Determination
of rosmarinic acid and its N-substituted analog A1 in rat plasma by
high-performance liquid chromatography-tandem mass spectrometry and its
application in pharmacokinetics
Shujie Fu1, Qinglang Zhang2, Shiyu
Zhang2, Weizhe Jiang1, Minjie
Jiang2*
1 School of Pharmaceutical, Guangxi Medical University, Nanning 530021,
China, 2 Guangxi University of Chinese Medicine, Nanning 530001, China
* Corresponding author. Tel.: +86 13768509293; fax: +86 07713137535.
E-mail address: jiangminjietp@me.com (M. Jiang).
Introduction
Caffeic acid esters, rosmarinic acid (RA, Fig. 1a), exhibit different
biological properties, such as antiviral, antibacterial,
anti-inflammatory, and antioxidant properties[1,2]. It has been
recently noted that RA pharmacology is important[2–5], but very few
papers have evaluated its pharmacokinetics and pharmacodynamics
[6–11]using high-performance liquid chromatography-tandem mass
spectrometry. In order to investigate the pharmacodynamic mechanisms of
RA in more depth, we synthesized many analogs based on RA, including
(E)-3-(3,4-dihydroxyphenyl)-2-(3-(3,4-dihydroxyphenyl)acrylamido)propanoic
acid (A1, Fig. 1b). Previous studies have shown that A1 has higher
pharmacological activity against tumors than RA[12]. Thus, in order
to simultaneously determine A1 and RA, pharmacokinetics (PK) must be
studied using a sensitive and precise method. Recently, researchers have
expressed concern about RA absorption and metabolism, but few papers
have used HPLC-MS to study the pharmacokinetics and pharmacodynamics of
RA. By avoiding the need to fully analyze the chromatograms, this method
guarantees high sensitivity and speedy quantification. The majority of
previous studies, however, only focused on administering one substance
at a time; thus, no one has conducted a simultaneous study on RA and
other compounds and their pharmacokinetics. The objective of this study
was to implement and validate a new method for estimating RA and A1 in
plasma samples collected from rats. Therefore, this method is very
useful for pharmacokinetics studies.
2. Experimental section
2.1. Reagents and chemicals
RA (batch number 111871) with a purity above 99% and pseudoephedrine
hydrochloride (PPD, batch number 171237-201510) were obtained from the
National Institute for the Control of Pharmaceutical and Biological
Products (Beijing, China) (Fig. 1c) and used as standards. A1 (99.8%
purity) was synthesized at the School of Pharmaceutical, Guangxi Medical
University (Nanning, China). Ethyl acetate was obtained from Dikma
Technologies, Inc. (Richmond Hill, ON, Canada). The methanol and
acetonitrile used were obtained from Sigma-Aldrich Chemicals (St. Louis,
MO, USA). Deionized water was purified with an Alpha-Q water
purification system and then filtered with 0.20-μm membranes.