After having dried and collected the leaves and seeds of Reseda luteola L. to extract dying agents, the researchers have used various methods to isolate individual molecules to test their effect on the inhibition of tyrosinase, the most commonly method used to lower the level of melanogenesis.
A bioguided purification procedure employing centrifugal partition chromatography, Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-HRMS) and nuclear magnetic resonance (NMR) was developed to isolate and identify the whitening agents (i.e., luteolin and apigenin) from aerial parts of Reseda luteola. The procedure also enabled the characterization of acetylated luteolin- and apigenin-O-glycosides, which occurrence is reported for the first time in Reseda luteola.
The in vitro biological tests carried out made it possible to highlight the promising whitening activity of Reseda luteola L. extract, and to isolate the flavones responsible for this mechanism. Collected data show that, beyond its traditional use as a dyestuff, Reseda luteola is potentially of great interest in the development of a natural whitening ingredient in cosmetic, cosmeceuticals, and eventually pharmaceutical products, once its safety and tolerability are assessed.
Need for botanical alternatives
Used to treat various skin pigmentation disorders, or simply to obtain a lighter skin tone, skin whitening agents occupy an important part of the global dermo-cosmetic market nowadays. These active agents may act at various levels of melanogenesis, however tyrosinase inhibitors are currently the most commonly used.
Due to the current boom of the natural beauty market, exploring new botanical sources of whitening products appears crucial nowadays, in particular given the fact that ancient skin whitening ingredients - such as hydroquinone, retinoic acids, corticoids, or mercury salts - are of safety concern as they display several severe side effects, resulting in their interdiction or restricted use under the European Cosmetic Regulation 1223/2009 and several other international regulations.