Saponins are naturally occurring surface-active glycosides produced by plants, lower marine animals, and some bacteria. Saponins occur constitutively in a great many plant species, in both wild plants and cultivated crops. In cultivated crops, the triterpenoid saponins are generally predominant, while steroid saponins are common in wild plants used as herbs [81]. Plant saponins have been shown to inhibit cholesterol absorption from the intestinal lumen in experimental animals and consequently to reduce the concentration of plasma cholesterol. This may be the result of interactions with cholesterol in the digestive tract or a direct effect of plant saponins on cholesterol metabolism.

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