URIC ACID LOWERING EFFECT BY INGESTION OF PROTEOLYTIC DIGEST OF SHARK CARTILAGE AND ITS BASIC FRACTION

Abstract

ABSTRACT Supplementing with proteolytic digest of shark cartilage (SCP) to give 1.5% and 2.5% in the diet significantly moderated hyperuricemia in rats induced by potassium oxonate in the diet. On the other hand, no significant effect was observed by a diet containing 2.5% proteolytic digest of cow cartilage. Hyperuricemia induced by a single intraperitoneal injection of potassium oxonate was also moderated by single ingestion of the proteolytic digest of shark cartilage in a dose-dependent manner. The proteolytic digest of shark cartilage was fractionated on the basis of the isoelectric point into acidic, weak acidic and basic fractions. Significant anti-hyperuricemic activity was observed only in the basic fraction, and ingestion of chondroitin sulfate free from protein, one of the major constituents of the digest, had no significant anti-hyperuricemic activity. Basic components, possibly peptide, might be responsible for anti-hyperuricemic activity in this rat model. PRACTICAL APPLICATIONS The present study demonstrates that ingestion of diet containing food-grade microbial protease digest of shark cartilage can lower the serum uric acid level of the oxonate-induced hyperuricemia rats, while that of cow cartilage has no significant activity. The shark cartilage digest was fractionated by large-scale preparative isoelectric focusing on the basis of amphoteric nature of sample without using chemically synthesized carrier ampholine, which is referred to autofocusing and has potential for further scale-up. Only basic fraction can significantly lower the serum uric acid. On the other hand, chondroichin sulfate, one of the major constituents of the acidic fraction has no significant activity. These results suggest the basic peptide fraction might responsible for the uric acid-lowering activity. This fraction could be prepared in an industrial scale and used for food ingredient to prevent and alleviate gout attack.