Five new natural compounds (1-5) along with four known ones, involving dibenzo-α-pyrone derivatives, a benzo-γ-pyrone derivative and an amide-type compound were obtained from Alternaria alternata, an endophyte isolated from Paeonia lactiflora. The structures of these isolates were elucidated by intensive analysis of spectroscopic data including NMR, HRMS (ESI and EI), UV and IR spectra. Compounds (1-4) were evaluated for their cytotoxicities against five selected human tumourtumour cell lines (A-549, MDA-MB-231, MCF-7, KB and KB-VIN), and compound 3 exhibited activities against MDA-MB-231and MCF-7 with IC50 values of 20.1 μM and 32.2 μM.
Keywords: Alternaria alternata; Paeonia lactiflora; benzo-α-pyrone derivatives; cytotoxic activity.