Topical pyroligneous extract hydrogel may improve wound shrinkage in diabetic foot ulcers

Pyroligneous extract, a refined wood vinegar from palm kernel shell biomass pyrolysis, could promote wound healing. The aim of the study was to assess the effect of a topical hydrogel containing this extract on diabetic foot ulcer. A double blind, randomised, placebo-controlled study was done. Sixteen volunteers with DFU were equally randomly assigned to either the treatment group receiving 150 μg/g extract in hydrogel or the control one receiving placebo. Hydrogels were applied to individual wounds once every other day for 13 weeks. Wound assessment and swab culture were done on weeks 1, 3, 5, 7, 9, 11 and 13. Tissues exfoliated during wound dressing were collected at baseline and completion for biomarkers detection. During the trial, three participants dropped out. No skin irritation was found in all participants. Mean wound shrinkage in the treatment group was significantly higher than that of the control from Week 7 onwards. The estimated half-lives presented as a 95% confidence limit of wound healing in the treatment and control groups were 4-7 days and 5-15 days, respectively. The extract may reduce the risk of infection as swab culture showed the decreased number of species of on-wounded site pathogens after treatment and so did the number of wounds with positive culture. mRNA expression of transdermal growth factor-β 1 in the treatment group significantly increased whereas tumour necrosis factor-α decreased compared with the placebo one. With clinical outcome, its TGF-βI up-regulating function with reduction of TNF-α level may decrease inflammatory response making Pyroligneous extract a novel agent to promote the healing in DFU wounds.