Moderation of oxonate-induced hyperuricemia in rats via the ingestion of an ethanol-soluble fraction of a shark cartilage proteolytic digest

A shark cartilage proteolytic digest was fractionated by selective extraction with 75% ethanol. Peptides in the digest were recovered in the 75% ethanol-soluble fraction. The ethanol-soluble fraction showed lower viscosity and higher solubility in water than the crude digest. Oxonate-induced hyperuricemia in rat was suppressed by the oral administration of the ethanol-soluble fraction of the digest (1 g/kg body weight/day) for 28 days. Single administration of the ethanol-soluble fraction also reduced blood uric acid level in a dose-dependent manner. Administration of the ethanol-soluble fraction of the digest (1 g/kg body weight/day) significantly increased serum inhibitory activity against xanthine oxidase, whereas the ethanol-soluble fraction had no in vitro xanthine oxidase inhibitory activity. These facts suggest that peptides in the ethanol-soluble fraction might be converted into smaller peptides with xanthine oxidase inhibitory activity during digestion, absorption, and metabolism.

► Peptides in shark cartilage digest were recovered in 75% ethanol-soluble fraction (ES).
► ES showed lower viscosity and higher solubility in water than the crude digest.
► Oral administration of ES exerted anti-hyperuricemic activity in rat models.
► Ingestion of ES significantly increases blood xanthine oxidase inhibitory activity.