Tetra-Carboxy-Methyl-Naringenin-Chalcone, a new active to treat rosacea
Tetra-carboxy-methyl-naringenin-chalcone (TCM-NC) is a new cosmetic active derived from naringenin, a flavanone naturally occurring in the peel of citrus fruit and tomato skin. The naringenin isomer naringenin-chalcone has been reported to have potent anti-allergic properties. For this reason the effect of TCM-NC was studied in an in vitro assay mimicking the inflammation pathway of rosacea skin and skin redness.
In rosacea skin, an overexpression and release of cathelicidin by surface keratinocytes leads to an inflammatory reaction in neighboring keratinocytes. If not treated, a chronic inflammation can develop inducing increased local blood flow and angiogenesis. In this paper, the inhibitory effect of the new TCM-NC on the cathelicidin-induced inflammatory reaction in human epidermal keratinocytes is reported. In a clinical study performed on volunteers with rosacea skin, TCM-NC clearly diminishes capillary blood flow and thereby the appearance of facial redness.
Naringenin-chalcone is a polyphenol occurring naturally in plants e.g. the skin of tomato and citrus fruits. Recent studies have reported that naringenin-chalcone has potent anti-allergic and anti-inflammatory properties (1). The chalcone spontaneously isomerizes in aqueous solutions from the flavanone naringenin (Figure 1), which, however, exhibits only weak anti-allergic activity (1). The equilibrium between the chalcone and the flavanone depends on the pH of the solution, a condition not suitable for cosmetic formulations. Apart from this instability, naringenin - chalcone has a low solubility in water and other cosmetic solvents.
Our first goal was to modify the naringenin - chalcone in order to block cyclisation and also to increase the solubility in water. To meet these challenges, tetra-carboxy-methyl-naringenin-chalcone (TCM-NC) (Figure 2) was designed and synthesized using the commercially available naringenin as a starting material. TCM-NC exhibits improved pH-stability and solubility in water. Having achieved this goal, we demonstrate the efficacy of TCM-NC on chronic skin inflammations, such as rosacea skin.