Chemical Analysis of an Ayurvedic Herbo-Metallic Preparation Containing Mercury: Speciation of Mercury

Ayurvedic medicine is a traditional medicine native to the Indian subcontinent [1] and is practiced in other parts of the world as alternative medicine. Ayurvedic practitioners developed a number of medicinal preparations from plants, animal products, fats and minerals. The majority of Ayurvedic medicines are plant based medicines, where as one group of medicine adds minerals to herbal medicine is known as rasa shastra [2]. Arogyavardhini Vati (means improves good health, AVV) is a one of the most commonly used multi-ingredient formulation in Ayurvedic system of medicine. AVV formulation has been successfully used by traditional practitioners for the treatment of various disorders especially to eliminate toxins by laxative action, therefore it is recommended in chronic constipation and skin disorders. Moreover, it possesses cholagogue, hepatoprotective [3] and liver stimulant action and is widely prescribed for jaundice, hepatitis [4] and chronic indigestion. Chemically, AVV is a mercury metal based formulation found to be stoichiometrically HgS, also contains Cu, Fe, and various other botanicals such as E. officinalis, T. chebula, T. bellirica, P. zeylanicum, Picrorhiza kurroa and gum of mukkul. Although generally safe, the ingredients used in Arogyavardhini have the potential to cause side effects due to heavy metals and toxic chemicals. To study the toxicity due to heavy metals in alternative medicine, various techniques like infrared spectroscopy (IR), HPTLC and ICP-MS [5] were used for characterization of AVV sample in triplicate. The results from IR and HPTLC revealed presence of metal oxides and organic matter from plant material, whereas ICP-MS method showed the presence of various proportions of elements such as Na, K, Ca, Cr, Mg, V, Fe, Cu, Mn, Ni, Zn which have been found in mg/g and some in µg/g amounts in addition to the major constituent element. This method also describes the HPLC coupled to inductively-coupled plasma mass spectrometry (ICP-MS) for the separation and determination of Hg species (inorganic Hg, methyl and ethyl mercury). The different chemical forms of mercury exhibit different toxicities, separating elemental mercury from the alkylated forms provide vital information on the actual risk by a sample.

Figure 1: HPLC-ICP-MS chromatograms of standard mix [Hg²⁺ (1), Me-Hg (2) and Et-Hg (3)] and AVV samples

Acknowledgements: This research is supported in part by „Science Based Authentication of Dietary Supplements“ and „Botanical Dietary Supplement Research“ funded by the Food and Drug Administration grant numbers 5U01FD002071–10 and 1U01FD003871–02, and the United States Department of Agriculture, Agricultural Research Service, Specific Cooperative Agreement No. 58–6408–2-0009.

References: [1] Chopra AS, (2003) "Ayurveda" In Selin, Helaine. Medicine Across Cultures: History and Practice of Medicine in Non-Western Cultures. Norwell, MA: Kluwer Academic Publishers. pp. 75–83. [2] "Ayurveda" New Delhi, India: Department of Ayurveda, Yoga & Naturopathy, Unani, Siddha and Homoeopathy, Ministry of Health & Family Welfare, Government of India. [3] Reddy BP, (1993) Indian J Pharmaceut Sci, 55(4): 137–40. [4] Antarkar DS, et al. (1980) The Indian J Med Res, 72: 588–93. [5] Caroli S, et al. (1996) Element Speciation in Bioinorganic Chemistry, Wiley, Chapter 13.