Quantitative Assay and Optimization of Ultrasonic-Assisted Extraction of Three Main Alkaloids from Plumula nelumbinis / 中国药学杂志

ABSTRACT

OBJECTIVE To establisha simultaneous determination method of three main alkaloids in Plumula nelumbinis by high performance liquid chromatography(HPLC), including liensinine, isoliensinine and neferine, and optinize the ultrasonic-assisted extraction process of total alkaloids from Plumula nelumbinis by using response surface methodology based on Box-Behnken design. METHODS The alkaloids were separated on a RP-HPLC C18 monolithic column(4.6 mm×50 mm, Merck, Darmstadt, German) with a mobile phase consisting of methanol-water-triethylamine-acetic acid(70∶30∶0.2∶0.05), and the method was validated for linearity, sensitivity and extraction recovery. Based on the single-factor analysis, a mathematical model was constructed to analyze the effects of each factor of the ultrasonic-assisted extraction and their interactions on alkaloids yields of Plumula nelumbinis. The three independent variables were volume fraction of ethanol(A), solid-liquid ratio(B) and ultrasound extraction time(C), respectively. RESULTS The HPLC method used to separate three alkaloids within 5 min showed an excellent linear correlation (r2>0.999) in the range of 3.4-340 μg·mL-1(liensinine), 3.47-347 μg·mL-1(isoliensinine) and 3.47-347 μg·mL-1 (neferine). The limits of detection(LODs) of three alkaloids were 0.17, 0.69 and 0.69 μg·mL-1, and the limits of quantification were 0.34, 1.73 and 1.73 μg·mL-1, respectively. The intra-day and inter-day variations of RSD were less than 5%, and the extraction recovery rang from 97.06% to 104.12% with RSD ranging from 0.08% to 0.87%(n=6). The optimum extraction conditions were solid-liquid ratio, 1∶30.3; volume fraction of ethanol, 69.8%; ultrasound extraction time, 29.0 min. The yield under the optimum conditions was found to be(14.82±0.42) mg·g-1, which was agreed closely with the predicted value of 14.70 mg·g-1. CONCLUSION The HPLC method used to determine the three main alkaloids in Plumula nelumbinis shows ideal characteristics of quickness, accuracy, high sensitivity and good repeatability.The optimum ultrasonic extraction technology has expressed excellent extraction ability of alkaloids in Plumula nelumbinis which indicates the RSM result is reasonable and effective.