Discovery of novel pyrido-pyrrolidine hybrid compounds as alpha-glucosidase inhibitors and alternative agent for control of type 1 diabetes

Discovery of Novel Pyrrolidine-Based Chalcones as Dual Inhibitors of α-Amylase and α-Glucosidase: Synthesis, Molecular Docking, ADMET Profiles, and Pharmacological Screening

A series of chalcones containing a pyrrolidine moiety were synthesized to examine their in vitro α-amylase and α-glucosidase inhibitory activities, for the treatment of Diabetes mellitus, which is one of the most dangerous and rapidly increasing disorders of today. Compound 3 exhibited an excellent dual inhibitory effect with an IC50 value of 14.61 ± 0.12 μM against α-amylase, and with an IC50: 25.38 ± 2.09 μM against α-glucosidase. The in vitro cytotoxic effects of all compounds against nonsmall lung cancer (A549) and bronchial epithelial normal (BEAS-2B) cell lines were also evaluated. Compound 5 (IC50: 82.20 μM) and compound 8 (IC50: 59.96 μM) showed better cytotoxic activity than cisplatin against A549 (IC50: 84.39 μM) cells. Furthermore, these compounds had no harmful effect on healthy BEAS-2B cells at the determined IC50 values. Moreover, the molecular docking and molecular dynamics simulation analysis revealed that all synthesized compounds exhibited stronger binding affinities toward α-glucosidase and α-amylase compared to the positive control acarbose.

Structural modification of tanshinone IIA and their α-glucosidase inhibitory activity

α-Glucosidase is one of the therapeutic approaches for treating type 2 diabetes mellitus. Almost 95 % of diabetes patients worldwide have been diagnosed with type 2 diabetes, resulting in 1.5 million fatalities each year. Newly synthesized oxazole-based tanshinone IIA derivatives (1a-n) were designed and evaluated for their inhibitory activity against α-glucosidase enzyme. Eight compounds (1a-d, 1f-g, 1j, and 1m) demonstrated excellent inhibition with IC50 values ranging from 0.73 ± 0.11 to 9.46 ± 0.57 μM as compared to tanshinone IIA (IC50 = 11.39 ± 0.77 μM) and standard acarbose (IC50 = 100.00 ± 0.95 μM). Among this series, 1j bearing two hydroxyls group over the phenyl ring was identified as the most potent α-glucosidase inhibitor with IC50 value of 0.73 ± 0.11 μM. Molecular docking simulations were done for the most active compound to identify important binding modes responsible for inhibition activity of α-glucosidase. In addition, the kinetic study was also performed to understand the mode of inhibition.

Discovery of triazole tethered thymol/carvacrol-coumarin hybrids as new class of α-glucosidase inhibitors with potent in vivo antihyperglycemic activities

Keeping in view the inhibitory potential of monoterpenes thymol and carvacrol as well as coumarin nucleus against α-glucosidase, novel series of thymol/carvacrol-coumarin hybrids was designed, synthesized and evaluated for α-glucosidase inhibitory potential. Among the series of hybrid molecules, AS14 with IC50 value of 4.32 ± 0.11 μM was selective α-glucosidase inhibitor over α-amylase (IC50 = 37.36 ± 0.84 μM). AS14 was non-toxic toward mouse normal fibroblast cells (L929: IC50 > 100 μM). Molecular docking and dynamic simulation studies confirmed desired interactions of AS14 with α-glucosidase responsible for the inhibition of its catalysis capabilities. Acute oral toxicity study confirmed AS14 as safer molecule for in vivo pharmacological investigations with LD50 value of 300 mg/kg. AS14 also showed acute hypoglycaemic effects [reduction in blood glucose levels at 1 h of administration in maltose loading test (at 10 and 20 mg/kg by 62.65 % and 70.12 %) and sucrose loading test (at 10 and 20 mg/kg by 59.65 % and 60.23 %), respectively] as well as long term (28 days) fasting blood glucose reduction (At day 28: 10 mg/kg = 54.69 % and 20 mg/kg = 62.23 % reduction in fasting blood glucose levels) capabilities in streptozotocin induced diabetic rats. Overall study represents, AS14 as potential α-glucosidase inhibitor with adequate efficacy and safety profile and act as an effective hit lead for the further development of potent and safer α-glucosidase inhibitors for the management of postprandial hyperglycemia in diabetic patients.

Pyrrole: A Decisive Scaffold for the Development of Therapeutic Agents and Structure-Activity Relationship

An overview of pyrroles as distinct scaffolds with therapeutic potential and the significance of pyrrole derivatives for drug development are provided in this article. It lists instances of naturally occurring pyrrole-containing compounds and describes the sources of pyrroles in nature, including plants and microbes. It also explains the many conventional and modern synthetic methods used to produce pyrroles. The key topics are the biological characteristics, pharmacological behavior, and functional alterations displayed by pyrrole derivatives. It also details how pyrroles are used to treat infectious diseases. It describes infectious disorders resistant to standard treatments and discusses the function of compounds containing pyrroles in combating infectious diseases. Furthermore, the review covers the uses of pyrrole derivatives in treating non-infectious diseases and resistance mechanisms in non-infectious illnesses like cancer, diabetes, and Alzheimer's and Parkinson's diseases. The important discoveries and probable avenues for pyrrole research are finally summarized, along with their significance for medicinal chemists and drug development. A reference from the last two decades is included in this review.

Synthesis of 1,2,3-triazole-1,3,4-thiadiazole hybrids as novel α-glucosidase inhibitors by in situ azidation/click assembly

α-Glucosidase inhibition is widely used in the oral management of diabetes mellitus (DM), a disease characterized by high blood sugar levels (hyperglycemia) and abnormal carbohydrate metabolism. In this respect, a series of 1,2,3-triazole-1,3,4-thiadiazole hybrids 7a-j were synthesized, inspired by a copper-catalyzed one-pot azidation/click assembly approach. All the synthesized hybrids were screened for inhibition of the α-glucosidase enzyme, displaying IC₅₀ values ranging from 63.35 ± 0.72 to 613.57 ± 1.98 μM, as compared to acarbose (reference) with IC₅₀ of 844.81 ± 0.53 μM. The hybrids 7h and 7e with 3-nitro and 4-methoxy substituents at the phenyl ring of the thiadiazole moiety were the best active hybrids of this series with IC₅₀ values of 63.35 ± 0.72 μM, and 67.61 ± 0.64 μM, respectively. Enzyme kinetics analysis of these compounds revealed a mixed mode of inhibition. Moreover, molecular docking studies were also performed to gain insights into the structure-activity-relationships of the potent compounds and their corresponding analogs.

Inhibition of α-glucosidase enzyme by 'click'-inspired pharmacophore framework 1,3,4-thiadiazole-1,2,3-triazole hybrids

Aim: α-Glucosidase inhibitors are important oral antidiabetic drugs that are used alone or in combination therapy. Materials & methods: In this regard, 1,3,4-thiadiazoles-1,2,3-triazoles were designed, synthesized and evaluated for α-glucosidase enzyme inhibition. Results: The applied synthesis protocol involved a 'click' reaction between a novel alkyne derived from a 1,3,4-thiadiazole derivative and phenylacetamide azides. The hybrid (9n) bearing 2-methyl and 4-nitro substituents was the best inhibitor with an IC₅₀ value of 31.91 μM (acarbose IC₅₀ = 844.81 μM). The blind molecular docking study of the best derivative (9n) showed that it interacted with the allosteric site's amino acid residues of α-glucosidase. Conclusion: 'Click'-inspired potential α-glucosidase inhibitors (1,3,4-thiadiazole-1,2,3-triazole hybrids) were identified and structure-activity relationship and kinetic and molecular docking studies accomplished.

Synthetic α-glucosidase inhibitors as promising anti-diabetic agents: Recent developments and future challenges

Diabetes mellitus is one of the biggest challenges for the scientific community in the 21st century. It is a well-recognized multifactorial health problem contributes significantly to high mortality rates by causing serious health complications mainly related to cardiovascular diseases, kidney damage and neuropathy. The inhibition of α-glucosidase (enzyme that catalyses starch hydrolysis in the intestine) is an effective therapeutic approach for controlling hyperglycemia associated with type-2 diabetes. However, the presently approved drugs/inhibitors such as acarbose, miglitol and voglibose have several undesirable gastrointestinal side effects impeding their applications. Therefore, search for novel and more effective inhibitors with reduced side effects and less cost remains a fascinating area of research. In this context, a large variety of α-glucosidase inhibitors have been identified in recent years that demands attention from drug development community. This review is therefore an effort to summarize and highlight the promising α-glucosidase inhibitors especially those which are primarily based on aromatic heterocyclic scaffolds such as coumarin, imidazole, isatin, pyrimidine, quinazoline, triazine, thiazole etc, having improved safety and pharmacological profiles.

Synthesis of Novel 2,3-Dihydro-1,5-Benzothiazepines as α-Glucosidase Inhibitors: In Vitro, In Vivo, Kinetic, SAR, Molecular Docking, and QSAR Studies

In the present study, a series of 2,3-dihydro-1,5-benzothiazepine derivatives 1B-14B has been synthesized sand characterized by various spectroscopic techniques. The enzyme inhibitory activities of the target analogues were assessed using in vitro and in vivo mechanism-based assays. The tested compounds 1B-14B exhibited in vitro inhibitory potential against α-glucosidase with IC50 = 2.62 ± 0.16 to 10.11 ± 0.32 μM as compared to the standard drug acarbose (IC50 = 37.38 ± 1.37 μM). Kinetic studies of the most active derivatives 2B and 3B illustrated competitive inhibitions. Based on the α-glucosidase inhibitory effect, the compounds 2B, 3B, 6B, 7B, 12B, 13B, and 14B were chosen in vivo for further evaluation of antidiabetic activity in streptozotocin-induced diabetic Wistar rats. All these evaluated compounds demonstrated significant antidiabetic activity and were found to be nontoxic in nature. Moreover, the molecular docking study was performed to elucidate the binding interactions of most active analogues with the various sites of the α-glucosidase enzyme (PDB ID 3AJ7). Additionally, quantitative structure-activity relationship (QSAR) studies were performed based on the α-glucosidase inhibitory assay. The value of correlation coefficient (r) 0.9553 shows that there was a good correlation between the 1B-14B structures and selected properties. There is a correlation between the experimental and theoretical results. Thus, these novel compounds could serve as potential candidates to become leads for the development of new drugs provoking an anti-hyperglycemic effect.

Flavone-1,2,3-triazole derivatives as potential α-glucosidase inhibitors: Synthesis, enzyme inhibition, kinetic analysis and molecular docking study

α-Glucosidase inhibitors are considered prime therapeutics in the management of type-2 diabetes and are preferred due to their localized action ushered by limited side effects. In this regard, nineteen new flavone-1,2,3-triazole derivatives have been designed and synthesized via utilizing an efficient click reaction protocol, and screened for the inhibition of the α-glucosidase enzyme. The reaction conditions were mild, good yielding and required easy work up. All the synthesized flavone-triazole derivatives were found more active against the yeast α-glucosidase with IC₅₀ values ranging from 24.37 ± 0.55-168.44 ± 0.77 μ M as compared to standard inhibitor acarbose (IC₅₀ = 844.81 ± 0.53 μM). The derivatives with 2,5‑dichloro 9k (IC₅₀ = 24.37 ± 0.55 μM) and 4‑chloro 9d (IC₅₀ = 24.77 ± 0.30 μM) substituent bearing an amide linkage were the most active. In the kinetic study of most active derivatives 9k and 9d, they were found to be mixed and uncompetitive inhibitors, respectively. In molecular docking studies, blind docking of the most active compounds was accomplished to find the interactions between the compounds and α-glucosidase that further confirms the mixed or uncompetitive nature of the inhibitors.

An approach to pharmacological targets of pyrrole family from a medicinal chemistry viewpoint

Pyrrole is one of the most widely used heterocycles in the pharmaceutical industry. Due to the importance of pyrrole structure in drug design and development, herein, we tried to conduct an extensive review of the bioactive pyrrole based compounds reported recently. The bioactivity of pyrrole derivatives varies, so in the review, we categorized them based on their direct pharmacologic targets. Therefore, readers are able to find the variety of biologic targets for pyrrole containing compounds easily. This review explains around seventy different biologic targets for pyrrole based derivatives, so, it is helpful for medicinal chemists in design and development novel bioactive compounds for different diseases. This review presents an extensive meaningful structure activity relationship for each reported structure as much as possible. The review focuses on papers published between 2018 and 2020.

Heterocyclic compounds as a magic bullet for diabetes mellitus: a review

Diabetes mellitus (DM) is a major metabolic disorder due to hyperglycemia, which is increasing all over the world. From the last two decades, the use of synthetic agents has risen due to their major involvement in curing of chronic diseases including DM. The core skeleton of drugs has been studied such as thiazolidinone, azole, chalcone, pyrrole and pyrimidine along with their derivatives. Diabetics assays have been performed in consideration of different enzymes such as α-glycosidase, α-amylase, and α-galactosidase against acarbose standard drug. The studied moieties were depicted in both models: in vivo as well as in vitro. Molecular docking of the studied compounds as antidiabetic molecules was performed with the help of Auto Dock and molecular operating environment (MOE) software. Amino acid residues Asp349, Arg312, Arg439, Asn241, Val303, Glu304, Phe158, His103, Lys422 and Thr207 that are present on the active sites of diabetic related enzymes showed interactions with ligand molecules. In this review data were organized for the synthesis of heterocyclic compounds through various routes along with their antidiabetic potential, and further studies such as pharmacokinetic and toxicology studies should be executed before going for clinical trials.

Diabetes mellitus (DM) is a major metabolic disorder due to hyperglycemia, which is increasing all over the world.

Washingtonia filifera seed extracts inhibit the islet amyloid polypeptide fibrils formations and α-amylase and α-glucosidase activity

Washingtonia filifera seeds have revealed to possess antioxidant properties, butyrylcholinesterase and xanthine oxidase inhibition activities. The literature has indicated a relationship between Alzheimer's disease (AD) and type-2 diabetes (T2D). Keeping this in mind, we have now evaluated the inhibitory properties of W. filifera seed extracts on α-amylase, α-glucosidase enzyme activity and the Islet Amyloid Polypeptide (IAPP) fibrils formation. Three extracts from seeds of W. filifera were evaluated for their enzyme inhibitory effect and IC50 values were calculated for all the extracts. The inhibition mode was investigated by Lineweaver-Burk plot analysis and the inhibition of IAPP aggregate formation was monitored. W. filifera methanol seed extract appears as the most potent inhibitor of α-amylase, α-glucosidase, and for the IAPP fibril formation. Current findings indicate new potential of this extract that could be used for the identification or development of novel potential agents for T2D and AD.

Design, synthesis, biological evaluation, and molecular modeling studies of pyrazole-benzofuran hybrids as new α-glucosidase inhibitor

In this work, new derivatives of biphenyl pyrazole-benzofuran hybrids were designed, synthesized and evaluated in vitro through enzymatic assay for inhibitory effect against α-glucosidase activity. Newly identified inhibitors were found to be four to eighteen folds more active with IC₅₀ values in the range of 40.6 ± 0.2-164.3 ± 1.8 µM, as compared to the standard drug acarbose (IC₅₀ = 750.0 ± 10.0 μM). Limited Structure-activity relationship was established. A kinetic binding study indicated that most active compound 8e acted as the competitive inhibitors of α-glucosidase with K_i = 38 μM. Molecular docking has also been performed to find the interaction modes responsible for the desired inhibitory activity. As expected, all pharmacophoric features, used in the design of the hybrid, are involved in the interaction with the active site of the enzyme. In addition, molecular dynamic simulations showed compound 8e oriented vertically into the active site from mouth to the bottom and stabilized the enzyme domains by interacting with the interface of domain A and domain B and the back side of the active site while acarbose formed non-binding interaction with the residue belong to the domain A of the enzyme.

Design and synthesis of novel quinazolinone-pyrazole derivatives as potential α-glucosidase inhibitors: Structure-activity relationship, molecular modeling and kinetic study

In this study, a new series of quinazolinone-pyrazole hybrids were designed, synthesized and screened for their α-glucosidase inhibitory activity. The results of the in vitro screening indicated that all the molecular hybrids exhibited more inhibitory activity (IC₅₀ values ranging from 60.5 ± 0.3 µM-186.6 ± 20 μM) in comparison to standard acarbose (IC₅₀ = 750.0 ± 10.0 µM). Limited structure-activity relationship suggested that the variation in the inhibitory activities of the compounds affected by different substitutions on phenyl rings of diphenyl pyrazole moiety. The enzyme kinetic studies of the most potent compound 9i revealed that it inhibited α-glucosidase in a competitive mode with a Ki of 56 μM. Molecular docking study was performed to predict the putative binding interaction. As expected, all pharmacophoric moieties used in the initial structure design playing a pivotal role in the interaction with the binding site of the enzyme. In addition, by performing molecular dynamic investigation and MM-GBSA calculation, we investigated the difference in structural perturbation and dynamic behavior that is observed over α-glycosidase in complex with the most active compound and acarbose relative to unbound α-glycosidase enzyme.

Research progress of indole compounds with potential antidiabetic activity

New types of antidiabetic agents are continually needed with diabetes becoming the epidemic in the world. Indole alkaloids play an important role in natural products owing to their variable structures and versatile biological activities like anticonvulsant, anti-inflammatory, antidiabetic, antimicrobial, and anticancer activities, which are a promising source of novel antidiabetic drugs discovery. The synthesized indole derivatives possess similar properties to natural indole alkaloids. In the last two decades, more and more indole derivatives have been designed and synthesized for searching their bioactivities. This present review describes comprehensive structures of indole compounds with the potential antidiabetic activity including natural indole alkaloids and the synthetic indole derivatives based on the structure classification, summarizes their approaches isolated from natural sources or by synthetic methods, and discusses the antidiabetic effects and the mechanisms of action. Furthermore, this review also provides briefly synthetic procedures of some important indole derivatives.

Interactions between Phenols and Alkylamides of Sichuan Pepper (Zanthoxylum Genus) in α-Glucosidase Inhibition: A Structural Mechanism Analysis

The phenols and alkylamides in 26 varieties of Zanthoxylum pericarps (ZP) were comparatively identified, and the contribution of these key components to the inhibition of in vitro α-glucosidase (α-Glu) was confirmed using principal component analysis (PCA) and ingredient recombination models. Additionally, spectrophotometric assays, nuclear magnetic resonance (NMR), and molecular docking (MD) were employed to characterize the interactions among key components in ZP when exposed to α-Glu. Four phenols and hydroxy-α-sanshool (α-SOH), which were recognized as main ingredients, presented an antagonistic effect in the inhibition of α-Glu. 1H NMR demonstrated chemical shifts of certain hydrogens in the B phenolic ring and tetraenyl group, indicating a possible p-π conjugation between phenols and α-SOH. In addition, using MD analysis, the phenol-binding sites were observed to be negatively affected when α-SOH initially interacted with α-Glu. The combined results of the NMR and MD clarified the structural mechanism behind phenol/α-SOH antagonistic behavior in α-Glu inhibition.

Lepipyrrolins A-B, two new dimeric pyrrole 2-carbaldehyde alkaloids from the tubers of Lepidium meyenii

Nine new pyrrole alkaloids, including two undescribed dimeric pyrrole 2‑carbaldehyde alkaloids, lepipyrrolins A-B (1-2), seven pyrrole-alkaloid derivatives, macapyrrolins D-J (3-9), along with three known ones (10-12) were isolated from the rhizomes of Lepidium meyenii. Their structures and absolute configurations were demonstrated by extensive spectroscopic data (1D, 2D NMR, HRESIMS), and calculated electronic circular dichroism (ECD) experiment. Compounds 1, 3-12 were tested for their nitric oxide inhibitory effects. Furthermore, compound 1 was evaluated for its cytotoxic activity against five human tumor cell lines (HL-60, SMMC-7221, A549, MCF-7, and SW480) in vitro, and displayed selective cytotoxicity against SMMC-7721 with IC₅₀ value of 16.78 ± 0.49 μM.

A new biological prospective for the 2-phenylbenzofurans as inhibitors of α-glucosidase and of the islet amyloid polypeptide formation

In this study, we have investigated a series of hydroxylated 2-phenylbenzofurans compounds for their inhibitory activity against α-amylase and α-glucosidase activity. Inhibitors of carbohydrate degrading enzymes seem to have an important role as antidiabetic drugs. Diabetes mellitus is a wide-spread metabolic disease characterized by elevated levels of blood glucose. The most common is type 2 diabetes, which can lead to severe complications. Since the aggregates of islet amyloid polypeptide (IAPP) are common in diabetic patients, the effect of compounds to inhibit amyloid fibril formation was also determined. All the compounds assayed showed to be more active against α-glucosidase. Compound 16 showed the lowest IC₅₀ value of the series, and it is found to be 167 times more active than acarbose, the reference compound. The enzymatic activity assays showed that compound 16 acts as a mixed-type inhibitor of α-glucosidase. Furthermore, compound 16 displayed effective inhibition of IAPP aggregation and it manifested no significant cytotoxicity. To predict the binding of compound 16 to IAPP and α-glucosidase protein complexes, molecular docking studies were performed. Altogether, our results support that the 2-phenylbenzofuran derivatives could represent a promising candidate for developing molecules able to modulate multiple targets involved in diabetes mellitus disorder.