Determination of swainsonine in the endophytic Undifilum fungi by high-performance liquid chromatography with evaporative light-scattering detector

Abstract

Endophytic Undifilum oxytropis found within toxic locoweeds (Astragalus and Oxytropis spp.) produces the indolizidine alkaloid swainsonine, which is responsible for locoism in grazing animals. The aim of the current study is to establish an easy and accurate method for the determination of swainsonine in the endophytic Undifilum fungi. High-performance liquid chromatography (HPLC) with evaporative light-scattering detector (ELSD) was used for the assay of swainsonine in this study for the first time. The HPLC conditions were Waters XBridge hydrophilic interaction liquid chromatography column using acetonitrile-5mM ammonium acetate (1:1, vol/vol) containing 0.02% (vol/vol) aqueous ammonium hydroxide as mobile phase at a flow rate of 0.5mL/min. ELSD conditions were optimized at nebulizer-gas flow rate of 25psi and drift tube temperature of 55°C. The method was validated to achieve the satisfactory precision and recovery, and the calibration range was 15.625–250μg/mL. Application of the developed analytical procedure to determine swainsonine content in the endophytic Undifilum fungi samples ensured its suitability for the routine analysis of swainsonine.