Estimation of Some Heavy Metals and Physico-Chemical Parameters in Selected Herbs Sold in Old Market Area, Sokoto-Nigeria

Abstract

The emerging global significance and faster rate of increase in interest on herbal drugs for treating various illnesses cannot be underestimated. This coupled with the associated health risk posed by these drugs due to hazardous metal contamination, gives credence to concerns raised by health conscious people. This study was aimed at determining the levels of heavy metals (Cr, Cd, Mn, Cu, Fe, Pb, Zn and Ni) concentration in selected crude medicinal plants sold in old market, Sokoto-Nigeria. The physico-chemical parameters were determined using standard analytical methods and the heavy metals were determined using Atomic Absorption Spectrophotometry (AAS) after wet digestion. The results show that moisture, total ash and acid insoluble ash were in the range of 3.33 – 5.67 %, 9.5 – 17.3 % and 1.4-7.2 % respectively. Also, the samples revealed maximum concentrations (mg/Kg) of the heavy metals in the samples as: 0.112±0.002, 0.038±0.001, 18.136±0.001, 0.218±0.001, 15.138±0.001, 0.943±0.001, 0.577±0.001 and 0.237±0.001 for Cr, Cd, Mn, Cu, Fe, Pb, Zn and Ni respectively. The herbs demonstrated good preservative condition but with relative silica contamination, while the levels of all the metals were found to be within the World Health Organization (WHO) limits for heavy metals in plant samples. The exception was for chromium (Cr) in Guiera senegalensis, leaves; as well as for manganese (Mn) in Cassia singueana, Guiera senegalensis, Combretum micranthum, Anogeissus leiocarpus and Detarium microcarpum; D Senegalense. It is therefore, suggested that the quality, safety and efficacy of these medicinal plants be improved through pharmacovigilance.

Keywords: Heavy Metals, Herbal Plants, Physico-chemical and Old market