Kaempferol promotes wound-healing in diabetic rats through antibacterial and antioxidant effects, devoid of proliferative action

The investigation of novel phytochemicals for the prevention and treatment of infections caused by multidrug-resistant pathogens is gaining attention. The current study evaluated the in-vitro antimicrobial activity of kaempferol against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Its in-vivo efficacy in inhibiting these pathogens was determined using an excision wound model in nicotinamide-streptozocin- -induced diabetic rats. Kaempferol displayed an inhibitory effect against the tested bacteria both in vitro and in vivo. It also healed excision wounds at a 1% (w/w) concentration. An increase in antioxidant enzymes in wounded tissue was observed on kaempferol treatment. A reduction in the MRSA and P. aeruginosa counts in wounded tissue together with a reduced epithelization period was observed when compared to the infected control. A thicker epithelium, new capillaries, and a decrease in inflammatory cells were detected by hematoxylin and eosin staining. Furthermore, an increase in collagen fibers and their deposition was observed by Masson's trichrome staining. Kaempferol at 40 mu M did not display any toxicity for human keratinocytes grown in media containing high glucose and it did not affect the expression of the pro-healing cytokines genes vascular endothelial growth factor (VEGF) and transforming growth factor-beta-1 (TGF beta 1). Kaempferol displayed antibacterial and antioxidant actions but did not increase the expression of proliferative genes.