Essential and potentially toxic trace elements in selected antimalarial plants: A pilot study in Kilembe copper mine catchment, Kasese District, Uganda

Majority of people in rural areas of Uganda and other malaria-endemic parts of the world use medicinal plants to treat the disease. This study documented medicinal plants used to treat malaria around Kilembe copper mines and assessed the presence of essential and potentially toxic elements. Household surveys and key informant interviews were carried out while anti-malarial plants were sampled, prepared and concentrations of Fe, Mn, Zn, Co, Cu and Ni determined by atomic absorption spectrometry. It was established that Vernonia amygdalina (40%), Ocimum suave (35%), Justicia betonica (32%) and Aloe felox (20%) were the most used plants to treat malaria. Leaves were the most commonly used plant part (83%) while decoctions were reported by 51% of respondents. Concentration of trace elements (mg/kg) in the four plant species ranged from 50.4-422 (Mn), 16.7-202 (Fe), and 19.6-198 (Zn) and from 1.6-44.1, 0-7, and 0.1-31.5 for Cu, Co and Ni, respectively. Fe, Cu and Ni exceeded the recommended thresholds in almost all Kilembe mine samples as well as controls while Mn, Zn and Co exceeded thresholds in more than 25% of the samples. Remediation of Kilembe catchment soils as well as public sensitisation on the safety of medicinal plants is recommended.