The utilization of UAE has proven to be more effective than CSE method for obtaining phenolic compounds from dried mangosteen pericarp powder. This study demonstrated that UAE improve the solvent extraction efficiency and reduce extraction time. UAE provided significantly higher extraction yield, phenolic contents and antioxidant capacity of crude extracts obtained. Therefore, this study suggests that UAE may be considered as an efficient method for extracting bioactive compounds from food by-products such as mangosteen pericarp. This is due to the potential for reduced time and energy.