**5. Conclusions**

In the present study, a comprehensive set of PAs in 21 types of (herbal) teas were analyzed using LC-MS/MS and the total PA levels were corrected by the REP factors for each PA. Based on these data, the risk assessment for (herbal) teas was performed using the MOE approach, assuming a daily consumption of one cup of tea. Most of the tea samples (92.5%) were detected with PAs. The measured total PA levels were ranged from 13.4 to 286,682.2 μg/kg d.m., while the levels were decreased by REP correction, ranging from 1.3 to 286,648.3 μg/kg d.m.. Senkirkine plus its isomer neosenkirkine were the dominant PAs in most of the (herbal) teas which were derived from PA-containing plants, while echinatine, retrorsine, integerrimine, senecionine and their *N*-ox isomers were the major PAs detected in the non-PA producing teas. In general, the PA levels in PA-producing plant-derived teas were higher than those from non-PA producing plants. Hence, efforts

should be made to reduce or avoid the use of raw materials from PA-producing plants as tea components in terms of controlling PA intake.

The MOEs for PAs due to the intake of (herbal) teas for a life-time and during a shortterm period of two weeks per year were calculated using the BMDL10 of riddelliine as the new PoD and 70 kg for the estimated adult body weight, amounting to values ranging from 29 to >1,000,000 and from 725 to >1,000,000, respectively. These values were increased by REP correction in most of the (herbal) teas. Despite this, our data indicate that daily consumption of tephroseris, borage and lemon balm (melissa) tea during a lifetime may raise a concern. In addition, shorter-than-lifetime exposure due to an intake of tephroseris tea would be a health concern and may pose a potential non-carcinogenic risk. Therefore, a priority for a risk management of tephroseris tea should be warranted.

To our best knowledge, this is the first study that applied the REP factors for risk assessment for PA exposure from (herbal) teas. In addition, 68 individual 1,2-unsaturated PAs were included to improve the accuracy of the assessment on associated health risks. The number of the analyzed PAs in our study is higher than the requirement of the ESFA as well as of that in the other studies [2,3,13,42,45,46]. On the other hand, there were some limitations in this study. For example, the lack of sufficient dietary survey data regarding tea consumption for different age population and in different scenarios leads to a compromised evaluation on the actual risks. Additionally, despite that applying Haber's rule may provide a reasonable first approach for an MOE-based risk assessment for a shorter-than-lifetime exposure, this approach awaits to be validated [21]. Nevertheless, the results of the current study present the need for the development of a widely accepted method for assessing the risks of botanicals and botanical preparations containing genotoxic and carcinogenic compounds during a shorter-than-lifetime exposure.

**Supplementary Materials:** The following supporting information can be downloaded at: https:// www.mdpi.com/article/10.3390/foods11192946/s1, Supporting data S1, Table S1: Mass parameters for individual PA compounds; Supporting data S1, Table S2: The REP factors of individual PA and their N-ox congeners in this study according to Merz and Schrenk (2016); Supporting data S2.

**Author Contributions:** Conceptualization, W.S.; formal analysis, Q.Z.; investigation, L.C., Z.Y., Y.C., W.X. and D.S.; writing—original draft preparation, L.C. and Q.Z.; writing—review and editing, W.S.; visualization, L.C.; supervision, W.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Data Availability Statement:** Data is contained within the article or supplementary material.

**Conflicts of Interest:** The authors declare no conflict of interest.
