Three New Homoisoflavanones from the Ophiopogon japonicus Ker‐Gawler (Liliaceae)

Three new homoisoflavanones, 1–3, together with a known one, 4, were obtained from the AcOEt extract of the tuberous roots of Ophiopogon japonicus (Liliaceae). They were identified as (3R)‐2,3‐dihydro‐7‐hydroxy‐5‐methoxy‐3‐(4‐methoxybenzyl)‐6,8‐dimethyl‐4H‐chromen‐4‐one (1), (3R)‐3‐(1,3‐benzodioxol‐5‐ylmethyl)‐2,3‐dihydro‐7‐hydroxy‐5‐methoxy‐6,8‐dimethyl‐4H‐chromen‐4‐one (2), (3R)‐3‐(1,3‐benzodioxol‐5‐ylmethyl)‐2,3‐dihydro‐7‐hydroxy‐5‐methoxy‐6‐methyl‐4H‐chromen‐4‐one (3), and ophiopogonanone A (4). Their structures were determined on the basis of extensive NMR‐spectroscopic and mass‐spectrometric analyses. The three new compounds are rare homoisoflavanones which contain a MeO group at C(5). Compounds 1 and 2 showed weak cytotoxicity against the HepG2 (human hepatoma G2), KB (human oral epidermoid carcinoma), and MCF‐7 (human breast adenocarcinoma) cell lines in an MTT assay. Compound 3 exhibited weak cytotoxicity against HepG2 and MCF‐7, and moderate cytotoxicity against KB cell lines. Compound 4 showed moderate cytotoxicity against HepG2, KB, and MCF‐7 cell lines.