Review of Compounds Affecting the Biosynthesis or Bioregulation of Anatoxins.

The effect of caffeine and theobromine on growth and ochratoxin A production by Aspergillus ochraceus was determined using microbiological medium. Caffeine produced a small decrease in growth, while reducing ochratoxin production as much as 98%. Theobromine had relatively little effect on growth or ochratoxin production. Screening of caffeine for its effect on the growth of a number of Aspergillus and Penicillium species indicated that caffeine may have biological activity against a variety of mycotoxigenic molds.

Caffeine Inhibition of Ochratoxin A Production

Aflatoxin production by pregrown cultures of Aspergillus parasiticus was completely inhibited by incorporation of 2 mg of caffeine per ml into the medium. This was accompanied by a decrease in glucose utilization and an inhibition of oxygen uptake and carbon dioxide evolution. Enzyme analyses indicated no significant differences in specific activities on glucose-6-phosphate dehydrogenase, mannitol dehydrogenase, phosphofructokinase, fructose 1,6-diphosphatase, pyruvate kinase, or malate dehydrogenase. Glucose uptake kinetics indicated a linear dose-related inhibition of glucose uptake. It appears likely that caffeine inhibits aflatoxin synthesis by restricting the uptake of carbohydrates which are ultimately used by the mold to synthesize this family of mycotoxins.

https://aem.asm.org/content/aem/47/6/1216.full.pdf

Caffeine inhibition of aflatoxin synthesis: probable site of action.

Evaluation of caffeine and a number of related methylxanthines indicated that the ability of the compound to inhibit growth and aflatoxin production by Aspergillus parasiticus is highly specific and does not involve an inhibition of cyclic AMP phosphodiesterase. Supplementation of the culture medium with purine bases, nucleosides, and nucleotides suggested that the inhibition of fungal growth could be partially overcome by adenine or guanine but that the purines had little effect on the inhibition of aflatoxin production. Likewise, increasing the levels of trace minerals did not overcome the inhibition of toxin production. Electron microscopic evaluation of caffeine-treated and -untreated cultures indicated that the compound produced observable changes in the ultrastructure of the fungus.

Caffeine inhibition of aflatoxin production: mode of action

, Microbiological medium was used to study the effect of caffeine on sterigmatocystin, citrinin, and patulin production by Aspergillus versicolor, Penicilliwn citrinum, and Penicillium urticae, respectively. Caffeine inhibited the growth of the three’ fungal species and de- creased sterigmatocystin and patulin production. The effect on citrinin production appeared to be limited to a delay in toxin synthesis. A preliminary examination of P. urticae suggested that caffeine’ s anti-mycotoxigenic activity does not involve a generalized inhibition of lipid synthesis. INTRODUCTION PREVIOUS INVESTIGATIONS have established that while cocoa and coffee beans are commonly contaminated with aspergilli (Hansen and Welty, 1970; Hiscocks, 1965), they are generally poor substrates for aflatoxin production (Levi et al., 1975; Nartowicz et al., 1979; Lenovich and Hurst, 1979; Llwewllyn et al., 1978). Nartowicz et al. (1979) and Lenovich (198 1) attributed this anti-aflatoxigenic activity to the caffeine content of these commodities. It has also been established that the addition of caffeine to micro- biological media at levels 21 mg/ml inhibits aflatoxin pro- duction (Buchanan and Fletcher, 1978), while theophyIline (Buchanan and Fletcher, 1978) and theobromine (Buchanan et al., 1978) have little activity. Similar results have been reported for ochratoxin A production by Aspergillus ochraceus (Buchanan et al., 1982). Buchanan et al. (1982) found that caffeine inhibited the growth of a number of mycotoxigenic Aspergillus and Penicillium species, and suggested that caffeine may have inhibitory activity against the production of a variety of polyketide mycotoxins. The objective of the present study was to characterize further caffeine’ s anti-myotoxigenic activity by determining its effect on the production of three additional polyketide mycotoxins; sterigmatocystin, citrinin, and patulin.

Caffeine inhibition of sterigmatocystin, citrinin, and patulin production.

Theobromine (0, 2, 4, and 8 mg/ml) had little effect on growth and aflatoxin production by Aspergillus parasiticus NRRL 2999 in a glucose-mineral salts-yeast extract medium, indicating that the anti-aflatoxigenic activity of cocoa beans is not due to the presence of this methylxanthine.

Effect of theobromine on growth and aflatoxin production by aspergillus parasiticus

Theobromine (0, 2, 4, and 8 mg/rnl) had little effect on growth and aflatoxin production by Aspergillus parasiticus NRRL 2999 in a glucose-mineral salts-yeast extract medium, indicating that the antiaflatoxigenic activity of cocoa beans is not due to the presence of this me thy lxan thine.

P. Conway

Papers

Effect of theobromine on growth and aflatoxin production by aspergillus parasiticus

Effect of theobromineon growth and aflatoxin productionby aspergillus parasiticus