Pharmacokinetic Analysis of Rosmarinic Acid and its Analog in Rat Plasma Using Liquid Chromatography-Tandem Mass Spectrometry.

The anticancer effects of rosmarinic acid (RA) are a hotspot of current research. In order to enhance its pharmacological activity, N-substituted RA was prepared, and it has been shown to exhibit notable antitumor effects. In order to elucidate the underlying mechanisms of action, pharmacokinetic analysis is necessary. In the present study, liquid chromatography-tandem mass spectrometric method, was used to determine the concentrations of RA and its analog, (E)-3-(3,4-dihydroxyphenyl)-2-(3-(3,4-dihydroxyphenyl)acrylamido)propanoic acid (A2) in plasma from rats. The analyses were divided into a C18 column (1.9 µm, 2.1 mm × 100 mm) with a security guard C18 column (5 µm, 2.1 mm × 10 mm) and a triple-quadrupole mass spectrometry with an electrospray ionization ion-source generates ions. The sample pretreatment is relevant to the one-step protein precipitation with isopropanol:ethyl acetate (v/v, 1:1) This method presented a linear association within ranges at the concentration of 5-2000 ng/mL for A2 and RA. Relative standard deviations in daily courses were <15% and the relative errors registered within 15%. The methods used in the present study make the unambiguous quantification and identification of RA and A2 possible in vivo. The present study is the first to focus on determining A2 and RA in rat plasma following oral administration. The results may provide a meaningful basis for the evaluation of the application of RA and its analog in clinical practice and also provide a reference method for the pharmacokinetic analysis of RA analogs.