Ultrasound-assisted extraction methodology as a tool to improve the antioxidant properties of herbal drug Xiao-chia-hu-tang.

Xiao-chai-hu-tang (XCHT) is an important Chinese herbal prescription for curing many types of liver diseases. The contents of bioactive constituents (saikosaponins a, c and d, baicalin, baicalein, and glycyrrhizic acid), and antioxidant properties of XCHT extracts prepared with ultrasound-assisted (US) extraction in combination with ethanol (up to 95%) as extraction modifier were studied. The results showed that the US extraction significantly increased the bioactive constituents concentrations and antioxidant properties of XCHT extracts when compared with the XCHT prepared with traditional boiling-water extraction. Among the XCHT extracts made with US extraction, the sample prepared with 95% ethanol showed the highest bioactive constituent concentrations and the best antioxidant functionalities. The results suggest that US extraction of XCHT is feasible to replace the traditional time-consuming and low efficiency preparation procedure in the future modernized and commercialized manufacture of this highly valuable Chinese herbal medicine.