Green Tea Polyphenols in Wound Healing: Therapeutic Mechanisms, Potential Applications and Challenges in Commercial Use for Diabetic Wound Healing

Wound healing remains a critical challenge in healthcare, especially with the increasing prevalence of diabetes and its associated complications, such as diabetic foot ulcers (DFUs). Delayed wound healing in diabetic patients is attributed to several factors, with a pathophysiology that is diverse and multifaceted, including decreased immune responses, microvascular dysfunction, oxidative stress and impaired collagen synthesis. Additionally, the development of an infection at the wound site further complicates and hinders the healing process, especially in DFUs. Epigallocatechin gallate (EGCG), a potent bioactive compound found in green tea, has shown promising effects in modulating various stages of wound healing by its antioxidant, anti-inflammatory and anti-bacterial properties in vitro and in vivo. This review discusses delayed wound healing in diabetic wounds, while highlighting the therapeutic potential of GT/EGCG in different stages of wound healing, including in diabetic wounds both in vitro and in vivo. Novel applications such as GT-/EGCG-loaded wound dressings have demonstrated significant positive impacts on wound healings, including in diabetic wounds, both in in vitro and in vivo studies. Despite its therapeutic potential, the commercial application of green tea in wound care faces significant challenges, including issues of bioavailability, stability, cytotoxicity, production costs, the lack of in-depth and complete in vivo studies and, most importantly, the lack of clinical trials. By consolidating current knowledge and identifying gaps, this review aims to inspire future research and innovations in using green tea for effective wound management and potential use in diabetic patients and DFUs, if the positive results from animal in vivo studies are equally effective in human clinical studies.