The dried and powdered green branch of G. dulcis (1.0 kg) were extracted with dichloromethane (8.0 L×2, 48 h each) at room temperature, and the extract was concentrated under vacuum condition. Then, the dichloromethane extract (32.89 g) was partitioned between CH2Cl2 and 5% NaOH. After work up, the aqueous layer (32.89 g) and CH2Cl2 layer (32.89 g) were obtained.