Inhibitory effect of enokitake extract on melanosis of shrimp

ABSTRACT:  The inhibitory effect of 70% acetone extract of enokitakemushroom Flammulina velutipes on the mealnosis of shrimp Trachypenaeuscurvirostris was investigated. The acetone extract effectivelyprevented the mushroom tyrosinase activity as well as melanosisof American crayfish Procambarus clarkii hemolymph. Wheneach of two fractions of the acetone extract, which were unadsorbedon both of Dowex 50W X8 and/or DEAE-TOYOPERAL 650 columns,was mixed with hemolymph of the American crayfish, the melanosisthat usually occurs in the heparinized hemolymph was effectivelyprevented. Immersing shrimp in the acetone extract of enokitakemushroom delayed the color darkening usually found in the post-mortemshrimp. These observations suggested that enokitake mushroom containedcertain compounds that inhibit the formation of melanin due to thecatalytic oxidation of polyphenol oxidase, as well as mushroom tyrosinaseactivity.