A New, Cost-Effective Facial Skin Care Serum, Rich in Bioactive Ingredients Isolated from Centaurea cyanus L. Flower Petals

This study developed a facial skin care serum based on extracts from cornflower petals (Centaurea cyanus L.). The study applied the concept of loan extraction, in which the ingredients of the final cosmetic product were used as the extraction medium. The extracts obtained were analyzed for stability and physicochemical parameters, as well as phytochemical composition, total phenolic content (TPC) and antioxidant activity. Among the tested solvents, the extract prepared with 1,3-propanediol aqueous solution exhibited the highest TPC (13.5 mg GAE/g) and demonstrated the strongest antioxidant activity measured by ABTS (20.12 d ± 0.07 mgTE/g). HPLC-MS/MS analysis revealed that the extract obtained using this medium showed the most complex profile of bioactive compounds among all the studied samples. After the extraction process the borrowed ingredients were returned together with the extracted ingredients to prepare cosmetic preparations—facial skin care serums. The finished model cosmetic products were evaluated for physicochemical parameters (stability, viscosity, color) and irritation potential, considering the extract used, which varied depending on the extraction agent borrowed from the formulated composition. The preparation obtained on the basis of an aqueous solution of 1,3-propanediol as an extraction agent showed the most favorable properties in terms of irritation, determined on the basis of the zein number (15 ± 4 mgN/100 mL), compared to facial skin face serum without extract addition (21 ± 1 mg N/100 mL). This extract was also characterized by the highest values of TPC and antioxidant activity, hence the observed reduction in irritation potential can be attributed to the beneficial effects of bioactive compounds derived from Centaurea cyanus L. extract.