Spirulina, Palmaria Palmata, Cichorium Intybus, and Medicago Sativa extracts in cosmetic formulations: an integrated approach of in vitro toxicity and in vivo acceptability studies.

Background/Aims: The selection of suitable raw materials in the cosmetic research and development is a key point, not only in order to obtain the expected results but also to avoid undesirable side effects. This study evaluated the in vitro toxicity potential of four different plant extracts and their in vivo acceptability studies. Methods:Spirulina, Palmaria palmata, Cichorium intybus and Medicago sativa extracts were analysed alone or in combination and added in cosmetic formulations. The in vitro toxicity evaluation, Hen's Egg Chorioallantoic Membrane Test (HET-CAM) and 3T3 NRU phototoxicity test were performed to evaluate in vitro potential ocular irritation and photo safety, respectively. Twenty subjects were enrolled in the acceptability studies, who were evaluated for the absence of harmful effects of the formulation by visual assessment and by transepidermal water loss, a biophysical technique, for 30 days. Results: HET-CAM assay showed that the studied extracts added to a gel-cream formulation had no irritant potential. In addition, the combination of Palmaria palmata, alfalfa and chicory extracts did not show phototoxic potential in vitro. Acceptability studies showed that the formulation containing the four extracts combined did not provoke any transepidermal water loss (TEWL) alteration, sensory irritation or erythema in the forearms for the period of analysis. Conclusion: The studied active ingredients, alone or in combination, present no cytotoxicity potential and when added to a gel-cream formulation had no irritant potential in vitro. These results predicting no harmful effects were confirmed in the acceptability tests, which showed no alteration on skin barrier function and no report of irritation perception of sign of erythema, suggesting the potential of these extracts for the development of safe cosmetic products.