Studies On The Bioactivities Of Squid Ink Melanin And Melanin-Fe

Squid ink is mainly composed of melanin and protein-polysaccharide compound. The physiological activities of squid ink,such as anti-tumor activity,immunity regulation or induction of many cytokines,have been widely researched in recent years.It has long been believed that the main active components are polypeptides fragments,acidic polysaccharide,tyrosinase and trae elements.Melanin is an irregular polymer consisting of indole structure,which can resist free radical chain reaction as an acceptor of free radicals,inhibit UVA/B and UVA-induced liposomal lipid peroxidation and chelate many kinds of metal ions.As to squid ink melanin,most researches focus on its structure and the physics and chemistry nature,there is few report concerns its biological activity,however.In this study,high-purity squid ink insoluble melanin(SM-I) was extracted from squid ink sac,then water-soluble melanin(SM-W) and squid ink melanin-Fe(SM-Fe) was prepared.The research on their bioaetivity were conducted in order to evaluate the nutritional and pharmaceutical virtue and encourage the reutilization of squid ink melanin.Hypoimmune model mice were induced by hydrocortisone subcutaneous injection and were given different dosages of SM-I,i.g.,respectively.The immunomodulatory effects of SM-I on hypoimmune mice were investigated.The results showed that Me-I significantly increased the spleen and thymus index,the amount of hemolytic antibody,enhanced the phagocytic activity of macrophages and response of Delayed-Type Hypersensitivity in model mice.It is suggested that insoluble squid ink melanin can stimulate both the non-specific and specific immuity in mice.Aged mice model were induced by injecting D-galactose(1000mg.kg^-1.d^-1).and were given Me-I of different dosages,respectively.The results showed that,ME-I significantly decreased the content of Malondialdehyde(MDA) and Lipofuscin (LIP),enhenced the activity of SOD and GSH-PX both in serum and liver,increased thymus weight and the content of Hydroxyproline(HYP),obviously(P＜0.05 or P＜0.01).The results suggest that Me-I can enhance the anti-oxidation function and postpone the aging process in aged model mice.The heavy-metal expelling effect of Me-I were investigsted.Mice were divided randomly into 4 groups:control,Me-I,heavy metal(HM) and heavy metal+ melanin(HM+Me-I) group,and were given bisic solution,Me-I,mixed heavy metal, HM+Me-I solution,respectively.The results show that,in comparation with heavy metal group,the content of heavy-metal ion derease significantly in thighbone and blood while increased in fecal in HM+Me-I group.The results indicat that Me-I can effectively prevent the absorption and cumulation and reduce the poison of heavy-metal ion in mice.Iron deficiency anemia(IDA) model rats were established by feeding with iron-deprived food and bleeding via tail vein.Several dosages of squid ink melanin-Fe(Me-Fe) were given to the model rats via gastric administration.It was evident that Me-Fe significantly enhanced the contents of hemoglobin(Hb),the number of red blood cell(RBC),hematocrit(HCT),mean corpuscular volume(MCV) and the content of serum iron(SI),while reduced free erythrocyte proloporphyrin (FEP) content.It appeared to promote the restoration of iron deficiency anemia. Me-Fe also has significant effects on stimulating erythropoiesis in IDA rats.The experimental hyperlipidemia model mice were established by high-fat-diet feeding.The effects of Me-I and Me-W on the lipid metabolism in hyperlipidemic-hypercholesteremic mice and the mechanism underlying such effects were investigated.The results showed that both Me-I and Me-W significantly decreased the contents of TC,TG,LDL-c(P＜0.05) and the AI(P＜0.05) in serum,and reduced the accumulation of TC and TG in liver,increased the contents of total lipids, TC(P＜0.01) and bile acid(P＜0.01) in fecal.They also enhanced the activity of CPT-1(P＜0.01),β-oxidation peroxisomal(P＜0.05) and PAP(P＜0.05) in liver markedly.It is suggested that both Me-I and Me-W can significantly improve lipid decompensation,inhibit the absorbtion of lipids in enteron and enhence the egestion of lipid in hyperlipidemia mice.The mechanisim is that Me-I and Me-W can enhance theβ-oxidation and dissimilation of lipids.MTT assay were used to test the influence of Me-W on proliferation activities of oxidative damaged endothelial cell.The results showed that Me-W could protect vascular endothellial cells from injury induced by H₂O₂.Cell proliferation activity and NO content were stimulated significantly(P＜0.05,P＜0.01).MTT assay were used to test the influence of Me-W on proliferation activities of Hela,S180,Caco-2 and B16.The results showed that Me-W could inhibit Cell proliferation activity of S180 but has no significant effect on proliferation activity of Caco-2,Hela and B16 cells.