Effect of oligofucose derivatives on acetic acid‐induced gastric ulcer in rats

Abstract

This study attempted to enhance the anti‐ulcer activity of fucoidan from Cladosiphon okamuranus TOKIDA by chemical modification with a hydrophobic group. The suitable number of fucose residues in the effective compound was also clarified to obtain a compound of constant quality. Degraded fucoidans were coupled with several hydrophobic groups via Schiff bases, and their anti‐ulcer activities were determined by acetic acid‐induced ulcer models in rats. Size‐fractionated oligofucose was also modified and assayed for anti‐ulcer activity. Among the modified oligofucoses, only the oligofucose‐dodecylaniline combination (OFDA) significantly promoted ulcer healing. The effective dose was 0.2 mg/kg/d. The most suitable number of fucose residues in the compound for the anti‐ulcer activity was determined to be around 12. We succeeded in enhancing the anti‐ulcer activity of Cladosiphon fucoidan by modification with dodecylaniline. The activity of this compound was comparable or greater than that of typical anti‐ulcer agents. By determination of the optimal OF chain length for the anti‐ulcer activity of OFDA, it became possible to obtain OFDA of constant quality.