Three monomers of G. elegans indole alkaloids (gelsemine, koumine and humantenmine) were simultaneously detected in porcine plasma for the first time with the development and validation of a sensitive and reliable LC-ESI-MS/MS method. Using a gradient mobile phase at a constant flow rate of 0.2 mL/min via electrospray ionization (positive ion mode) in a multiple reaction monitoring (MRM) scan, gelsemine, koumine and humantenmine were eluted, separated and detected at an appropriate retention time. The porcine plasma was prepared using protein precipitation with 1% formic acid-acetonitrile: methanol (2:1, v/v). Using matrix-matched calibration curves and weighted least squares linear regression, a good linearity (r2 > 0.99) was achieved with a concentration range of 0.1-200 μg/L for gelsemine, koumine and humantenmine; estimated LOD and LOQ values were 0.10 μg/L and 0.2 μg/L, respectively. The mean of the recoveries was in the range of 82.68-100.35% of porcine plasma at four different levels, and the intra-day and inter-day precision (CV) were lower than 15% with a range of 2.46-8.76% and 2.73-10.83%, respectively. The proposed method has proved to be suitable for accurate, quantitative determination of gelsemine, koumine and humantenmine in porcine plasma.
Keywords: Gelsemine; Gelsemium elegans; Humantenmine; Indole alkaloid; Koumine; Plasma.
Copyright © 2018. Published by Elsevier B.V.