Bioactivities of Chitosan and Its Derivatives - Chitosan Based Hydrogels: Functions and Applications - page 152

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Basal Chitosan Basal Chitosan ↵

Very low-density lipoproteins, low-density lipoproteins, and high-density lipoproteins.

Figure 3.21
Relative concentration of LDLs, very low-density lipoproteins, and HDLs.

and growth. The concentration of liver cholesterol and triglyceride also decreased sig-
nificantly. Plasma, but not liver cholesterol-lowering effect, was roughly comparable
with that of cholestyramine. Chitosan at the 10% level further reduced plasma choles-
terol, but depressed growth. Also, finer chitosan particles tended to restrain growth
even at the 2% level. In rats fed a cholesterol-free diet containing 0.5% chitosan for 81
days, the concentration of serum cholesterol was the same as that of the corresponding
control, but relatively more cholesterol existed as HDLs and less as very low-density
lipoproteins (Figure 3.21). Dietary chitosan increased the fecal excretion of cholesterol,
both exogenous and endogenous, while that of bile acids remained unchanged. There
was no constipation or diarrhea. A proper supplementation of chitosan to the diet seemed
to be effective in lowering plasma cholesterol.
Helgason et al. [173] investigated the effect of molecular characteristics of chitosan on its
ability to bind fat in an in vitro simulation model for digestion. It was concluded that physi-
cochemical properties of chitosan and environmental conditions greatly influenced the
interaction between chitosan and oil micelles ( Figures 3.22 and 3.23) .

3.4.3.2 Characterization

Cholesterol absorption efficiency: : Cholesterol absorption was measured by a modification of
the fecal dual isotope ratio method. Rats were gavaged on two consecutive days at 100 h
with 5.0 kBq 14 C-bsitosterol (2.05 GBq/mmol; Amersham Life Sciences, Arlington Hills, IL)
and 34.7 kBq 3 H-cholesterol (130 GBq/mmol, Amersham Life Sciences) using soybean oil
as the vehicle. Two consecutive 24-h fecal collections were taken beginning at 1800 h of
gavage day 1. Collections were individually lyophilized and stored at 220°C until analysis.
Fecal lipids were extracted from each collection by homogenizing ground feces with
chloroform/methanol (2:1). The homogenate was filtered and then rinsed twice with nor-
mal saline. The filtrate was dried under nitrogen gas and reconstituted with chloroform/