An actinomycete strain TRM20105 with antifungal activity was identified as Nocardiopsis dassonvillei subsp. dassonvillei DSM43111 (98.34% similarity) by 16S rDNA phylogenetic analysis and morphology observation. The fermentation broth of TRM20105 cultured with oat-soybean medium was subjected to discover bioactive compounds. Guided by antifungal bioassay against Candida albicans, a new diketopiperazine compound was purified via various column chromatographies together with pHPLC. The purified active compound was identified as 1-demethylnocazine A, (3Z,6Z)-5-methoxy-3,6-bis(4-methoxybenzylidene) -1,6-dihydropyrazin-2(3H)-one by the analyses of 1D & 2D NMR data.
Keywords: 1-demethylnocazine A; antifungal activity; diketopiperazine.