Isolation of Various Flavonoids with TRAIL Resistance-Overcoming Activity from .

Eighteen compounds, including fourteen flavonoids (-), one steroid (), two fatty acids (,), and one nitrogen-containing compound (), were isolated from the methanol extract of the whole plant collected in Thailand. Compounds - and - exhibited tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) resistance-overcoming activity. Among them, bonanzin () and cirsilineol () had particularly strong TRAIL resistance-overcoming activity, where the IC values against the human gastric adenocarcinoma cell line AGS in the presence of TRAIL (100 ng/mL) were 10.7 μM and 5.9 μM, respectively.