Investigation of targeted pyrrolizidine alkaloids in traditional Chinese medicines and selected herbal teas sourced in Ireland using LC-ESI-MS/MS

Abstract

Publications linking hepatotoxicity to the use of herbal preparations are escalating. Herbal teas, traditional Chinese medicines (TCMs) and dietary supplements have been shown to contain pyrrolizidine alkaloids (PAs). Acute PA toxicosis of the liver can result in sinusoidal-obstruction syndrome, also known as veno-occlusive disease (VOD). This paper describes a sensitive and robust method for the detection of targeted PAs and their N-oxides (PANOs) in herbal products (selected herbal teas and TCMs) sourced within Ireland. The sample preparation includes a simple acidic extraction with clean-up via solid-phase extraction (SPE). Sample extracts were accurately analysed by using LC-ESI-MS/MS applying for the first time a pentafluorophenyl (PFP) core-shell column to the chromatographic separation of PAs and PANOs. The method was validated for selectivity, taking into consideration matrix effects, specificity, linearity, precision and trueness. Limits of detection (LOD) and limits of quantitation (LOQ) were quantified for all PAs and PANOs ranging from 0.4 to 1.9 µg kg⁻¹ and from 1.3 to 6.3 µg kg⁻¹, respectively. In this study 10 PAs and four PANOs were targeted because they are commercially available as reference standards. Therefore, this study can only report the levels of these PAs and PANOs analysed in the herbal teas and TCMs. The results reported represent the minimum levels of PAs and PANOs present in the samples analysed; commercially available herbal teas (n = 18) and TCMs (n = 54). A total of 50% herbal teas and 78% Chinese medicines tested positive for one or more PAs and/or PANOs included within this study, ranging from 10 to 1733 and from 13 to 3668 µg kg⁻¹, respectively.

Occurrence of Pyrrolizidine Alkaloids in food

“…The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors. The results obtained in this survey for (herbal) teas correlate well with the results reported from other recent studies (BfR, 2013;Bodi et al, 2014;Mathon et al, 2014;Griffin et al, 2014;Schulz et al, 2015). The most important results of these recent studies will be briefly discussed below.…”

“…Since the start of this project some data on the occurrence of PAs in (herbal) teas and supplements have been published elsewhere (Bodi et al, 2014;Griffin et al, 2014;Mathon et al, 2014;Schulz et al, 2015).…”

“…The study of Griffin et al included a smaller number of (herbal) teas. Griffin et al (2014) analysed 18 herbal dry teas available from the Irish market using LC-MS/MS. The method included 10 PA FBs and 4 PANOs and the LODs (0.4-1.5 µg/kg in dry tea) were comparable to this study (Table 16).…”

Dehydropyrrolizidine Alkaloid Toxicity, Cytotoxicity, and Carcinogenicity

“…Most of these products are not regulated and many, inadvertently or intentionally, contain DHPA-producing plants [10]. Some traditional Chinese medicines and other herbal teas sourced in Ireland have been found to contain DHPAs, even though DHPA-containing plants are not listed as ingredients [11]. Similar problems are likely elsewhere.…”

Novel strategies for risk assessment of pyrrolizidine alkaloids

“…In hot water extracts from intact and comminuted leaves the amount of PA N-oxides dominated over that of PA free bases, which is in line with other studies However, in the herbal medicines the PAs were present solely in the free-base form. In line with this, Griffin et al (2014) reported that only 6 samples out of a total of 54 herbal medicines contained PA Noxides (Griffin et al, 2014).…”