Current anti-diabetic agents and their molecular targets: A review

Novel acyl hydrazide derivatives of polyhydroquinoline as potent anti-diabetic and anti-glycating agents: Synthesis, in vitro α-amylase, α-glucosidase inhibition and anti-glycating activity with molecular docking insights

In this study, eleven novel acyl hydrazides derivative of polyhydroquinoline were synthesized, characterized and screened for their in vitro anti-diabetic and anti-glycating activities. Seven compounds 2a, 2d, 2i, 2 h, 2j, 2f, and 2 g exhibited notable α-amylase inhibitory activity having IC50 values from 3.51 ± 2.13 to 11.92 ± 2.30 µM. Similarly, six compounds 2d, 2f, 2 h, 2i, 2j, and 2 g displayed potent α-glucosidase inhibitory activity compared to the standard acarbose. Moreover, eight derivatives 2d, 2 g, 2f, 2j, 2a, 2i, 2 g, and 2e showed excellent anti-glycating activity with IC50 values from 6.91 ± 2.66 to 15.80 ± 1.87 µM when compared them with the standard rutin (IC50 = 22.5 ± 0.90 µM). Molecular docking was carried out to predict the binding modes of all the compounds with α-amylase and α-glucosidase. The docking analysis revealed that most of the compounds established strong interactions with α-amylase and α-glucosidase. All compounds fitted well into the binding pockets of α-amylase and α-glucosidase. Among all compounds 2a and 2f were most potent based on docking score -8.2515 and -7.3949 against α-amylase and α-glucosidase respectively. These results hold promise for the development of novel candidates targeted at controlling postprandial glucose levels in individuals with diabetes.

Facile synthesis and in silico studies of benzothiazole-linked hydroxypyrazolones targeting α-amylase and α-glucosidase

Aim: The objective of the present investigation was to design and synthesize new heterocyclic hybrids comprising benzothiazole and indenopyrazolone pharmacophoric units in a single molecular framework targeting α-amylase and α-glucosidase enzymatic inhibition. Materials & methods: 20 new benzothiazole-appended indenopyrazoles, 3a-t, were synthesized in good yields under environment-friendly conditions via cycloaddition reaction, and assessed for antidiabetic activity against α-amylase and α-glucosidase, using acarbose as the standard reference. Results: Among all the hydroxypyrazolones, 3p and 3r showed the best inhibition against α-amylase and α-glucosidase, which finds support from molecular docking and dynamic studies. Conclusion: Compounds 3p and 3r have been identified as promising antidiabetic agents against α-amylase and α-glucosidase and could be considered valuable leads for further optimization of antidiabetic agents.

A Non-Toxic Binuclear Vanadium(IV) Complex as Insulin Adjuvant Improves the Glycemic Control in Streptozotocin-Induced Diabetic Rats

Diabetes mellitus (DM) complications are a burden to health care systems due to the associated consequences of poor glycemic control and the side effects of insulin therapy. Recently. adjuvant therapies, such as vanadium compounds, have gained attention due to their potential to improve glucose homeostasis in patients with diabetes. In order to determine the anti-diabetic and antioxidant effects of the oxidovanadium(IV) complex (Et3NH)2[{VO(OH}2)(ox)2(µ-ox)] or Vox2), rats with streptozotocin (STZ)-induced diabetes were treated with 30 and 100 mg/kg of Vox2, orally administered for 12 days. Vox2 at 100 mg/kg in association with insulin caused a 3.4 times decrease in blood glucose in STZ rats (424 mg/dL), reaching concentrations similar to those in the normoglycemic animals (126 mg/dL). Compared to insulin alone, the association with Vox2 caused an additional decrease in blood glucose of 39% and 65% at 30 and 100 mg/kg, respectively, and an increased pancreatic GSH levels 2.5 times. Vox2 alone did not cause gastrointestinal discomfort, diarrhea, and hepatic or renal toxicity and was not associated with changes in blood glucose level, lipid profile, or kidney or liver function. Our results highlight the potential of Vox2 in association with insulin in treating diabetes.

An insight into the mechanistic role of (-)-Ampelopsin F from Vatica chinensis L. in inducing insulin secretion in pancreatic beta cells

Resveratrol oligomers, ranging from dimers to octamers, are formed through regioselective synthesis involving the phenoxy radical coupling of resveratrol building blocks, exhibiting remarkable therapeutic potential, including antidiabetic properties. In this study, we elucidate the mechanistic insights into the insulin secretion potential of a resveratrol dimer, (-)-Ampelopsin F (AmF), isolated from the acetone extract of Vatica chinensis L. stem bark in Pancreatic Beta-TC-6 cell lines. The AmF (50 µM) treated cells exhibited a 3.5-fold increase in insulin secretion potential as compared to unstimulated cells, which was achieved through the enhancement of mitochondrial membrane hyperpolarization, elevation of intracellular calcium concentration, and upregulation of GLUT2 and glucokinase expression in pancreatic Beta-TC-6 cell lines. Furthermore, AmF effectively inhibited the activity of DPP4, showcasing a 2.5-fold decrease compared to the control and a significant 6.5-fold reduction compared to the positive control. These findings emphasize AmF as a potential lead for the management of diabetes mellitus and point to its possible application in the next therapeutic initiatives.

Exploiting π and Chalcogen Interactions for the β-Selective Glycosylation of Indoles through Glycal Conformational Distortion

Harnessing unconventional noncovalent interactions (NCIs) is emerging as a formidable synthetic approach in difficult-to-access glycosidic chemical space. C-Glycosylation, in particular, has gained a flurry of recent attention. However, most reported methods are restricted to the relatively facile access to α-C-glycosides. Herein, we disclose a β-stereoselective glycosylation of indoles by employing a phosphonoselenide catalyst. The robustness of this protocol is exemplified by its amenability for reaction at both the indolyl C- and N- reactivity sites. In contrast to previous reports, in which the chalcogens were solely involved in Lewis acidic activation, our mechanistic investigation unraveled that the often neglected flanking aromatic substituents of phosphonoselenides can substantially contribute to catalysis by engaging in π-interactions. Computations and NMR spectroscopy indicated that the chalcogenic and aromatic components of the catalyst can be collectively exploited to foster conformational distortion of the glycal away from the usual half-chair to the boat conformation, which liberates the convex β-face for nucleophilic attack.

New chromone derivatives bearing thiazolidine-2,4-dione moiety as potent PTP1B inhibitors: Synthesis and biological activity evaluation

A series of chromone derivatives bearing thiazolidine-2,4-dione moiety (5 ∼ 37) were synthesized and evaluated for their PTP1B inhibitory activity, interaction analysis and effects on insulin pathway in palmitic acid (PA)-induced HepG2 cells. The results showed that all derivatives presented potential PTP1B inhibitory activity with IC50 values of 1.40 ± 0.04 ∼ 16.83 ± 0.54 μM comparing to that of positive control lithocholic acid (IC50: 9.62 ± 0.14 μM). Among them, compound 9 had the strongest PTP1B inhibitory activity with the IC50 value of 1.40 ± 0.04 μM. Inhibition kinetic study revealed that compound 9 was a reversible mixed-type inhibitor against PTP1B. CD spectra results confirmed that compound 9 changed the secondary structure of PTP1B by their interaction. Molecular docking explained the detailed binding between compound 9 and PTP1B. Compound 9 also showed 19-fold of selectivity for PTP1B over TCPTP. Moreover compound 9 could recovery PA-induced insulin resistance by increasing the phosphorylation of IRSI and AKT. CETSA results showed that compound 9 significantly increased the thermal stability of PTP1B.

Antidiabetic Potential of a Trimeric Anthranilic Acid Peptide Isolated from Malbranchea flocciformis

Compound 3, a trimeric anthranilic acid peptide, and another three metabolites were isolated from an organic extract from the culture medium of Malbranchea flocciformis ATCC 34530. The chemical structure proposed previously for 3 was unequivocally assigned via synthesis and X-ray diffraction analysis. Tripeptide 3 showed insulinotropic properties by decreasing the postprandial peak in healthy and hyperglycemic mice. It also increased glucose-induced insulin secretion in INS-1E at 5 μM, specifically at higher glucose concentrations. These results revealed that 3 might act as an insulin sensitizer and a non-classical insulin secretagogue. Altogether, these findings are in harmony with the in vivo oral glucose tolerance test and acute oral hypoglycemic assay. Finally, the chemical composition of the extract was established by the Global Natural Products Social Molecular Network platform. Phylogenetic analysis using the internal transcribed spacer region revealed that M. flocciformis ATCC 34530 is related to the Malbrancheaceae.

Recent Studies of Nitrogen and Sulfur Containing Heterocyclic Analogues as Novel Antidiabetic Agents: A Review

The prevalence of diabetes mellitus is on the rise, which demands the identification of novel antidiabetic drugs. There is a need for safer and more effective alternatives because the therapy methods now available to manage diabetes have limits. Due to their diverse pharmacological characteristics, heterocyclic molecules with nitrogen and Sulfur atoms have become intriguing candidates in medicinal chemistry. These substances have a wide variety of structures that can be customized to target different pathways associated with diabetes and can affect important biological targets involved in glucose homeostasis. This review provides a thorough summary of the most recent studies on heterocyclic analogues of nitrogen and Sulfur as prospective antidiabetic agents. This review examines the variety of their structural forms, their methods of action, and assesses the results of preclinical and clinical investigations on their effectiveness and safety. Additionally, further optimization and development of innovative antidiabetic medications are highlighted, as well as the difficulties and prospects for the future in utilizing the therapeutic potential of these analogues. This study seeks to stimulate additional investigation and cooperation between researchers and medicinal chemists, promoting improvements in the creation of efficient and secure antidiabetic medicines to fulfill the needs in the management of diabetes.

Synthesis and biological evaluation of indole derivatives containing thiazolidine-2,4-dione as α-glucosidase inhibitors with antidiabetic activity

In order to develop potential α-glucosidase inhibitors with antidiabetic activity, twenty-six indole derivatives containing thiazolidine-2,4-dione were synthesized. All compounds presented potential α-glucosidase inhibitory activities with IC50 values ranging from 2.35 ± 0.11 to 24.36 ± 0.79 μM, respectively compared to acarbose (IC50 = 575.02 ± 10.11 μM). Especially, compound IT4 displayed the strongest α-glucosidase inhibitory activity (IC50 = 2.35 ± 0.11 μM). The inhibition mechanism of compound IT4 on α-glucosidase was clarified by the investigation of kinetics studies, fluorescence quenching, CD spectra, 3D fluorescence spectra, and molecular docking. In vivo antidiabetic experiments demonstrated that oral administration of compound IT4 would suppress fasting blood glucose level and ameliorate their glucose tolerance and dyslipidemia in diabetic mice.

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.

Potential Therapeutic Targets for the Management of Diabetes Mellitus Type 2

Diabetes is one of the lifelong chronic metabolic diseases which is prevalent globally. There is a continuous rise in the number of people suffering from this disease with time. It is characterized by hyperglycemia, which leads to severe damage to the body's system, such as blood vessels and nerves. Diabetes occurs due to the dysfunction of pancreatic β -cell which leads to the reduction in the production of insulin or body cells unable to use insulin produce efficiently. As per the data shared International diabetes federation (IDF), there are around 415 million affected by this disease worldwide. There are a number of hit targets available that can be focused on treating diabetes. There are many drugs available and still under development for the treatment of type 2 diabetes. Inhibition of gluconeogenesis, lipolysis, fatty acid oxidation, and glucokinase activator is emerging targets for type 2 diabetes treatment. Diabetes management can be supplemented with drug intervention for obesity. The antidiabetic drug sale is the second-largest in the world, trailing only that of cancer. The future of managing diabetes will be guided by research on various novel targets and the development of various therapeutic leads, such as GLP-1 agonists, DPP-IV inhibitors, and SGLT2 inhibitors that have recently completed their different phases of clinical trials. Among these therapeutic targets associated with type 2 diabetes, this review focused on some common therapeutic targets for developing novel drug candidates of the newer generation with better safety and efficacy.

Association between illness perception and medication adherence in patients with diabetes mellitus in North Shoa, Zone: cross-sectional study

Background

Although the impact of illness perception on medication adherence is well-established, its specific influence on medication adherence in Ethiopia remains unclear. Consequently, the objective of this study was to examine the association between illness perception and medication adherence among patients with diabetes mellitus in the North Shoa Zone.

Methods

An institution-based cross-sectional study was conducted from 24 May to 25 June 2022 in the North Shoa zone. The study included a random sample of 552 individuals with diabetes from four public hospitals. Data was collected and entered into Epi Data V.3.1, and analysis was performed using SPSS version 22. Descriptive statistics were used to summarize continuous variables as means with standard deviations, while categorical variables were presented as percentages. The study variables were analyzed using binary logistic regression models to assess the associations between illness perception and medication adherence. In the bivariable analysis, variables with p-values less than 0.20 were entered into a multivariable logistic regression model. Associations with a p-value ≤0.05 and an odds ratio with a 95% confidence interval were considered statistically significant.

Results

The study results revealed that medication adherence was 64.4% (95% CI: 60.1, 67.9), while illness perception was 54.7% (95% CI, 41.2, 49.4). There was a significant and strong association between illness perception and medication adherence (p < 0.0001). In the adjusted model, the illness perception components of consequence showed a significant association with medication adherence (AOR = 3.10, 95% CI: 2.11, 4.55). Similarly, personal control (AOR = 1.77, 95% CI: 1.20, 2.61) and emotional representation of diabetes (AOR = 2.26, 95% CI: 1.54, 3.32) were also significantly associated with medication adherence in patients with diabetes.

Conclusion

The findings of this study indicate a positive association between higher illness perception and increased medication adherence and practice. Therefore, when engaging in discussions about diabetic self-management, diabetes educators should employ psychoeducational approaches that take into account the illness perceptions of patients.

Tetrazoles and Related Heterocycles as Promising Synthetic Antidiabetic Agents

Tetrazole heterocycle is a promising scaffold in drug design, and it is incorporated into active pharmaceutical ingredients of medications of various actions: hypotensives, diuretics, antihistamines, antibiotics, analgesics, and others. This heterocyclic system is metabolically stable and easily participates in various intermolecular interactions with different biological targets through hydrogen bonding, conjugation, or van der Waals forces. In the present review, a systematic analysis of the activity of tetrazole derivatives against type 2 diabetes mellitus (T2DM) has been performed. As it was shown, the tetrazolyl moiety is a key fragment of many antidiabetic agents with different activities, including the following: peroxisome proliferator-activated receptors (PPARs) agonists, protein tyrosine phosphatase 1B (PTP1B) inhibitors, aldose reductase (AR) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide 1 (GLP-1) agonists, G protein-coupled receptor (GPCRs) agonists, glycogen phosphorylases (GP) Inhibitors, α-glycosidase (AG) Inhibitors, sodium glucose co-transporter (SGLT) inhibitors, fructose-1,6-bisphosphatase (FBPase) inhibitors, IkB kinase ε (IKKε) and TANK binding kinase 1 (TBK1) inhibitors, and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). In many cases, the tetrazole-containing leader compounds markedly exceed the activity of medications already known and used in T2DM therapy, and some of them are undergoing clinical trials. In addition, tetrazole derivatives are very often used to act on diabetes-related targets or to treat post-diabetic disorders.

The importance of including the C-terminal domain of PTP1B1-400 to identify potential antidiabetic inhibitors

In the present work, we studied the inhibitory and kinetic implications of classical PTP1B inhibitors (chlorogenic acid, ursolic acid, suramin) using three enzyme constructs (hPTP1B_1-285, hPTP1B_1-321, and hPTP1B_1-400). The results indicate that the unstructured region of PTP1B (300-400 amino acids) is very important both to obtain optimal inhibitory results and propose classical inhibition mechanisms (competitive or non-competitive) through kinetic studies. The IC₅₀ calculated for ursolic acid and suramin using hPTP1B_1-400 are around four and three times lower to the short form of the enzyme, the complete form of PTP1B, the one found in the cytosol (in vivo). On the other hand, we highlight the studies of enzymatic kinetics using the hPTP1B_1-400 to know the type of enzymatic inhibition and to be able to direct docking studies, where the unstructured region of the enzyme can be one more option for binding compounds with inhibitory activity.

An alternative route for tricyclic quinazolinone-iminosugars and their glucosidase inhibitory activities

A series of novel tricyclic quinazolinone-iminosugars 5 and their derivatives 7 were obtained from the tosylated sugars by three steps. Firstly, the reaction of the isopropylidene protected sugar tosylate 1 and o-aminobenzylamine 2 generated the precursor tricyclic quinazolin-iminosuar 3, which was then oxidized by KMnO4 to produce the corresponding quinazolinone 4. Finally, removal of the isopropylidene group yielded the target tricyclic quinazolinone iminosugars 5. In addition, quinazolinone-iminosugars 4ac, 4bc and 4cc who contain bromine in the aromatic region underwent Suzuki reaction with phenylboronic acid, followed with the removal of the isopropylidene group to afford the derivatives 7. This strategy will help to construct such fused multicyclic quinazolinone-iminosugars efficiently. Some compounds show certain inhibition against α-glucosidase (saccharomyce cerevisiae).

Research Progress on the Relationship between Vitamins and Diabetes: Systematic Review

Diabetes is a serious chronic metabolic disease that causes complications over time, bringing serious public health challenges that affect different countries across the world. The current clinical drugs for diabetes may lead to adverse effects such as hypoglycemia and liver and abdominal distension and pain, which prompt people to explore new treatments for diabetes without side effects. The research objective of this review article is to systematically review studies on vitamins and diabetes and to explain their possible mechanism of action, as well as to assess the role of vitamins as drugs for the prevention and treatment of diabetes. To achieve our objective, we searched scientific databases in PubMed Central, Medline databases and Web of Science for articles, using "vitamin" and "diabetes" as key words. The results of numerous scientific investigations revealed that vitamin levels were decreased in humans and animals with diabetes, and vitamins show promise for the prevention and/or control of diabetes through anti-inflammation, antioxidation and the regulation of lipid metabolism. However, a few studies showed that vitamins had no positive effect on the development of diabetes. Currently, studies on vitamins in the treatment of diabetes are still very limited, and there are no clinical data to clarify the dose-effect relationship between vitamins and diabetes; therefore, vitamins are not recommended as routine drugs for the treatment of diabetes. However, we still emphasize the great potential of vitamins in the prevention and treatment of diabetes, and higher quality studies are needed in the future to reveal the role of vitamins in the development of diabetes.

Phytochemical Content and Antidiabetic Properties of Most Commonly Used Antidiabetic Medicinal Plants of Kenya

Traditional medicinal plants have been used for decades in folk medicines in the treatment and management of several ailments and diseases including diabetes, pain, ulcers, cancers, and wounds, among others. This study focused on the phytochemical and antidiabetic activity of the commonly used antidiabetic medicinal species in Kenya. Phytochemical profiling of these species revealed flavonoids and terpenoids as the major chemical classes reported which have been linked with strong biological activities against the aforementioned diseases, among others. However, out of the selected twenty-two species, many of the natural product isolation studies have focused on only a few species, as highlighted in the study. All of the examined crude extracts from thirteen antidiabetic species demonstrated strong antidiabetic activities by inhibiting α-glucosidase and α-amylase among other mechanisms, while nine are yet to be evaluated for their antidiabetic activities. Isolated compounds S-Methylcysteine sulfoxide, quercetin, alliuocide G, 2-(3,4-Dihydroxybenzoyl)-2,4,6-trihydroxy-3 (2H)-benzofuranone, Luteolin-7-O-D-glucopyranoside, quercetin, 1,3,11α-Trihydroxy-9-(3,5,7-trihydroxy-4H-1-benzopyran-7-on-2-yl)-5α-(3,4-dihydroxy-phenyl)-5,6,11-hexahydro-5,6,11-trioxanaphthacene-12-one and [1,3,11α-Trihydroxy-9-(3,5,7-trihydroxy-4H-1-benzopyran-7-on-2-yl)-5α-(3,4-dihydroxy-phenyl)-5,6,11-hexahydro-5,6,11-trioxanaphthacene-12-one]-4'-O-D-gluco-pyranoside from Allium cepa have been found to exhibit significant antidiabetic activities. With the huge number of adults living with diabetes in Kenya and the available treatment methods being expensive yet not so effective, this study highlights alternative remedies by documenting the commonly used antidiabetic medicinal plants. Further, the study supports the antidiabetic use of these plants with the existing pharmacological profiles and highlights research study gaps. Therefore, it is urgent to conduct natural products isolation work on the selected antidiabetic species commonly used in Kenya and evaluate their antidiabetic activities, both in vitro and in vivo, to validate their antidiabetic use and come up with new antidiabetic drugs.

Stereoselective Synthesis of Indolyl-C-glycosides Enabled by Sequential Aminopalladation and Heck Glycosylation of 2-Alkynylanilines with Glycals

An efficient and general approach for the synthesis of indolyl-C-glycosides via aminopalladation and subsequent Heck-type glycosylation of easily available 2-alkynylanilines and glycals has been developed. This protocol features excellent stereoselectivity, a broad substrate scope, and mild reaction conditions. In addition, 2,3-pseudoglycals also successfully participated in this cascade reaction, affording C2/C3-branched indolyl glycosides with high regio-/stereoselectivity. The utility of this protocol was also demonstrated by a large-scale reaction and diversified synthetic transformations of the desired products.

Cobalt's Dual Role in Promoting C3-Glycosylation of Indoles: Unraveling Mechanistic Insights

In this study, we present a cobalt-catalyzed C3-glycosylation of indoles using unfunctionalized glycals, yielding 3-indolyl-C-deoxyglycosides. These compounds hold promise as sodium-dependent glucose cotransporter 2 (SGLT2) inhibitors for treating type 2 diabetes. Control experiments unveiled that cobalt assumes a dual role, facilitating catalytic C-glycosylation while unexpectedly driving the anomerization of α-anomers through endocyclic cleavage of the C1-O5 bond, resulting in the formation of β-C-deoxyglycosides. Furthermore, density functional theory (DFT) calculations shed light on the reaction mechanism, emphasizing the significant role of the pyridine group of indole in stabilizing transition states and intermediates.

Anti-Diabetic Activity of Glycyrrhetinic Acid Derivatives FC-114 and FC-122: Scale-Up, In Silico, In Vitro, and In Vivo Studies

Type 2 diabetes (T2D) is one of the most common diseases and the 8th leading cause of death worldwide. Individuals with T2D are at risk for several health complications that reduce their life expectancy and quality of life. Although several drugs for treating T2D are currently available, many of them have reported side effects ranging from mild to severe. In this work, we present the synthesis in a gram-scale as well as the in silico and in vitro activity of two semisynthetic glycyrrhetinic acid (GA) derivatives (namely FC-114 and FC-122) against Protein Tyrosine Phosphatase 1B (PTP1B) and α-glucosidase enzymes. Furthermore, the in vitro cytotoxicity assay on Human Foreskin fibroblast and the in vivo acute oral toxicity was also conducted. The anti-diabetic activity was determined in streptozotocin-induced diabetic rats after oral administration with FC-114 or FC-122. Results showed that both GA derivatives have potent PTP1B inhibitory activity being FC-122, a dual PTP1B/α-glucosidase inhibitor that could increase insulin sensitivity and reduce intestinal glucose absorption. Molecular docking, molecular dynamics, and enzymatic kinetics studies revealed the inhibition mechanism of FC-122 against α-glucosidase. Both GA derivatives were safe and showed better anti-diabetic activity in vivo than the reference drug acarbose. Moreover, FC-114 improves insulin levels while decreasing LDL and total cholesterol levels without decreasing HDL cholesterol.

Antimicrobial, Cytotoxic, and α-Glucosidase Inhibitory Activities of Ethanol Extract and Chemical Constituents Isolated from Homotrigona apicalis Propolis-In Vitro and Molecular Docking Studies

The chemical investigation of Homotrigona apicalis propolis collected in Binh Dinh province, Vietnam, led to the isolation of nine compounds, including four sesquiterpenes: spathulenol (1), 1αH,5βH-aromandendrane-4β,10α-diol (2), 1β,6α-dihydroxy-4(15)-eudesmene (3), and 1βH,5βH-aromandendrane-4α,10β-diol (4); three triterpenes: acetyl oleanolic acid (5), 3α-hydroxytirucalla-8,24-dien-21-oic acid (6), and ursolic acid (7); and two xanthones: cochinchinone A (8) and α-mangostin (9). Sesquiterpens 1-4 and triterpene 6 were isolated for the first time from stingless bee propolis. Plants in the Cratoxylum and Aglaia genus were suggested as resin sources of the propolis sample. In the antibacterial activity evaluation, the EtOH extract only showed moderate activity on S. aureus, while the isolated compounds 7-9 showed good antibacterial activity, with IC50 values of 0.56 to 17.33 µg/mL. The EtOH extract displayed selective cytotoxicity against the A-549 cancer cell line, with IC50 values of 22.82 ± 0.86 µg/mL, and the xanthones 8 and 9 exhibited good activity against the KB, HepG-2, and A-549 cancer cell lines, with IC50 values ranging from 7.55 ± 0.25 µg/mL to 29.27 ± 2.07 µg/mL. The cytotoxic effects of xanthones 8 and 9 were determined by the inhibition of the EGFR and HER2 pathways using a molecular docking study. Compounds 8 and 9 displayed strong binding affinity with EFGR and HER2, with values of -9.3 to -9.9 kcal/mol. Compounds 5, 8, and 9 showed potential α-glucosidase inhibitory activities, which were further confirmed by computational studies. The binding energies of compounds 5, 8, and 9 were lower than that of arcabose.

In-vitro and in-vivo assessment of the anti-diabetic, analgesic, and anti-inflammatory potenstials of metal-based carboxylates derivative

In the current research work, an amide based metal carboxylate chemical ([((5-((5-(2-hydroxyethyl)-4-methylthiazol-3-ium-3-yl)methyl)-2-methylpyrimidin-4-yl)amino)bis((4-((4-methoxy-2-nitrophenyl)amino)-4-oxobutanoyl)oxy)zinc]) was identified as anti-diabetic analgesic and anti-inflammatory. The identified chemical(MT-1) was tested for acute toxicity (the MT-1 was fund safe), antidiabetic analgesic, and anti-inflammatory potentials. The in-vitro study was conducted for antidiabetic enzyme inhibition (α-amylase and α-glucosidase) and the in-vivo studies included analgesic (acetic acid-induced writing and hot plate model) and anti-inflammatory (carrageenan etc induced edema) effects. The tested compound showed 88.63% (IC50 = 3.23 μg/ml) and 89.10%(IC50 = 5.10 μg/ml) againstα-amylase and α-glucosidase respectively. A significant (p < 0.001) analgesic effect was noted by MT-1 in acetic acid-induced animal models with a percent effect of 86.00, 60.,06, and 55.29 at the tested doses of 20, 1,0, and 5 mg/kg respectively. In the case of the hot plate model, the MT-1 showed a significant (p < 0.001) effect with maximum percent prolongation in latency observed after 60 min.08, 22.2,9, and 11.61) against 20, 1,0, and 5 mg/kg. The analgesic effect in the hot plate model was significantly (p < 0.01) reversed by the injection of naloxone (0.125 mg/kg). The paw edema induced by carrageenan, histamine, bradykinin, arachidonic acid, and PGE2 was significantly antagonized with percent attenuation of 34.09, 33.57, 34.60, 34.14, and 48.04 respectively. Furthermore, to predict the interactions between the MT-1 compound and COX-2 molecular docking was carried out and the result was compared with the standard compound. The docking score of MT-1 was predicted as -6.30 while that of Diclofenac was predicted as -6.82. Both compounds made several hydrogen bond interactions with the active site of the COX-2 enzyme. The docking study revealed the potent inhibitory potential of the compound MT-1 against the COX-2 receptor.

Anti-α-Glucosidase, SAR Analysis, and Mechanism Investigation of Indolo[1,2-b]isoquinoline Derivatives

To find potential α-glucosidase inhibitors, indolo[1,2-b]isoquinoline derivatives (1-20) were screened for their α-glucosidase inhibitory effects. All derivatives presented potential α-glucosidase inhibitory effects with IC₅₀ values of 3.44 ± 0.36~41.24 ± 0.26 μM compared to the positive control acarbose (IC₅₀ value: 640.57 ± 5.13 μM). In particular, compound 11 displayed the strongest anti-α-glucosidase activity, being ~186 times stronger than acarbose. Kinetic studies found that compounds 9, 11, 13, 18, and 19 were all reversible mix-type inhibitors. The 3D fluorescence spectra and CD spectra results revealed that the interaction between compounds 9, 11, 13, 18, and 19 and α-glucosidase changed the conformational changes of α-glucosidase. Molecular docking and molecular dynamics simulation results indicated the interaction between compounds and α-glucosidase. In addition, cell cytotoxicity and drug-like properties of compound 11 were also investigated.

Potential Application of Marine Fucosyl-Polysaccharides in Regulating Blood Glucose and Hyperglycemic Complications

Diabetes mellitus (DM) has become the world's third major disease after tumors and cardiovascular disease. With the exploitation of marine biological resources, the efficacy of using polysaccharides isolated from marine organisms in blood glucose regulation has received widespread attention. Some marine polysaccharides can reduce blood glucose by inhibiting digestive enzyme activity, eliminating insulin resistance, and regulating gut microbiota. These polysaccharides are mainly fucose-containing sulphated polysaccharides from algae and sea cucumbers. It follows that the hypoglycemic activity of marine fucosyl-polysaccharides is closely related to their structure, such as their sulfate group, monosaccharide composition, molecular weight and glycosidic bond type. However, the structure of marine fucosyl-polysaccharides and the mechanism of their hypoglycemic activity are not yet clear. Therefore, this review comprehensively covers the effects of marine fucosyl-polysaccharides sources, mechanisms and the structure-activity relationship on hypoglycemic activity. Moreover, the potential regulatory effects of fucosyl-polysaccharides on vascular complications caused by hyperglycemia are also summarized in this review. This review provides rationales for the activity study of marine fucosyl-polysaccharides and new insights into the high-value utilization of marine biological resources.

Dianthrone derivatives from Polygonum multiflorum Thunb: Anti-diabetic activity, structure-activity relationships (SARs), and mode of action

PTP1B plays an important role as a key negative regulator of tyrosine phosphorylation associated with insulin receptor signaling in the therapy for diabetes and obesity. In this study, the anti-diabetic activity of dianthrone derivatives from Polygonum multiflorum Thunb., as well as the structure-activity relationships, mechanism, and molecular docking were explored. Among these analogs, trans-emodin dianthrone (compound 1) enhances insulin sensitivity by upregulating the insulin signaling pathway in HepG2 cells and displays considerable anti-diabetic activity in db/db mice. By using photoaffinity labeling and mass spectrometry-based proteomics, we discovered that trans-emodin dianthrone (compound 1) may bind to PTP1B allosteric pocket at helix α6/α7, which provides fresh insight into the identification of novel anti-diabetic agents.

An Overview of the Potential Medicinal and Pharmaceutical Properties of Ru(II)/(III) Complexes

This review examines the existing knowledge about Ru(II)/(III) ion complexes with a potential application in medicine or pharmacy, which may offer greater potential in cancer chemotherapy than Pt(II) complexes, which are known to cause many side effects. Hence, much attention has been paid to research on cancer cell lines and clinical trials have been undertaken on ruthenium complexes. In addition to their antitumor activity, ruthenium complexes are under evaluation for other diseases, such as type 2 diabetes, Alzheimer's disease and HIV. Attempts are also being made to evaluate ruthenium complexes as potential photosensitizers with polypyridine ligands for use in cancer chemotherapy. The review also briefly examines theoretical approaches to studying the interactions of Ru(II)/Ru(III) complexes with biological receptors, which can facilitate the rational design of ruthenium-based drugs.

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.

Synthesis and Molecular Docking Studies of Alkoxy- and Imidazole-Substituted Xanthones as α-Amylase and α-Glucosidase Inhibitors

Current antidiabetic drugs have severe side effects, which may be minimized by new selective molecules that strongly inhibit α-glucosidase and weakly inhibit α-amylase. We have synthesized novel alkoxy-substituted xanthones and imidazole-substituted xanthones and have evaluated them for their in silico and in vitro α-glucosidase and α-amylase inhibition activity. Compounds 6c, 6e, and 9b promoted higher α-glucosidase inhibition (IC₅₀ = 16.0, 12.8, and 4.0 µM, respectively) and lower α-amylase inhibition (IC₅₀ = 76.7, 68.1, and >200 µM, respectively) compared to acarbose (IC₅₀ = 306.7 µM for α-glucosidase and 20.0 µM for α-amylase). Contrarily, derivatives 10c and 10f showed higher α-amylase inhibition (IC₅₀ = 5.4 and 8.7 µM, respectively) and lower α-glucosidase inhibition (IC₅₀ = 232.7 and 145.2 µM, respectively). According to the structure-activity relationship, attaching 4-bromobutoxy or 4'-chlorophenylacetophenone moieties to the 2-hydroxy group of xanthone provides higher α-glucosidase inhibition and lower α-amylase inhibition. In silico studies suggest that these scaffolds are key in the activity and interaction of xanthone derivatives. Enzymatic kinetics studies showed that 6c, 9b, and 10c are mainly mixed inhibitors on α-glucosidase and α-amylase. In addition, drug prediction and ADMET studies support that compounds 6c, 9b, and 10c are candidates with antidiabetic potential.

Diabetic vascular diseases: molecular mechanisms and therapeutic strategies

Vascular complications of diabetes pose a severe threat to human health. Prevention and treatment protocols based on a single vascular complication are no longer suitable for the long-term management of patients with diabetes. Diabetic panvascular disease (DPD) is a clinical syndrome in which vessels of various sizes, including macrovessels and microvessels in the cardiac, cerebral, renal, ophthalmic, and peripheral systems of patients with diabetes, develop atherosclerosis as a common pathology. Pathological manifestations of DPDs usually manifest macrovascular atherosclerosis, as well as microvascular endothelial function impairment, basement membrane thickening, and microthrombosis. Cardiac, cerebral, and peripheral microangiopathy coexist with microangiopathy, while renal and retinal are predominantly microangiopathic. The following associations exist between DPDs: numerous similar molecular mechanisms, and risk-predictive relationships between diseases. Aggressive glycemic control combined with early comprehensive vascular intervention is the key to prevention and treatment. In addition to the widely recommended metformin, glucagon-like peptide-1 agonist, and sodium-glucose cotransporter-2 inhibitors, for the latest molecular mechanisms, aldose reductase inhibitors, peroxisome proliferator-activated receptor-γ agonizts, glucokinases agonizts, mitochondrial energy modulators, etc. are under active development. DPDs are proposed for patients to obtain more systematic clinical care requires a comprehensive diabetes care center focusing on panvascular diseases. This would leverage the advantages of a cross-disciplinary approach to achieve better integration of the pathogenesis and therapeutic evidence. Such a strategy would confer more clinical benefits to patients and promote the comprehensive development of DPD as a discipline.

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.

Benefits of Whey Proteins on Type 2 Diabetes Mellitus Parameters and Prevention of Cardiovascular Diseases

Type 2 diabetes mellitus (T2DM) is a major cause of morbidity and mortality, and it is a major risk factor for the early onset of cardiovascular diseases (CVDs). More than genetics, food, physical activity, walkability, and air pollution are lifestyle factors, which have the greatest impact on T2DM. Certain diets have been shown to be associated with lower T2DM and cardiovascular risk. Diminishing added sugar and processed fats and increasing antioxidant-rich vegetable and fruit intake has often been highlighted, as in the Mediterranean diet. However, less is known about the interest of proteins in low-fat dairy and whey in particular, which have great potential to improve T2DM and could be used safely as a part of a multi-target strategy. This review discusses all the biochemical and clinical aspects of the benefits of high-quality whey, which is now considered a functional food, for prevention and improvement of T2DM and CVDs by insulin- and non-insulin-dependent mechanisms.

Immobilized enzyme for screening and identification of anti-diabetic components from natural products by ligand fishing

Diabetes is a chronic metabolic disease caused by insufficient insulin secretion and insulin resistance. Natural product is one of the most important resources for anti-diabetic drug. However, due to the extremely complex composition, this research is facing great challenges. After the advent of ligand fishing technology based on enzyme immobilization, the efficiency of screening anti-diabetic components has been greatly improved. In order to provide critical knowledge for future research in this field, the application progress of immobilized enzyme in screening anti-diabetic components from complex natural extracts in recent years was reviewed comprehensively, including novel preparation technologies and strategies of immobilized enzyme and its outstanding application prospect in many aspects. The basic principles and preparation steps of immobilized enzyme were briefly described, including entrapment, physical adsorption, covalent binding, affinity immobilization, multienzyme system and carrier-free immobilization. New formatted immobilized enzymes with different carriers, hollow fibers, magnetic materials, microreactors, metal organic frameworks, etc., were widely used to screen anti-diabetic compositions from various natural products, such as Ginkgo biloba, Morus alba, lotus leaves, Pueraria lobata, Prunella vulgaris, and Magnolia cortex. Furthermore, the challenges and future prospects in this field were put forward in this review.

Formation of nitrogen-containing six-membered heterocycles on steroidal ring system: A review

Steroidal heterocyclic compounds constitute interesting and promising scaffolds for drug discovery as they have displayed diverse chemical reactivity and several types of biological activities. This study is a concise report on the most recent advancements in the chemistry of the steroid skeleton, including reactions at the A, B, and D ring systems. The modern synthetic methods for the steroidal nitrogen-containing six-membered heterocyclic derivatives from 3-keto-, 6-keto-, 17-keto-, and 20-keto-steroids, as well as 2-Aldo-, 4-Aldo-, 6-Aldo-, and 16-Aldo-steroids, are discussed. However, some other methods for the synthesis of steroidal N-containing 6-membered heterocyclic derivatives are also included. These compounds have shown therapeutic potential as cytotoxic agents against various cell lines and have also shown antiproliferative, anti-inflammatory, and antioxidant activities. Therefore, they could be used as prospective candidates for the development of various medications. This paper not only describes synthetic details involved in creating N-containing 6-membered heterocyclic steroid derivatives, but also provides a brief overview of the medicinal applications of these compounds. This information will be highly useful for the medicinal chemists conducting research in this field.

Dual-target affinity analysis and separation of α-amylase and α-glucosidase inhibitors from Morus alba leaves using a magnetic bifunctional immobilized enzyme system

Morus alba leaves are a natural product with great antidiabetic potential. However, the therapeutic efficacy of natural products is usually achieved through the interaction of active compounds with specific targets. Among them, active compounds with multi-target therapeutic functions are more effective than single-target enzymes. In this study, a bienzyme system was constructed by co-immobilizing α-amylase and α-glucosidase onto Fe₃ O₄ for affinity screening of dual-target active components in the complex extract from M. alba leaves. As a result, a potential active compound was selectively screened by ligand fishing, separated by high-speed countercurrent chromatography using a solvent system of ethyl acetate-n-butanol-water (3:2:5, v/v), and identified as rutin. In addition, the result of molecular docking showed that rutin could interact with the active center of α-amylase and α-glucosidase through multiple hydrogen bonds, van der Waals forces, etc. to play an inhibitory role. These results demonstrate the effectiveness of the polydopamine magnetically immobilized bienzyme system for dual-target affinity screening of active substances. This study not only reveals the chemical basis of the antidiabetic activity of M. alba leaves from a dual-target perspective, but also promotes the progress of multitarget affinity screening.

Lead modification via computational studies: Synthesis of pyrazole-containing β-amino carbonyls for the treatment of type 2 diabetes

This article describes studies on the design, synthesis, and biological evaluation of pyrazole-containing β-amino carbonyl compounds (5a-5q) as DPP-4 inhibitors and anti-diabetic agents. In contrast, mannich reactions went smoothly with bismuth nitrate (Bi (NO₃ )₃ ) catalyst in the presence of ethanol and produced pyrazole-containing β-amino carbonyl compounds in good yield. Molecular docking studies of designed derivatives with DPP-4 enzyme (PDB: 2OLE), compounds 5d, 5h, 5j, and 5k showed excellent interaction. 3D QSAR and pharmacophoric model studies were also carried out. ADMET parameters, pharmacokinetic properties, and in vivo toxicity studies further confirmed that all the designed compounds were found to have good bioavailability and were less toxic. Further, these compounds were evaluated as enzyme-based in vitro DPP-4 inhibitory activity, and 5d, 5h, 5i, 5j, and 5k exhibited IC₅₀ toward DPP-4 enzyme of 10.52, 10.41, 5.55, 4.16, and 7.5 nM, respectively. The most potent compound, 5j, was further selected for in vivo anti-diabetic activity using an STZ-induced diabetic mice model, and 5j showed a significant diabetic control effect.

Design, synthesis, and molecular modeling of heterodimer and inhibitors of α-amylase as hypoglycemic agents

A series of rosiglitazone-based heterodimers were designed and synthesized, and their α-amylase and antioxidant activity was evaluated. The binding mode of the compounds at the active site of PPARγ and α-amylase enzyme was explored using MolDock docking method. In molecular docking studies against crystal structure of PPARγ (PDB code: 1FM6), compounds 10 and 13 showed interaction with amino acids Arg379, Asp379, Asn385, Ala387, Glu388, Val389, Glu390, and Lys438. Docking results of α-amylase enzyme (PDB code: 5EOF) with compounds 10 and 13 showed excellent interaction with amino acids Ala169, Lys172, Asp173, Tyr174, Val175, Arg176, and Lys178. Depending on the docking score, the designed compounds were selectively prioritized for synthesis. All synthesized compounds were subjected to in vitro α-amylase activity and antioxidant activity. Compounds 10 and 13 were to possess higher potency than acarbose, and most of the compounds showed antioxidant activity. Additionally, the most active compound 10 was evaluated for in vivo anti-diabetic activity.

Synthesis and Biological Evaluation of Substituted Pyrazole-Fused Oleanolic Acid Derivatives as Novel Selective α-Glucosidase Inhibitors

A series of novel substituted pyrazole-fused oleanolic acid derivative were synthesized and evaluated as selective α-glucosidase inhibitors. Among these analogs, compounds 4a-4f exhibited more potent inhibitory activities compared with their methyl ester derivatives, and standard drugs acarbose and miglitol as well. Besides, all these analogs exhibited good selectivity towards α-glucosidase over α-amylase. Analog 4d showed potent inhibitory activity against α-glucosidase (IC₅₀ =2.64±0.13 μM), and greater selectivity towards α-glucosidase than α-amylase by ∼33-fold. Inhibition kinetics showed that compound 4d was a non-competitive α-glucosidase inhibitor, which was consistent with the result of its simulation molecular docking. Moreover, the in vitro cytotoxicity of compounds 4a-4f towards hepatic LO2 and HepG2 cells was tested.

Synthesis and structure-activity relationship study of aldose reductase inhibiting marine alkaloid lukianol A and its derivatives

Lukianol A (1a) and its six derivatives 1b-1g, in which each hydroxyl groups of 1a was individually modified, were synthesized via the common intermediate 7a, which was obtained by condensation of the styryl carbazate 10 with p-hydroxyphenylpyruvic acid and subsequent [3,3]-sigmatropic rearrangement. The synthesized lukianol derivatives were evaluated for their ability to inhibit human aldose reductase. 4'-O-methyl (1b) and 4'-dehydroxy (1g) derivatives showed the same level of inhibitory activity as 1a (IC50 2.2 µm), indicating that the 4'-OH is irrelevant for the activity. In contrast, methylation of the hydroxyl group at the 4″'-position (1d) resulted in the loss of activity at a concentration of 10 µm, and masking the hydroxyl group at the 4″-position (1e) caused a 9-fold decrease in activity compared with that of 1b, suggesting that the 4″-OH is an essential group, and the 4″'-OH is required for higher activity.

Pyrazole scaffold-based derivatives: A glimpse of α-glucosidase inhibitory activity, SAR, and route of synthesis

The α-glucosidase is a validated target to develop drugs for treating type 2 diabetes mellitus. The existing α-glucosidase inhibitors have certain shortcomings related to side effects and route of synthesis. Accordingly, it is inevitable to develop new chemical templates as α-glucosidase inhibitors. Pyrazole derivatives have a special place in medicinal chemistry because of various biological activities. Recently, pyrazole-based heterocyclic compounds have emerged as a promising scaffold to develop α-glucosidase inhibitors. This study focuses on the recently reported pyrazole-based α-glucosidase inhibitors, including their biological activity (in vivo, in vitro, and in silico), structure-activity relationship, and ways of synthesis. The literature revealed the development of several promising pyrazole-based α-glucosidase inhibitors and new synthetic routes for their preparation. The encouraging α-glucosidase inhibitory results of the pyrazole-based heterocyclic compounds make them an attractive target for further research. The authors also foresee the arrival of the pyrazole-based α-glucosidase inhibitors in clinical practice.

A new series of hydrazones as small-molecule aldose reductase inhibitors

In the search for small-molecule aldose reductase (AR) inhibitors, new tetrazole-hydrazone hybrids (1-15) were designed. An efficient procedure was employed for the synthesis of compounds 1-15. All hydrazones were subjected to an in vitro assay to assess their AR inhibitory profiles. Compounds 1-15 caused AR inhibition with K_i values ranging between 0.177 and 6.322 µM and IC₅₀ values ranging between 0.210 and 0.676 µM. 2-[(1-(4-Hydroxyphenyl)-1H-tetrazol-5-yl)thio]-N'-(4-fluorobenzylidene)acetohydrazide (4) was the most potent inhibitor of AR in this series. Compound 4 markedly inhibited AR (IC₅₀  = 0.297 µM) in a competitive manner (K_i  = 0.177 µM) compared to epalrestat (K_i  = 0.857 µM, IC₅₀  = 0.267 µM). Based on the in vitro data obtained by applying the MTT test, compound 4 showed no cytotoxic activity toward normal (NIH/3T3) cells at the tested concentrations, indicating its safety as an AR inhibitor. Compound 4 exhibited proper interactions with crucial amino acid residues within the active site of AR. In silico QikProp data of all hydrazones (1-15) were also determined to assess their pharmacokinetic profiles. Taken together, compound 4 stands out as a promising inhibitor of AR for further in vivo studies.

Therapeutic role of kaempferol and myricetin in streptozotocin-induced diabetes synergistically via modulation in pancreatic amylase, glycogen storage and insulin secretion

Kaempferol and Myricetin alone have promising benefits on diabetes and related complications, yet the effectiveness of cotreating the two compounds on diabetes have not been studied. The existing investigation was to study the combined anti-diabetic effect of kaempferol and myricetin in Streptozotocin (STZ)-activated diabetes in rats. To evaluate the anti-diabetic activity, 36 Wistar rats were segregated into six groups; Normal, 50 mg/kg STZ-induced diabetes, and four (50 mg/kg kaempferol, 50 mg/kg myricetin, 25 mg/kg kaempferol + myricetin, and 5 mg/kg glibenclamide) compound-treated diabetic groups. The effects of co-treatment on parameters, glucose, insulin, lipid profile, liver enzymes, antioxidant biomarkers, and inflammatory cytokines were measured. The study revealed that combined treatment restored the assessed parameters including glucose levels, inflammatory cytokines, oxidative markers, and lipid and liver enzymes in diabetic rats. The results indicate that cotreatment of kaempferol and myricetin has a beneficial role against diabetes suggesting that cotreatment of these compounds can be used therapeutically in treating diabetes.

Antidiabetic Potential of Novel 1,3,5-Trisubstituted-2-Thioxoimidazloidin-4-One Analogues: Insights into α-Glucosidase, α-Amylase, and Antioxidant Activities

As the ninth leading cause of death globally, diabetes mellitus (DM) is considered to be the worst chronic metabolic disease requiring an enormous need for healthcare with over 578 million expected cases by 2023. Several recent findings have demonstrated that mediating the activity of carbohydrate-hydrolyzing enzymes, including α-amylase and α-glucosidase, could be a potential strategy for managing the development of DM. In the presented study, a novel set of 1,3,5-trisubstituted-2-thioxoimidazolidin-4-ones was designed, synthesized, and characterized. The antidiabetic activity of the synthesized compounds was explored by assessing their inhibitory activity toward α-amylase and α-glucosidase enzymes. The results demonstrated that this class of compounds exhibits considerable inhibitory activity toward both α-amylase and α-glucosidase enzymes. Among the synthesized compounds, compound 5a demonstrated the most inhibitory activity with IC₅₀ of 5.08 and µg/mL and 0.21 µg/mL toward α-glucosidase and α-amylase activities, respectively, as compared to the drug Acarbose (IC₅₀ = 5.76 µg/mL and 0.39 µg/mL, respectively). To gain insights into the antidiabetic potential of compound 5a, we assessed the cytotoxic and antioxidant activities. Our findings indicated that compound 5a displays considerable cytotoxicity toward WI-38 cells with an IC₅₀ of 88.54 µg/mL, as compared to the drug Celecoxib (IC₅₀ = 93.05 µg/mL). Further, compound 5a exhibited a high scavenging activity toward 2,2-Diphenyl1-picrylhydrazyl (DPPH) free radicals (IC₅₀ = 51.75 µg/mL) and showed a low potential to produce ROS as indicated by the monitoring of the generated H₂O₂ (132.4 pg/mL), as compared to Trolox (IC₅₀ = 58.09 µg/mL) and Celecoxib (171.6 pg/mL). Finally, we performed extensive molecular modeling studies to affirm the binding affinity of this class of compounds to the binding pocket of α-amylase and α-glucosidase enzymes. Collectively, our findings indicate that this class of compounds, particularly compound 5a, could be utilized as a lead structure for the development of novel compounds with potential antidiabetic and antioxidant activities.

Moderate Hyperglycemia-Preventive Effect and Mechanism of Action of Periplaneta americana Oligosaccharides in Streptozotocin-Induced Diabetic Mice

Periplaneta americana is a kind of medicinal and edible insect, and its oligosaccharides (PAOS) have been reported to exert anti-inflammatory effects by regulating immunity, reducing oxidative stress, and meliorating gut microbiota. We hypothesized PAOS might benefit experimental diabetes mellitus (DM), an inflammatory disease coordinated by both innate and adaptive immunity. This study aimed to evaluate the effect of PAOS on glycemia and its potential mechanisms. Mice model of diabetes was established, and then the potential effects of PAOS was tested in vivo. Here, we found that PAOS triggered a moderate hyperglycemia-preventive effect on DM mice, showing markedly alleviated symptoms of DM, reduced blood glucose, and meliorated functions of liver and pancreas β cell. Deciphering the underlying mechanism of PAOS-improving diabetes, the results revealed that PAOS downregulated the blood glucose level by activating PI3K/AKT/mTOR and Keap/Nrf2/HO-1 pathways, meanwhile inhibiting TLR4/MAPK/NF-κB, Beclin1/LC3, and NLRP3/caspase1 pathways in vivo. Furthermore, analyses of the microbial community intriguingly exhibited that PAOS promoted the communities of bacteria producing short-chain fatty acids (SCFAs), whereas attenuating lipopolysaccharides (LPS)-producing ones that favored inflammatory tolerance. Collectively, balancing the intestinal bacterial communities by PAOS, which favored anabolism but suppressed inflammatory responses, contributed substantially to the glycemia improvement of PAOS in DM mice. Accordingly, PAOS might function as complementary and alternative medicine for DM.

Serrulatane diterpenoids with unusual side chain modifications from root bark of Eremophila longifolia

The plant genus Eremophila is endemic to Australia and widespread in arid regions. Root bark extract of Eremophila longifolia (R.Br.) F.Muell. (Scrophulariaceae) was investigated by LC-PDA-HRMS, and dereplication suggested the presence of a series of diterpenoids. Using a combination of preparative- and analytical-scale HPLC separation as well as extensive 1D and 2D NMR analysis, the structures of 12 hitherto unreported serrulatane diterpenoids, eremolongine A-L, were established. These structures included serrulatanes with unusual side chain modifications to form hitherto unseen skeletons with, e.g., cyclopentane, oxepane, and bicyclic hexahydro-1H-cyclopenta[c]furan moieties. Serrulatane diterpenoids in Eremophila have recently been shown to originate from a common biosynthetic precursor with conserved stereochemical configuration, and this was used for tentative assignment of the relative and absolute configuration of the isolated compounds. Triple high-resolution α-glucosidase/α-amylase/PTP1B inhibition profiling demonstrated that several of the eremolongines had weak inhibitory activity towards targets important for management of type 2 diabetes.

Identification of a novel PPARγ modulator with good anti-diabetic therapeutic index via structure-based screening, optimization and biological validation

PPARγ is well-known as the target receptor of TZD anti-diabetic drugs. However, recently the therapeutic benefits of these TZD drugs have been compromised by many severe side effects because of their full PPARγ agonistic action to lock the AF-2 helix. Herein, we conducted a virtual screening in the combination with structure-based design, synthesis and biological evaluation both in vitro and in vivo, leading to the identification of a potent candidate YG-C-20 as the SPPARγM with improved and safer anti-diabetic therapeutics. Mechanistically, this compound presented such desired pharmacological profiles (e.g., preferable anti-diabetic efficiencies and minimized side effects) mainly via selectively inhibiting the CDK5-mediated phosphorylation of PPARγ-Ser273 and up-regulating the expression of insulin-sensitive genes Adiponectin and Glut4, yet lacking the classical full agonism to induce the adipogenesis and the expression of key adipogenic genes including PPARγ, aP2, CD36, LPL, C/EBPα and FASN. Further validation led to the final recognition of its (R)-configured isomer as the potential conformational form. Subsequent molecular docking studies revealed a unique hydrogen-bonding network of (R)-YG-C-20 with three full PPARγ agonism-unrelated residues, especially with PPARγ-Ser273 phosphorylation-associated site Ser342, which not only gives a clear verification for our structure-based design but also provides a proof of concept for the abovementioned molecular mechanism.

Palladium-Catalyzed Direct C-H Glycosylation of Free (N-H) Indole and Tryptophan by Norbornene-Mediated Regioselective C-H Activation

We describe the palladium-catalyzed direct C-H glycosylation of free N-H indole or tryptophan for the stereoselective synthesis of 2-glycosylindoles and tryptophan-C-glycosides. This reaction relies on the ortho-directing transient mediator norbornene, which underwent regioselective C-H functionalization at the indole or tryptophan ring, providing high chemoselectivity. This method offers a more straightforward, step-economical, and cost-effective route to construct C-glycosides. The gram-scale amenable building blocks can be further functionalized at C3 and N-H, displaying the robustness of present method.