A LC–ESI–MS/MS analysis procedure coupled with solid phase extraction and MeOH extraction method for determination of pyrrolizidine alkaloids in Tussilago farfara and Lithospermi erythrorhzion

Pyrrolizidine alkaloids (PAs) that are plant toxin naturally produced for protection against herbivores in some plant families. They are associated with the potential hepatotoxic and carcinogenic diseases serious hepatic disease in humans and animals. As the concern of human health risk posed by exposure to PAs has been gradually increased, precise and reliable analysis is required for monitoring PAs. The present study developed a new and simple pretreatment using 50% MeOH (methanol) for quantification analysis of the PAs contained with high content in the herbal medicines. Another pretreatment method using cation-ion exchange solid-phase extraction (MCX-SPE) was employed for determining most of the PAs that are not contained in the herbal medicines. That is, the proposed LC–MS/MS method coupled with MCX-SPE extraction and 50% MeOH extraction method was developed. And to evaluate the reliability of its application for Farfarae Flos and Lithospermi Radix, a validation study was conducted. In addition, monitory study was performed with ten samples in each herbal medicine. As a result, the proposed method had good linearity with r2 ≥ 0.997. Also, the recoveries indicated to be in the ranges of 70.4–118.0% for the Farfarae Flos, 70.2–119.7% for the Lithospermi Radix. In two herbal medicines, the intra-day precision was revealed to satisfy the reference criteria in most of the PAs. In monitoring results, most of the PAs were not contained in two herbal medicines, whereas a part of PAs revealed to have high concentration in Farfarae Flos and Lithospermi Radix. The proposed method is considered as a simple and reliable method to quantify 28 PAs present in two herbal medicines. Especially, the simple MeOH extraction method seems to be available for quantification analysis of certain PAs in herbal medicines with high content.