Assessment of Trans-Environmental Transitions of Heavy Metals and Arsenic in Herbal Drugs and Herbal Medicinal Products of Valerian Rhizomes with Roots and Motherwort Herb

Abstract

Scientific relevance. In the context of pharmacopoeial harmonisation, the available methods for quantifying the total heavy metal content in tinctures are not sufficient to demonstrate the safety of liquid dosage forms based on herbal drugs. However, the establishment of individual limits for the heavy metal content requires analysing the patterns of environmental toxicant transitions from plant raw materials to herbal medicinal products in finished dosage forms.Aim. This study aimed to analyse the trans-environmental transitions of heavy metals and arsenic from the soil through plants to herbal medicinal products using a case study of aqueous and alcoholic extracts of valerian and motherwort herbal drugs.Materials and methods. The study focused on motherwort herb and valerian rhizomes with roots, the corresponding herbal medicinal products, and the rhizospheric soil. The elemental composition of the studied samples was determined by inductively coupled plasma mass spectrometry.Results. The authors determined the content of 15 elements (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Cd, Sb, Hg, and Pb) in plant raw materials, the rhizosphere, and herbal drug infusions and tinctures. The concentrations of elements were 0.002–109.884 mg/kg in motherwort herb samples and 0.017–866.618 mg/kg in the samples of valerian rhizomes with roots. Pb, Cd, and As were detected in all plant raw materials, while Hg was found only in 25% of the study samples. The content of these elements was within acceptable limits. Valerian and motherwort infusions contained all elements, except for Hg; valerian tinctures were free from Fe and Hg; and motherwort tinctures included no Fe, Hg, Sr, Cd, and Pb. The concentrations of elements in the infusions did not exceed 3.169 mg/kg, while the concentrations of elements in the tinctures were below 1.27 mg/kg. In the tinctures, Zn, Cu, Mg, and Ti were the most abundant elements, and Sb and Cd were present in minimum amounts.Conclusions. Valerian and motherwort plants can concentrate Cu, Cr, Fe, and V from the soil. The transition of heavy metals and arsenic into infusions did not exceed 65% of the content of these elements in herbal drugs, while tinctures contained less than 30% of the content of heavy metals and arsenic in herbal drugs. Some elements passed into infusions 1.5–5 times more efficiently than into tinctures.