Gelsemium elegans ( G. elegans ) is an extremely poisonous plant that is widely distributed in southern China and southeastern Asia. G. elegans poisoning events occur frequently in southern China, and are therefore an urgent public health problem requiring multidisciplinary action. However, the toxic components and toxicological mechanisms remain unclear. Here, we describe a systematic investigation on the toxic components of G. elegans , resulting in the isolation and identification of 120 alkaloids. Based on acute toxicity screening, the structure–toxicity relationship of Gelsemium alkaloids was proposed for the first time. Moreover, gelsedine- and humantenine-type alkaloids were detected in the clinical blood sample, and were confirmed to be causative in the poisoning. The most toxic compound, gelsenicine ( 1 ), had selective inhibitory effects toward ventral respiratory group (VRG) neurons in the medulla, which is the main brain region controlling respiration in the central nervous system. Gelsenicine ( 1 ) strongly inhibited the firing of action potentials in VRG neurons through its ability to stimulate GABA A receptors, the main receptors involved in inhibitory neurotransmission. Application of GABA A receptor antagonists successively reversed action potential firing in gelsenicine ( 1 )-treated VRG neurons. Importantly, the GABA A receptor antagonists securinine and flumazenil significantly increased the survival of poisoned animals. Our findings provide insight into the components and mechanisms of G. elegans toxicity, and should assist the development of effective emergency treatments for G. elegans poisoning.
Dong Qu,Dong-Fang Qiao,Xun-Cai Chen,Chun-Qiong Feng,Qi-Zhi Luo,Xiao-Hui Tan
We present a case of fatal poisoning from accidental ingestion of Gelsemium elegans ( G. elegans ), a rarely toxic plant. A 41-year-old man was found dead, at his home, 6 h after drinking homemade herbal liqueur during lunch. Autopsy and routine toxicological analyses identified neither significant pathological findings nor routine poisons. However, a local botanist revealed that the homemade herbal liqueur contained G. elegans , a poisonous plant specific to Asia. To ascertain whether the decedent had ingested G. elegans , we performed liquid chromatography-mass spectrometry (LC-MS) and found two alkaloids (gelsemine and koumine) in his blood, gastric contents, as well as the suspected herbal liqueur. The cause of death was therefore confirmed to be G. elegans poisoning. Case reports of fatal poisoning due to ingestion of G. elegans are quite rare in English. Therefore, the present case broadens the scope on the possibility of death due to ingestion of G. elegans for forensic pathologists and toxicologists.