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Study of essential and toxic elements content in medicinal herbs harvested in Ukraine

Purpose: Medicinal plants can origin both from their cultivation, and from collection in natural locations, therefore investigation of their chemical composition is indispensable for assuring the appropriate quality. Thus, the aim of the studies was evaluation of medicinal plants collected in natural locations in Ukraine in the light of their elemental contents, taking into consideration both essential elements - P, Cu, Zn, Fe, and toxic – Cr, Pb, Cd and Ni. Methods: The microwave-assisted digestion was applied for preparation of the samples prior to analysis of plant samples to quantitative determination of investigated elements by the flame technique of atomic absorption spectroscopy. Results: The results of studies show that there is a large differentiation of medicinal herbs originating from Ukraine from the point of view of their elemental contents. In many cases, e.g. birch leaves, the impact of botanical plant species on the level of elements was crucial. Hence, the loadings of principal components confirmed that the highest influence on the differentiation of studied plant samples had the concentrations of Cr, Zn, Cd and Fe. The impact of a place of growth on the level of selected elements such as Cd and Fe in St John’s wort was noticed, too. The analysis of toxic metals concentration in all studied plant samples has also shown that Pb and Cd level didn’t exceed the norms established by the European Union Commission in 2006. Conclusion: It is recommended to monitor heavy metals concentrations in medicinal herbs originating from Ukraine available in the European pharmaceutical market.