Nigerian herbal remedies and heavy metals: violation of standard recommended guidelines

Abstract

ObjectiveThe growing popularity of herbal remedies approved by the National Agency for Food and Drug Administration and Control (NAFDAC), in Nigeria necessitates a critical re-evaluation of the risks associated with their use. Arsenic, cadmium, chromium, cobalt, lead and nickel contents of were analysed to ascertain their compliance with the recommended limits of the World Health Organization, European Union and United States Environmental Protection Agency. MethodsTwenty four different Nigerian herbal remedies (NHR) in two types of pharmaceutical dosage forms – liquid and capsules, were sampled using basket market protocol in the Niger Delta, Nigeria, in December, 2010. The NHR were ashed before digestion using conc aqua regia HCL: HNO3 (3:1) and arsenic, cadmium, chromium, cobalt, lead and nickel were assayed with Atomic Absorbtion Spectrophotometer, AAS 205A. Arsenic, cadmium, chromium, cobalt, lead and nickel contents of were compared with the recommended limits of the World Health Organization (WHO), European Union (EU) and United States Environmental Protection Agency(USEPA). ResultsThe highest concentrations of the heavy metals were found in the solid dosage forms whereas the lowest concentrations were found in the liquid preparations. Our study shows the percentage violation of the WHO and EU limits for the six metals were arsenic (0%); cadmium (58:3%); chromium (4.16%); cobalt (0%); lead (54.1%) and nickel (54.1%). ConclusionsThis study highlights the need for pharmaco-vigillance especially with respect to metalo-toxicity of Nigerian herbal remedies and need for in-depth risk assessment to understand the extent of the problem.