Brain Tissue Distribution of Spinosin in Rats Determined by a New High-Performance Liquid Chromatography-Electrospray Ionization-Mass/Mass Spectrometry Method

Spinosin, a flavone-C-glycoside, is a bioactive ingredient isolated from a traditional Chinese herb Zizyphi Spinosi Semen. In this study, a new high-performance liquid chromatography-electrospray ionization-mass/mass spectrometry method was developed and validated to determine spinosin in brain tissues including olfactory region, hippocampus, corpus striatum, cerebrum (cerebral cortex) and cerebellum, after intravenous administration with the dose of 5 mg/kg. The tissue homogenate samples were pretreated and extracted with acetonitrile by a simple protein precipitation method. The separation was performed on a YMC ODS-AQ(TM) column (250 × 2.0 mm, 3.5 μm) with the mobile phase of acetonitrile-aqueous phase (0.1% formic acid) (25 : 75, v/v) at a flow rate of 0.3 mL/min. The retention times of spinosin and naringin (internal standard) were 3.3 and 5.1 min, respectively. Multiple reaction monitoring mode was used to monitor precursor/product ion transitions of m/z 607.2 → 427.0 for spinosin and m/z 579.2 → 271.0 for naringin. The proposed method was successfully applied to the preclinical brain tissue distribution of spinosin in rats. The results showed that there was a wide brain regional tissue distribution of spinosin. The concentrations of spinosin in corpus striatum and hippocampus were higher than that in other areas.