Selection of Macroporous Resins for the Separation and Detection of Tomato Saponins

This study was conducted to select a type of macroporous resin most suitable for the separation and purification of tomato saponins. The content of esculeoside A which is the major part of total tomato saponins was detected by colorimetry, and extraction rate of esculeoside A was used as an indicator to select the best type of macroporous resin for the isolation of tomato saponins. D101 has the highest adsorption efficiency for esculeoside A, with which, 0.25g esculeoside A can be obtained from 1 kg tomato fruit. Tomato (Lycopersicon esculentum Mill.), a member of the genus Lycopersicon in the family Solanaceae, is native to South America and widely planted in China nowadays. Two structurally complex steroidal saponins were isolated from fresh ripe tomato by Fujiwara from Kumamoto University, Japan in 2004, and named esculeoside A and esculeoside B-[1]. Then, their physicochemical properties, physiological and pharmacological activities were systematically studied, and the results revealed that they were capable of reducing blood lipid, cholesterol, inhibiting cancer cell proliferation, anti-atherosclerosis, anti-oxidation and so on ([2]). Therefore, esculeoside A and esculeoside B have attracted much attention of experts in cardiovascular diseases all over the world. Macroporous resin is an organic adsorbent composed of high polymers and was developed in the 1960s. It has an internal three-dimensional stereoscopic pore structure, and good adsorption properties due to the numerous reticular cavities with a large specific surface area ([3-4]). Macroporous resin can be used for purifying chemical substances from plant materials according to the polarity, relative molecular weight and different solubility of the objects ([5]). In the present study, the adsorption capacity of 16 different types of macroporous resins to total tomato saponins were measured with spectrophotometry and compared to select the best macroporous resin type, and provide technical support for in-depth study of tomato saponins.