Impromptu Effects of Nt8U with Soyasaponins on Obesity-related Lipid Parameters in High Fat Fed C57BL/6 Mice

Nt8U is a peptide analog of the N-terminal 13 residue fragment of the satiety peptide obestatin with Gly (8) being replaced by α-amino isobutyric acid (Aib). As a consequence of introducing a conformationally constrained, unusual amino acid Aib, it has a longer half-life of 30 min in circulation against 5 min for obestatin. It was found to be as effective as obestatin in modulating lipid parameters favorably in mice. Saponins have also been studied extensively for their anti-obesity effects. Though saponins from soyabean have been reported to have lipid lowering activities, the studies are largely carried out with group B saponins. We hypothesized that Nt8U could be a better anti-obesity lead candidate if co-administered with other lipid lowering nutraceuticals. Hence in the present study, we evaluated the combined effect of Nt8U and the under-exploited soyasaponins on lipid parameters in high fat fed (HFD) C57BL/6 mice. Mice fed HFD for 18 weeks were administered Nt8U with soyasaponins A or B for a period of 8 days. Although there was no significant difference in food intake, Nt8U with soyasaponins A was found to be the best combination that reduced perirenal, retroperitoneal and axillary fat.