Antitumor components isolated from the heartwood extract of Dalbergia odorifera

Ongoing search for promising antitumor components from plant resources, we found that the methanol extract from the heartwood of Dalbergia odorifera (Leguminosae) demonstrated a significant inhibition on the proliferation of human tumor cell lines including multidrug resistant cells in vitro. Intensive bioassay-guided purification of the extract finally led to the isolation of seven flavonoids and two phenolic components as active constituents for antitumor property, in vitro, i.e., medicarpin (1), 2-hydroxy-3,4-dimethoxybenzaldehyde (2), formononetin (3), tectorigenin (4), mucronulatol (5), (3R)-5′-methoxyvestitol (6), hydroxyobtustyrene (7), liquiritigenin (8), and (3R)-calussequinone (9), respectively.