella thickness. In particular, the complexes exhibited higher contents of slowly digestible starch (SDS) and resistant starch (RS). Furthermore, wheat, rice, and soybean peptides exhibited a mixed type of competitive inhibition against PPA, whereas maize peptides exhibited competitive inhibition. The findings provide valuable insights into the role of BPPs in regulating starch digestion. Moreover, BPPs hold potential for enhancing the nutritional value and health benefits of foods.

Biological, phytochemical and molecular docking characteristics of Laurus nobilis L. fresh leaves essential oil from Palestine

BackgroundThe historical use of Laurus nobilis L., the plant is native to the Mediterranean region and has been cultivated for its aromatic leaves, which are used as a flavoring agent in cooking and for their potential therapeutic properties.MethodsThe purpose of the current investigation was to characterize the essential oil composition of the fresh L. nobilis leaves from Palestine by using the gas chromatography-mass spectrometry (GC-MS) technique. DPPH (2,2-diphenyl-1-picrylhydrazyl), p-nitrophenyl butyrate, and 3,5-dinitro salicylic acid (DNSA) methods were employed to estimate the antioxidant, antiobesity, and antidiabetic effects of the essential oil. While MTS assay were used to evaluate their antiproliferative activities on panels of cell lines. Moreover, the docking studies were aided by the Prime MM GBSA method for estimating binding affinities.ResultsThe GC-MS investigation demonstrated that the fresh L. nobilis leaves essential oil has a variety of chemicals, about 31 different biochemicals were identified, and the major compounds were 1,8-cineole (48.54 ± 0.91%), terpinyl acetate (13.46 ± 0.34%), and α-terpinyl (3.84 ± 0.35%). Furthermore, the investigated oil demonstrated broad-spectrum antimicrobial activity against all tested bacterial and candidal strains and significantly inhibited the growth of MCF-7 cancerous cells more than the chemotherapeutic drug Doxorubicin. Furthermore, it contains robust DPPH free radicals, as well as porcine pancreatic α-amylase and lipase enzymes. Using the 1,8-cineole compound as the predominant biomolecule found in the L. nobilis essential oil, molecular docking studies were performed to confirm these observed fabulous results. The molecular docking simulations proposed that these recorded biological activities almost emanated from its high ability to form strong and effective hydrophobic interactions, this led to the getting of optimal fitting and interaction patterns within the binding sites of the applied crystallographic protein targets.ConclusionThe results of these experiments showed that the fresh L. nobilis leaves essential oil has outstanding pharmacological capabilities, making this oil a potential source of natural medications.

Dietary fibre from seeds of Australia native Plantago species as modulators of quality and glycaemic response in starch gels

Dietary fibre (DF) is a non-digestible nutrient which has important roles in the digestive system including mantaining regularity, and reducing the risk of certain cancers and non-communicable diseases, such as metabolic syndrome. Even though the positive health effects of DF have long been established, it has been shown that DF intake for children and adults in Australia is below the recommended range – less than 20% of adults met the suggested intake for reducing risk of chronic diseases(1). Plantago ovata, also known as psyllium, is widely used as DF supplement with evidence showing positive effects on weight control, hyperglycaemic response, cholesterol levels, and irritable bowel syndrome(2). P. ovata seed husk produces a highly viscous gel called mucilage when seeds are exposed to moisture. This mucilage is nearly pure DF and has an intricately layered structure which can be further fractionated and studied as a proxy for different gelling systems. Interestingly, Australia is home to many mucilage-producing Plantago species, most of which are underexplored and underutilised, but show remarkable gelling properties and hypoglycaemic potential(3). In this work, we compare structural and functional properties of fractionated DF from P. ovata, and two promising Australian native relatives, P. turrifera and P. drummondii, and their effect on enzymatic hydrolysis in potato starch gels. Using a 3-step fractionation method, we have separated distinct fractions and explored their individual properties(4). P. turrifera and P. drummondii have higher water absorbing capacity, DF yield, and viscosity compared to P. ovata. Monosaccharide composition of all three species is similar – they are highly substituted heteroxylans with minor pectic component. Notably, arabinose to xylose ratio in all species increases with further extraction steps, which is different from cereal arabinoxylans. In an attempt to explore impact of DF in starch-rich systems, we have fabricated DF-potato starch gels and measured enzymatic hydrolysis (with porcine pancreatic α-amylase), freeze-thaw stability, and colour change. Addition of DF reduced syneresis (water separation) during 15 day freeze-thaw cycle measurement, which can lead to prolonged storage stability and has positive implications for shelf life. Colour change was most noticeable when P. drumondii DF were added, while colour of P. ovata and P. turiferra DF gels was similar to control potato starch gel. Effects on α-amylase starch hydrolysis were significant as well, and depended on species and fractions. Certain DFs had impacts on constant k (speed of hydrolysis), while effects on the extent of hydrolysis are still being explored. In conclusion, utility of Australia native P. turrifera and P. drumondii DFs are evident when applied to starch gels, and should be further explored in food products such as bread to increase DF intake and possibly lower glycaemic index.

Total phenolic contents, cytotoxic, free radicals, porcine pancreatic α-amylase, and lipase suppressant activities of Artemisia dracunculus plant from Palestine.

Artemisia dracunculus: L. (A. dracunculus) is a popular vegetable and spice cultivated across many Middle Eastern countries. The herb's aqueous extract has significant folkloric medicinal importance for treating various disorders. Hence, the present investigation aimed to investigate A. dracunculus hydrophilic extract phytochemical constituents and pleiotropic biological potentials, as no previous studies have investigated the antilipase and anti-α-amylase effects of the A. dracunculus plant. Total phenol content and phytochemical screening assays were performed utilizing standard analytical methods. While the α-amylase inhibition, free radical-scavenging, antilipase, and cytotoxic activities were determined using dinitrosalicylic acid (DNSA), DPPH, p-nitrophenyl butyrate (PNPB), and MTS assays, respectively. The standard phytochemical analysis of A. dracunculus aqueous extract shows that this extract contains only a phenolic group. The total phenol content was 0.146 ± 0.012mg GAE/g of the plant dry extract. The A. dracunculus aqueous extract exhibited potent DPPH free radical inhibitory (IC50 dose of 10.71 ± 0.01μg/mL) and anti-lipase activities (IC50 dose of 60.25 ± 0.33μg/mL) compared with Trolox (IC50 = 5.7 ± 0.92μg/mL) and Orlistat (IC50 = 12.3 ± 0.35μg/mL), respectively. However, it showed a weak anti-α-amylase effect (IC50 value > 1,000μg/mL) compared with Acarbose (IC50 = 28.18 ± 1.27μg/mL). A. dracunculus has a cytotoxic effect against the HeLa cancer cell line compared with the chemotherapeutic agent Doxorubicin. The extract has the same percent of inhibition as Doxorubicin (99.9%) at 10mg/mL. Overall, these results pointed out for the first time the importance of considering A. dracunculus effects as a favorite candidate for preventing and treating metabolic disorders. Also, our results confirm the findings of previous reports on the role of A. dracunculus in the management of cancer and disorders resulting from the accumulation of harmful free radicals. On the contrary, the current study concluded that the antidiabetic role of A. dracunculus could be minimal. Further in-depth investigations are urgently warranted to explore the importance of A. dracunculus in pharmaceutical production.

Molecular interactions between polyphenols and porcine α-amylase: An inhibition study on starch granules probed by kinetic, spectroscopic, calorimetric and in silico techniques

Inhibition of α-amylase activity to limit the rise in postprandial glucose is one of the most notable effects of dietary plant (poly)phenols. The rate and extent of inhibition depend on many factors, including the structure of (poly)phenols and the substrate used for the inhibition study. While soluble/gelatinised starch is widely used as a substrate for studying inhibition mechanisms, the formation of (poly)phenol-amylose complexes can reduce susceptibility to α-amylase catalysis. Therefore, the extent of inhibition may not truly represent the inhibition of α-amylase by (poly)phenols. To elucidate mechanisms of interactions between a (poly)phenol and the enzyme, this study compared the inhibition of porcine pancreatic α-amylase (PPA) by three differently structured (poly)phenols: p-coumaric acid, quercetin, and cyanidin-3-glucoside, using solid maize starch as a substrate, that limits the formation of starch-(poly)phenol complexes due to the compact structure of starch granules. The inhibition kinetics were investigated and supported by complementary techniques: in silico analysis (molecular docking and molecular dynamic simulation), fluorescence quenching, circular dichroism and differential scanning calorimetry. Quercetin exhibited the strongest inhibition, followed by cyanidin-3-glucoside and p-coumaric acid, with apparent modes of mixed, mixed, and competitive inhibition, respectively. The specific binding of (poly)phenols to PPA involved hydrogen bonds and hydrophobic interactions, as indicated by in-silico studies. Multi-spectroscopic analysis of the PPA structure unveiled changes or peak shifts due to ligand binding, resulting in structural alterations. These findings were consistent with the kinetic data, emphasising the importance of the structural aspects of each individual (poly)phenol in relation to their interaction with PPA. The study articulated the in-depth mechanism of molecular interaction mechanism between (poly)phenols and enzymes and provided evidence that the structural alterations of enzymes are not a strong indicator of inhibition efficacy, but rather inhibition is due to the binding of (poly)phenols to the enzyme structure limiting the catalysis.

Comparative analysis of granular starch hydrolysis and multi-structural changes by diverse α-amylases sources: Insights from waxy rice starch

Three cultivars of waxy rice starch with different multi-scale structures were subjected to α-amylase hydrolysis to determine amylopectin fine structure, production of oligosaccharides, morphology, and crystallinity of the partially hydrolyzed starch granules. α-amylases hydrolyzed the amylopectin B2 chain during the initial stage of hydrolysis, suggesting that it is primarily located in the outer shell of the granules. For waxy rice starch with loose structure, α-amylases attacked the crystalline and amorphous regions simultaneously in the initial stage, while for starch granules with compact structure, the outer shell blocklet (crystalline structure) can be a hurdle for α-amylases to proceed to hydrolysis of the internal granule structure. The ability of α-amylases from porcine pancreatic α-amylases to attack the outer shell crystalline structure was lower than that of α-amylases from Bacillus amyloliquefaciens and Aspergillus oryzae. These results show that α-amylase source and rice cultivar combinations can be used to generate diverse structures in degraded waxy rice starch.

Phytochemical investigation of Mezoneuron benthamianum Baill, isolation, in vitro antioxidant, alpha-amylase inhibition, and in silico modelling studies

Mezoneuron benthamianum (Leguminosae-caesalpinioideae family), is widely used across West Africa for the treatment of bacterial, fungal, and inflammatory diseases. This study is aimed at investigating the antioxidant and antidiabetic activities of extracts and isolated compounds from Mezoneuron benthamianum leaf and root. The pulverized leaf (1 kg) was extracted by maceration with dichloromethane and methanol to give the dichloromethane (MBLD) and methanol (MBLM) extracts, while the root (2 kg) samples were extracted using dichloromethane and methanol (1:1) to give the dichloromethane-methanol extract (MBRDM) which was further partitioned to give the hexane (MBRH), ethyl acetate (MBRE) and methanol (MBRM) extracts respectively. The leaf methanol extract (MBLM) was fractionated using column chromatography (70–230 mesh size) which led to the isolation of compound 1. The extracts and isolated compounds were subjected to in-vitro antioxidant assay with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and α-amylase inhibitory assay using porcine pancreatic α-amylase respectively. FT-IR spectroscopic analysis compound 1 showed strong peaks at 1678 and 1612 cm−1 suggesting the presence of a carbonyl and an aromatic group respectively. 1H NMR spectroscopic analysis of compound 1 showed two peaks at 3.80 (3H, s) and 7.04 ppm (2H, s) indicating methoxy and aromatic protons respectively. 13C NMR also confirmed the presence of the methoxy peak at 50.8 ppm, four aromatic peaks at 108.76, 120.19, 131.25, 145.14 ppm indicating a para-disubstituted benzene ring, and a carbonyl peak at 167.80 ppm, this led to the elucidation of compound 1 known as methyl gallate. The antioxidant activities of the extracts and compounds showed that MBLM (IC50 = 112.0 μg/ml) and MBRE (IC50 = 91.84 μg/ml) had the highest activity of the leaf and root extracts respectively while methyl gallate (IC50 = 91.84 μg/ml) had lower activity than gallic acid (IC50 = 27.4 μg/ml), ascorbic acid (IC50 = 43.94 μg/ml) and BHT (68.94 μg/ml). The α-amylase inhibitory activities showed that MBLD (IC50 = 27.4 μg/ml), MBRE (IC50 = 72.2 μg/ml), gallic acid (IC50 = 27.4 μg/ml) and methyl gallate (IC50 = 43.9 μg/ml) had higher activity than the standard drug acarbose (IC50 = 378.2 μg/ml). For the In silico study, methyl gallate was docked into the active site of the targeted diabetic proteins; human pancreatic alpha-amylase, pig pancreatic alpha-amylase, and tetrameric IIB-HSDI. The results showed that methyl gallate had good interactions with the proteins, with binding affinities of −4.8, −4.8 and −6.5 kcal/mol respectively. Furthermore, in silico pharmacokinetics and toxicology properties of methyl gallate using the AdmetSAR and SwissADME software showed that the compound has good pharmacokinetic properties and it is generally non-toixc. This research has revealed detailed chemical and biological studies on Mezoneuron benthamianum and its isolated compound as an antioxidant and antidiabetic.

Eucalyptus camaldulensis Dehnh Leaf Essential Oil from Palestine Exhibits Antimicrobial and Antioxidant Activity but No Effect on Porcine Pancreatic Lipase and α-Amylase.

Eucalyptus camaldulensis Dehnh is a tree species that is commonly used for various purposes, including forestry, agroforestry, and conservation. The present investigation was designed to determine the composition of E. camaldulensis leaves essential oil and estimate its free radicals, porcine pancreatic lipase, α-amylase inhibitory, and antimicrobial properties in vitro. The chemical constituents were analyzed using the gas chromatography-mass spectrometry (GC-MS) technique. DPPH (2,2-diphenyl-1-picrylhydrazyl), p-nitrophenyl butyrate, and 3,5-dinitro salicylic acid (DNSA) methods were employed to estimate the antioxidant, antiobesity, and antidiabetic effects of the essential oil. The microdilution assay was employed to assess the antimicrobial efficacy of the substance against a total of seven distinct microbial species. The GC-MS results revealed that E. camaldulensis essential oil contains 52 components that makeup 100% of the entire oil. The main chemical constituents in E. camaldulensis essential oil are p-cymene (38.64%), followed by aromadendrene (29.65%), and 1,8-cineol (6.45%), with monocyclic monoterpene being the most abundant phytochemical group, followed by the sesquiterpene hydrocarbon group, representing 44.27 and 31.46%, respectively. The essential oil showed a weak antioxidant effect and had no antilipase or antiamylase effects. At the same time, the oil showed a strong antimicrobial effect against methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, and Proteus vulgaris, which was even more potent than the positive controls, ciprofloxacin and ampicillin, which had MIC doses of 0.2 ± 0.01, 0.2 ± 0.01, and 6.25 ± 0.1 µg/mL, respectively. It also has a strong anti-Candida albicans effect with a MIC of 0.2 ± 0.01 µg/mL. In light of these findings, in vivo studies should be conducted to determine the efficiency of the E. camaldulensis essential oil in treating microbial infections.

α-Amylase and mycobacterium-TB H37Rv antagonistic efficacy of novel pyrazole-coumarin hybrids: an in vitro and in silico investigation

The present investigation of minutiae to acquire structural information of the novel pyrazole-coumarin hybrids (PC1-PC10) synthesized using ultrasound methods and characterized using different spectroscopic techniques: mass, 1H-NMR, 13 C-NMR and IR spectroscopy, and theoretically explored using the DFT approach with a B3LYP/6–311G (d, p) basis set, and there in vitro, antagonistic efficacy against α-amylase and mycobacterium-TB H37Rv are described in this article. Pyrazole-coumarin hybrids (PC1-PC10) showed α-amylase inhibition ranging from IC50 (0.32–0.58 mM) when compared with acarbose (IC50 = 0.34 mM). Similarly, Mycobacterium-TB H37Rv strain inhibition screening showed MIC values ranging from 62.5 to 1000 µg/mL when compared with rifampicin and isoniazid MIC = 0.25 and 0.20 µg/mL, respectively. Molecular docking and MD simulation studies were performed to determine the active sites and rationalize the activities of the active compounds. To investigate the binding conformation and dynamics responsible for their activity, the three most active compounds (PC1, PC3 and PC6) were docked into the porcine pancreatic α-amylase active site (PDB ID:1OSE), and mycobacterium-TB H37Rv active site (PDB ID: 4TZK). The binding interactions between PC1, PC3, and PC6 with α-amylase were like those responsible for inhibiting α-amylase by acarbose. Also, the mycobacterium-TB H37Rv inhibiting responsible residues were compared with standard isoniazid and rifampicin. Communicated by Ramaswamy H. Sarma

The inhibition mechanism of bound polyphenols extracted from mung bean coat dietary fiber on porcine pancreatic α-amylase: kinetic, spectroscopic, differential scanning calorimetric and molecular docking

The inhibitory mechanisms of purified bound polyphenols extracted from mung bean coat dietary fiber (pMBDF-BP) on porcine pancreatic α-amylase (PPA) were investigated through inhibition kinetics, fluorescence spectroscopy, circular dichroism, differential scanning calorimetry and molecular docking. It was shown that pMBDF-BP exerted significant reversible inhibition on PPA in a mixed-type inhibition manner (IC50 = 18.57 ± 0.30 μg/mL), and the combination of the three major components exhibited a synergistic inhibitory effect on PPA. Further, pMBDF-BP bound to the active site or form a polyphenol-enzyme complex at the inactive site through hydrogen bonding and hydrophobic forces, via enhancing the hydrophobicity of the microenvironment surrounding tryptophan and tyrosine residues and promoting the secondary structure of PPA towards a more stable conformation, eventually reducing the enzyme activity. This study provided theoretical evidences for the utilization of bound polyphenols extracted from mung bean coat dietary fiber as a functional component in natural inhibitors of α-amylase.

Physicochemical characterizations, α-amylase inhibitory activities and inhibitory mechanisms of five bacterial exopolysaccharides

Inhibiting pancreatic α-amylase activity can decrease the release rate of glucose, thereby delaying postprandial blood glucose. This study aimed to investigate the physicochemical properties and porcine pancreatic α-amylase (PPA) inhibitory activities of five bacterial exopolysaccharides (EPSs). We also aimed to analyze the differences of their inhibitory activities, exploring the inhibition mechanism between EPSs and PPA. Five EPSs had a low molecular weight (55–66 kDa), which were mainly composed of mannose and glucose with total content exceeding 86 %. The IC50 values of five EPSs (0.162–0.431 mg/mL) were significantly lower than that of acarbose (0.763 mg/mL), indicating that the inhibitory effects of five EPSs on PPA were stronger than acarbose, especially the EPS from Bacillus subtilis STB22 (BS–EPS). Moreover, BS–EPS was a mixed-type inhibitor, whereas other EPSs were noncompetitive inhibitors of PPA. Five EPSs quenched the fluorophore of PPA by the mixed quenching or apparent static quenching. Interestingly, BS–EPS showed stronger binding affinity to PPA than other EPSs. It can be speculated that EPSs with low molecular weight, high carboxylic acid content, and α-glycosidic bond exhibited high PPA inhibitory activity. These results suggest that BS-EPS can effectively inhibit PPA activity and has potential applications in reducing postprandial hyperglycemia.

Brown sugar polyphenols as natural inhibitors of α‐amylase and α‐glucosidase enzymes

SummaryThis study investigated the compositional profile and inhibitory effect of brown sugar polyphenols (BSPs) on porcine pancreatic α‐amylase (PPA) and Baker's yeast α‐glucosidase (BYG) activities. The HPLC‐ESI‐MS (high‐performance liquid chromatography‐electrospray ionisation‐mass spectrometry) analysis showed that BSPs comprised of four hydroxybenzoic acids including protocatechuic, p‐hydroxybenzoic, vanillic and syringic acids (PA, PHBA, VA and SA, respectively) and three hydroxycinnamic acids including chlorogenic, p‐coumaric and ferulic acids (CHA, PCA and FA, respectively), where CHA (29.24%) and SA (31.31%) were the main BSPs. The enzyme inhibition analysis expressed as IC50 values (except PA and VA) showed that CHA, PCA and FA exhibited higher PPA and BYG inhibitory activities than PHBA and SA, following the order of CHA > PCA > FA > PHBA > SA. Moreover, the BSPs showed better inhibitory activities against BYG than PPA. The inhibition mechanism analysis through inhibitory kinetics, fluorescence quenching, differential scanning calorimetry and molecular docking demonstrated that the BSPs inhibited the enzymes by binding with them mainly via hydrogen bonds. The results suggested that BSPs could be natural inhibitors of PPA and BYG.

An Accessible Method to Improve the Stability and Reusability of Porcine Pancreatic α-Amylase via Immobilization in Gellan-Based Hydrogel Particles Obtained by Ionic Cross-Linking with Mg2+ Ions.

Amylase is an enzyme used to hydrolyze starch in order to obtain different products that are mainly used in the food industry. The results reported in this article refer to the immobilization of α-amylase in gellan hydrogel particles ionically cross-linked with Mg2+ ions. The obtained hydrogel particles were characterized physicochemically and morphologically. Their enzymatic activity was tested using starch as a substrate in several hydrolytic cycles. The results showed that the properties of the particles are influenced by the degree of cross-linking and the amount of immobilized α-amylase enzyme. The temperature and pH at which the immobilized enzyme activity is maximum were T = 60 °C and pH = 5.6. The enzymatic activity and affinity of the enzyme to the substrate depend on the particle type, and this decreases for particles with a higher cross-linking degree owing to the slow diffusion of the enzyme molecules inside the polymer's network. By immobilization, α-amylase is protected from environmental factors, and the obtained particles can be quickly recovered from the hydrolysis medium, thus being able to be reused in repeated hydrolytic cycles (at least 11 cycles) without a substantial decrease in enzymatic activity. Moreover, α-amylase immobilized in gellan particles can be reactivated via treatment with a more acidic medium.

Pasta fortified with C-glycosides-rich carob (Ceratonia siliqua L.) seed germ flour: Inhibitory activity against carbohydrate digesting enzymes

Carob (Ceratonia siliqua L.) seed germ flour (SGF) is a by-product resulting from the extractionextraction of locust bean gum (E410), which is a texturing and thickening ingredient used for food, pharmaceutical and cosmetic preparations. SGF is a protein-rich edible matrix and contains relatively high amounts of apigenin 6,8-C-di- and poly-glycosylated derivatives. In this work, we prepared durum wheat pasta containing 5 and 10 % (w/w) of SGF and carried out inhibition assays against type-2 diabetes relevant carbohydrate hydrolysing enzymes, namely porcine pancreatic α-amylase and α-glycosidases from jejunal brush border membranes. Nearly 70–80% of the SGF flavonoids were retained in the pasta after cooking in boiling water. Extracts from cooked pasta fortified with 5 or 10% SGF inhibited either α-amylase by 53% and 74% or α-glycosidases by 62 and 69%, respectively. The release of reducing sugars from starch was delayed in SGF-containing pasta compared to the full-wheat counterpart, as assessed by simulated oral-gastric-duodenal digestion. By effect of starch degradation, the SGF flavonoids were discharged in the water phase of the chyme, supporting a possible inhibitory activity against both duodenal α-amylase and small intestinal α-glycosidases in vivo. SGF is a promising functional ingredient obtained from an industrial by-product for producing cereal-based foods with reduced glycaemic index.

Antidiabetic Effect of Zygophyllum geslini Aerial Part: In Vivo and In Vitro Studies

Zygophyllum geslini Coss. is widely found in the Algerian Sahara. This species is known to treat diabetes mellitus. The objective of this study is to evaluate the glucoselowering effect of aqueous extract of the defatted aerial part from Zygophyllum geslini. Extract was prepared by macerating the plant powder during 24 h in chloroform followed by acetone and water separately. Finally, the aqueous extract (Zygophyllum geslini aqueous extract [ZgAE]) was tested in normal and streptozotocin-induced diabetic rats. In addition, the inhibitory effect of the extract on porcine pancreatic α-amylase was tested. ZgAE is rich with saponins, flavonoids, alkaloids, mucilage, and amino acids. On the fast hyperglycemia, the decrease level is of 21% for the diabetic treated rats by ZgAE (100 mg/kg) and 31% for diabetic treated rats by glimepiride (100 μg/kg). In addition, ZgAE at 0.429 mg/ml can inhibit 50% of the porcine pancreatic α-amylase activity. Plant, especially ZgAE, can be considered as excellent candidate for future studies on diabetes mellitus.

Synthesis and Biological Activity Evaluations of Green ZnO-Decorated Acid-Activated Bentonite-Mediated Curcumin Extract (ZnO@CU/BE) as Antioxidant and Antidiabetic Agents

Green ZnO-decorated acid-activated bentonite-mediated curcumin extract (ZnO@CU/BE) was prepared as a multifunctional antioxidant and antidiabetic agent based on the extract of curcumin, which was used as a reducing and capping reagent. ZnO@CU/BE showed notably enhanced antioxidant properties against nitric oxide (88.6 ± 1.58%), 1,1-diphenyl-2-picrylhydrazil (90.2 ± 1.76%), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (87.3 ± 1.61%), and superoxide (39.5 ± 1.12%) radicals. These percentages are higher than the reported values of ascorbic acid as a standard and the integrated components of the structure (CU, BE/CU, and ZnO). This signifies the impact of the bentonite substrate on enhancing the solubility, stability, dispersion, and release rate of the intercalated curcumin-based phytochemicals, in addition to enhancing the exposure interface of ZnO nanoparticles. Therefore, effective antidiabetic properties were observed, with significant inhibition effects on porcine pancreatic α-amylase (76.8 ± 1.87%), murine pancreatic α-amylase (56.5 ± 1.67%), pancreatic α-glucosidase (96.5 ± 1.07%), murine intestinal α-glucosidase (92.5 ± 1.10%), and amyloglucosidase (93.7 ± 1.55%) enzymes. These values are higher than those determined using commercial miglitol and are close to the values measured using acarbose. Hence, the structure can be applied as an antioxidant and antidiabetic agent.

Design and synthesis of novel 1,2,3-triazole linked hybrids: Molecular docking, MD simulation, and their antidiabetic efficacy as α-Amylase inhibitors

Novel 1,2,3-triazole linked coumarin and cinnamic acid analogs were designed, synthesized, characterized, and evaluated for their ability to inhibit the α-amylase enzyme in order to treat diabetes. Porcine pancreatic α-amylase isoenzyme II was used in the investigation and analysis of in silico molecular docking and molecular dynamic simulations. The server PreADME/toxicity was used to predict pharmacokinetics and pharmacodynamics properties. In vitro and in silico results revealed that compounds 7d, 7e and 7f showed excellent antidiabetic activity with IC50 in the range of 0.133–0.192 μM and percentage inhibitions in the range of 88.22±1.43 to 98.87±2.63%, respectively, indicating their better potency than the standard acarbose. Furthermore, synthesized compounds were docked into the active sites of the porcine pancreatic alpha-amylase isoenzyme II to evaluate binding affinity and hybrid most potent 7f was lodged in the active site via many strong hydrogen and hydrophobic interactions. Through a 100-ns dynamic simulation research, stability and binding interactions between the promising hybrid 7f and the active residues of the investigated α-amylase isoenzyme II were confirmed. The biological assessments, ADMET, molecular docking, and MD simulations of synthesized analogs allude to the possibility of using hybrids 7d, 7e, and 7f in the development of new antidiabetic therapeutics.