Novel indolyl linked para-substituted benzylidene-based phenyl containing thiazolidienediones and their analogs as α-glucosidase inhibitors: synthesis, in vitro, and molecular docking studies

Thiazolidine-2,4-dione hybrids as dual alpha-amylase and alpha-glucosidase inhibitors: design, synthesis, in vitro and in vivo anti-diabetic evaluation

Twelve 3,5-disubstituted-thiazolidine-2,4-dione (TZD) hybrids were synthesized using solution phase chemistry. Continuing our previous work, nine O-modified ethyl vanillin (8a-i) derivatives were synthesized and reacted with the TZD core via Knoevenagel condensation under primary reaction conditions to obtain final derivatives 9a-i. Additionally, three isatin-TZD hybrids (11a-c) were synthesized. The intermediates and final derivatives were characterized using 1H and 13C NMR spectroscopy, and the observed chemical shifts agreed with the proposed structures. The in vitro alpha-amylase and alpha-glucosidase inhibitory evaluation of newly synthesized derivatives revealed compounds 9F and 9G as the best dual inhibitors, with IC50 values of 9.8 ± 0.047 μM for alpha-glucosidase (9F) and 5.15 ± 0.0017 μM for alpha-glucosidase (9G), 17.10 ± 0.015 μM for alpha-amylase (9F), and 9.2 ± 0.092 μM for alpha-amylase (9G). The docking analysis of synthesized compounds indicated that compounds have a higher binding affinity for alpha-glucosidase as compared to alpha-amylase, as seen from docking scores ranging from -1.202 to -5.467 (for alpha-amylase) and -4.373 to -7.300 (for alpha-glucosidase). Further, the molecules possess a high LD50 value, typically ranging from 1000 to 1600 mg kg-1 of body weight, and exhibit non-toxic properties. The in vitro cytotoxicity assay results on PANC-1 and INS-1 cells demonstrated that the compounds were devoid of significant toxicity against the tested cells. Compounds 9F and 9G showed high oral absorption, i.e., oral absorption >96%, and their molecular dynamics simulation yielded results closely aligned with the observed docking outcomes. Finally, compounds 9F and 9G were evaluated for in vivo antidiabetic assessment by the induction of diabetes in Wistar rats using streptozotocin. Molecule 9G has been identified as the most effective anti-diabetic molecule due to its ability to modulate several biochemical markers in blood plasma and tissue homogenates. The results were further confirmed by histology investigations conducted on isolated pancreas, liver, and kidney.

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 and studies of thiazolidinedione-isatin hybrids as α-glucosidase inhibitors for management of diabetes

Aim: Keeping in view the side effects associated with clinically used α-glucosidase inhibitors, novel thiazolidinedione-isatin hybrids were synthesized and evaluated by in vitro, in vivo and in silico procedures. Materials & methods: Biological evaluation, cytotoxicity assessment, molecular docking, binding free energy calculations and molecular dynamics studies were performed for hybrids. Results: The most potent inhibitor A-10 (IC₅₀ = 24.73 ± 0.93 μM) was competitive in manner and observed as non-cytotoxic. A-10 possessed higher efficacy than the standard drug (acarbose) during in vivo biological testing. Conclusion: The enzyme inhibitory potential and safety profile of synthetic molecules was recognized after in vitro, in vivo, in silico and cytotoxicity studies. Further structural optimization of A-10 can offer potential hit molecules suitable for future investigations.