Terretonin P and additional new compounds from mesophilic <i>Aspergillus terreus</i> MSM18

We present terretonin P (<b>1</b>), a novel oxygenated tetracyclic meroterpenoid derived from the mesophilic <i>Aspergillus terreus</i> MSM18, alongside a tetra-hydrofurano-acrylic acid derivative (<b>2a</b>), its 5'-epimer (<b>3a</b>), the respective 5'-methylethers (<b>2b, 3b</b>), the new microbial 3-prenyl-4-hydroxy-benzaldehyde (<b>4a</b>), and our previously reported terretonins M-O (<b>5-7</b>). Structurally, the new compounds (<b>1-4a</b>) have been clarified through comprehensive analyses of NMR (1D, 2D) spectroscopy and HR-ESIM spectrometry. The relative configuration of compounds <b>1-3a,b</b> was established through NOESY experiment. The separation and taxonomical characterisation of <i>A. terreus</i> MSM18, along with the antimicrobic properties of the newly identified compounds (<b>1-4a</b>) as well as the corresponding fungal extract were investigated as well.