Cytotoxic Natural Products from (Thunb. ex L.) D.Don.

is a commercially important tree native to Japan. The tree belongs to the ancient genus and has found important uses as a medicinal plant, as well as a main source of timber in Japan. In recent years, there has been an increased interest in discovering extended uses of as a source of novel bioactive natural products with potential applications as lead compounds for active principles of future drugs. The compounds were isolated by a combination of two-phase extraction, XAD-7 Amberlite column chromatography, Sephadex LH-20 column chromatography and preparative High Performance Liquid Chromatography (HPLC). The structures were determined by a combination of several 1D and 2D Nuclear Magnetic Resonance (NMR) experiments and high-resolution mass spectrometry. Here, we report on the isolation and characterization of the novel biflavone glucoside hinokiflavone 7″--β-glucopyranoside, in addition to sixteen known compounds including the flavonols quercetin, quercetin 3--α-rhamnopyranoside and quercetin 3--β-galactopyranoside, the dihydroflavonols taxifolin 3--β-glucopyranoside, taxifolin 7--β-glucopyranoside, the flavanones naringenin, naringenin 7--β-galactopyranoside and eriodictyol 4'--β-glucopyranoside, the flavanol catechin, the biflavonoid amentoflavone, the dihydrochalcone phloretin 2'--β-glucopyranoside, the sesquiterpenoid roseoside, the polyphenolic compounds chlorogenic acid, methyl chlorogenate and the flavanocoumarins catechin-(7,8)-7″-(3,4 dihydroxyphenyl)-dihydro-8″(3H)-pyranone, and mururin A. The compounds exhibited low-to-moderate cytotoxic activity against MOLM-13 leukemia cells.