Efficacy of topical application of standardized extract of Tragopogon graminifolius in the healing process of experimental burn wounds

Abstract

Tragopogon graminifolius DC. is a perennial plant from the family Asteraceae which grows in West parts of Iran. Several biological activities like antimicrobial, antioxidant and anti-inflammatory effects are reported for the plant. The aim of this study was to assess the wound healing activity of standardized extract from T. graminifolius (TG) aerial parts. Topical standardized TG extract with 5% and 10% concentrations in eucerine base was assessed for its healing properties on second degree burn in rats during a 14-day period. Biomarkers of oxidative damage including total antioxidant power, lipid peroxidation and total thiol molecules of the skin tissue samples were also evaluated. Results showed that 10%TG had the best efficacy with 80 ± 3% wound closure and tissue repair in comparison to negative control (p < 0.05). Significant reduction of tissue oxidative stress biomarkers was also observed. Histological analyses confirmed wound healing activity of TG extract, as well. Considering the antioxidative stress and anti-inflammatory activities of TG, explained by the high content of phenolic compounds of the plant, standardized TG extract could be considered as a natural remedy for the treatment of burn wounds. Further clinical studies are suggested to confirm the effectiveness of TG as a wound healing agent.

Keywords: Medicinal plant; Oxidative stress; Second-degree burn; Tragopogon graminifolius.

Graphical abstract

Fig. 1

Macro-area of wounds in 1st, 7th, and 14th day of experiment. TG: Tragopogon graminifolius.

Fig. 2

Microscopic images of skin tissue samples of 14th day with magnification of × 400. C+: PMNs population decrease and epithelium regeneration is observable in wound edge but not in wound center (neovascularization: +). C-: high density of blood vessels and no re-epithelialization, only reduction in PMNs and macrophages (neovascularization: +). TG5: high density of blood vessels and connective cells, no healing and extreme bleeding in dermis layer (neovascularization: ++++). TG10: re-generation is almost complete, only stratum keratinosum need to be complete.

Fig. 3

Comparing effect of different treatments on total thiol content of skin tissue on day 14. TTM: total thiol molecules. C-: negative control, C+: positive control, TG5: 5% extract ointment, TG10: 10% extract ointment. Significant difference in comparison to negative control: *: P < 0.05, **: P < 0.01, ***: P < 0.001.

Fig. 4

Comparing effect of different treatment on lipid peroxidation in skin tissue on day 14. LPO: lipid peroxidation, C-: negative control, C+: positive control, TG5: 5% extract ointment, TG10: 10% extract ointment. Significant difference in comparison to negative control: *: P < 0.05, **: P < 0.01, ***: P < 0.001.

Fig. 5

Comparison of different treatments on total antioxidant power of skin tissue samples on day 14. TAP: total antioxidant power, C-: negative control, C+: positive control, TG5: 5% extract ointment, TG10: 10% extract ointment. Significant difference in comparison to negative control: *: P < 0.05, **: P < 0.01, ***:P < 0.001.