Nano-Engineered Epigallocatechin Gallate (EGCG) Delivery Systems: Overcoming Bioavailability Barriers to Unlock Clinical Potential in Cancer Therapy.

Epigallocatechin gallate (EGCG), a bioactive polyphenol derived from Camellia sinensis, exhibits multimodal anticancer activity through mechanisms such as apoptosis induction, metastasis suppression, and chemoresistance reversal. Despite its therapeutic promise, clinical application is constrained by rapid metabolism, poor bioavailability, and inconsistent biodistribution. Recent advances in nanotechnology have enabled the development of innovative delivery systems including pH-responsive nanoparticles, lipid-polymer hybrids, and ligand-functionalized carriers that enhance EGCG stability, tumor targeting, and bioavailability by 3- to fivefold in preclinical models. These platforms also facilitate synergistic co-delivery with chemotherapeutics like doxorubicin, amplifying cytotoxicity and overcoming multidrug resistance. Mechanistically, EGCG modulates oncogenic pathways via NF-κB suppression, caspase activation, and MMP-9 downregulation, demonstrating efficacy across diverse cancer types. However, translational challenges persist, such as nanoparticle toxicity, variable tumor accumulation, and insufficient penetration in hypoxic microenvironments. Regulatory hurdles, including the lack of harmonized global standards for herbal medicinal products, further complicate clinical adoption. To bridge these gaps, future research must prioritize scalable cGMP-compliant manufacturing, rigorous preclinical toxicity profiling, and robust clinical trials to validate safety and efficacy. Addressing these issues could position nanoengineered EGCG as a paradigm-shifting therapy in precision oncology, aligning with ESCOP's mission to integrate evidence-based phytomedicines into conventional cancer care. This review underscores the necessity of interdisciplinary collaboration to standardize phytopreparations, refine regulatory frameworks, and advance biomarker-driven clinical validation, ultimately unlocking the full potential of EGCG in modern therapeutics.