The biological action of saponins in animal systems: a review

Abstract

Saponins are steroid or triterpenoid glycosides, common in a large number of plants and plant products that are important in human and animal nutrition. Several biological effects have been ascribed to saponins. Extensive research has been carried out into the membrane-permeabilising, immunostimulant, hypocholesterolaemic and anticarcinogenic properties of saponins and they have also been found to significantly affect growth, feed intake and reproduction in animals. These structurally diverse compounds have also been observed to kill protozoans and molluscs, to be antioxidants, to impair the digestion of protein and the uptake of vitamins and minerals in the gut, to cause hypoglycaemia, and to act as antifungal and antiviral agents. These compounds can thus affect animals in a host of different ways both positive and negative.

Bioactivity of phytochemicals in some lesser-known plants and their effects and potential applications in livestock and aquaculture production systems

“…Therefore, it was hypothesised that induction of changes in LH secretory pattern by QS or its degraded products absorbed Effects and applications of phytochemicals from the intestine might be responsible for the effects that have been observed on reproduction. QS was found to stimulate LH release from dispersed tilapia pituitary cells in vitro (Francis et al, 2002d). This effect was abolished in the presence of dilute calf serum.…”

“…Cholesterol-reducing effects of fenugreek seeds (rich in saponins) have also been demonstrated in rats and humans (Petit et al, 1993;Al-Habori and Raman, 1998). Antiviral activity of saponins from Glycyrrhiza radix, immunostimulant activity of saponins from Quillaja saponaria Molina, and hypoglycaemic and antidiabetic activity of saponins from fenugreek (see Francis et al, 2002d) have also been demonstrated. Yucca, quillaja, S. rarak and Enterolobium cyclocarpum saponins have been shown to increase productive parameters such as wool production, growth and milk production in animals on roughage-based diets (Wina et al, 2005c).…”

“…Diverse effects of dietary saponins include an increase in the permeability of intestinal membranes to dietary nutrients (Francis et al, 2002d) and/or a stimulation of the activity of digestive enzymes, which increases the efficiency of feed nutrient utilisation. Dietary QS increased significantly the activity of intestinal enzymes, amylase and trypsin, suggesting stimulation of protein and carbohydrate digestion in the intestine.…”

“…From the extent of effects that saponins have on various physiological processes it is expected that either saponins or their breakdown products enter the body through the intestinal membranes. We have described the ability of saponins to influence serum hormone levels (Francis et al, 2002d). However, some dietary components may produce systemic effects even without actually entering the body.…”

Natural alternatives to in-feed antibiotics in pig production: can immunomodulators play a role?

“…An extract of the South American tree Quillaja saponaria is widely used as a vaccine adjuvant (Kensil et al, 2004), and whose active ingredient appears to be the saponin fraction (Milgate and Roberts, 1995). As saponins are known to enhance immunity via the intestinal route, their use in animal nutrition has been the subject of investigation (Francis et al, 2002). Dietary treatment with crude soap bark of Q. saponaria, ranging from 125 to 500 mg/kg, did not counteract the negative effects on feed intake and growth induced transiently by a challenge with Salmonella enterica serovar Typhimurium (Turner et al, 2002b).…”