Arginine Modification And Biological Activity Of Melanin From Lachnum Sp.

In the present study,an intracellular melanin of Lachnum YM226 was obtained by fermentation,extraction,separation and purification.The antioxidation and lipid lowering activities of LM were studied.ALM was prepared by modifying LM with arginine,and the anti-tumor effects of LM and ALM in H22-hepatoma bearing mice were studied.The results show that LM has good scavenging ability to DPPH·?·OH and O~2-·free radicals,which increased with the increase of melanin concentration.In vitro blood lipid lowering experiment showed that LM had remarkable inhibition activity on pancreatic lipase and the anti-hyperlipidemic effect of LM in vivo was studied further.The model of hyperlipidemia in mice was induced by high-fat diet,and the hypolipidemic effect of LM on hyperlipidemia mice was preliminary studied.The results showed that different doses of LM could effectively reduce the body weight,total cholesterol(TC),Triglyceride(TG),low-density lipoprotein cholesterol(LDL-C),atherogenic index(AI),and increased high density lipoprotein cholesterol(HDL-C).Meanwhile,LM increased the antioxidant enzymes activities of superoxide dismutase(SOD)and glutathione peroxidase(GSH-PX)and reduced malondialdehyde(MDA)content.Compared with the model group,LM significantly reduced alanine aminotransferase(ALT),aspartate aminotransaminase(AST),alkaline phosphatase(ALP),creatinine(CRE),blood urea nitrogen(BUN)and uric acid(UA)in serum of mice,which suggested that LM has protective effect on liver and kidney injury induced by high-fat-diet.In addition,LM also increased the activities of hepatic lipase(HL)and lipoprotein lipase(LPL)in the serum and liver.The murine H22 hepatocarcinoma model was established and the anti-tumor activities of LM and its derivative(ALM)was investigated.The results showed that LM and ALM could effectively inhibit the tumor growth of H22 tumour-bearing mice,improved the body weight,liver,spleen and thymus weight,significantly reduced the levels of ALT,AST),ALP,CRE,BUN,UA,vascular endothelial growth factor(VEGF)and basic fibroblast growth factor(bFGF),raised serum cytokines of interleukin-2(IL-2),interleukin-6(IL-6),tumor necrosis factor-?(TNF-?)and interferon-?(IFN-?)levels.The anti-tumor effect of ALM was more remarkable than that of LM at the same dose.