Bioactive coumarins from Boenninghausenia sessilicarpa

Bioassay guided fractionation of Boenninghausenia sessilicarpa (Rutaceae) resulted in the isolation of a new dimeric coumarin glucoside 9′-methoxyl rutarensin (1) and a cytotoxic compound rutamarin (4), as well as an antivirus component leptodactylone (8), together with six known coumarins. Their structures were elucidated by 1D- and 2D NMR spectroscopy and ESI-MS analyses, respectively. Rutamarin (4) showed significant inhibitory activities against A-549, Bel-7402, HepG-2 and HCT-8 tumour cell lines with IC50s of 1.318, 2.082, 2.306 and 2.497 μg/ml. In addition, leptodactylone (8) showed potent protective activity on cells infected by SARS-CoV with ratio of 60% at 100 μg/ml.