Determination and assay validation of luteolin and apigenin in human urine after oral administration of tablet of Chrysanthemum morifolium extract by HPLC. 
A simple, selective, precise, and accurate RP-HPLC assay for simultaneous analysis of luteolin and apigenin in human urine was developed and validated.  Prior to HPLC analysis, urine samples were incubated with beta-glucuronidase/sulfatase.  Separation and quantification were achieved on an Agilent C18 column under isocratic conditions using a mobile phase (methanol:0.2% phosphoric acid aqueous solution 55:45, v/v) maintained at 1.0 ml/min at 30 degrees C. The standard curves were linear over the range of 0.0975-7.800 and 0.1744-13.95 microg/ml for luteolin and apigenin, respectively (r > 0.999).  The assay recoveries for luteolin and apigenin were above 85.7%.  The intra-day and inter-day precision (R.S.D.) for luteolin were below 2.2 and 4.0%, respectively, and for apigenin were less than 2.8 and 5.4%, respectively.  Stability studies showed three concentration of luteolin and apigenin in urine quality control samples were stable undergoing three freeze-thaw cycles, storage at room temperature for 4 h, and at -20 degrees C for 3 days.  The limit of quantitation was 39.20 ng/ml (n = 5) for luteolin and 31.45 ng/ml (n = 5) for apigenin in human urine.  The method developed was employed successfully to determine luteolin and apigenin in urine samples obtained from eight healthy volunteers following oral administration of tablet of Chrysanthemum morifolium extract (CME).