Comparative Oxidative Metabolism of Aflatoxin B₁ and Palmotoxins B₀ and G₀ by Rat Liver Microsomal Fractions

Abstract

1. The enzymic transformations of aflatoxin B₁ and palmotoxins B₀ and G₀ by cell fractions of rat liver have been studied. Metabolism involves NADPH-dependent enzymes with max. activity in the presence of nicotinamide, MgCl₂, glucose-6-phosphate and NADP.

2. The substances all undergo demethylation with production of formaldehyde. With both aflatoxin B₁ and palmotoxin B₀, two metabolites were detected by t.l.c. The two metabolites of aflatoxin B₁ correspond to aflatoxin M₁ and possibly aflatoxin B_2a. The two derivatives of palmotoxin B₀ have not been characterized but, like those of aflatoxin B₁, are probably hydroxylation products, as they are more polar than the parent compound. Only one derivative of palmotoxin G₀ was detected.

3. Aflatoxin B₁ showed a higher rate of metabolism than the two other substances.