Wound healing and anti-inflammatory activities induced by a Plantago australis hydroethanolic extract standardized in verbascoside

Ethnopharmacological relevance: Plantago australis is a popular plant found to be widely spread in Latin America. In folk medicine, the seeds and leaves are used mainly for anti-inflammatory, wound healing, among others. The verbascoside, a phenolic glycoside, is an active chemical component described in this species of plant, which has antioxidant, anti-inflammatory and healing effects.

Purpose: The aim of the present study was to evaluate whether P. australis hydroethanolic extract (PAHE) standardized in verbascoside could promote wound healing associated with anti-inflammatory action within both in vitro and in vivo models.

Methods: For the wound healing activity, we used a Scratch Test, an assay capable of evaluating the migratory ability of keratinocyte cells (HaCat) in vitro and thereby confirming the activity in rats. For the anti-inflammatory activity, the inflammation was induced with LPS in microglial murine cells (N9). Inflammatory mediators (IL-6, IL-10, IL-12p70, INFγ, MCP-1 and TNFα) were measured and the activity of superoxide dismutase (SOD), catalase (CAT), and mitochondrial membrane potential were evaluated. In addition, using paw edema induced by carrageenan in rats, the anti-inflammatory activity in vivo was analyzed.

Results: The PAHE and verbascoside, induced a significant increase in migration of keratinocytes, at all concentrations tested when compared to the negative control. The wound healing activity in vivo showed that the PAHE accelerated the process. The treatments with PAHE and verbascoside induce increases in the antioxidants enzymes, suggesting a possible activation of these enzymes. However, this did not result in an increase in the expression of inflammatory mediators in microglial cells. In LPS activated cells the verbascoside displayed a significant reduction of TNFα, IL-6, IL-12p70, MCP-1 and INFγ, while the PAHE only displayed statistically significant reduction in TNFα. Interestingly, both the compounds could reduce the oxidative parameters in N9 cells activated by LPS. Additionally, pretreatment with PAHE inhibited the paw edema in rats.

Conclusion: The results suggest that PAHE has wound healing activity, improving cells migration and, as well as was able to reverse the oxidation effect in LPS-activated N9 cells. The wound-healing and anti-inflammatory activities of PAHE were confirmed in vivo. In addition, the presence of verbascoside can be related to PAHE effects, since this compound was capable of increase keratinocytes migration and inhibiting inflammation mediators.