Nutrients and toxic heavy metals in Strychnos cocculoides (Loranthaceae): Implications for traditional medicine

This study investigates the medicinal and toxicological profiles of Strychnos cocculoides, used in traditional medicine in Zambia, focusing on its nutrient content and heavy metal accumulation. Metals were extracted from dried plant samples using microwave digestion, and metal concentrations were determined using inductively coupled plasma optical emission spectrometry (ICP-OES). The concentrations of key nutrients such as calcium (Ca), potassium (K), and magnesium (Mg) were quantified in the plant's root, stem, and leaves, revealing its medicinal potential. However, some heavy metals were detected at concentrations above recommended values, raising concerns about health risks. Elevated metal concentrations in the plant include cadmium (Cd) at 2.8 mg/kg in the root and stem and 3.0 mg/kg in the leaf, exceeding the 0.3 mg/kg WHO/FAO limit; chromium (Cr) at 60.4 mg/kg in the root and 29.8 mg/kg in the stem, surpassing the 25.0 mg/kg guideline; iron (Fe) at 15,433.0 mg/kg in the root and 1421.8 mg/kg in the leaf, far exceeding the 425.5 mg/kg limit; and manganese (Mn) at 379.6 mg/kg in the root, 963.0 mg/kg in the stem, and 2069.0 mg/kg in the leaf, which exceeds the 200 mg/kg threshold. Toxicological profiling predicted neurotoxicity and ecotoxicity for aluminum (Al), Cd, Cr, and nickel (Ni), with a particular focus on their ability to cross the blood-brain barrier and cause long-term damage. While S. cocculoides offers medicinal benefits, its heavy metal content poses significant health risks, necessitating further research on safe processing techniques and its role in environmental management. These findings emphasize caution in traditional medicine and the plant's potential for human health and environmental remediation.