| Abstract: | A novel benzofuran lactone, named concentricolide (= rel‐(6R)‐6‐ethylbenzo2,1‐b:3,4‐c′]difuran‐8(6H)‐one; 1 ), was isolated along with four known compounds (friedelin, cytochalasin L‐696,474, armillaramide, and russulamide) from the fruiting bodies of the xylariaceous ascomycete Daldinia concentrica. The structure of 1 was established by spectroscopic methods and X‐ray crystallographic analysis. Its anti‐HIV‐1 activity was tested. Results showed that 1 inhibited HIV‐1 induced cytopathic effects. The EC50 value was 0.31 μg/ml. The therapeutic index (TI) was 247. Concentricolide exhibited the blockage (EC50 0.83 μg/ml) on syncytium formation between HIV‐1 infected cells and normal cells. |
