Isocoumarins from American cockroach (Periplaneta americana) and their cytotoxic activities.

Four new isocoumarins (1-4), along with three known ones (5-7), were isolated from the 70% ethanol extract of the whole body of the traditional Chinese insect medicine, American cockroach (Periplaneta americana). The structures with absolute configurations of new compounds were elucidated by extensive spectroscopic methods in combination with X-ray diffraction experiment and CD analyses. Compounds 3-5 showed significant cytotoxic activities in HepG2 and MCF-7 cells with IC50 values in the ranges 6.41-23.91 µM and 6.67-39.07 µM, respectively.