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

Picrasma quassioides (D. Don) Benn. is a widely used traditional Chinese medicine for anti-inflammation and antibiosis. Canthinone and ß-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.

Metabolic profile of 5-hydroxy-4-methoxycanthin-6-one, a typical canthinone alkaloid, in rats determined by liquid chromatography-quadrupole time-of-flight tandem mass spectrometry together with multiple data processing techniques.

Picrasma quassioides (D. Don) Benn. is a traditional Chinese medicine used clinically to treat gastrointestinal disorders and as a vermifuge. 5-Hydroxy-4-methoxycanthin-6-one (CAN), a major canthinone alkaloid found in P. quassioides, has significant pharmacological activities. In the present study, a method using liquid chromatography-quadrupole time-of-flight tandem mass spectrometry together with multiple data processing techniques, including extracted ion chromatogram, multiple mass defect filter, precursor/product ion scanning and neutral loss scanning was developed to screen and characterize the phase I and II metabolites of CAN in plasma, bile, urine and feces of rats after a single oral dose of 20mg/kg. A total of 17 metabolites were tentatively or conclusively identified. Pathways for the metabolism of CAN have been proposed, and include hydroxylation, N-decarbonylation, methylation, oxidation and sequential conjugation. A previously unknown metabolically active site at the C4-C6 position and a novel N-decarbonylation-oxidation metabolic pathway for the prototypical canthinone alkaloid, CAN, were discovered. Our results provide valuable information about the in vivo metabolism of CAN that can also be used as a comprehensive guide for the biotransformation of other canthinone alkaloids.

The pharmacokinetics and bioavailability of three canthinone alkaloids after administration of Kumu injection to rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Kumu injection (KMI) is made from the branches and stems of Picrasma quassiodes (D. Don) Benn. and has been used clinically for the treatment of upper respiratory tract infection, acute tonsillitis, enteritis and bacillary dysentery. 3-methylcanthin-2,6-dione, 5-hydroxy-4-methoxycanthin-6-one, 4,5-dimethoxycanthin-6-one are the active ingredients of KMI because of its therapeutic effects. AIM OF THE STUDY: To develop a LC-MS/MS method for simultaneous determination of three active canthinone alkaloids (4,5-dimethoxycanthin-6-one, 5-hydroxy-4-methoxycanthin-6-one and 3-methylcanthin-2,6-dione) in rat plasma and for the pharmacokinetic study of them after administered of KMI to rats. MATERIALS AND METHODS: Rats were divided into 5 groups (n=5 per group), 3 groups administered intramuscularly with a single dose of KMI at 0.30, 0.45 and 0.90mL/kg respectively, and the other 2 groups administered intragastically or intravenously a single dose of KMI at 0.9mL/kg respectively. The concentrations of 4,5-dimethoxycanthin-6-one, 5-hydroxy-4-methoxycanthin-6-one and 3-methylcanthin-2,6-dione in plasma were determined by the established LC-MS/MS method at different time points and the pharmacokinetic parameters were estimated by non-compartmental analysis. RESULTS: Pharmacokinetic results indicated that all of the alkaloids were absorbed rapidly and 3-methylcanthin-2,6-dione was eliminated fastest in rats. After intramuscular administration of KMI to rats, the absolute bioavailability is excellent, and the pharmacokinetic profiles are characterized by the first order kinetics. CONCLUSION: The established method is suitable for the quantitation of the three alkaloids in rat plasma. And this pharmacokinetic study suggested that intramuscular injection of KMI was suitable in clinical usage.

Simultaneous quantification of two canthinone alkaloids of Picrasma quassioides in rat plasma by liquid chromatography-tandem mass spectrometry and its application to a rat pharmacokinetic study.

Picrasma quassioides (D. Don) Benn. is used in traditional Chinese medicine for the treatment of inflammation. Characteristic components of the medicinal extract are canthinone alkaloids. In this study, a sensitive and rapid liquid chromatography with tandem mass spectrometry method has been developed for simultaneous quantification of two major canthinone alkaloids, 5-hydroxy-4-methoxycanthin-6-one and 4,5-dimethoxycanthin-6-one, in rat plasma after oral administration of P. quassioides extract (200 mg/kg). The chromatographic separation was performed on a C18 column using acetonitrile-aqueous 0.1% formic acid (90:10, v/v) as the mobile phase. Plasma samples were prepared for analysis using a simple liquid-liquid extraction with ethyl acetate. Analytes were detected using tandem mass spectrometry in positive multiple reaction monitoring mode. Method validation revealed excellent linearity over the range 1.25-900 ng/mL for 5-hydroxy-4-methoxycanthin-6-one and 0.5-800 ng/mL for 4,5-dimethoxycanthin-6-one with satisfactory intra- and inter-day precision, accuracy and recovery. Samples were stable under the conditions tested. The pharmacokinetic profiles of the analytes in rats showed that both canthinones were rapidly absorbed and that 4,5-dimethoxycanthin-6-one was eliminated faster than 5-hydroxy-4-methoxycanthin-6-one.

The antiplasmodium effects of a traditional South American remedy: Zanthoxylum chiloperone var. angustifolium against chloroquine resistant and chloroquine sensitive strains of Plasmodium falciparum

Zanthoxylum chiloperone var. angustifolium Engl., Rutaceae, is used in traditional medicine to treat fungal and protozoal infections in the central area of South America. Considering the increasing resistance of Plasmodium falciparum in malarial ridden areas, we explored the anti-plasmodial effects of three compounds isolated from Z. chiloperone. The pyranocoumarin transavicennol and the canthinone alkaloids, canthin-6-one and 5-methoxycanthin-6-one, were found to have IC50 on chloroquine/mefloquine resistant and sensitive strains of P. falciparum of 0.5-2.7, 2.0-5.3 and 5.1-10.4 ƒÊg/mL, respectively. Moreover, the formation of heme adducts by these compounds is described by a novel alternative method based on MS-CID methods. The alkylamide sanshool was also identified, for first time in this plant, in the dichloromethanic and ethanolic extracts and the extracts were found to be notably non-toxic and displayed good anti-plasmodial effects.