Simultaneous extraction and separation of flavonoids and alkaloids from Crotalaria sessiliflora L. by microwave-assisted cloud-point extraction

A novel method of simultaneous extraction and separation of flavonoids and alkaloids from Crotalaria sessiliflora L., was developed by microwave-assisted cloud-point extraction (MACPE) using Triton X-100-NaCl-HCI system as extractant. The optimum conditions including Triton X-100 concentration, NaCl concentration, HCl concentration, solvent-to-material ratio, extraction temperature and time were investigated by orthogonal test on the single factor experiment. The extraction yields of vitexin, isovitexin and monocrotaline reached respectively up to 601.4, 386.7 and 105.5 mu g under the optimum conditions. Compared with heating reflux extraction (HRE) and ultrasonic-assisted extraction (UAE), MACPE exhibited a significantly higher extraction yields and took a shorter time (only 10 min). The MACPE mechanism was discussed based on phase's shift and extraction property. As a result, flavonoids and alkaloids can be transferred respectively to bottom phase and top phase after simultaneous extraction. The proposed method integrated MAE with cloud-point extraction (CPE) in one-step procedure took both advantages. It provided a simple and efficient alternative to extraction and separation of active constituents from the herb materials. (C) 2016 Elsevier B.V. All rights reserved.