Simultaneous Quantification of Four Compounds in Rat Plasma by HPLC-MS/MS and Its Application to Pharmacokinetic Study after Oral Administration of Pomegranate Flowers.

Pomegranate flowers (PFs) were reported to possess various biological activities such as antidiabetic, anti-inflammatory and hepatoprotective activities, and using to treat diabetes. Although chemical constituents and pharmacological activities of PFs have been studied, unfortunately, there was no report on the pharmacokinetic profile of PFs in vivo. In this study, a selective high-performance liquid chromatography triple quadrupole tandem mass spectrometry (HPLC-QQQ-MS/MS) method was developed and validated for simultaneous quantification of four compounds (corilagin, ellagic acid, gallic acid and brevifolincarboxylic acid) in rat plasma after oral administration of PFs. The good linearity concentration ranges for the four analytes were from 2.5 to 3000 ng/mL with coefficient value R2 > 0.99 in calibration curves. The intra- and inter-day accuracy of the four analytes was in the range of 85.33-102.50%, with relative standard deviation (RSD) of <14.81%. The stability results showed that accuracy of the four analytes was in the range of 81.88-104.74%, with RSD of <14.86%. The validation method was successfully applied to pharmacokinetic profiles of the four analytes in rats after oral administration of PFs extract. This pharmacokinetic study can provide better understanding to clarify in vivo mechanisms of PFs and may facilitate its further development as therapeutic agent.

A comprehensive study of pomegranate flowers polyphenols and metabolites in rat biological samples by high-performance liquid chromatography quadrupole time-of-flight mass spectrometry.

Pomegranate flowers is an ancient medicine that has commonly been used to treat various diseases such as diabetes. However, no reports are available on the metabolic profile of pomegranate flowers in vivo. In the present study, with the aid of HPLC-Q-TOF-MS2, 67 compounds were identified in pomegranate flowers extract, including 18 ellagitannins, 14 gallic acid and galloyl derivatives, five anthocyanins and 18 flavonoids. Seven compounds were firstly identified. In vivo, 22 absorbed compounds and 35 metabolites were identified in rat biosamples (urine, feces, plasma and tissues) after orally administered with pomegranate flowers extract. This result showed that not all compounds abundant in pomegranate flowers extract could be absorbed well in plasma and tissues. This finding also suggested a potential correlation between study on metabolic profile of these compounds in vivo and study on strategy of screening bioactivity of the isolates with in vitro cell systems evaluation. Notably, mono-glucuronide conjugated metabolite of ellagitannin compound (corilagin) was firstly identified. In addition, this is first report to identify phase II conjugate metabolites of ellagitannins in vivo after oral administration of ellagitannins-rich extracts (or foods). Thus, characterizing its multiple constitution, absorption and metabolic fate of these compounds in vivo is helpful to better analyze the active components in pomegranate flowers.