Fractions 12–13 (CH2Cl2: MeOH, 98:2) were combined (104.0 mg) and resubmitted to a silica gel column (10 g) eluted with CH2Cl2 containing increasing amounts of MeOH (up to 3%) to give dihydrochelerythrine (4, 21.0 mg) and dihydroavicine (5, 32.0 mg). Fractions 25–26 (CH2Cl2: MeOH, 80:20) were combined (287.0 mg) and crystallized from MeOH-diethyl ether to give chelerythrine (10, 150.0 mg).