Separation of camptothecin from Camptotheca acuminate samples using cloud point extraction

Abstract

Micelle-mediated extraction and cloud point preconcentration has been successfully applied to the separation of camptothecin (CPT) from Camptotheca acuminate. The CPT was first extracted from Camptotheca acuminate samples by aqueous non-ionic surfactant X-114 solution with ultrasonic assistance. A small volume of surfactant-rich phase was then obtained by preconcentrating CPT and analyzed by high performance liquid chromatography. Various experimental conditions were investigated to obtain the highest extraction yield. The optimum parameters for the micelle-mediated extraction process were as follows: Triton X-114 concentration was 7%, pH was 7, the ratio of liquid to solid was 125/1 (mL g⁻¹) and ultrasonic time was 40 min. The highest extraction recovery was obtained with 25% (m/v) sodium chloride and equilibration at 50 °C for 20 min. Compared with other extraction methods, this technique showed significant advantages including low cost and toxicity. In addition, it had the ability to preconcentrate CPT with an enhancement factor of 5 and obtained a higher extraction yield. In this paper, the kinetics of cloud point extraction were also discussed, and the process could be described mathematically by a second-order kinetic model. The limit of detection for CPT was 0.7 μg mL⁻¹. The precision of the proposed method was indicated by a relative standard deviation of 5.4% (n = 5). Finally, the method was successfully applied to extract CPT from Camptotheca acuminate fruit, bark and leaf, and the extraction yields obtained were 0.1157%, 0.0926% and 0.0612%, respectively. The recoveries of CPT were in the range of 92.3–93.6%.