Author's Organization：Osaka University of Pharmaceutical Sciences Institute of Chinese Materia Medica, China Academy of Traditional Chinese Medicine Osaka University of Pharmaceutical Sciences
Three novel cyclospirobifuranocoumarins, cyclorivulobirins A-C (1-3), were isolated from the underground part of Pleurospermum rivulorum. They are characterized as three stereoisomers having a different configuration at the C-2 and C-2' position resulting from the condensation of two heraclenol units, respectively, on the basis of chemical and spectral methods.
