Rice seedlings (10 g fresh weight) were homogenized with 100 mL of 50% (v/v) aqueous methanol and the homogenate was filtered through filter paper (No. 2). The residue was homogenized again with 100 mL of methanol and filtered. The two filtrates were combined and evaporated to yield an aqueous residue. Then, the aqueous residue was loaded onto a column of synthetic polystyrene adsorbent and purified, and momilactone B was quantified as described by Kato-Noguchi et al. (2002). The experiment was repeated six times with three assays for each determination. Significant differences were evaluated by Tukey’s HSD test.