Application of riboflavin-deficient rat erythrocytes in the in vitro assay of faba bean toxicity

ABSTRACT

Faba bean toxicity [favism] is a common condition observed in our region. To develop a short and simple technique involving the use of riboflavin-deficient rats to test in vivo faba bean toxicity. Methods/Sprague Dawley rats were maintained on a riboflavin- deficient diet and their vitamin B2 status was monitored by the assay of erythrocyte glutathione reductase [EGR]. Their blood was found to be sensitive enough as early as 5 weeks of eating the deficient diet. Initially RBC preparations from the riboflavin-deficient rats were used to test the toxicity of different concentrations of divicine [0.0-13.5 microM]. It was found that an increase in divicine concentration resulted in an appreciable drop in reduced glutathione [GSH] of RBC. The assay procedure was then used to test the effectiveness of certain detoxification treatments of faba beans. A high correlation [r= 0.9] was noted between residual vicine [the main favism factor] concentration and the toxicity index [TI] of treated samples indicating the suitability of the above procedure for toxicity assay. It is recommended to use blood from Sprague Dawley rats that have been fed a riboflavin-deficient diet for about 5 weeks or longer, in the bioassay of toxicity of faba beans and their isolated favism principles