Isolation of quaternary benzo[c]phenanthridine alkaloids from Macleaya microcarpa (MAXIM.) FEDDE: comparison of maceration, Soxhlet extraction and pressurised liquid extraction.

Introduction: Macleaya microcarpa (Papaveraceae family) has been of considerable interest in recent years as a prospective source of quaternary benzo[c]phenanthridine alkaloids (QBAs) related to many pharmaceutical beneficial effects. For this purpose, a quantitative, efficient and fast method to isolate the QBAs from the plant material is required.
Objective: To optimise and compare pressurised liquid extraction (PLE) with Soxhlet extraction and maceration in order to estimate extraction conditions for fast and efficient isolation of QBAs contained in the roots of Macleaya microcarpa.
Methodology: The QBAs were extracted by PLE, Soxhlet extraction and maceration at different conditions (solvent, time, etc.). Reversed phase HPLC with diode-array detector was utilised for their determination and quantification. To optimise the PLE procedure, the variable parameters, including temperature (40-150 °C), sample-to-inert material ratio, extraction time (5-30 min) and number of extraction cycles (1-4), were also tested.
Results: Quantitative determination of QBAs resulted in 0.2-2.8 mg/g, 0.3-2.5 mg/g and 0.3-3.1 mg/g for PLE, Soxhlet extraction and maceration. To produce the yields mentioned above, PLE required only up to 30 min compared with 21 h for Soxhlet extraction and 49 days for maceration.
Conclusion: PLE provided an effective and fast extraction of QBAs from M. microcarpa roots and can be recommended as an alternative isolation method to conventional techniques for QBAs from the plant sources.
(Copyright © 2012 John Wiley & Sons, Ltd.)