Comprehensive chemical profiling and human health risk assessment of potentially toxic heavy metals in some traditional herbal concoctions from Botswana

Ontlametse H.E Phiri^*Lucia M LepodiseTshepo Pheko-Ofitlhile

• Botswana International University of Science and Technology, Palapye, Botswana

Traditional herbal mixtures are still used extensively in Botswana because of their claimed therapeutic benefits, although their chemistry and safety are undocumented. Therefore, this study aims to conduct the analysis and human health risk assessment of some herbal concoctions in Botswana. The spectra of the herbal concoction samples sourced from three different street vendors were recorded at room temperature using the Fourier Transform Infrared (FT-IR) technique. The three samples exhibited comparatively similar spectral profiles, indicating that they may contain chemical compounds vibrating at similar energies. FT-IR analysis revealed the presence of characteristic functional groups which includes phenolics, alcohols, alkene, alkanes and aromatic groups some of which were identified through gas chromatography-mass spectrometry (GC-MS) analysis. GC-MS analysis of all the hexane extracts identified octane and 3-methylheptane as the major constituents. Hexadecane, tetradecane and 5-Aminovaleric acid were major compounds identified in ethyl acetate extracts. Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) results revealed that the heavy metal concentrations of herbal concoctions that ranged between 1.00 x 10 -4 mg/kg and 2.43 x 10 1 mg/kg. The concentrations of all the heavy metals were below the acceptable limits set by World Health Organization (WHO).Trace metal concentrations of Mg, Ca, K and Na in the samples ranged from 1.