Furandiones from an endophytic Aspergillus terreus residing in Malus halliana

Two new furandiones named asperterone B (1) and C (2) together with four known metabolites (3-6) were isolated from the liquid culture of the endophytic fungus Aspergillus terreus MHL-P22 residing in the fresh leaves of Malus halliana. The structures of the new compounds were elucidated by analysis of their MS, IR, 1D- and 2D-NMR spectra. 1 and 2 showed moderate cytotoxic activities against human colorectal carcinoma SW1116 cells with IC(50) values of 57.5 and 71.0 µM, respectively. The biosynthetic pathway for 1, 2 and their analogues was also postulated and briefly discussed.