Schinus terebinthifolius Raddi extract and linoleic acid from Passiflora edulis synergistically decrease melanin synthesis in B16 cells and reconstituted epidermis

Synopsis Several treatments for skin whitening are available today, but few of them are completely adequate, especially owing to the carcinogenic potential attributed to classical drugs like hydroquinone, arbutin and kojic acid. To provide an alternative and safer technology for whitening, we developed two botanical compounds originated from Brazilian biodiversity, an extract of Schinus terebinthifolius Raddi and a linoleic acid fraction isolated from Passiflora edulis oil. The whitening effect of these compounds was assessed using biochemical assays and in vitro models including cellular assays and equivalent skin. The results showed that S. terebinthifolius Raddi extract is able to reduce the tyrosinase activity in vitro, and the combination of this extract with linoleic acid is able to decrease the level of melanin produced by B16 cells cultured with melanocyte‐stimulating hormone. Furthermore, melanin was also reduced in human reconstituted epidermis (containing melanocytes) treated with the compounds. The combination of the compounds may provide a synergistic positive whitening effect rather than their isolated use. Finally, we demonstrated that the performance of these mixed compounds is comparable to classical molecules used for skin whitening, as kojic acid. This new natural mixture could be considered an alternative therapeutic agent for treating hyperpigmentation and an effective component in whitening cosmetics. Résumé On trouve un bon nombre de produits proposés pour éclaircir la peau, mais peu parmi eux s'avèrent acceptables, en particulier à cause du potentiel carcinogène attribué aux ingrédients classiques tels que l'hydroquinone, l'arbutine et l'acide kojique. Pour trouver une alternative plus sure, nous avons développé deux composés d'origine végétale issus de la biodiversité Brésilienne, à savoir un extrait de Schinus terebinthifolius Raddi et une fraction d'acide linoléique isolée de l'huile de Passiflora edulis. L'effet éclaircissant de ces composes a été évalué à l'aide de tests biochimiques et de modèles in vitro, y compris de cellules et de peaux équivalentes. Les résultats montrent que l'extrait de Schinus terebinthifolius Raddi est capable de réduire l'activité de la tyrosinase in vitro, et que la combinaison de cet extrait avec l'acide linoléique permet de diminuer la quantité de mélanine produite par les cellules B16 cultivées en présence de l'hormone de stimulation des mélanocytes (MSH). La quantité de mélanine produite diminue