Antioxidant effect of protein-free silkworm hemolymph extract in mitochondrial membrane potential

Abstract

Silkworm was used in the sericulture industry and also processed for food sources in some of Asian countries. In previous studies, it was reported that the 30K protein in silkworm, Bombyx mori hemolymph inhibited animal cell apoptosis. In this work, the antioxidative function of silkworm hemolymph was investigated using its protein-free extract. H2O2-induced ROS and O2·− were efficiently scavenged in Chinese hamster ovary cells when the culture medium was supplemented with silkworm hemolymph. The hemolymph extract prepared by deproteinization through ethanol precipitation completely scavenged DPPH radicals (IC50=0.025 mg/mL). When the extract was supplemented with protein-free medium, oxidative damage to mitochondria was efficiently diminished with the maintenance of the mitochondrial membrane potential. Lutein was identified as the major antioxidative constituents in the extract (52.06 μg/mg).