Evaluation of the concentration of minerals and heavy metals in some medicinal plants and the safety of their consumption

Besides their therapeutic value, medicinal plants can also contain varying levels of minerals and heavy metals, affecting the quality and safety for use. This could affect how safe and of what quality they are when taken by humans. In this case, we analyzed a series of elements (Na, K, Ca, Mg, Fe, Mn, Zn, Ni, Cr, and Pb) found in plants like Trifolium pratense L., Urtica dioica L., Sideritis scardica Griseb., Origanum vulgare L., Allium ursinum L., and Althaea officinalis L. The analytical method used in order to quantify these concentrations was Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), which is very precise for such an analysis. We noticed that the levels of these elements were not equal across the plants — they were significantly different from each other. Most of the mineral levels were within what is considered acceptable under the Recommended Dietary Allowance (RDA) and Estimated Daily Intake (EDI). In the case of heavy metals (i.e., Cr, Ni, and Pb), Target Hazard Quotient (THQ) and Hazard Index (HI) values came out lower than 1, which means that presumably there is no considerable health hazard in the event of consuming these plants in normal contents. These results indicate the necessity for the systematic evaluation of concentrations of such elements in plant-based drugs and general environmental assessment of their natural habitats to ensure consumer safety.