Wound repair and anti-inflammatory potential of Lonicera japonica in excision wound-induced rats

BACKGROUND Lonicera japonica Thunb. (Caprifoliaceae), a widely used traditional Chinese medicinal plant, is used to treat some infectious diseases and it may have uses as a healthy food and applications in cosmetics and as an ornamental groundcover. The ethanol extract of the flowering aerial parts of L. japonica (LJEE) was investigated for its healing efficiency in a rat excision wound model. METHODS Excision wounds were inflicted upon three groups of eight rats each. Healing was assessed by the rate of wound contraction in skin wound sites in rats treated with simple ointment base, 10% (w/w) LJEE ointment, or the reference standard drug, 0.2% (w/w) nitrofurazone ointment. The effects of LJEE on the contents of hydroxyproline and hexosamine during healing were estimated. The antimicrobial activity of LJEE against microorganisms was also assessed. The in vivo anti-inflammatory activity of LJEE was investigated to understand the mechanism of wound healing. RESULTS LJEE exhibited significant antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Candida albicans, and Candida tropicalis. The ointment formulation prepared with 10% (w/w) LJEE exhibited potent wound healing capacity as evidenced by the wound contraction in the excision wound model. The contents of hydroxyproline and hexosamine also correlated with the observed healing pattern. These findings were supported by the histopathological characteristics of healed wound sections, as greater tissue regeneration, more fibroblasts, and angiogenesis were observed in the 10% (w/w) LJEE ointment-treated group. The results also indicated that LJEE possesses potent anti-inflammatory activity, as it enhanced the production of anti-inflammatory cytokines that suppress proinflammatory cytokine production. CONCLUSIONS The results suggest that the antimicrobial and anti-inflammatory activities of LJEE act synergistically to accelerate wound repair.