Studies on biological activities of melanin from marine animals. I. Purification of melanin from Ommastrephes bartrami Lesuel and its inhibitory activity on gastric juice secretion in rats.

Abstract

Crude squid melanin obtained from ink bags of Ommastrephes bartrami LESUEL was found to exhibit a strong inhibitory effect on gastric secretion in rats. The crude melanin was separated into high molecular fraction SM I (mol. wt.>160000) and low molecular fraction SM II (average mol. wt. ca. 39000) by gel filtration on a Sephadex G-100 column, and Fr. SM II showed a stronger biological activity. Fr. SM II contained a melanoprotein composed of melanin pigment 90%, protein 5.8% and carbohydrate 0.8%, and significantly decreased gastric secretion at the dosage of 1 mg/kg, i.p. or i.v. Fr. SM II also prevented ulcer formation in pylorus-ligated rats and aspirin-induced ulcer.