Japonicasins A and B, two new isoprenylated flavanones from Sophora japonica.

Two new flavanones with a C15 isoprenoid group, japonicasins A and B (1 and 2), were isolated from the leaves of Sophora japonica. This is the first report on the presence of the (2E,7E)-6-isopropyl-3,9-dimethyldeca-2,7,9-trien-1-yl group (C15 isoprenoid group) in isoprenylated flavonoids. Their structures were determined by spectroscopic methods, including UV, IR, 1D and 2D NMR, HRESIMS, and CD experiments. In addition, the antioxidant activities of compounds 1 and 2 were determined through DPPH radical scavenging assays. They exhibited potential antioxidant activities, with IC50 values of 35.1±0.8 μM and 88.7±1.1 μM for compounds 1 and 2, respectively.