Bioassay-guided fractionation of an EtOAc extract of the leaves of Rosa laevigata afforded two new 19-oxo-18,19-seco-ursane-type triterpenes (1 and 3), a new ursane-type nortriterpene (2), a new ursane-type triterpene lactone saponin (4), and two new oleanane-type triterpenoids (5 and 6), together