A new flavonol from Sophora tonkinensis

A new flavonol, tonkinensisol, was isolated from the roots of Sophora tonkinensis, together with three known compounds named as bayin, vitexin and lupeol. Their structures were elucidated on the basis of spectroscopic evidence. Additionally, tonkinensisol showed moderate cytotoxicity suppressing the proliferation of HL-60 cells in vitro.