Isolation, purification and detection of soyasaponins and their associated bioactivities in cultured hepatocarcinoma cells

Abstract

Soyasaponins are one of phytochemical groups in Soy (Glycine Max Merr) and other legumes such as green peas (Pisum sativum L) and lentils (Lens culinaris). Soyasaponins are structurally complex amphiphilic oleanane triterpenoids molecules, with polar water soluble sugar moieties attached to a non polar, water insoluble pentacyclic ring structure. Soyasaponins are classified into five groups based on the chemical structure of their respective aglycones but the two main groups are A and B. In legumes, soyasaponins are present primarily as glycosides which are storage forms of saponins and are secondary plant metabolites. These molecules serve as defensive molecules for the plant to defend against biological predators such as fungi and herbivores. A resurgence of interest into secondary plant metabolites has emerged as many of these compounds possess diverse biological activity which includes the potential to act as chemo-preventive agents. Group B soyasaponins are the most abundant group of saponins found in soy (Glycine max) and are thought to contribute to the bulk of soy?s chemo-preventative properties attributed to soyasaponins. In this project, a simple and efficient method for isolation, purification and analysis of group B soyasaponins and their aglycones with a high purity (over 80%) were developed. Furthermore group B soyasaponins were found to be bioactive on human hepatocarcinoma (Hep-G2) cells, soyasaponin aglycones expressed stronger cell growth inhibition and induced apoptosis in compared to their correspondence glycones. An enzyme biotransformation method of the biological modification of the phytochemical profile of group B soyasaponins was also developed in this project.