Abstract
Rhizome coptidis is a common traditional herb in China with an abundant alkaloid content that has remedial effects on various chronic diseases. In this study, an acid-assisted extraction method was developed for the extraction of the alkaloids from rhizome coptidis, and response surface methodology was applied to optimize the extraction process conditions. Individual alkaloids were isolated and identified using high performance liquid chromatography with an ultraviolet detector (HPLC-UV). Five different acids were tested, and the highest total alkaloid content including berberine and palmatine content were detected in phosphoric acid extracts. A box-Behnken design with 3 levels and 3 variables was employed and optimal conditions were obtained as follows: 0.34 % phosphoric acid concentration, 5.00 h extraction time, and 51.45 mL/g solvent to sample ratio. A verification experiment was carried out under the estimated optimal conditions, and a good correlation between estimated and observed values indicated that the fitted model was valid and the prediction was successful. Compared with other extraction methods, acid-assisted extraction is simpler, safer and more economic with a high alkaloid yield which could be potentially used as alternative choice for industrial production.
