Soyasaponins: The Relationship Between Chemical Structure and Colon Anticarcinogenic Activity

Abstract

Soyasaponins are bioactive compounds found in many legumes. Although crude soyasaponins have been shown to have anti-colon carcinogenic activity, there have been no structure-activity studies. In this study, therefore, purified soyasaponins and soyasapogenins were tested for their ability to suppress the growth of HT-29 colon cancer cells, as determined by the WST-1 assay, over a concentration range of 0-50 ppm. Soyasaponin I and III, soyasapogenol B monoglucuronide, soyasapogenol B, soyasaponin A1, soyasaponin A2, and soyasapogenol A were evaluated. Also tested were mixtures comprising acetylated group A soyasaponins, deacetylated group A soyasaponins, and group B soyasaponins. The most potent compounds were the aglycones soyasapogenol A and B, which showed almost complete suppression of cell growth. The glycosidic soyasaponins by comparison were largely inactive. Soyasaponin A(1), A(2), and I, group B and deacetylated and acetylated group A fractions had no effect on cell growth. Soyasaponin III and soyasapogenol B monoglucuronide were marginally bioactive. These results suggested that the bioactivity of soyasaponins increased with increased lipophilicity. Results from in vitro fermentation suggested that colonic microflora readily hydrolyzed the soyasaponins to aglycones. These observations suggest that the soyasaponins may be an important dietary chemopreventive agent against colon cancer, after alteration by microflora.

An Insight of Pulses: From Food to Cancer Treatment

“…Soybean saponins are renowned anticarcinogens which is evident from many cell culture studies and few animal studies [86]. The effect of soybean saponins on colon cancer has been studied by Gurfinkel et al [89]. Polyphenols: Phenolic compounds serve many diverse functions in a plant such as coloring the leaves and fruits, attracting or repelling insects and protecting plants from herbivores.…”

Phytochemicals in Soy and Their Health Effects

“…Soyasaponins and soyasapogenols have been reported to display diverse health effects (78), including anticancer, cardiovascular protective effects, anti-virus, hepatoprotective actions and antioxidant activities (24,27,79,80). Their health effects largely depend on their chemical structures (81). Since this class of soy compounds are so poorly absorbed, their bioactivity maybe caused by indirect actions within the GI tract.…”

Mechanism of Action of Nigella sativa on Human Colon Cancer Cells: the Suppression of AP-1 and NF-κB Transcription Factors and the Induction of Cytoprotective Genes

“…For example, soybean saponins have been demonstrated to suppress the growth of colon cancer cells (Gurfinkel and Rao, 2003) and Ginseng saponin metabolite, 20 (S)-protopanaxadiol, exhibited anti-proliferative effects on HCT116 colon cancer cells and reduced tumor size in a xenograft model (Gao et al, 2013). Meanwhile, other saponins such as methyl protoneogracillin, methyl protogracillin, protoneodioscin and protodioscin have been identified as potential anticancer agents by the National Cancer Institute's (NCI) anticancer drug screening program (Guclu-Ustundag and Mazza, 2007).…”