Aflatoxin Metabolites in the Urine of Nigerians Comparison of Chromatographic Methods

Abstract

Some of the animal metabolites of the aflatoxins have not been detected in humans. To understand the occurrence of these metabolites in societies with high liver cancer incidence, urine samples were collected from 161 Nigerians residing at Lagos, Nigeria. The samples were screened for the natural aflatoxins B₁ and G₁ and the mixed function oxidase and cytosol-chloroform soluble metabolites of B₁: Q₁, B_2a, M₁ and L. Both natural aflatoxins, B₁ and G₁, and three of the metabolites, L, B_2a and M₁ were found in the urine samples. All of the aflatoxins observed were detected by HPLC. Levels were below the detection limits of the HPTLC method. The aflatoxin in greatest percentage was B_2a at 32.7%. Aflatoxin B₁ occurred in 3.1% of the urine samples. Aflatoxin M₁ occurred at 8.7%, G₁ at 9.9%, and L at 9.3%. The highest average concentration among aflatoxins was aflatoxin G₁ at approximately 12 ng/100 ml urine. The order in concentration was G₁B₁M₁B_2aL. Clinicians and others desiring to establish relationships between aflatoxins and disease could miss important information without low-level multi-aflatoxin methods of analysis.