Toxicity assessment of gelsenicine and the search for effective antidotes.

BACKGROUND: Gelsenicine, one of the most toxic alkaloids of Gelsemium elegans Benth (G. elegans), causes severe respiratory depression. However, its toxicity mechanisms are yet to be elucidated and no effective antidotes are available. OBJECTIVE: This study aimed to analyse the toxicity characteristics of gelsenicine. METHODS: Both acute and sub-acute toxicities were evaluated. Gelsenicine distribution and elimination in the central nervous system (CNS) and blood were observed. Effective antidotes for gelsenicine poisoning were screened. RESULTS: In the acute toxicity study, gelsenicine was highly toxic, and female rats exhibited greater sensitivity to gelsenicine than male rats (LD50 0.520 mg/kg vs 0.996 mg/kg, respectively). Death was primarily caused by respiratory failure. However, in the sub-acute toxicity study, no significant organ damage was observed. Gelsenicine was easily absorbed from the gastrointestinal tract and penetrated the blood-brain barrier, reaching peak concentrations in the CNS within 15 min and rapidly decreasing thereafter. Flumazenil or diazepam combined with epinephrine reversed gelsenicine toxicity and significantly improved survival rate in mice. CONCLUSIONS: Gelsenicine is a highly toxic substance that affects nerve conduction without causing damage; the potential toxic mechanism is possibly associated with GABAA receptors. Our findings provide insights into the clinical treatment of gelsenicine-related poisoning and its toxicity mechanisms.

The multicomponent residue depletion of Gelsemium elegans in pig tissues, urine, and plasma.

Introduction: Gelsemium elegans (G. elegans) as a traditional medicinal plant used in livestock production. The use of G. elegans in veterinary clinics may pose safety risks to human health. Objectives: The aim of this study was to investigate tissue residue depletion in pigs fed G. elegans powder. Methods: A precise quantitation method and a simultaneous semi-quantitation method for multiple components independently of standards in pig tissues were developed for the first time. The two methods were validated in terms of specificity, LODs, LOQs, linearity, accuracy, precision, and matrix effects. They were then applied to a tissue residue depletion study after G. elegans powder at a dose of 2% per kg feed were fed to pigs. Results: Compared with precise quantitation, the method validation results indicated that the semi-quantitation method was reliable and acceptable for multicomponent quantification independent of standards. Many G. elegans alkaloids are widely distributed in most tissues of pigs. Tissue residue depletion studies indicated that 14-hydroxygelsenicine, 11-hydroxygelsenicine, and gelsemoxonine could be used as potential residue markers, and pancreas, small intestine, and lung tissues could be considered as potential residue target tissues of G. elegans. In addition, both urine and plasma could be used to predict 14-hydroxygelsenicine and gelsemoxonine residues in the liver, pancreas, and small intestinal tissues of pigs. Conclusion: The developed semi-quantification method can be applied to monitor the application and residue of G. elegans. The results provide scientific evidence for evaluating the safety of animal-derived food from G. elegans for consumers and will be helpful for its application and future development.

Comparative toxicokinetic profiles of multiple-components of Gelsemium elegans in pigs and rats after a single oral administration.

Gelsemium elegans Benth (G. elegans) is highly toxic to humans and rats, but has insecticides and growth promoting effects on pigs and goats. G. elegans is widely used in livestock, but its in vivo dynamics are entirely unknown. Hence, we investigated the toxicokinetic profiles of G. elegans alkaloids after a single oral dose of G. elegans to pigs (1.0 g/kg) and rats (0.1 g/kg). The results indicated that rats were more susceptible to the toxicity of G. elegans than pigs. The toxicokinetic parameters of 22 and 6 components were obtained in pigs and rats, respectively. The components included 9 and 5 gelsedine-type alkaloids in pigs and rats, respectively. The Tmax results of the 5 gelsedine-type alkaloids indicated that these alkaloids were rapidly absorbed in pigs and rats. The T1/2 values of the 5 gelsedine-type alkaloids indicated that the elimination rates of these alkaloids in pigs were slower than those in rats. In addition, the Cmax and AUC results indicated that the degrees of absorption and exposure of most alkaloids in pigs were higher than those in rats except GS-2. However, the Cmax value of GS-2 (11-methoxy-14-hydroxygelsenicine) in rats was greater than that of pigs, and the Cmax value of 14-hydroxygelsenicine in pigs was merely greater than 3 times that of rats. The present results suggested that the cause of the toxicological differences species of G. elegans might be related to the degrees of absorption and exposure of gelsedine-type alkaloids, especially for the 14-hydroxygelsenicine and GS-2 in different animals.

An analytical strategy to explore the multicomponent pharmacokinetics of herbal medicine independently of standards: Application in Gelsemium elegans extracts.

The multicomponent pharmacokinetic study of herbal medicine is a great challenge due to the low plasma concentrations, large range of concentration scales, lack of authentic standards and uncertain interactions of the components. The aim of this work was to explore the in vivo pharmacokinetics of herbal medicine independently of authentic standards using an integrated analytical strategy. First, ion pairs of multiple components were tuned and selected, and then major parameters were optimized for derivative multiple reaction monitoring (DeMRM) by LC-MS/MS, which was combined with characterization of the chemical profiles of the herbal medicine by LC-QqTOF/MS. Second, different concentrations of herbal extracts were employed instead of authentic standards to construct calibration curves for the semiquantitative determination of multiple components in plasma. Taking Gelsemium elegans as an example, in addition to the fully validated and sufficient methodological results, a total of 27 alkaloid components, major bioactive constituents of Gelsemium elegans, were simultaneously monitored in pig plasma. The concentration-time profiles and pharmacokinetic properties of these 27 components were characterized. The absolute quantification of three components was compared with the results obtained using authentic standards, and the method showed very similar analytical characteristics, such as linearity, precision, accuracy, and the values of the pharmacokinetic parameters Tmax, Vd, Cl and MRT. This analytical strategy was found to be capable of assessing herbal pharmacokinetics independently of specific authentic compounds for each component. This study was the first attempt to systematically reveal the in vivo pharmacokinetics of Gelsemium elegans. This strategy and methodology will find widespread use in the quantitative pharmacokinetic analysis of multiple components independently of standards for herbal medicine, among other applications.

Development and in-house validation of a sensitive LC-MS/MS method for simultaneous quantification of gelsemine, koumine and humantenmine in porcine plasma.

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.