Chitooligosaccharide Hypocholesterolemic Properties: Structure-Function Relationships

Abstract

Chitooligosaccharides have been described as hypocholesterolemic compounds, although their structure-function relationships are not fully known. Targeting to understand their mechanisms of action, in this work, commercial chitooligosaccharides (average degree of polymerization of 10, 90% deacetylation, 20 mV surface charge potential and 2.4 cP viscosity) was used. Their hypocholesterolemic effect was assessed by NMR, measuring cholesterol bioaccessibility and bile salt sequestration in an in vitro intestinal model. Bile salt sequestration capacity was also determined by zeta potential measurements. Electrostatic interactions between negatively charged bile salts and positively charged chitooligosaccharide were observed. Solid state NMR chemical shift analysis showed also hydrophobic interactions between bile salts and chitooligosaccharides acetyl groups. Viscosimetry and diffusion DOSY NMR measurements showed that chitooligosaccharides viscosity do not affect hypocholesterolemic properties. These results highlight that chitooligosaccharides hydrophobic character, even at a high degree of deacetylation, together with positive charges, is a relevant structural feature to tailor cholesterol lowering properties.

Keywords: chitooligosaccharides, cholesterol bioaccessibility, bile salts sequestration, hypocholesterolaemia