The Effect of Polysaccharides on Cholesterol Metabolism

Abstract

The authors previously reported that the konjac flour prepared from the tubers of Amorphophallus Konjac K. KOCH (Araceae) showed a significant hypocholesterolemic activity.In the present paper, a comparative study was carried out on its hypocholesterolemic activity using refined konjac mannan and edible-konnyaku (a processed food made from the konjac flour).1. Male rats of the Wistar strain were fed hypercholesterolemic diets for 8 days, which contained 5% of the crude konjac mannan (CKM), refined konjac mannan (RKM) or lyophilized edible konnyaku (LEK), respectively.Food intake, body weight gain and liver weight of rats fed on CKM or RKM diets decreased as compared with those of the control group.The serum and liver cholesterol level, liver total lipids and total fatty acid concentration which were elevated by dietary cholesterol plus bile acids were significantly depressed when CKM or RKM was added to the hypercholesterolemic diet. Considerable changes by the addition of CKM or RKM were also observed in the fatty acid composition of liver lipids.On the other hand, the serum and liver cholesterol or liver fatty acid depressing activity was not seen in rats placed on the LEK diet.2. When edible konnyaku was given for 5 days to six young men whose serum cholesterol level was elevated by pre-feeding butter fat for 7 days, no hypocholesterolemic activity was observed.3. These findings may suggest that an unprocessed konjac mannan itself (macromolecule with viscosity and water-soluble), is essential for the hypocholesterolemic activity.