Euphorbia hirta accelerates fibroblast proliferation and Smad-mediated collagen production in rat excision wound

Euphorbia hirta L. (Euphorbiaceae) is a traditional herbal medicine used for treatment of various diseases. E. hirta was investigated for in vitro/in vivo wound healing activity using human dermal fibroblast cell line and Wistar rats. Petroleum ether, chloroform, methanol and water successive extracts of E. hirta leaves were evaluated for antioxidant, antimicrobial and fibroblast proliferation activities. Among different extracts, the promising methanol extract was screened for wound healing activity in Wistar rats, using gentamicin sulfate (0.01% w/w) as a reference. Wound contraction, hydroxyproline content and the protein expression of COL3A1, bFGF, Smad-2,-3,-4 and -7 were measured. The E. hirta methanol extract showed a potent antimicrobial (MIC 0.250 mg/ml against Escherichia coli and Klebsiella pneumoniae, both), antioxidant activities (IC50 = 10.57 μg/ml, 2,2-diphenyl-1-picrylhydrazyl; 850.23 μg/ml, superoxide-anion radical scavenging activity and 23.63 mg gallic acid equivalent per gram extract) with significant fibroblast proliferating activity (112% at 12.5 μg/ml) as compared to other extracts. In vivo study also supported the wound healing potential of methanol extract, as evidenced by faster wound contraction, higher hydroxyproline (4.240 mg/100 mg tissue) and improved histopathology of granulation tissue as compared to control groups and gentamicin sulfate-treated ones. Western blot also revealed a significantly altered expression of Smad-mediated proteins resulting in collagen production. The study suggested that E. hirta accelerates the wound healing by augmenting the fibroblast proliferation and Smad-mediated collagen production in wound tissue.