Comparison of synthetic saponin cholesterol absorption inhibitors in rabbits: evidence for a non-stoichiometric, intestinal mechanism of action

Abstract

The hypocholesterolemic activities of pamaqueside and tiqueside, two structurally similar saponins, were evaluated in cholesterol-fed rabbits. The pharmacological profiles of the saponins were virtually identical: both dosedependently decreased the intestinal absorption of labeled cholesterol 25-75%, increased fecal neutral sterol excretion up to 2.5-fold, and decreased hepatic cholesterol content 10-55%. High doses of pamaqueside ( Ͼ 5 mg/kg) or tiqueside ( Ͼ 125 mg/kg) completely prevented hypercholesterolemia. Decreases in plasma and hepatic cholesterol levels were strongly correlated with increased neutral sterol excretion. Ratios of neutral sterol excreted to pamaqueside administered were greater than 1:1 at all doses, in opposition to the formation of a stoichiometric complex previously suggested for tiqueside and other saponins. Ratios in tiqueside-treated rabbits were less than unity, a reflection of its lower potency. Pamaqueside-treated rabbits exhibited a more rapid decline in plasma cholesterol concentrations than control animals fed a cholesterol-free diet, indicating that the compound also inhibited the absorption of biliary cholesterol. Intravenous administration of pamaqueside had no effect on plasma cholesterol levels despite plasma levels twice those observed in rabbits given pamaqueside orally. These data indicate that pamaqueside and tiqueside induce hypocholesterolemia by blocking lumenal cholesterol absorption via a mechanism that apparently differs from the stoichiometric complexation of cholesterol hypothesized for other saponins. -Morehouse, L.

Effect of Yucca Schidigera Addition to Ducks Diet on Productive Characteristics and Economical Evaluation Through Summer Conditions

“…Also, saponins could lessen the cholesterol captivation and ease neuter sterols emission (Jenkins and Atwal, 1994), that lessening it absorption and hepatic substance. The current results showed that YS saponins attenuated serum cholesterol and agreed with Aslan et al (2004) in laying hens and Morehouse et al (1999) in rabbits. Cholesterol level was diminished by adding 120 mg YS/kg for laying hens diet (Kutlu et al, 2001).…”

Impacts of Natural Saponin Plant Extract Without or With Fresh Baker’s Yeast in Buffaloe Heifers Rations on Nutrients Digestibility, Some Ruminal Fermentation and Blood Serum Parameters.

“…A number of studies, such as those of Malinow et al (1977), have shown that alfalfa saponins have hypocholesterolemic activity in nonhuman primates. A number of synthetic saponins have been shown to be cholesterol absorption inhibitors (Harwood et al, 1993;Morehouse et al, 1999), causing reduction in plasma low-density-lipoprotein cholesterol fractions. Although it is generally accepted that the principal action of saponins on blood cholesterol is by sequestration of cholesterol and bile acids in the intestine, thus preventing the cholesterol from being recycled again into the blood stream again (Cheeke and Otero ( 2005) and Cheeke et al, (2006).…”

Effect of Dietary Inclusion of Galangal (Alpinia Galanga) on Growth Performance and Some Physiological Parameters of Broiler Chicks

“…By inhibiting the enzyme 3-hydroxy-3-Metilglutaril-CoA (HMG-CoA reductase), which plays a role in cholesterol synthesis, as well as the LDL receptor through SERBP, flavonoids and essential oils can decrease cholesterol biosynthesis and absorption (Sunarto, 2012;Lovita, 2013 andAbdel-Azeem &Basyony, 2019). Saponins and tannins also have a role in cholesterol uptake suppression by inhibiting lipase activity, binding cholesterol, and lowering surface tension by the action of saponin binding cholesterol in the gut lumen, which influences fat metabolism in the body (Morehouse et al, 1999). Table (5) shows the effect of galangal supplements on antioxidant levels in the blood serum of treated broiler chicks.…”