Seasonal Variability in Pyrrolizidine Alkaloids in Jacobaea alpina from the Trentino-Alto Adige Region (Northern Italy)

In recent years, increased attention has been given to plants containing toxic pyrrolizidine alkaloids (PAs). Jacobaea alpina (syn. Senecio cordatus) is a tall forb growing on mountain pastures and meadows containing such alkaloids and therefore, the plant is considered as a noxious weed in these environments. The repartition of toxic macrocyclic PAs in the plant and their evolution during the vegetation period has been studied in two populations. Eight PAs were found where senciphylline and senecionine accounted in most samples for more than 85 % of total alkaloids. Leaves in April and stems in May started with high PA concentrations (19-22 mg/g dry matter), then alkaloid levels declined. This decrease was more rapid in stems than in leaves. Depending on the population, fully developed inflorescences in June and July PA contents were higher or lower than in the respective leaves. Later, also in the inflorescences PA concentration decreased. Combined with growth data total alkaloid content in the whole plant as mg/plant was highest in midsummer and declined afterwards. Finally, new emerging leaves in September had high PA levels, which declined markedly towards the end of the season in November. In sum, over a large period PA concentration appeared to be high enough to present a health risk for grazing animals.

LC-MS/MS method for determination of seneciphylline and its metabolite, seneciphylline N-oxide in rat plasma, and its application to a rat pharmacokinetic study

A rapid and sensitive ultra-performance liquid chromatography-tandem electrospray ionization mass spectrometry (UPLC-ESI/MS) method was established and validated for simultaneous determination of seneciphylline and its main metabolite in rat plasma. The plasma sample was prepared by simple methanol-mediated precipitation. Chromatographic separation was achieved within 3 min by gradient elution using acetonitrile and water containing 0.1% formic acid as mobile phase on a Waters ACQUITY BEH C18 column (100 × 2.1 mm, i.d. 1.7  μm). Quantitation was conducted in a positive multiple reaction monitoring mode. The linearity of the method was over the range of 1-1,000 ng/mL, with the lower limit of quantification of 1 ng/mL. The intra- and inter-day precision and accuracy, extraction recovery, and matrix effect of analytes were within the acceptable limit. The analytes were stable during the process of sample collection, preparation, and analysis. The validated method was further applied to a pharmacokinetic study of seneciphylline in rats after oral and intravenous administration. The results revealed that seneciphylline was quickly absorbed into plasma (T_max , 0.23-0.32 h) and reached the maximum concentration of 0.82-1.75 μg/mL after oral administration. Both seneciphylline and seneciphylline N-oxide were eliminated from plasma quickly. The low system exposure (oral bioavailability, 5.43-10.31%) was related to the extensive metabolism in the liver and microflora.

Seneciphylline, a main pyrrolizidine alkaloid in Gynura japonica, induces hepatotoxicity in mice and primary hepatocytes via activating mitochondria-mediated apoptosis

Herbal drug-induced liver injury has been reported worldwide and gained global attention. Thousands of hepatic sinusoidal obstruction syndrome (HSOS) cases have been reported after consumption of herbal medicines and preparations containing pyrrolizidine alkaloids (PAs), which are natural phytotoxins globally distributed. And herbal medicines, such as Gynura japonica, are the current leading cause of PA-induced HSOS. The present study aimed to reveal the mechanism underlying the hepatotoxicity of seneciphylline (Seph), a main PA in G. japonica. Results showed that Seph induced severe liver injury through apoptosis in mice (70 mg/kg Seph, orally) and primary mouse and human hepatocytes (5-50 μM Seph). Further research uncovered that Seph induced apoptosis by disrupting mitochondrial homeostasis, inducing mitochondrial depolarization, mitochondrial membrane potential (MMP) loss, and cytochrome c (Cyt c) release and activating c-Jun N-terminal kinase (JNK). The Seph-induced apoptosis in hepatocytes could be alleviated by Mdivi-1 (50 μM, a dynamin-related protein 1 inhibitor), as well as SP600125 (25 μM, a specific JNK inhibitor) and ZVAD-fmk (50 μM, a general caspase inhibitor). Moreover, the Seph-induced MMP loss in hepatocytes was also rescued by Mdivi-1. In conclusion, Seph induced liver toxicity via activating mitochondrial-mediated apoptosis in mice and primary hepatocytes. Our results provide further information on Seph detoxification and herbal medicines containing Seph such as G. japonica.