Ultrasonic cell grinder extraction of anthraquinones from radix et rhizoma Rhei and determination by...

An ultrasonic cell grinder extraction (UCGE) method has been developed and applied to extract five anthraquinones (physcion, chrysophanol, emodin, rhein, and aloe-emodin) from radix et rhizoma Rhei. Several parameters of UCGE procedure, including ultrasonic cell grinder running mode, type and volume of extraction solvent and extraction time, were optimized. The determination was preformed on a Waters ultra-performance LC BEH C(18) column using gradient elution system. A baseline separation could be achieved in less than 7.5 min with high resolution. Under the optimized conditions, contents of physcion, chrysophanol, emodin, rhein and aloe-emodin in radix et rhizoma Rhei collected from different cultivated areas were 0-4.22, 0.11-27.64, 0.09-3.49, 0.31-3.31 and 0.13-2.93 mg/g, respectively. Compared with reflux, maceration and ultrasonic bath extractions, the UCGE method was more efficient, faster and easier to be operated, and required lower extraction temperature and less solvent. The results indicated that UCGE was a novel and ideal method for extracting bioactive constituents from plant samples.