Human Salivary Α-amylase Research Articles

Study on the interaction mechanism of virgin olive oil polyphenols with mucin and α-amylase

The interaction mechanism of mucin and α-amylase with virgin olive oil (VOO) polyphenols (oleuropein (OL), tyrosol (TY), hydroxytyrosol (HT)) was analyzed by fluorescence, ultraviolet (UV) absorption, attenuated total reflection Fourier transform infrared (ATR-FTIR), circular dichroic (CD) spectroscopy and molecular docking. A total of 17 polyphenols have been identified in the selected VOO, and the TY, HT and OL were the main compounds. The quenching mechanism between mucin/α-amylase and three VOO polyphenols was static, mainly through van der Waals forces and hydrogen bonds. The results of UV absorption, ATR-FTIR, and CD spectroscopy revealed that the conformation of mucin changed after combining with the three polyphenols, while that of the α-amylase changed little. Molecular docking predicted the interaction sites of the three polyphenols with human salivary mucin and α-amylase. The present study could provide the theoretical foundation for further research on the interaction between human salivary protein and phenolic compounds in VOO.

Human Salivary α-Amylase and Starch Digestion: A Simple and Inexpensive At-Home Laboratory Experience in Times of the COVID-19 Pandemic.

The first case of coronavirus disease 2019 in Colombia was detected on March 6, 2020. Subsequently, schools, colleges, and universities were closed on March 26, which forced a massive migration to virtual education and impacted laboratory-based teaching courses. The teaching of biochemistry requires an experimental component that virtual laboratories cannot emulate. To address this concern, the article describes an at-home biochemistry laboratory experience that explores the hydrolysis of starch by α-amylase as a function of enzyme concentration, reaction time, and pH. The general success of the experience was assessed through the quality of information submitted through laboratory reports and feedback from students. A total of 19 laboratory reports were reviewed, and 50 students were surveyed. The analysis indicated that approximately 90% of students expressed favorable opinions about the experience. They understood the objective of the practice, identified the function of each material, and explained the relationship between the obtained results and concepts of enzyme activity presented in theoretical classes. Finally, the study concluded that the at-home laboratory experience is inexpensive and easy to perform outside the traditional laboratory. Furthermore, it enables a genuine practical experience with observations, data collection, analysis, and discussion of results, which meets the expectations for pharmaceutical chemistry students at the Universidad El Bosque in Bogotá, Colombia.

Probing the interaction of iminium form of sanguinarine with human salivary α-amylase by multi-spectroscopic techniques and molecular docking

Human salivary α-Amylase (HSAmy) non-catalytic but cellular interaction with sanguinarine (SG), a bioalkaloid with a high therapeutic promise, was sought through multiple spectroscopic approaches and molecular docking under simulated salivary physiological conditions. The formation of the stable HSAmy-sanguinarine complex was from a coalesce of static and dynamic fluorescence quenching mechanisms. The enzyme has one binding site for sanguinarine ( iminium form) with a binding constant (Ka) of 1.14 × 104 L·mol−1 at 25° C. The values of enthalpy change (ΔH) and entropy change (ΔS) were found to be 7.46 kJ mol−1 and 102.68 J·mol−1 K−1, respectively at pH 6.4. This indicated that the formation of the HSAmy-sanguinarine complex was an endothermic reaction and entropy-driven process, consequently perturbing the enzyme secondary and tertiary structures. HSAmy intrinsic surface hydrophobicity was also traded-off for the stabilization of the complex formation. The spontaneous interaction was predominantly characterized by hydrophobic (π → π) bonding. Sanguinarine (iminium) prefentially and prudentially binds, with high energy of −9.5 kcal/mol, to the HSAmy active site. The salient role of HSAmy as a reluctant surrogate payload for sanguinarine (iminium) is undeniable, but the interaction has greater pharmcological significance in sugar regulation and HSAmy linked oral health challenges.

Food grade silica nanoparticles cause non‐competitive type inhibition of human salivary α‐amylase because of surface interaction

AbstractGiven the potential of ingested particles to interact with enzymes in oral cavity, we compared different grades of SiO2 particles (food‐grade and non‐food grade nanoparticles (FG‐SiO2‐NP, NFG‐SiO2‐NP), and food grade microparticles (FG‐SiO2‐MP)) for their interaction with human salivary α‐amylase (HSA). There were differences in the agglomeration behavior and relative abundance of silanol and siloxane groups among different grades of SiO2 particles where FG‐SiO2‐NPs contained less cyclic siloxane groups but more silanol groups. Secondary structure and function of HSA were negatively impacted by FG‐SiO2‐NPs. In order to verify if this inhibition is mediated through surface interactions, pristine particles were compared with those interacted with pure protein (bovine serum albumin‐BSA) and with food matrix (milk) for HSA inhibition. BSA coating of SiO2 particles ameliorated HSA inhibition, but milk interacted ones showed an enhanced the HSA inhibition because of the presence of milk protease suggesting the relevance of surface interactions in manifesting potential negative impacts of silica particles used in food.

Colorado potato beetle alpha-amylase: Purification, action pattern and subsite mapping for exploration of active centre

Colorado potato beetle is an invasive insect herbivore and one of the most challenging agricultural pests globally. This study is the first characterization of the active centre of Colorado potato beetle (Leptinotarsa decemlineata) α-amylase (LdAmy). Bond cleavage frequency values for LdAmy were determined by HPLC product analysis on a chromophore labelled maltooligomer substrate series. Binding energies between amino acid moieties of subsites and glucose residues of substrate were calculated. Active site contains six subsites in the binding region of LdAmy; four glycone- (−4, −3, −2, −1) and two aglycone-binding sites (+1, +2). Subsite map calculation resulted in apparent binding energies −11.8 and − 11.0 kJ/mol for subsites (+2) and (−3), respectively, which revealed very favorable interactions at these positions. Structures of binding sites of LdAmy and mammalian α-amylases show similarity, but there are variations in the binding energies at subsite (−2) and (−4). Differences were interpreted by comparison of amino acid sequences of human salivary α-amylase (HSA) and porcine pancreatic α-amylase (PPA) and two insect (Leptinotarsa decemlineata and Tenebrio molitor) enzymes. The observed substitution of positively charged His305 in HSA at subsite (−2) with an acidic Asp in LdAmy in the same position may explain the obtained energy reduction.

Inhibition of starch digestion by flavonoids: Role of flavonoid-amylase binding kinetics

In this study, kinetics of binding between α-amylase and green tea flavonoids were investigated by fluorescence quenching (FQ). Their effect on α-amylase inhibition was evaluated. Whereas epicatechin (EC) and epigallocatechin (EGC) exhibited slow binding kinetics (in the order of minutes), epicatechin gallate (ECG) and epigallocatechin gallate (ECGC) exhibited very rapid binding (in the order of seconds) with Human Salivary α-amylase (HSA) and Porcine Pancreatic α-amylase (PPA). EGCG reached maximum inhibition of HSA and PPA with short incubation time whereas maximum inhibition of HSA and PPA by EC was reached only after 45 to 60 min of incubation. Similar results with ECG and EGC, but not in line with FQ kinetics, highlighted possible interferences of starch-flavonoid interaction in the binding and inhibition process. These results suggest that incubation times of enzymes and flavonoids shall be evaluated prior to enzyme inhibition testing in order to ensure consistent and reliable results.

Reclamation of beneficial bioactivities of herbal antioxidant condensed tannin extracted from Euonymus laxiflorus

Natural condensed tannins (CT) have received great interest due to their vast beneficial bioactivities. Recently, Euonymus laxiflorus, an edible medicinal herb collected in the Central Highlands of Vietnam, was newly recognized as a natural source rich in antioxidant CT. The aim of this study is to scale up extraction and investigate various novel bioactivities of the isolated CT. The screening of the parts used rich in CT, such as heartwood, trunk bark, branch, and the leaves of EL, indicated that the EL trunk bark (ELTB) has the highest CT content. E. laxiflorus CT (ELCT) was extracted with high-level scale from ELTB via several techniques and then was qualified by NMR spectra and HPLC finger printing. A condensed tannin ELBT-3.1.d was isolated and showed its high molecular weight of ≥ 10 kDa and various in vitro bioactivities. ELBT-3.1.d demonstrated high antioxidant capacity (IC50 = 6.11 µg/mL), and potent enzymes inhibition targets in anti-diabetes, especially showing novel potential inhibition against human salivary α-amylase with IC50 value of 3.01 µg/mL. ELBT-3.1.d displayed no anti-NO effect but did show moderate to effective anticancer activities against A549, MCF-7, HepG2, and WiDr. Notably, condensed tannin ELBT-3.1.d displayed no toxicity to normal cells and a novel potential prebiotic effect on Lactobacillus paracasei BCRC14023 and Lactobacillus rhamnosus BCRC16000. In the animal test, ELCT demonstrated significant effect on reducing plasma glucose in mice at the doses of 50–100 mg/kg BW. The current study contributes to enrich the novel bioactivities of ELCT which may be suggested as functional food or drugs due to processing numerous beneficial bioactivities.

Identification, biochemical characterization and biological role of defense proteins from common bean genotypes seeds in response to Callosobruchus maculatus infestation

Common bean is a legume of significant socioeconomic importance and is cultivated worldwide. This crop is affected by several pests and diseases, which cause considerable economic losses and reduce yield. In recent years, several studies have demonstrated the role of proteins and peptides with activity against a wide range of insects and pathogens. The objective of this work was to identify defense proteins, such as antimicrobial peptides, protease and amylases inhibitors in common bean genotypes and evaluate the relationship of these proteins with Phaseolus vulgaris seed resistance to Callosobruchus maculatus infestation. Nineteen common bean genotypes were subjected to protein extraction, pH 5.4, and precipitation with ammonium sulfate at 70% saturation. The obtained extracts were separated by tricine gel electrophoresis. Experiments were carried out with natural seeds of common beans and artificial seeds (Vigna unguiculata seeds covered with seed coats of common beans) to evaluate the rate of oviposition and development of the insect species Callosobruchus maculatus. Lipid-transfer proteins were identified in nine genotypes whereas defensins were present in all genotypes. The inhibitory activity of α-amylases and trypsin and fungal development were determined in crude extracts (50 μg mL−1). The results also indicated that the extracts from all bean genotypes inhibited the activity of human salivary α-amylase and C. maculatus larval α-amylase. Except for the extracts of four genotypes, all other extracts inhibited trypsin activity. None of the extracts from the evaluated bean genotypes inhibited the growth of tested fungi. Natural seeds from all genotypes did not inhibit insect oviposition, however, the larvae did not survive after feeding on these seeds. Artificial seeds containing seed coat flour of all genotypes inhibited the oviposition of C. maculatus, indicating that the seed coat was also repellent to insect.

Inhibition mechanism of human salivary α-amylase by lipid transfer protein from Vigna unguiculata

VuLTP1.1, a LTP1 from Vigna unguiculata, inhibits 78.1 % of the human salivary α-amylase (HSA) activity at 20 μM. We had performed a correlation study between VuLTP1.1 structure and HSA inhibitory activity and showed that two VuLTP1.1 regions are responsible for HSA inhibition. In one of them we had characterized the crucial importance of an Arg39 for inhibition. In this work, we analyzed the VuLTP1.1-HSA interaction by protein-protein docking to understand the most probable interaction model and the mechanism of HSA inhibition by VuLTP1.1. The VuLTP1.1 tertiary structure quality and refinement as well as the docking assay between VuLTP1.1 and HSA were done by bioinformatic programs. HSA inhibition occurs by direct interaction of the VuLTP1.1 with the HSA causing the obstruction of the carbohydrate biding cleft with Gibbs free energy of -18.5 Kcal/mol and the dissociation constant of 2.6E−14 M. The previously identified Arg39 of VuLTP1.1 is burrowed into the active site of the HSA and there it interacts with the Asp300 of HSA catalytic site by a hydrogen bond. We had confirmed the importance of the Arg39 of VuLTP1.1 for the HSA inhibition which interacts with the Asp300 at the HSA active site. I-2, a LTP-like peptide, presents the same HSA inhibition pattern that VuLTP1.1, which indicates that the inhibition mechanism of the LTPs towards α-amylase is very similar. For the best of our knowledge, it is the first time that the HSA inhibition mechanism was understood and described for the LTP1s using VuLTP1.1 and I-2 as prototype inhibitors.

Fluorescence Polarization-Based Rapid Detection System for Salivary Biomarkers Using Modified DNA Aptamers Containing Base-Appended Bases.

The field of care testing toward the analysis of blood and saliva lacks nowadays simple test techniques for biomarkers. In this study, we have developed a novel nucleobase analog, Ugu, which is a uracil derivative bearing a guanine base at the 5-position. Moreover, we attempted the development of aptamers that can bind to secretory immunoglobulin A (SIgA), which has been examined as a stress marker in human saliva. It was observed that the acquired aptamer binds strongly and selectively to the SIgA dimer (Kd = 13.6 nM) without binding to the IgG and IgA monomers of human serum. Reduction of the aptamer length (41 mer) successfully improved 4-fold the binding affinity (Kd = 3.7 nM), compared to the original, longer aptamer (78 mer). Furthermore, the development of a simple detection system for human saliva samples by fluorescence polarization was investigated, using the reported human salivary α-amylase (sAA) and the SIgA-binding aptamer. Comparison of the present method with conventional enzyme-linked immunosorbent assay techniques highlighted a significant Pearson's correlation of 0.94 and 0.83 when targeting sAA and SIgA, respectively. It is thus strongly suggested that a new simple test of stress markers in human saliva can be quantified quickly without bound/free (B/F) separation.

Inhibition of α-amylase Activity by Zn2+: Insights from Spectroscopy and Molecular Dynamics Simulations.

Inhibition of α-amylase activity is an important strategy in the treatment of diabetes mellitus. An important treatment for diabetes mellitus is to reduce the digestion of carbohydrates and blood glucose concentrations. Inhibiting the activity of carbohydrate-degrading enzymes such as α-amylase and glucosidase significantly decreases the blood glucose level. Most inhibitors of α-amylase have serious adverse effects, and the α-amylase inactivation mechanisms for the design of safer inhibitors are yet to be revealed. In this study, we focused on the inhibitory effect of Zn2+ on the structure and dynamic characteristics of α-amylase from Anoxybacillus sp. GXS-BL (AGXA), which shares the same catalytic residues and similar structures as human pancreatic and salivary α-amylase (HPA and HSA, respectively). Circular dichroism (CD) spectra of the protein (AGXA) in the absence and presence of Zn2+ were recorded on a Chirascan instrument. The content of different secondary structures of AGXA in the absence and presence of Zn2+ was analyzed using the online SELCON3 program. An AGXA amino acid sequence similarity search was performed on the BLAST online server to find the most similar protein sequence to use as a template for homology modeling. The pocket volume measurer (POVME) program 3.0 was applied to calculate the active site pocket shape and volume, and molecular dynamics simulations were performed with the Amber14 software package. According to circular dichroism experiments, upon Zn2+ binding, the protein secondary structure changed obviously, with the α-helix content decreasing and β-sheet, β-turn and randomcoil content increasing. The structural model of AGXA showed that His217 was near the active site pocket and that Phe178 was at the outer rim of the pocket. Based on the molecular dynamics trajectories, in the free AGXA model, the dihedral angle of C-CA-CB-CG displayed both acute and planar orientations, which corresponded to the open and closed states of the active site pocket, respectively. In the AGXA-Zn model, the dihedral angle of C-CA-CB-CG only showed the planar orientation. As Zn2+ was introduced, the metal center formed a coordination interaction with H217, a cation-π interaction with W244, a coordination interaction with E242 and a cation-π interaction with F178, which prevented F178 from easily rotating to the open state and inhibited the activity of the enzyme. This research may have uncovered a subtle mechanism for inhibiting the activity of α-amylase with transition metal ions, and this finding will help to design more potent and specific inhibitors of α-amylases.

An enzymatically controlled mucoadhesive system for enhancing flavour during food oral processing

While a good mucoadhesive biopolymer must adhere to a mucus membrane, it must also have a good unloading ability. Here, we demonstrate that the biopolymer pullulan is partially digested by human salivary α-amylase, thus acting as a controlled release system, in which the enzyme triggers an increased release of flavour. Our oral processing simulations have confirmed an increase in the bioavailability of aroma and salt compounds as a function of oral pullulan degradation, although the release kinetics suggest a rather slow process. One of the greatest challenges in flavour science is to retain and rapidly unload the bioactive aroma and taste compounds in the oral cavity before they are ingested. By developing a cationic pullulan analogue we have, in theory, addressed the “loss through ingestion” issue by facilitating the adhesion of the modified polymer to the oral mucus, to retain more of the flavour in the oral cavity. Dimethylaminoethyl pullulan (DMAE-pullulan) was synthesised for the first time, and shown to bind submaxillary mucin, while still retaining its susceptibility to α-amylase hydrolysis. Although DMAE-pullulan is not currently food grade, we suggest that the synthesis of a sustainable food grade alternative would be a next generation mucoadhesive targeted for the oral cavity.

The Potential Role of Rosmarinic Acid and Sinensetin as α-Amylase Inhibitor: In Silico Study

The study of natural compound as α-amylase inhibitor has been a concern since the synthetic drugs for the management of type 2 diabetes mellitus have several side effects. The present study was carried out to predict the ability of rosmarinic acid and sinensetin as human α-amylase inhibitor by in silico study. All of the prepared 3D structures were used in the molecular docking by using Hex 8.0.0. The visualization of the molecular interactions of those compounds with human salivary α-amylase or human pancreatic α-amylase was established in the Discovery Studio Client 4.1 software. The result of this study determined that rosmarinic acid and sinensetin bound to the A domain of human pancreatic α-amylase and human salivary α-amylase. Rosmarinic acid-human salivary α-amylase complex was observed to possess high number of hydrogen bonds compared to sinensetin-human salivary α-amylase complex. The similar result was observed in the comparison of rosmarinic acid-human pancreatic α-amylase complex and sinensetin-human pancreatic α-amylase complex. The rosmarinic acid was able to bind the Glu233 of human pancreatic α-amylase. These data suggest rosmarinic acid as a potential inhibitor of human salivary α-amylase and human pancreatic α-amylase. Further experimental evidence is needed to confirm this observation.

Insight into the α-Amylase Inhibitory Activity of Plant Lipid Transfer Proteins.

We previously characterized the inhibitory activity of human salivary α-amylase (HSA) and Callosobruchus maculatus intestinal α-amylases by the plant lipid transfer protein from Vigna unguiculata ( Vu-LTP). Herein, we further study this inhibitory activity. First by an analysis of protein α-amylase inhibitors complexed with α-amylase, we find that positively charged amino acids of inhibitors interact with the active site of α-amylases and we know that Vu-LTP is rich in positively charged amino acid residues. For this reason, we model Vu-LTP, and based on its three-dimensional structure, we choose five peptides to be synthesized. Herein, we report that two peptides of Vu-LTP are responsible for HSA inhibition. A comparison of primary and tertiary structures of LTPs with and without inhibitory activity against α-amylase, superimposed with the sequence of Vu-LTP mapped for HSA inhibition, reinforces our suggestion that positively charged amino acids in loops are responsible for the inhibition. To prove our observation, one modified peptide is synthesized in which Arg39 is replaced by Gln. This modified peptide loses the HSA inhibitory property presented by the unmodified peptide. Therefore, we describe a new biological active for Vu-LTP, i.e. the α-amylase inhibitory activity that is not a fortuitous biological activity and probably has evolved to perform a biological function which is still unknown. A good candidate should be defense against insects. The results of this study also expand the possible biotechnological applications of LTPs.

Purification and characterization of alpha‐amylase inhibitor from the seeds of underutilized legume,Mucuna pruriens

An α-amylase inhibitor (EC 3.2.1.1) was purified by buffer extraction, ammonium sulfate fractionation, CM-cellulose, and sephadex G-75 chromatography from the soaked seeds of Mucuna pruriens. The molecular weight determined by gel permeation chromatography on Sephadex G-100 and SDS-PAGE, both in the presence and absence of 2-mercaptoethanol, was found to be 27.24 kDa and 25.6 kDa, respectively. The purified Mucuna pruriens amylase inhibitor showed a specific inhibitor activity of 61.18, fold purity of 36.68, and the yield obtained was 14.01%. The purified amylase inhibitor was found to be heat-stable and retained 80.50% activity at 65°C. Inhibitor was found to have pH optima of 6.9. Hundred percent zone of inhibition was observed when added on the plated organisms of purified inhibitor. Purified amylase inhibitor was found to inhibit the activity of human salivary α-amylase. Inhibitory activity of α-amylase inhibitor against mammalian amylases could suggest its potential in treatment of diabetes and cure of nutritional problems, which results in obesity. Practical applications Purified amylase inhibitor was found to inhibit the activity of human salivary α-amylase. The potential of this inhibitory activity from α-amylase inhibitors, especially in the mammalian α-amylase, could play an important role in the management of nutritional and diabetes-related disorders. Mucuna, an underutilized legume found in tropical region and also cultivated as food by various tribal's in Asia and Africa can be used as a potential source for extraction of these beneficiary protease inhibitors, which in turn finds its applications in various human therapeutic and/or disorder management.

Oro-gastro-intestinal digestion of starch in white bread, wheat-based and gluten-free pasta: Unveiling the contribution of human salivary α-amylase

Starch is a major determinant of the glycemic responses elicited by our diets, but the exact contribution of the two main amylolytic enzymes (salivary and pancreatic α-amylases) remains a matter of debate. Our aim was to investigate the contribution of the oral, gastric and intestinal phases to the hydrolysis of starch in bread and pasta during dynamic in vitro digestions using DiDGI®. Before its inactivation by the low gastric pH, salivary α-amylase released about 80% of the starch in bread and 30% of that in pasta, hydrolysing over half of it into oligosaccharides. Accordingly, the contribution of pancreatic α-amylase during the intestinal phase was lower for bread than pasta. Our results are well correlated with in vivo data, and demonstrate the importance of salivary α-amylase during oro-gastric processing of starchy foods. This finding is discussed in relation with observations regarding salivary α-amylase from other fields of knowledge.

Chlorogenic and phenolic acids are only very weak inhibitors of human salivary α-amylase and rat intestinal maltase activities

There is increasing evidence that consumption of polyphenol and phenolic-rich foods and beverages have the potential to reduce the risk of developing diabetes type 2, with coffee a dominant example according to epidemiological evidence. One of the proposed mechanisms of action is the inhibition of carbohydrate-digesting enzymes leading to attenuated post-prandial blood glucose concentrations, as exemplified by the anti-diabetic drug, acarbose. We determined if the phenolic, 5-caffeoylquinic acid, present in coffee, apples, potatoes, artichokes and prunes, for example, and also selected free phenolic acids (ferulic acid, caffeic acid and 3,4-dimethoxycinnamic acid), could inhibit human salivary α-amylase and rat intestinal maltase activities, digestive enzymes involved in the degradation of starch and malto-oligosaccharides. Using validated assays, we show that phenolic acids, both free and linked to quinic acid, are poor inhibitors of these enzymes, despite several publications that claim otherwise. 5-CQA inhibited human α-amylase only by <20% at 5 mM, with even less inhibition of rat intestinal maltase. The most effective inhibition was with 3,4-dimethoxycinnamic acid (plateau at maximum 32% inhibition of human α-amylase at 0.6 mM), but this compound is found in coffee in the free form only at very low concentrations. Espresso coffee contains the highest levels of 5-CQA among all commonly consumed foods and beverages with a typical concentration of ~5 mM, and much lower levels of free phenolic acids. We therefore conclude that inhibition of carbohydrate-digesting enzymes by chlorogenic or phenolic acids from any food or beverage is unlikely to be sufficient to modify post-prandial glycaemia, and so is unlikely to be the mechanism by which chlorogenic acid-rich foods and beverages such as coffee can reduce the risk of developing type 2 diabetes.

Study on interaction between human salivary α-amylase and sorghum procyanidin tetramer: Binding characteristics and structural analysis

As one of receptors of the acquired membrane, human salivary α‑amylase (HSA) plays an important role in the formation of caries. In vitro conditions, sorghum procyanidins (SPC) tetramer has a better inhibitory effect on the adhesion of Streptococcus mutans to hydroxyapatite than SPC-dimer and SPC-trimer. This study investigated the interaction mechanism between HSA and SPC-tetramer using spectroscopic techniques including fluorescence, UV–vis absorption, and circular dichroism (CD). Fluorescence data revealed that the fluorescence quenching of HSA by SPC-tetramer was a static quenching process, and that the SPC-tetramer was bound with HSA at the ratio of 1:1 in SPC-tetramer-protein complex. Meanwhile, the analysis of CD demonstrated that the conformation of HSA was altered in the presence of SPC-tetramer. The conformation changes of HSA might contribute to the reduction of the adhesion of cariogenic bacteria and finally decrease the occurrence of dental caries.

Inhibition studies on α-amylase using isothermal titration calorimetry

AbstractThe control of postprandial blood glucose level via the inhibition of α‐amylase is a relevant strategy for the treatment of type 2 diabetes. Several antidiabetic plants are known but there is no information about their α-amylase inhibitory activity. This in vitro study tries to reveal the answer. Hot water extracts of 58 medicinal plants and spices were examined. Activity measurements of human salivary α-amylase (HSαA) on 0.14 m/v % starch substrate was carried out by isothermal titration calorimetry in the presence or absence of plant extracts. Water soluble antioxidant capacity of each extract was measured with photo-chemiluminescence method. Results have confirmed the inhibitory activity of several plant extracts against HsαA. The green tea, cinnamon and allspice, furthermore leaves of blackberry, raspberry and strawberry deserve particular mention (IC50≤ 1.2 mg/mL). A few extracts had significant water-soluble antioxidant capacity compared to ascorbic acid and a weak correlation was recognised between the obtained IC50and antioxidant capacity values. Inhibition of amylases located in digestive system can be reached via daily intake of most active extracts. These plants could be inserted effectively into a diabetic diet as food supplements.

Correction to: Inhibitor discovery from pomegranate rind for targeting human salivary α-amylase

The original version of this article unfortunately contained error in the captions of Figs. 10–12. The correct figure captions are presented with this erratum.