ABSTRACT
Objective: To compare the brain pharmacokinetics of five protoberberine-type alkaloids (i.e. berberine, palmatine, coptisine, epiberberine, and jatrorrhizine), which were the main bioactive constituents of Jiaotai Pills (JTP), in normal and insomnic rats orally administrated with JTP. Methods: The detection was conducted by a fully validated liquid chromatography-tandem mass spectrometry combinated with brain microdialysis method. Brain microdialysis probes were inserted into the hippocampus of rats. JTP extracts were administrated intragastrically and then brain microdialysates were collected at 30 min time intervals for 10 h. The separation of the five protoberberine-type alkaloids was carried out on a BDS Hypersil C18 column using a mobile phase consisting of acetonitrile and water (containing 5 mmol ammonium acetate adjusted to pH 5.0) within 4 min. The quantification was performed by multiple reaction monitoring with the transitions of m/z 336.0-320.1 for berberine, m/z 352.0-336.1 for palmatine, m/z 338.0-322.1 for jatrorrhizine, m/z 336.0-320.1 for epiberberine, m/z 320.0-292.1 for coptisine and m/z 356.4-192.1 for IS. Results: The lower limit of quantification for five protoberberine-type alkaloids was 0.05 ng/mL. Linearity, accuracy, precision, stability and matrix effect of five analytes were all satisfactory. Five protoberberine-type alkaloids were quickly distributed in the brain. Moreover, significant differences in the principal pharmacokinetic parameters such as AUC and T1/2 of the analytes were observed between two groups. Conclusion: The LC-MS/MS method combinated with microdialysis is useful in the brain pharmacokinetic study of five protoberberine-type alkaloids. The results indicated that the rates of analytes absorption in insomnic rats were significantly higher than those in normal rats. Besides, the protoberberine-type alkaloids could bring a direct effect on the neuron in the hippocampus.