| Description |
The leaf powder of rice (90 g) was extracted with 90 % methanol as described in a previous study (Matsuda et al. 2012). The extract was dissolved, suspended in water, and partitioned into a hexane and water layer. The water layer was subjected to ODS column chromatography and eluted with CH3OH–H2O (0:100 → 100:0 v/v; containing 0.05 % formic acid) to afford nine fractions (Fr.1–9). These fractions were purified using semipreparative HPLC performed under the following conditions: column, Cadenza CD-C18 or Unison UK-C18 columns, Imtakt 150 9 10 mm i.d.; particle size, 3 lm; solvents, water and methanol or acetonitrile, containing 0.1 %v/v formic acid; and flowrate, 3.0 mL/min. The following compounds were obtained: 1 (4.52 mg), 2 (12.69 mg), 3 (2.07 mg), 4 (2.57 mg), 5 (1.15 mg), 6 (0.94 mg), 7 (1.51 mg), 8 (1.23 mg), 9 (0.71 mg), 10(2.53 mg), 11 (1.63 mg), 12 (3.93 mg), 13 (2.74 mg), 14 (0.58 mg), 15 (0.96 mg), 16 (1.89 mg), 17 (0.22 mg), 18 (0.09 mg), 19 (0.65 mg), 20 (0.20 mg), 21 (0.28 mg), 22 (0.64 mg), 23 (1.04 mg), 24 (0.76 mg), 25 (2.31 mg), 26 (2.20 mg), 27 (2.04 mg), 28 (1.25 mg), 29 (0.64 mg), 30 (0.29 mg), 31 (0.63 mg), 32 (2.29 mg), 33 (4.84 mg), 34 (4.99 mg), 35 (1.13 mg), and 36 (2.70 mg). For details regarding the isolation procedures from rice, see Supplementary data file S1. |