Comparative Analysis of Heavy Metal and Arsenic Content in Various Herbal Dosage Forms Marketed in Russia

Abstract

The inclusion of requirements for independent determination of arsenic, cadmium, mercury, and lead, and the current sample preparation techniques into the State Pharmacopoeia of the Russian Federation (Ph. Rus.) requires the revision of the existing limits for elemental toxicants in herbal substances and herbal medicinal products produced from them.The aim of the study was to analyse the data on elemental toxicant content obtained during quality control of herbal substances (herbs, medicinal herb mixtures, extracts, and tinctures) using current test methods and sample preparation techniques, and to compare the obtained results with the Russian and foreign scientific and specialist literature.Materials and methods: the internal data on the content of critical heavy metals and arsenic in different dosage forms of herbal medicinal products, which were obtained by inductively coupled plasma mass spectrometry after sample preparation by decomposition in closed vessels, were compared with literature data. Results: it was demonstrated that the content of lead, cadmium, and mercury in all the test samples did not exceed the Ph. Rus. limits and was consistent with the analysed literature. The arsenic content in some herbal medicinal products was higher than the established Ph. Rus. limits, but complied with the less stringent Ph. Eur. and USP requirements for herbal substances. The authors investigated the link between the content of elemental toxicants and the place of collection and the part of the plant being tested. It was shown that different types of medicinal plants had a tendency to accumulate particular elements. The authors determined the content of the elements to be controlled in extracts and tinctures. The differences in the Russian and foreign requirements for the content of elemental toxicants may be attributed to the method of obtaining experimental data that form the basis for the setting of limits.Conclusions: the results of the study confirm the validity of the existing limits for elemental toxicants in herbal medicinal products. The authors demonstrated the need to revise the existing limits for arsenic in herbal medicinal products.

Chemistry of medicinal plants as an integral part of ecological education

“…Increased impurities in wild plants are usually associated with human economic activity. Excessive accumulation of toxic contaminants in plants does not always affect their appearance [22]. It creates an additional danger of consuming contaminated plants, which cannot be foreseen only by external inspection.…”

“…Other plants, known as accumulators, show the effect of hyperaccumulation of cadmium or other ions [18,19]. However, even the high content of toxic elements can sometimes not affect plant appearance [22]. Therefore, contaminated and clean plants can be difficult or impossible to distinguish.…”

Accumulation of heavy metals in the organs of herbaceous plants

“…HM are among the most widespread and dangerous for biota environmental pollutants [2]. On the one hand, they are necessary for the normal course of physiological processes, and on the other hand, at high concentrations of HM, they are toxic [3,4,5]. In this regard, the determination of the level of HM content in plants plays an important role in the assessment of biogenic migration and is necessary for control for their environmentally safe use [6].…”

Limits for the Content of Heavy Metals and Arsenic as a Means of Ensuring Safe Use of Herbal Medicinal Products

“…Современные исследования новых и традиционно используемых видов ЛРС, как правило, включают раздел по оценке содержания ТМ и мышьяка. Однако исследования, касающиеся возможности и последствий их поступления в организм человека с ЛРП, немногочисленны [6][7][8][9][10][11].…”

“…Вследствие высокого сродства ТМ к сере сульфгидрильные группы таких белков прочно связывают ионы, защищая клетки от их токсического действия. Реакция образования сульфидов лежит в основе полуколичественного определения ТМ в лекарственных препаратах 6 [16].…”