Ultrasound-surfactant synergistic extraction of saponins from balsam pear

Abstract: Balsam pear (Momordica charantia L.), a climber belonging to family Cucurbitaceae, is commonly known as bitter gourd or bitter melon in English. It is cultivated throughout the world for use as vegetable as well as medicine. Balsam pear has been used traditionally as medicine in developing countries. Some of its common uses in most countries are for diabetes, a carminative and in treatment of colics. Topically it is used for treatment of wounds, internally as well as externally for management of worms and parasites. It is also used as emmenagogue, antiviral for measles and hepatitis. Balsam pear contains biologically active chemicals that include glycosides, saponins, alkaloids, fixedoils, triterpenes. Saponins from all parts of the plant (fruit pulp, seed, leaves and whole plant) are most widely studied with regard to its antidiabetic effect. Ultrasound and surfactants have been individually shown to enhance saponins extraction. In this study, we investigated the synergistic effect of ultrasound and surfactants on saponins extraction. In order to explore effective extracting method of saponins from balsam pear, response surface was used to study the effect of ultrasonic power (133-167 W/g), ethanol volume fraction (60%-80%) and mass concentrations of SDS (15-25 mg/mL) on extraction rate of saponins from balsam pear. Ultrasound-surfactant synergistic extraction was compared with ethanol and ultrasound, respectively. The structures of the prepared saponins from balsam pear were identified. Results showed that the established model of extraction could well predict extraction rate of saponins from balsam pear under different conditions. Extraction rate of saponins from balsam pear was significantly (p<0.05) influenced by ultrasonic power, ethanol volume fraction and mass concentrations of SDS, and there was synergistic effect between ultrasonic power and the mass concentration of SDS. Various factors affecting extraction rate of saponins from balsam pear in a descending order was as follows: mass concentrations of SDS, ultrasonic power, ethanol volume fraction. Extraction rate of saponins from balsam pear was 3.22% at ultrasonic power of 153 W/g, ethanol volume fraction of 74%, mass concentrations of SDS of 16 mg/mL, significantly higher (p<0.05) than that of ethanol and ultrasound extraction. Liquid chromatography-mass spectrometry revealed that extracted saponins included momordicoside L and F2. Ultrasound-surfactant synergistic extraction is an effective method for extraction of saponins, which is worth further development and application.