A novel flavonoid and other constituents from Rubus rosifolius S.Vidal (Rosaceae)

Various reports revealed that chemical constituents from many species of Rubus exhibit diverse biological activities. In this study, a novel flavonoid with a 2-(phenanthren-9-yl)-4H-chromen-4-one structure (1), a 5-phenylthiophene-2-carbaldehyde derivative (5) first isolated from a natural source, together with five known compounds including three polyketides (2-4) and two sesquiterpenoids (6-7) were isolated from a traditional Chinese medicine Rubus rosifolius S.Vidal (Rosaceae). The structures of new compounds were elucidated by detailed spectroscopic analysis including NMR and X-ray single-crystal diffraction. The bioassays results indicated that, compound 1 displayed significant cytotoxicity against human colon cancer cell line HCT116 with IC₅₀ value of 8.6 ± 1.9 μM, and compound 5 exhibited moderate cytotoxicity against human breast cancer cell line MDA-MB-435 with IC₅₀ value of 24.1 ± 0.8 μM.