Soyasaponin and α-tomatine inhibit in vitro bioaccessibility of cholesterol
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Date
2008-03-31T13:45:12Z
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Abstract
Saponins are a structurally diverse family of secondary plant metabolites that confer protection against pathogens and predators. These compounds consist of triterpene or steroidal nuclei (aglycones) covalently linked to either mono- or oligo-saccharides. In vitro and several in vivo studies have suggested that these amphipathic compounds possess anti-carcinogenic, hypo-lipemic, hypo-cholesterolemic and immuno-enhancing activities. Limited investigations indicate that saponins are poorly absorbed, but their potential impact on digestion and gut health remains unknown. We have initiated studies to compare the effects of saponins extracted from soy, tomato, chickpea, fenugreek and a commercial mixture of phytosterols (positive control) on cholesterol absorption and metabolism, as well as on interactions between microflora and the gut epithelium. Pilot studies demonstrate significant differences in the ability of equimolar concentrations of saponins from these sources to inhibit micellarization of cholesterol from a food matrix during simulated digestion with α-tomatine >> phytosterols > soyasaponin. Removal of the oligosaccharide from tomatine to generate tomatidine markedly decreased activity. Saponins from soya and tomato, as well as their aglycones, and phytosterols all slightly, but significantly, impaired transfer of cholesterol from micelles to human intestinal Caco-2 cells. These preliminary observations suggest that saponins from crops important to Ohio economic status can modulate the bioavailability of dietary cholesterol.
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soy, tomato, cholesterol, Saponins