A survey of swainsonine content in Swainsona species

Abstract

The indolizidine alkaloid swainsonine is an inhibitor of α-mannosidase and mannosidase II that causes lysosomal storage disease and alters glycoprotein processing. Several plant species worldwide contain swainsonine, grazing these plants may cause severe toxicosis in livestock, leading to a chronic disease characterised by altered behaviour, depression, weight loss, decreased libido, infertility and death. Swainsona is a large genus of the Fabaceae family with all species but one being endemic to Australia. Swainsonine has previously been reported to be, or expected to be, present in 26 Swainsona species in Australia. Methods of detection in these 26 species were a jack bean α-mannosidase inhibition assay, gas chromatography, or gas or liquid chromatography coupled with mass spectrometry. Seven of these 26 Swainsona species are reported to be toxic, and for three of these no chemical assay for swainsonine has been undertaken. Only 1 of the 26 species has been analysed for swainsonine using modern instrumentation such as gas or liquid chromatography coupled with mass spectrometry. Using both liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry, 248 specimens representing 41 Swainsona species were screened in the present study for swainsonine. Swainsonine was detected in 9 of the 41 Swainsona species, eight of which had not been determined to contain swainsonine previously using modern instrumentation. The list of swainsonine-containing taxa reported here will serve as a reference for diagnostic purposes and risk assessment.