The petroleum ether was fractionated by silica gel chromatography using a stepwise gradient of petroleum ether/EtOAC
(1:0e0:1) to yield sixteen fractions (Fr.1-16), Fr.4 was repeatedly applied to silica gel eluted with petroleum ether-EtOAC
(1:0e0:1) and further purified by Sephadex LH-20 with CHCl3eMeOH (1:1) to obtain 9 (4.2 mg) and 10 (4.5 mg); Fr.9 was
subjected to chromatography on silica gel to give 8 (6.7 mg) and 11 (7.8 mg).