Preparation and purification of canthinone and β‐carboline alkaloids from Picrasma quassioides based on bioautography and mass‐spectrometry‐directed autopurification system.

Abstract: Picrasma quassioides (D. Don) Benn. is a widely used traditional Chinese medicine for anti‐inflammation and antibiosis. Canthinone and β‐carboline alkaloids are the main characteristic constituents that possess diverse pharmacological effects, such as anti‐inflammatory and anti‐infectious properties. In this study, bioautography in thin‐layer chromatography indicated that the antiradical activity compound may be alkaloids. Then, a simple, fast, and efficient method was established for the separation and purification of two types of alkaloids from P. quassioides by mass‐spectrometry‐directed autopurification system. Eight alkaloids were isolated and purified in this one‐step methodology. Among them, five compounds (3, 95.1%, 58.8 mg; 4, 98.4%, 71.7 mg; 6, 97.8%, 365.4 mg; 7, 97.7%, 172.7 mg; 8, 98.2%, 180.3 mg) were obtained in large amounts with extremely high purities. Then, the antiradical activities of the isolates showed that 4‐methoxy‐5‐hydroxycanthin‐6‐one (6) exhibited obvious 1,1‐diphenyl‐2‐picryl‐hydrazyl free radical scavenging activity with an IC50 value of 84.037 μM. This study offers a new method for the preparation of targeted bioactive alkaloids in P. quassioides. This work also provides a reference for the separation of other targeted chemical components with potential activities from traditional Chinese herbal medicines. [ABSTRACT FROM AUTHOR]