A Phytocomplex Consisting of Tropaeolum majus L. and Salvia officinalis L. Extracts Alleviates the Inflammatory Response of Dermal Fibroblasts to Bacterial Lipopolysaccharides

Background: The antimicrobial activity and effects of a phytocomplex consisting of Tropaeolum flos (T) and Salviae folium (S) extracts on the cytokine levels and transcription factors on dermal fibroblast BJ exposed to bacterial lipopolysaccharides were examined.

Methods: In order to select the most optimal combination ratio of the two extracts for using in vitro, the physicochemical characterization of vegetal extract mixtures was performed and the antioxidant and antibacterial activities were evaluated on five different formulations of T : S, namely, 1 : 1, 1 : 2, 2 : 1, 3 : 1, and 1 : 3. The best combination of bioactive compounds with regard to antioxidant and antibacterial activities (T : S 1 : 2) was selected for in vitro evaluation of the anti-inflammatory effect. Human dermal fibroblast BJ cells were treated with two doses of the extract mixture and then exposed to bacterial lipopolysaccharides (LPS). The levels of the cytokines involved in inflammatory response, namely, interleukin- (IL-) 6, tumor necrosis factor- (TNF-) α, IL-31, and IL-33, were quantified by ELISA, and the expression of transcription factors, namely, signal transducer and activator of transcription (STAT) 3, nuclear factor kappa B (NFκB), and phosphorylated NFκB (pNFκB), were evaluated by western blot analysis.

Results: The results have shown that the mixture of T : S 1 : 2 exhibited significant antibacterial effects on Staphylococcus aureus ATCC 25923. LPS exposure increased the cytokine levels in BJ cells and enhanced the NFκB expression. The pretreatment of BF cells exposed to LPS with the two doses of the extract mixture markedly inhibited the increase of IL-33 and TNF-α levels and amplified the NFκB expression and its activation, especially with the high dose. The low doses of the extract reduced NFκB expression but increased its activation.

Conclusions: These experimental findings suggest that the mixture of T : S 1 : 2 can exert some protection against bacterial infections and inflammation induced by LPS in BJ cells being a good therapeutic option in related conditions associated with inflammation.