Gamahonolides A, B, and Gamahorin, Novel Antifungal Compounds from Stromata of Epichloe typhina on Phleum pratense.

Four novel antifungal compounds, gamahonolides A and B, gamahorin, and 5-hydroxyl-4-phenyl-2(5H)-furanone, were isolated from stromata of Epichloe typhina on Phleum pratense. Their structures were determined by spectroscopic methods. The absolute configuration of gamahonolide A was determined by its ORD spectrum and (1)H-NMR shift difference between the diastereomeric pair of its O-methylmandelates. The stereochemistry of gamahorin was determined by NOE difference spectra and its CD spectrum.