Improved extraction efficiency of bakuchiol with antioxidant and whitening bioactivities from the seeds of Psoralea corylifolia L.

Abstract

Mining new whitening ingredients from plants is an effective way to develop new cosmetic products. Bakuchiol, as one of the main active ingredients from the seeds of Psoralea corylifolia L, displays whitening, antioxidant, antiaging, and free radical-scavenging activities and attracts wide attention especially in the cosmetics industry. However, environmentally friendly extraction technologies with high efficiency and high product purity remain to be developed for the scale production of bakuchiol. In this study, a new approach (acetic acid–steaming–assisted technique) was developed to improve the extraction efficiency of bakuchiol. The factors influencing the extraction efficiency of bakuchiol, including seed powder granularity, acetic acid volume, temperature, and time, were optimized based on single-factor experiments. The extraction conditions were optimized as steaming the seed powder (100 g) of 40–100 meshes with acetic acid (50 mL) for 10 minutes, from which a crude extract (25.1 g) containing bakuchiol was obtained. High purity (99.1) of bakuchiol (6.02 g) was then prepared by silica gel column chromatography in a one-step process. The method established in this study had higher extraction rate than other methods. The antioxidant potential of bakuchiol was evaluated based on the ABTS free radical scavenging activity and ferric reducing antioxidant power. Furthermore, bakuchiol demonstrated stronger tyrosinase inhibitory activity than the positive control (arbutin). Compared with the available methods, the method established in this study has increased extraction rate of bakuchiol and is environmentally friendly and economical, demonstrating the potential for industrial production.