Enhanced wound healing by an epigallocatechin gallate‐incorporated collagen sponge in diabetic mice

Abstract

Epigallocatechin-3-O-gallate (EGCG), the major polyphenolic compound present in green tea, has potent anti-oxidant and free radical-scavenging activities. In this study, various concentrations (10, 100, and 1,000 ppm) of EGCG were incorporated into a collagen sponge (CS) in order to investigate its healing effects on full-thickness wounds created in type 2 diabetic mice. After 14 days, the residual wound size of the mice treated with 10 ppm EGCG-incorporated collagen sponge (E-CS) decreased significantly faster than that of the other mice. Moreover, significant increases in the degree of reepithelialization, the thickness of the granulation tissue, and the density of the capillaries were also histologically observed in the wound sites exposed to 10 ppm E-CS in comparison with the others. Furthermore, 10 ppm E-CS resulted in significant increases in the immunoreactivity of Ki-67 (reepithelialization at the wound site), CD31 (formation of blood vessels), and alpha-smooth muscle actin (the induction of myofibroblasts across the dermis). These results suggest that a CS incorporated with EGCG at low concentrations can enhance wound healing in diabetic mice by accelerating reepithelialization and angiogenesis as well as improving the cellular reorganization of granulation tissue by triggering the activity of myofibroblasts.

Antimicrobial activity of the green tea polyphenol (−)-epigallocatechin-3-gallate (EGCG) against clinical isolates of Stenotrophomonas maltophilia

“…However, further data are required regarding its effect at a higher concentration. EGCG may also help to accelerate wound healing owing to antioxidant and free-radical scavenging properties [21], making it an ideal candidate for topical application to infected wounds and burns. Alternatively, there may be potential for development as a surface disinfectant or antibacterial hand rub.…”

Polymers in Wound Repair

“…Plant polyphenolic extracts of varying structures from simple molecules to highly polymerised compounds are well-known for their antioxidant capacity and scavenging activity over free radical and non-radical reactive species [72], metalchelating capability [73] and inhibitory activity over radical-generating enzymes [74]. Plant polyphenols also possess anti-inflammatory [75], antimicrobial [76] and wound healing promoting properties [77]. Some polyphenolic extracts are widely used in the therapy of skin conditions, skin damages such as burns, and as protective component in cosmetic formulations [78,79].…”

Recent developments in novel drug delivery systems for wound healing

“…EGF and vitamin C derivative releasing wound dressing spongy sheet made from hyaluronic acid and collagen was also successfully developed [84] whereas chitosan-hyaluronic acid/VEGF-loaded fibrin nanoparticles composite sponges were also shown to enhance angiogenesis in wounds which is indicated for rapid healing [85]. Collagen sponge were also shown to effectively deliver herbal drugs such as Macrotyloma uniflorum extracts [86] and epigallocatechin-3-O-gallate, the major polyphenolic compound present in green tea [87] to wounds (Figures 4 and 5). …”

“…Up to 72 h drug release (streptomycin and diclofenac) was also obtained with composite films prepared and from a blend of synthetic polymer (Polyox Ò ) with hydrophilic natural polymers (HPMC, carrageenan, sodium alginate and chitosan) plasticized with 25% glycerin [95]. Other polymers forming films such as collagen and silk fibroin were also developed to deliver a wide range of Reproduced from [87] with permission of John Wiley and Sons. EGCG: Epigallocatechin gallate.…”