Tabebuia rosea (Bertol.) DC. is a neotropical tree belonging to the Bignoniaceae family. It is widely planted in the tropics as an avenue tree, for the greening of urban landscapes. Previous chemical investigations of this plant have shown the presence of iridoids, and several naphthoquinones exhibiting cytotoxic effects. As part of our ongoing research program searching for cytotoxic natural products from Thai medicinal plants, two new cyclopentene dialdehydes, tabebuialdehydes A and B (1 and 2) and a new dihydrocyclopenta[c]furan monoaldehyde, tabebuialdehyde C (3), along with ten known compounds were isolated from the roots of T. rosea. Their structures were elucidated by interpretation of spectroscopic data, as well as comparisons with previous literature data. Moreover, compounds 1-13 were evaluated for their cytotoxicity (KB and HeLa cell lines). Compounds 2, 3 and 4 showed significant cytotoxicity against both KB and HeLa cells with IC50 values of 1.36 and 1.15, 0.57 and 0.77, and 1.79 and 0.73mg/mL, respectively.
Keywords: Bignoniaceae, Tabebuiarosea, Tabebuialdehydes A-C and Cytotoxicity.
