Heavy metal analysis of polyherbal formulations marketed in Ilorin

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Faculty of Pharmaceutical Sciences, University of Ilorin


Globally, consumption of herbal preparations is on the increase with corresponding increase in the numbers of pharmaceutical industries engaged in herbal production. There is need for regular assessment of the quality of these herbal products to safeguard the health of the consumers of herbal drugs. Besides other quality parameters for evaluation of herbal products, heavy metals analysis is essential due to the potential health hazards implicated in their consumptions. Therefore, the study evaluates the heavy metal contents of two polyherbal liquid preparations marketed in Ilorin, North Central, Nigeria. Samples of the two herbal products (AMO and ZAK herbal bitters) were pre-treated and analyzed for the presence of iron, lead, cadmium, Copper, manganese and zinc using a validated Atomic Absorption Spectrophotometric (AAS) method. The analysis was done in triplicate and International Conference on Harmonization (ICH) guideline followed. Validation results showed linearity between 5-50 mg/L, 0.1-0.4 mg/L, 1-4 mg/L, 0.02-1.0 mg/L, 0.2-1.6 mg/L and 1-4 mg/L for iron, manganese, lead, copper, zinc and cadmium respectively, while the limit of detection was 0.001 mg/L, 0.001 mg/L, 0.002 mg/L, 0.005 mg/L, 0.025 mg/L, and 0.002 mg/L, for copper, manganese, cadmium, iron, lead, and zinc respectively. The findings showed higher concentrations of iron above the World Health Organization (WHO) permissible limit in the two preparations at 15.1 mg/L and 42.6 mg/L for AMO and ZAK herbal bitters respectively. However, lead, cadmium, and zinc were undetectable in both samples and the observed amount for copper and manganese were below the WHO limit. Our findings revealed the presence of iron at concentrations exceeding WHO permissible limits in both polyherbal preparations evaluated. This indicates a potential risk for iron poisoning with long term consumption of these products. Intensive effort by regulatory agencies to ensure the safety and quality of polyherbal formulations is recommended.



polyherbal, heavy metals, atomic absorption spectrophotometry, WHO


Eniayewu, O.I., Bamidele, O.D., Ogunremi, B.I., Afosi, A.B, Ibrahim, S.A., Abdullahi, S.T. & Njinga, N.S. (2020): Heavy metal analysis of polyherbal formulations marketed in Ilorin. Journal of Pharmaceutical Research, Development and Practice, 4(1): 20-29.