Studies On The Bioactivities Of Docosahexaenoic Acid-phosphatidylcholine

Docosahexaenoic Acid-Phosphatidylcholine(DHA–PC)was a new functional component existed in muscle and spawn of cuttlefish. PC was a basic component of the cell membrance skeleton of plants and animals, playing the vital role in transfering information both internal and external membrane by phospholipid bilayers structure. Previous studies has already confirmed that DHA showedpossessed broad physiological activities including the excellent immunomodulatory, anti-lipid peroxidation, free radical scavenging, antitumor and so on. In this study, DHA–PC from cuttlefish spawn was extracted to investigate the anti-tumor effects and mechanisms .Meantime, the effects of DHA–PC on the intelligence and lipid metabolism in mice were conducted. results are as follows:The antitumor effects of DHA–PC in vitro was studied on HepG-2 cells. It was proved that DHA-PC could significantly inhibit HepG-2 cell proliferation by MTT assay (P<0.05, P<0.01); induce HepG-2 cell apoptosis by AO/EB staining method; arrest cell cycle at G1/G0 phase. The effects of DHA-PC on the invasion and metastasis on HepG–2 cells were investigated through cell–base adhesion assay, wound healing assay, invasion assay and chorioallntoic membnare assay. The results showed that the DHA–PC could decrease the adhesion rate in dose dependent manner and inhibit the cellular motility(P<0.05, P<0.01); inhibit invasion of HepG–2 cells in dose dependently (P<0.05, P<0.01); inhibit the generation of new blood vessels; reduce the expression of Vascular Endothelial Growth Factor (VEGF). The results suggested that the DHA–PC could induce apoptosis and inhibit the metastasis of HepG–2 cellsThe effects of DHA–PC on anti–tumor in vivo were investigated using transplanted tumor–bearing mice. Different dosages of DHA–PC(50 and 200mg/kg.bw) were given to the S₁₈₀ bearing mice respectively for 14d, The results showed that DHA–PC could inhibit the growth of tumor in mice remarkably, the average inhibitory rate was 38.06%; increase the activities of GST, GSH–PX(P<0.05, P<0.01)and the content of GSH(P<0.05, P<0.01) both in serum and liver; drcrease the MVD of tumor remarkably by immunohistochemical analysis(P <0.05). It is suggested that the anti-tumor ability of DHA–PC may be associated with advance the antioxidant level, decrease the MVD expression in tumor tissue.The effects of DHA–PC on immune regulation in transplanted tumor–bearing mice were investigated by intragastric administration different dosage of DHA-PC(67, 134 and 268mg/kg.bw). The results showed that DHA–PC could enhance spleen indexes; increase hemolysin content(P<0.01), delayed hypersensitivity level (P<0.05, P<0.01); promote the phagocytosis ability of celiac macrophage(P<0.01). It is suggested that DHA–PC can regulate both specific and non–specific immune function, inhibit the growth of tumor cells.The effects of DHA–PC on anti dementia were investigated by administered orally different dosages of DHA–PC(50, 100 and 200mg/kg.bw) on the dementia mouce which was established using scopolamine. The results showed that DHA–PC could inhibit the activities of MAO(P<0.01)and TChE(P<0.01); increase the activity of SOD(P<0.05, P<0.01), heighten the contents of DHA in brain(P<0.01) compared with model control. The result suggested that DHA–PC can improve the intelligence induced by scopolamine in mice by lowering the activities of MAO and TChE; increasing the activity of SOD and the content of DHA in brain.The normal rats were fed with semisynthetic diets contained 1% or 4%DHA–PC to detect the effect of DHA–PC on improving lipid metabolism.The contents of TC and TG were detemined by enzyme assay kits and the fatty acid composition were analysed by GC. The results showed that compared with normal control, DHA–PC could decrease the contents of TC and TG(P<0.01) in serum and liver, increase the content of DHA(P<0.01) in liver tissue; compared with S–PC control, DHA–PC could decrease the contents of TC and TG in serum (P<0.01) and contents of TC and TG in liver(P<0.05, P<0.01), increase the contents of DHA(P<0.01) in liver; compared with DHA control, DHA–PC could heighten the contents of HDL-C, reduce the contents of TG(P<0.05) in liver. It can be concluded that DHA–PC could regulate the lipid metabolism effectively, mainly through the way of promoting the absorption and utilize of DHA in mice.In summary, DHA–PC can inhibit the growth of tumor in vitro and vivo through antioxidation, cell apoptosis and inhibiting the metastasis. DHA–PC also can improve the intelligence on dementia mice induced by scopolamine and regulate the lipid metabolism in normal mice.