Findings on the heavy metal content in herbal drugs and essential oils – An updated database evaluation

Abstract

In order to guarantee the safety of patients and consumers, the European legal framework restricts the content of heavy metals and further elements in plant material used for the production of medicinal and food products. This data evaluation comprises findings on seven elements between 2016 and 2021 which were assessed against the requirements of the European Pharmacopoeia (Ph.Eur.) and the ICH Q3D guideline on elemental impurities. !5.328 herbal drug samples from 427 products and 537 essential oil samples from 25 products were included in this evaluation which demonstrates that the Ph. Eur. limits set for cadmium, lead and mercury are considered appropriate. Samples from organic production revealed a lower occurrence of cadmium, lead and mercury as compared to samples from conventional production. With regard to the ICH Q3D requirements, none of the herbal drug samples exceeded the respective limit for cobalt, nickel and vanadium, while for arsenic higher values were observed in individual cases. A comparison of the findings with a former period of evaluation showed an increase in positive findings and also a few more exceedances of the Ph.Eur. limits. For essential oils, it can be confirmed that independent from the production process, the probability of heavy metal contamination is low.