Polysaccharide Composition of a Gel Fraction Derived from Fenugreek and Its Effect on Starch Digestion and Bile Acid Absorption in Rats

The soluble gel fraction of fenugreek seeds constituted the major portion of the seed coat (including the endosperm) polysaccharides, most of which consisted of galactomannan with mannose:galactose ratio of 1.5:1. The relatively small amount of the insoluble cell wall included mainly cellulose (as glucose) and pectin (as galacturoinic acid). In vivo nutrition experiments in rats and in vitro studies using inverted gut showed that the gel fraction decreased both digestion and absorption of starch and uptake of bile acid (taurocholate and deoxycholate). Whereas 600 mg of the gel fraction was required to inhibit 50% of starch digestion, as little as 80 mg inhibited 50% of bile salt uptake. The present study indicated that the gel fraction, i.e., galactomannan, in the fenugreek seed is the factor which may be of potential benefit of fenugreek seeds in controlling plasma glucose and cholesterol levels.