Aflatoxin B ₂ : Chemical Identity and Biological Activity

Abstract

Aflatoxin B(2), a blue-fluorescent metabolite of Aspergillus flavus, was isolated from cultures grown on crushed wheat. Chemical structure of the compound was elucidated as dihydroaflatoxin B(1). Biological activity was determined in day-old male white Pekin ducklings. The criteria of activity were reduction in growth and liver size and the extent of bile-duct hyperplasia.

Production of Aflatoxins in Submerged Culture1

“…With the strain and conditions used, the other aflatoxins did not constitute more than 10 to 15% of the total, so that little error in determination of total aflatoxin is introduced by assuming all of the absorption at 362 mus to be due to aflatoxin B. The extinction coefficients at 362 mys of aflatoxin G and dihydroaflatoxin B are 16,100 and 20,800, respectively (Asao et al, 1963;Chang et al, 1963).…”

“…The principal compounds are aflatoxins B and G, having the structures shown in Fig. 1; the secondary compounds, dihydroaflatoxins B and G, are distinguished by the reduced terminal dihydrofuran (Asao et al, 1963;Chang et al, 1963;van Dorp et al, 1963;Hartley, Nesbitt, and O'Kelly, 1963).…”

“…Because their chemical synthesis has not yet been achieved, they must be produced by biological means. Though this may readily be done by growth of A. flavus on solid substrates such as ground peanuts (Codner, Sargeant, and Yeo, 1963) or crushed wheat (Chang et al, 1963), their production in submerged culture on synthetic or semisynthetic media would be preferable because of ease in scale-up, simplicity of extraction and purification, and the suitability of these media for studies of the physiology of aflatoxin production. The production of aflatoxin on synthetic liquid media has been reported briefly (de Iongh et al, 1962;Nesbitt et al, 1962), but no details were given and the yields apparently were quite low (P. de Vogel, personal communication).…”

Aflatoxin Production and Degradation by Aspergillus flavus in 20-Liter Fermentors

“…Aflatoxin, a mixture of at least four toxic and carcinogenic metabolites, is known to be produced by only a few fungi, Aspergillus flavus (18), A. parasiticus (5), and Penicillium puberulum (13). Although various methods for the biological production of aflatoxins have been reported (1,4,5), none of these processes has proved satisfactory for synthesis of large amounts of toxin; a maximal yield of only 30 to 50 mg per liter was reported in 5-liter fermentors by Mateles and Adye (16). We investigated aflatoxin production in 20-liter fermentors in conjunction with studies being carried out at the Northern Regional Research Laboratory on degradation of mycotoxins.…”

DNA Damage and Mutation Caused by Vital Biomolecules, Water, Nitric Oxide, and Hypochlorous Acid

“…Improvement in production processes and working environments have reduced the incidence of cancer. The storage and cooking of food can generate carcinogens such as a‰atoxin from fungus on food and heterocyclic amines by roasting meat (5,6). These risks are also avoidable by controlling preservation conditions and changing food preparation methods; however, several mutagens such as hydrazine compounds of mushrooms and quercetin in citrus fruit are included in food itself (7)(8)(9).…”