Development of a UPLC-MS/MS Method for Simultaneous Determination of Six Flavonoids in Rat Plasma after Administration of Maydis stigma Extract and Its Application to a Comparative Pharmacokinetic Study in Normal and Diabetic Rats

Abstract

Maydis stigma is an important medicine herb used in many parts of the world for treatment of diabetes mellitus, which main bioactive ingredients are flavonoids. This paper describes for the first time a study on the comparative pharmacokinetics of six active flavonoid ingredients of Maydis stigma in normal and diabetic rats orally administrated with the decoction. Therefore, an efficient and sensitive ultra high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous determination of six anti-diabetic ingredients (cynaroside, quercetin, luteolin, isorhamnetin, rutin and formononetin) of Maydis stigma in rat plasma has been developed and validated in plasma samples, which showed good linearity over a wide concentration range (r² > 0.99), and gave a lower limit of quantification of 1.0 ng·mL^-1 for the analytes. The intra- and interday assay variability was less than 15% for all analytes. The mean extraction recoveries and matrix effect of analytes and IS from rats plasma were all more than 85.0%. The stability results showed the measured concentration for six analytes at three QC levels deviated within 15.0%. The results indicated that significant differences in the pharmacokinetic parameters of the analytes were observed between the two groups of animals, whereby the absorptions of these analytes in the diabetic group were all significantly higher than those in the normal group, which provides an experimental basis for the role of Maydis stigma in anti-diabetic treatment.

Keywords: Maydis stigma; UPLC-MS/MS; anti-diabetic ingredients; pharmacokinetics; rat plasma.

Figure 1

Chemical structures and full scan product ion of precursor ions of cynaroside (A), quercetin (B), luteolin (C), isorhamnetin (D), rutin (E), formononetin (F) and baicalin (G; IS).

Figure 1

Chemical structures and full scan product ion of precursor ions of cynaroside (A), quercetin (B), luteolin (C), isorhamnetin (D), rutin (E), formononetin (F) and baicalin (G; IS).

Figure 1

Chemical structures and full scan product ion of precursor ions of cynaroside (A), quercetin (B), luteolin (C), isorhamnetin (D), rutin (E), formononetin (F) and baicalin (G; IS).

Figure 2

Typical chromatograms of (A) blank rat plasma; (B) blank rat plasma spiked with six analytes and IS at LLOQ; (C) normal group rat plasma sample 2 h after administration of Maydis stigma decoction at a dose of 5.0 g·kg⁻¹. Representative MRM chromatograms of cynaroside (I), quercetin (II), luteolin (III), isorhamnetin (IV), rutin (V), formononetin (VI) and baicalin (VII; IS).

Figure 2

Typical chromatograms of (A) blank rat plasma; (B) blank rat plasma spiked with six analytes and IS at LLOQ; (C) normal group rat plasma sample 2 h after administration of Maydis stigma decoction at a dose of 5.0 g·kg⁻¹. Representative MRM chromatograms of cynaroside (I), quercetin (II), luteolin (III), isorhamnetin (IV), rutin (V), formononetin (VI) and baicalin (VII; IS).

Figure 3

Plasma concentration-time curves for cynaroside (A), quercetin (B), luteolin (C), isorhamnetin (D), rutin (E), formononetin (F) in rat plasma after oral administration of Maydis stigma decoction at 5.0 g·kg⁻¹ to rats in normal and diabetic groups. Each point represents the mean ± S.D. (n = 6).

Figure 3

Plasma concentration-time curves for cynaroside (A), quercetin (B), luteolin (C), isorhamnetin (D), rutin (E), formononetin (F) in rat plasma after oral administration of Maydis stigma decoction at 5.0 g·kg⁻¹ to rats in normal and diabetic groups. Each point represents the mean ± S.D. (n = 6).