Heavy Metals (Lead and Cadmium) in some Medicinal Herbal Products in Iranian Market

The use of herbal or medicinal plants in various forms has been popular for thousands of years. It is estimated that about 70–80% of the world’s population relies on alternative medicine, mainly of herbal origin. However, due to the nature and sources of these plants, they are sometimes contaminated with toxic heavy metals, which pose serious health risks to consumers. Herbal formulations, especially those used in the treatment of diseases such as hypertension, diabetes, and weight loss may require long-term usage and the patient might be at risk of heavy metal poisoning. In this study, the levels of toxic heavy metals (Pb, Cd) were evaluated in 11 Iranian common herbal drugs for their health implications. In this investigation, concentrations of lead and cadmium were quantitatively determined in Iranian herbal drugs sampled from pharmacies in Tehran, Iran, using atomic absorption spectrophotometry (wet digestion). The results indicated that lead and cadmium were present in all investigated herbal drugs. The concentrations of metals in drugs ranged from 0.19 to 1.75 µg/g for Cd and 9.61 to 52.74 µg/g for Pb. The concentrations of lead and cadmium were higher than the maximum permissible daily levels in the majority of these herbal drugs, whereas the quantities of Pb and Cd were well below provisional tolerable weekly intake (PTWI). Daily total intake of these metals is considered in accord with the recommended daily intake of their corresponding formulations.