tectoridin and puerarin

A highly sensitive and specific method of rapid resolution liquid chromatography tandem mass spectrometry (RRLC-MS/MS) in positive ionization mode has been developed and validated for pharmacokinetic study of puerarin in rat plasma. Chromatography was carried out on a Zorbax XDB C18 reversed-phase column using a mobile phase comprising a mixture of methanol and 0.05% acetic acid in water (35:65, v/v) with a flow rate of 0.3 mL/min from 0 min to 5.4 min and then 0.6 mL/min from 5.41 min to 12 min. The mass spectrometer operated in ESI positive ionization mode. Multiple reaction monitoring (MRM) was used to measure puerarin and tectoridin (internal standard). The method was sensitive with a detection limit of 0.33 ng/mL. A good linear response was observed over a range of 10-2000 ng/mL in rat plasma. The inter- and intra-day precision ranged from 2.97% to 7.52% and accuracy from 93.70% to 101.60%. This validated method was applied successfully to a pharmacokinetic study in rat plasma after intravenous administration of puerarin. The main pharmacokinetic parameters were as follows: AUC(0→t) 45.37±13.19 (mgh/L), AUC(0→∞) 47.03±14.78 (mgh/L), MRT 1.03±0.46 (h), T(1/2) 1.31±0.31 (h), V(ss) 0.09±0.02 (L), V(z) 0.17±0.04 (L), Cl 0.10±0.04 (L/h).

Topics: Animals; Chromatography, Liquid; Female; Isoflavones; Least-Squares Analysis; Male; Rats; Rats, Sprague-Dawley; Reproducibility of Results; Sensitivity and Specificity; Tandem Mass Spectrometry; Vasodilator Agents

Puerarin is a major active ingredient of Pueraria radix. Puerarin may exert its medicinal functions in part via its metabolites. In this study, we identified these metabolites to better understand and elucidate puerarin's metabolic pathway. Puerarin was intravenously administered to rats and then metabolites in plasma samples were identified by rapid resolution liquid chromatography electrospray ionization-collision induced dissociation tandem mass spectrometry (RRLC-ESI-CID-MS/MS). Chromatography was conducted on a Zorbax SB C18 column (2.1x100 mm, 1.8 microm) at 30 degrees C, with a gradient mobile phase consisting of 0.05% formic acid and acetonitrile, a flow rate of 0.2 mL min(-1), and a total run time of 14 min. MS/MS acquisition parameters were as follows: positive ionization mode, dry gas: nitrogen, 10 L min(-1), dry temperature: 350 degrees C, nebulizer: 40 psi, capillary: -3500 V, scan range: 250-800. The autoMS, manual, or multiple reaction monitoring mode was selected as required. Two glucuronidated metabolites of puerarin (M1 and M2) were detected. M1 and M2 are presumed to be puerarin-7-O-glucuronide and puerarin-4'-O-glucuronide, respectively, and M2 likely is suspected to be the major metabolite because it represented the predominate peak. Kinetic studies of metabolites demonstrated that M1 and M2 were detected in rat plasma at 5 min after intravenous administration of puerarin, the levels of M1 and M2 then reached their peaks at 10-15 and 15-30 min, respectively. The metabolic profiles were similar in rat liver and intestine investigated by in situ liver and intestine perfusion, indicating that no metabolic regioselectivity of puerarin occurs in the two organs.

Topics: Animals; Chromatography, Liquid; Intestinal Mucosa; Isoflavones; Liver; Molecular Weight; Rats; Rats, Sprague-Dawley; Tandem Mass Spectrometry