Dual-Target Compounds against Type 2 Diabetes Mellitus: Proof of Concept for Sodium Dependent Glucose Transporter (SGLT) and Glycogen Phosphorylase (GP) Inhibitors

Synthesis, In Silico and Kinetics Evaluation of N-(β-d-glucopyranosyl)-2-arylimidazole-4(5)-carboxamides and N-(β-d-glucopyranosyl)-4(5)-arylimidazole-2-carboxamides as Glycogen Phosphorylase Inhibitors

Recently studied N-(β-d-glucopyranosyl)-3-aryl-1,2,4-triazole-5-carboxamides have proven to be low micromolar inhibitors of glycogen phosphorylase (GP), a validated target for the treatment of type 2 diabetes mellitus. Since in other settings, the bioisosteric replacement of the 1,2,4-triazole moiety with imidazole resulted in significantly more efficient GP inhibitors, in silico calculations using Glide molecular docking along with unbound state DFT calculations were performed on N-(β-d-glucopyranosyl)-arylimidazole-carboxamides, revealing their potential for strong GP inhibition. The syntheses of the target compounds involved the formation of an amide bond between per-O-acetylated β-d-glucopyranosylamine and the corresponding arylimidazole-carboxylic acids. Kinetics experiments on rabbit muscle GPb revealed low micromolar inhibitors, with the best inhibition constants (Kis) of ~3-4 µM obtained for 1- and 2-naphthyl-substituted N-(β-d-glucopyranosyl)-imidazolecarboxamides, 2b-c. The predicted protein-ligand interactions responsible for the observed potencies are discussed and will facilitate the structure-based design of other inhibitors targeting this important therapeutic target. Meanwhile, the importance of the careful consideration of ligand tautomeric states in binding calculations is highlighted, with the usefulness of DFT calculations in this regard proposed.

Structurally Diverse Triterpene-26-oic Acids as Potential Dual ACL and ACC1 Inhibitors from the Vulnerable Conifer Keteleeria fortunei

A preliminary phytochemical investigation on the 90% MeOH extract from the twigs and needles of the vulnerable conifer Keteleeria fortunei led to the isolation and characterization of 17 structurally diverse triterpen-26-oic acids, including nine previously undescribed ones (fortunefuroic acids A-I, 1-9) featuring a rare furoic acid moiety in the lateral chain. Among them, 1-5 are uncommon 9βH-lanostane-type triterpenoic acids. Friedo-rearranged triterpenoids 6 and 7 feature a unique 17,14-friedo-lanostane skeleton, whereas 9 possesses a rare 17,13-friedo-cycloartane-type framework. Their structures and absolute configurations were elucidated by extensive spectroscopic (e.g., detailed 2D NMR) and computational (NMR/ECD) calculations and the modified Mosher's method. In addition, the absolute structure of compound 1 was ascertained by single-crystal X-ray diffraction analyses. Fortunefuroic acids B (2), G (7), and I (9), along with isomangiferolic acid (12) and 3α,27-dihydroxycycloart-24E-en-26-oic acid (14), exhibited dual inhibitory effects against the adenosine triphosphate (ATP)-citrate lyase (ACL, IC50s: 5.7-11.4 μM) and acetyl-CoA carboxylase 1 (ACC1, IC50s: 7.5-10.5 μM), both of which are key enzymes for glycolipid metabolism. The interactions of the bioactive triterpenoids with both enzymes were examined by molecular docking studies. The above findings reveal the important role of protecting plant species diversity in support of chemical diversity and potential sources of new therapeutics for ACL-/ACC1-associated diseases.

Design and Synthesis of 3-(β-d-Glucopyranosyl)-4-amino/4-guanidino Pyrazole Derivatives and Analysis of Their Glycogen Phosphorylase Inhibitory Potential

Glycogen phosphorylase (GP) is a key regulator of glucose levels and, with that, an important target for the discovery of novel treatments against type 2 diabetes. β-d-Glucopyranosyl derivatives have provided some of the most potent GP inhibitors discovered to date. In this regard, C-β-d-glucopyranosyl azole type inhibitors proved to be particularly effective, with 2- and 4-β-d-glucopyranosyl imidazoles among the most potent designed to date. His377 backbone C=O hydrogen bonding and ion-ion interactions of the protonated imidazole with Asp283 from the 280s loop, stabilizing the inactive state, were proposed as crucial to the observed potencies. Towards further exploring these features, 4-amino-3-(β-d-glucopyranosyl)-5-phenyl-1H-pyrazole (3) and 3-(β-d-glucopyranosyl)-4-guanidino-5-phenyl-1H-pyrazole (4) were designed and synthesized with the potential to exploit similar interactions. Binding assay experiments against rabbit muscle GPb revealed 3 as a moderate inhibitor (IC50 = 565 µM), but 4 displayed no inhibition at 625 µM concentration. Towards understanding the observed inhibitions, docking and post-docking molecular mechanics-generalized Born surface area (MM-GBSA) binding free energy calculations were performed, together with Monte Carlo and density functional theory (DFT) calculations on the free unbound ligands. The computations revealed that while 3 was predicted to hydrogen bond with His377 C=O in its favoured tautomeric state, the interactions with Asp283 were not direct and there were no ion-ion interactions; for 4, the most stable tautomer did not have the His377 backbone C=O interaction and while ion-ion interactions and direct hydrogen bonding with Asp283 were predicted, the conformational strain and entropy loss of the ligand in the bound state was significant. The importance of consideration of tautomeric states and ligand strain for glucose analogues in the confined space of the catalytic site with the 280s loop in the closed position was highlighted.

Synthesis, X-ray diffraction analysis, quantum chemical studies and α-amylase inhibition of probenecid derived S-alkylphthalimide-oxadiazole-benzenesulfonamide hybrids

Sulphonamide and 1,3,4-oxadiazole moieties are present as integral structural parts of many drugs and pharmaceuticals. Taking into account the significance of these moieties, we herein present the synthesis, single-crystal X-ray analysis, DFT studies, and α-amylase inhibition of probenecid derived two S-alkylphthalimide-oxadiazole-benzenesulfonamide hybrids. The synthesis has been accomplished in high yields. The final structures of both hybrids have been established completely with the help of different spectro-analytical techniques, including NMR, FTIR, HR-MS, and single-crystal X-ray diffraction analyses. In an effort to confirm the experimental findings, versatile quantum mechanical calculations and Hirshfeld Surface analysis have been performed. α-Amylase inhibition assay has been executed to investigate the enzyme inhibitory potential of both hybrids. The low IC50 value (76.92 ± 0.19 μg/mL) of hybrid 2 shows the good α-amylase inhibition potential of the respective compound. Ultimately, the binding affinities and features of the two hybrids are elucidated utilising a molecular docking technique against the α-amylase enzyme.

First Synthesis of 3-Glycopyranosyl-1,2,4-Triazines and Some Cycloadditions Thereof

C-glycopyranosyl derivatives of six-membered heterocycles are scarcely represented in the chemical literature and the title 3-glycopyranosyl-1,2,4-triazines are completely unknown. In this paper, the first synthesis of this compound class is accomplished by the cyclocondensation of C-glycosyl formamidrazones and 1,2-dicarbonyl derivatives. In addition, the synthesis of C-glycopyranosyl 1,2,4-triazin-5(4H)-ones was also carried out by the transformation of the above formamidrazones with α-keto-carboxylic esters. Inverse electron demand Diels-Alder reactions of 3-glycopyranosyl-1,2,4-triazines with a bicyclononyne derivative yielded the corresponding annulated 2-glycopyranosyl pyridines.

Knowledge and practice of community pharmacists towards SGLT2 inhibitors

Background: Sodium/glucose cotransporter 2 (SGLT2) inhibitors are a new class of oral anti-diabetic drugs which improve glycaemic control in type 2 diabetes mellitus (T2DM) by preventing the kidney from reabsorbing glucose back to blood. Community pharmacists have long-term relationships with most of their chronic patients, so they play a key role in care for people with diabetes. Therefore, the objective of this study was to assess pharmacists’ knowledge and practice towards SGLT2 inhibitors. Thus, improving pharmacists’ knowledge about this group of medications could improve the treatment outcome of people with diabetes. Methods: A cross-sectional study was conducted to meet the study objectives. A convenience sample of 348 community pharmacists in Jordan was recruited. knowledge and practice were assessed using a self-administered questionnaire created for the purpose of this study. Results: A total of 400 community pharmacists were reached, of whom 348 answered the survey (response rate 87%). The results indicated that SGLT2 inhibitors knowledge score among community pharmacists in Jordan was 6.61 (out of 12). Factors like age, gender, location of the pharmacy, years of pharmacists’ experience had no effect on knowledge score; however, pharmacists who attended training courses on diabetes had higher knowledge scores. Additionally, pharmacists’ dispensing practice toward SGLT2 inhibitors had insufficient knowledge, such as lack of knowledge about the superiority of SGLT2 inhibitors over other anti-diabetics and inability to give the best advice to patients. Conclusions: Our findings reflect a moderate knowledge among community pharmacists about SGLT2 inhibitors which may negatively affect the patients’ outcome; thus, continuous education for the pharmacists is essential.