Diterpenoids of the oidiolactone family and other metabolites from a hawaiian fungicolous fungal isolate

During our ongoing studies of mycoparasitic and fungicolous fungi, a fungal isolate identified as Neofusicoccum parvum (MYC-1674=NRRL 46122) was collected from a basidioma of Rigidoporus microsporus found on a dead branch in an alien wet forest on the island of Hawaii. The ethyl acetate extract of solid-substrate fermentation cultures of this isolate demonstrated antifungal activity against Fusarium verticillioides and was therefore subjected to chemical investigation. Column chromatography, VLC, and HPLC were used to separate the various metabolites of this extract. Eight compounds were identified. Oidiolactone E, LL-Z1271β, and three other known diterpenoids of the oidiolactone family were identified [1–4]. One of these is a new natural product, for which we propose the name oidiolactone G. In the process of isolating LL-Z1271β under acidic conditions, a second new compound was formed as a cyclized dehydration product. One of the oidiolactone analogues showed antifungal activity towards F. verticillioides. The known antimicrobial compound asperlin as well as two hydroxymellein derivatives were also encountered in this extract.

Acknowledgements: National Institutes of Health (GM 60600), National Science Foundation (CHE 0315591), USDA National Center for Agricultural Utilization Research, and University of Iowa NMR and Mass Spectrometry facilities.

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