Determination of As, Cd, Cr and Co in some herbal medicines sold in the markets of Zaria using neutron activation analysis

Abstract

The levels of elements with genotoxic potentials; As, Cd, Cr and Co in herbal medicines obtained from stem barks of Boswellia serrata, Prosopis africana, Anogeissus leiocarpus and Sclerocarya birrea were determined by instrumental neutron activation analysis and compared to WHO/EU (2007) permissible values in herbal products. The results of standard material IAEA 1515 (apple leaves) were not significantly different from the certificate values. Arsenic in the samples ranged from ND to 0.037 mg/kg. The maximum value (0.037mg/kg) was obtained in Boswellia serrata which was ten times and two times the value in Sclerocarya birrea and Anogeissus leiocarpus respectively. This maximum was below WHO/EU (2007) values. Arsenic was not detected in Prosopis africana herbal medicine. Cadmium in all the samples was below detection limit except in Anogeissus leiocarpus herbal medicine where the concentration was 0.0012mg/kg his was below WHO/EU (2007) values. Chromium in the samples ranged from ND to 0.06 mg/kg, the maximum was in Anogeissus leiocarpus herbal medicine; this concentration was slightly above EU (2007) values of 0.050 mg/kg but, below WHO (2007) value of 2.0 mg/kg. Cobalt was detected in all the samples, the concentrations ranged from 0.01mg/kg to 0.16 mg/kg with the highest concentration in Sclerocarya birrea herbal medicine, this concentration was about two and half times the concentration in Boswellia serrata . The Co concentration in Anogeissus leiocarpus herbal medicine was about five times lower than the concentration in Boswellia serrata. The concentrations of Co in the herbal medicines were in the order, Sclerocarya birrea > Boswellia serrata > Prosopis africana > Anogeissus leiocarpus. WHO/EU (2007) have not set Co permissible limits in food and drinking water. Although, most of the genotoxicants were below WHO/EU (2007) values none the less, these herbal medicines should be investigated further for other toxic and genotoxic compounds as a means of quality control because, genotoxicants have no threshold limit to cause cancer therefore, quality assurance measures should always be taken in the produc ion and use of these substances.

Keywords: Elements, genotoxic, herbal medicines, instrumental neutron activation analysis, Zaria