Anti-Inflammatory Effect of Urtica urens on LPS-Challenged Keratinocytes

Keratinocytes, the predominant cells in the uppermost layer of the skin, serve as theprimary protection against environmental threats. These cells exhibit activation in the presence of physical trauma, ultraviolet radiation, chemical agents, or allergenic substances. Once activated, keratinocytes release a variety of immunomodulatory soluble mediators that initiate and propagate the inflammatory response. However, dysregulation of this response and the consequent overactivation of pro-inflammatory mediators within the skin may contribute to the pathogenesis of diverse conditions, including cancer, psoriasis, chronic inflammation, autoimmune diseases, hyperpigmentation, and skin aging. Thus, downregulating pro-inflammatory mediators and recovering the physiological balance between factors that promote and those that counteract inflammation represent crucial steps in managing inflammatory skin disorders. Valued in folk medicine for its anti-inflammatory effects, Urtica urens can be found across South America (Argentina, Brazil, Bolivia, Chile, and Uruguay), Africa, Australia, Europe, and Asia.

This investigation sought to determine the anti-inflammatory properties of an ethanolic extract of U. urens through the use of an in vitro model involving keratinocytes stimulated with lipopolysaccharide (LPS). In particular, the research examined the extract's effects on the generation of nitric oxide (NO), the expression of pro-inflammatory cytokines, and its wound healing potential.

The extract's analysis revealed the presence of polyphenols and flavonoids, with chlorogenic acid identified as the predominant polyphenol. Notably, it effectively counteracted the LPS-induced elevation in NO production and also reduced release of pro-inflammatory cytokines such as IL-6, TNF-α, and IL-1β. Additionally, the extract exhibited the potential to accelerate wound closure in an in vitro setting.

The present findings suggest that U. urens extract may hold therapeutic potential as a topical treatment for chronic inflammatory skin conditions.