• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1099-1101
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• 2001

In an attempt to search for serotonin N-acetyltransferase (arylalkylamine N-acetyltransferasem, AA-NAT) inhibitors from microbial metabolites, we fecund the culture broth of Penicillium sp. 80722 which showed a strong inhibitory activity against AA-NNT. The active principle has been identified as citrinin hydrate through bioassay-guided fractionation of cultural broth, and structure elucidation derived by spectroscopic analyses. Citrinin hydrate inhibits AA-NAT with an $IC_50$ value of $173{\mu}M$ in a dose-dependent manner. Although citrinin hydrate was previously isolated as human rhinovirus 3C-protease inhibitor, this was recognized as the first AA-NAT inhibitor isolated from natural sources.