Enhancement of silymarin solubility and bioactivities using betaine/ascorbyl glucoside DES

Betaine/ascorbyl glucoside (Bet/AA-2G) deep eutectic solvents (DES) composed of betaine and ascorbyl glucoside had been successfully used to improve the solubility of silymarin in this study. Under appropriate conditions, the solubility of silymarin in a 5 wt% Bet/AA-2G DES solution increased by 17.7% and 60.9% compared to a 50 wt% 1,3-butanediol solution and a 50 wt% ethanol solution, respectively. In addition, quantum chemical simulations showed that silymarin has a strong binding capacity to Bet/AA-2G DES and can remain stable after binding. The combination of Bet/AA-2G DES with silymarin enhanced the skin permeability and antioxidant capacity of silymarin. Moreover, SM-DES promoted the synthesis of type I collagen and significantly reduced the expression of MMP-1, indicating potential anti-wrinkle and firming properties. Overall, Bet/AA-2G DES showed great potential for improving the solubility and stabilizing the bioactivity of silymarin.