Pressurized Hot Water Extraction of Alkaloids in Goldenseal

Abstract

A quick, efficient and environmentally beneficial approach for the extraction of alkaloids in goldenseal based on pressurized hot water extraction (PHWE) is presented. PHWE was evaluated following the extraction of hydrastine and berberine which are the two main alkaloids of goldenseal. The effect s of temperature and other parameters on extraction yields were monitored by high performance liquid chromatography coupled to diode array detector (HPLC-DAD) . The extraction yields were compared to those achieved through reflux and ultrasonic extraction methods. PHWE employed hot water at an optimal temperature of 140℃, a pressure of 50 bars and flow rate of 1 mL . min - 1 for extraction experiments conducted in the dynamic mode. Both PHWE and conventional methods achieved comparable extraction yields. Reflux and ultrasonic extractions had procedures that were slower (over 6 h) and employed large quantities (200 mL) of organic solvents. The PHWE method was simple and relatively fast as extraction was achieved in 15 min. At 95% con fidence level (n = 3), reflux and ultrasonic methods recorded extraction yields that were not significantly different from that of PHWE. Moreover, PHWE employed a more readily available “ green ” solvent, (water) to achieve comparable results to those of conventional methods which utilize d organic solvents. The percentage relative standard deviations (%RSD) for the extraction yields were less than 3% in all cases indicating the high reproducibility of the method. However, when using PHWE to extract thermally labile analytes like alkaloids, degradation effects also occurred. Increasing the temperatures certainly achieved higher extraction yields but also led to degradation of these thermally labile compounds indicating a necessity for optimization.