Use of Silybum marianum Extract and Bio-Ferment for Biodegradable Cosmetic Formulations to Enhance Antioxidant Potential and Effect of the Type of Vehicle on the Percutaneous Absorption and Skin Retention of Silybin and Taxifolin

In the present study, extract (E) and bio-ferment (B) were obtained from ground and defatted thistle seeds of Silybum marianum. Their antioxidant activity was assessed using the DPPH, ABTS, and FRAP techniques, while total polyphenols were measured by the Folin–Ciocalteu method. High antioxidant activity was found in both the E (0.91 mmol Trolox/L ± 0.2) and B (1.19 mmol Trolox/L ± 0.2) using DPPH methods, so the obtained cosmetic raw materials were incorporated into hydrogel and organogel substrates to obtain cosmetic formulations with antioxidant activity. However, there is a scarcity of research providing information on the skin penetration of the main active components of S. marianum, which have an antioxidant effect. Therefore, we assessed in vitro the penetration through pig skin of the main components contained in the obtained B and E, such as silybin and taxifolin, which are part of the silymarin complex. We also used pure silymarin (S) for comparison. Among the tested preparations, H-S showed the utmost significant penetration of taxifolin, having a cumulative permeation of 87.739 ± 7.457 μg/cm2. Biodegradation tests of the prepared formulations were also performed, containing cosmetic raw materials and S. Studies of the effect of the cosmetic formulations on aerobic biodegradation showed a good level of degradation for the prepared formulations, some of which (O-B and O-S) were classified as easily degradable (OECD).