Cytotoxic Flavonoids from the Flower Buds of Rosa rugosa
Eight new flavonoids, rugosaflavonoids A-H (1-8), together with eleven known compounds, were isolated from the flower buds of Rosa rugosa. All structures were determined by spectroscopic methods. 1 is a flavone possessing a unique 8,9-seco skeleton. 2 displayed cytotoxicity against NB4, SHSY5Y and MCF7 cells with IC50 values of 2.2, 2.5 and 2.3 µM, respectively; and 3 was toxic to A549 and MCF7 cells with IC50 values of 1.2 and 2.8 µM, respectively.