Penitremones A–C, Penicillium metabolites containing an oxidised penitrem carbon skeleton giving insight into structure–tremorgenic relationships

Abstract

A new group of microbial metabolites, designated penitremones A–C, have been characterised by mass spectrometry and ¹H and ¹³C NMR spectroscopy as 10-keto, 11,33-dihydro-variants of the penitrem indole-isoprenoid skeleton. The principal metabolite penitremone A, produced with penitrem A by a Penicillium sp., is an isomer of penitrem E and was also similarly tremorgenic. Reduction of the carbonyl of penitremones A and B with NaHB₄ altered tremorgenic activity, thereby indicating potential for new insights into structure–activity relationships in tremorgenic mycotoxins, particularly with respect to neurological disorders in agricultural ruminants caused by the related keto-alkaloid lolitrem B.