Fr. C (3.2 g) was purified by Sephadex LH-20 CC and eluted with CHCl3–MeOH (1:1) to yield three fractions(Fr. C1-Fr. C3), and 20 (5.4 mg).
Fr. C2 was further purified by ODS CC and eluted with a MeOH–H2O gradient system (from 60:40 to 90:10) to yield three major subfractions (Fr. C2A- Fr.C2C).
Fr. C2B was separated by preparative TLC with a developing solvent system of P. E.-acetone (2:1) to provide 9 (6.1 mg) and 10 (3.2 mg), which were further purified by Sephadex LH-20 CC in MeOH. Compound 16 (4.8 mg) was isolated from Fr. C2C by repeated silica gel CC with P. E.-acetone (20:1).