Three new ɑ-pyrone derivatives induced by chemical epigenetic manipulation of Penicillium herquei , an endophytic fungus isolated from Cordyceps sinensis .

Chemical epigenetic manipulation was applied to explore secondary metabolite of an endophytic fungus Penicillium herquei , which was obtained from the fruiting body of Cordyceps sinensis , and three previously undescribed polyketides with pyran-2-one scaffold were isolated from its fermentation broth containing 10 mg/L 5-aza-2-deoxycytidine (a frequently-used DNA methyltransferase inhibitor). The structures of these new compounds were identified by extensive spectroscopic analyses, and their absolute configurations were elucidated by quantum chemical ECD calculations.