ABSTRACT
BACKGROUND: Herbal extracts contain multiple active constituents, so the sample preparation based on the liquid-liquid extraction (LLE) is demanding, especially when a study subsequent to extraction is needed. Since the laminar flow occurring in microchannels can be formed between two miscible organic phases, a new method of extracting polar compounds from the crude extract of Panax ginseng Meyer in aqueous ethanol by pure n-butanol in the three-phase laminar flow microfluidic chip was established. METHODS: A new chip consisting of long microchannels with a guide structure was employed to improve the extraction efficiency caused by the low diffusion ability of saponins. The method was evaluated by using the extraction yields and purities of ginsenosides Rg1, Re and Rb1 as the indicators, and extraction conditions such as flow rate, temperature and other governing factors were optimized. RESULTS: Using the new chip method, the extraction efficiencies of ginsenoside Rg1, Re and Rb1 were 63.1%, 69.5% and 71.6%, respectively, which are higher than the 26% achieved in a previous report. The extraction yields of 1.53, 0.51, 0.90 mg/g were also higher than those obtained previously by the successive laminar flow microchip method. CONCLUSION: The proposed new microfluidic chip method has simplified the sample pretreatment steps to improve the yield of ginsenoside extraction from ginseng samples.
