Molecular strategies for heterocyclic frameworks in antidiabetic drug discovery: a vision from 2020-2024

Diabetes mellitus represents a global health crisis requiring innovative therapeutic strategies beyond traditional treatments. This comprehensive review analyzes heterocyclic frameworks developed between 2020-2024 for antidiabetic drug discovery, highlighting structure-activity relationships (SAR), molecular docking insights, and therapeutic mechanisms. Key scaffold classes emerged as potent antidiabetic agents, with benzimidazoles and triazoles demonstrating dual α-amylase/α-glucosidase inhibition (IC₅₀ values 1.20-22.46 µg/mL), thiazolidinediones and quinazolines showing PPAR-γ agonism with improved insulin sensitivity and reduced cardiovascular risks, DPP-4 inhibitory scaffolds (pyrrolidines, pyrimidines) achieving IC₅₀ values as low as 0.021 µM, and SGLT2-targeting heterocycles exhibiting glucose-lowering effects with cardio-renal protection. Major findings revealed that electron-donating groups (methoxy, hydroxyl) consistently enhanced binding affinity across multiple targets, halogen substitutions (fluoro, chloro, bromo) improved metabolic stability and selectivity, hybrid molecules combining multiple pharmacophores achieved superior multi-target effects, and natural product-derived heterocycles (flavonoids, coumarins, alkaloids) showed IC₅₀values 10-100× better than acarbose. Emerging frontiers include multi-agonist therapies (GLP-1/GIP, dual SGLT1/SGLT2 inhibitors), glucokinase activators for insulin-independent glucose control, microbiome-targeting agents, and AI-driven rational drug design integrating SAR, docking, and ADMET prediction. This review provides a strategic framework for developing safer, more selective antidiabetic agents through systematic exploitation of heterocyclic chemistry, advancing toward personalized diabetes management.