Up to 500 species of Panicum (panic grasses) are recognised worldwide, of which 24 species are indigenous to Australia and nine introduced. Recently, some of the introduced summer-growing annual Panicum spp. have been identified with high prevalence across southern Australia. Certain Panicum species have also been implicated in severe outbreaks of hepatogenous photosensitization in livestock, characterized by crystal-associated cholangiohepatopathy. The causal compound(s) responsible for liver dysfunction in livestock ingesting Panicum spp. have been previously identified as steroidal saponins. Although metabolic profiling of Panicum spp. has been undertaken in the USA and NZ, the saponins implicated in toxic outbreaks in Australia have not yet been identified. In this study, fresh shoot tissue from three introduced (P. capillare,P. hillmanii and P. gilvum) and two native (P. decompositumand P. effusum) species were extracted in methanol and analysed by UPLC/QTOF mass spectrometry. The relative abundance of key steroidal saponins was determined based on specific molecular features including retention time, mass spectra and fragmentation pattern when compared to saponin analytical standards. Distinct qualitative and quantitative differences were observed in the saponin profiles of the Panicum species evaluated, including in the type, number and abundance of the saponins detected, such as protodioscin and pseudoprotodioscin. In vitro cytotoxicity assays of shoot extracts collected from Panicum-related photosensitization outbreaks will be performed to further identify key steroidal saponins and saponin profiles associated with hepatogenous photosensitization in grazing livestock.
|Number of pages||1|
|Publication status||Published - 2018|
|Event||10th International Symposium on Poisonous Plants : ISOPP 10 - Red Lion Conference Center, St George , United States|
Duration: 16 Sep 2018 → 20 Sep 2018
|Conference||10th International Symposium on Poisonous Plants|
|Period||16/09/18 → 20/09/18|
Chen, Y. (2018). Metabolic profiling of cytotoxic steroidal saponins in five Australian Panicum species. 71-71. Abstract from 10th International Symposium on Poisonous Plants , St George , United States.