Harnessing Medicinal Plants Through Advanced Drug Delivery: A New Era in Type 2 Diabetes Management

Type 2 diabetes mellitus (T2DM) remains a global health crisis, with nearly 589 million adults currently affected and projections pointing toward 853 million by 2050. Despite an expanding pharmacological armamentarium, a significant proportion of patients fail to achieve adequate glycaemic control, and the limitations of existing therapies, including adverse effects, cost, and limited accessibility, underscore the compelling need for novel therapeutic approaches. Phytochemicals such as curcumin, berberine, quercetin, resveratrol, and epigallocatechin gallate possess well-documented antidiabetic activity, operating through the PI3K/Akt, AMPK (activated protein kinase), NF-κB/JNK (nuclear factor kappa-B), and GLP-1R (glucagon-like peptide-1) signalling axes to improve insulin sensitivity, suppress gluconeogenesis, protect pancreatic beta-cells, and attenuate chronic metabolic inflammation. However, their clinical utility has been fundamentally constrained by poor oral bioavailability arising from low aqueous solubility, gastrointestinal instability, extensive first-pass metabolism, and P-glycoprotein-mediated efflux. Advanced drug delivery systems, including liposomes, solid lipid nanoparticles (SLN), nanostructured lipid carriers, PLGA (Poly (lactic-co-glycolic acid)) and chitosan nanoparticles, nanoemulsions, self-nanoemulsifying drug delivery systems, and phytosomes have demonstrated the capacity to overcome these barriers, achieving five- to ten-fold improvements in systemic bioavailability and substantially enhanced antidiabetic efficacy in preclinical models. Emerging mechanistic evidence further positions gut microbiota modulation and epigenetic reprogramming as additional therapeutic axes through which nano-encapsulated phytochemicals may exert durable metabolic benefits. Nonetheless, critical translational challenges persist, encompassing nanotoxicological risks, herb–drug interactions, the absence of harmonised regulatory frameworks for nano-phytomedicine products, phytochemical raw material variability, and formidable technical and economic barriers to scalable nanoparticle manufacturing. This review synthesises the current mechanistic, formulation, and clinical evidence within a unified analytical framework and identifies the strategic priorities of rigorous clinical development, regulatory clarity, and manufacturing standardisation required to translate nano-phytomedicine science into evidence-based T2DM therapeutics.