Mycotoxins of Penicillium Species

Penicillium species produce various mycotoxins. Strains of Penicillium citreo-viride, which infect rice, produce the mycotoxin, dtreoviridin (9.20). This compound is the cause of a condition known as cardiac beriberi , which is characterized by cardiovascular disorders, difficulty in breathing and nausea. The mechanism of action involves the inhibition of mitochondrial ATP synthesis. Cardiac beriberi was a serious infection of people eating rice as a staple diet, causing many fatalities until the origin was identified. 

Citrinin (9.22) is a widespread mycotoxin that is formed by many Penicillium and Aspergillus species, particularly P. citrinum, P. expansum and P. roqueforti. It was first isolated in 1931 by the Raistrick group and described as an antibiotic. It has been shown to have carcinogenic effects and to produce kidney damage. Evidence for its structure and biosynthesis is discussed in Chapter 4. 

The amino acid tryptophan is a precursor of several fungal metabolites that affect the central nervous system. We have already met it as a constituent of the ergot alkaloids. Roquefortine (9.25) is a metabolite of Penicillium roqueforti and P. camemberti, which are found on some cheeses. Roquefortine is one of a series of mycotoxins that affect the central nervous system and induce tremors. The more complex penitrems are tremorogenic neurotoxins that are produced by the P. crustosum series. They are biosynthesized from a tryptophan and a triterpene unit. 

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