本研究以大白鼠為實驗模型,經口投予不同添加量之綠藻六週,以測量:(1)抗氧化物質濃度、(2)抗氧化酵素活性、(3)抗氧化能力、(4)總抗氧化狀態,綜合評估綠藻對實驗動物之抗氧化力的影響。實驗一綠藻添加量為1%, 5%, 10%,結果顯示:綠藻飼料並不會影響實驗動物正常的生長。不同添加量的綠藻飼料不會影響血漿中二價、三價、總鐵離子濃度及二價鐵離子/三價鐵離子的比值,但皆明顯升高紅血球及肝中GSH-Px活性,而1%與5%綠藻飼料可提高紅血球中GSH-Rd及SOD的活性。10%綠藻飼料能有效降低LDL中脂質過氧化物的濃度,但卻造成肝中脂質過氧化物濃度的增加。實驗二綠藻添加量為0.1%, 0.5%, 4%,結果顯示:0.5% 與4% 綠藻飼料明顯降低50~70% 血漿中二價鐵離子濃度,而0.1%、0.5% 與4% 綠藻飼料皆可升高血漿中三價鐵離子及總鐵離子濃度,而降低血漿中二價鐵離子/三價鐵離子的比值。0.1%、0.5% 與4% 綠藻飼料皆明顯升高紅血球中GSH-Rd活性,而降低肝中SOD活性。0.5% 與4% 綠藻飼料則明顯升高紅血球中SOD活性至1.5倍。不同添加量的綠藻飼料並不會影響紅血球中GSH-Px及過氧化氫酉每活性、肝中GSH-Rd與過氧化氫酉每活性。0.1%、0.5% 與4% 綠藻飼料分別降低13%、68% 及57% LDL中脂質過氧化物的濃度,但並不影響肝中脂質過氧化物的濃度。與控制組相較,0.1%、0.5% 與4% 綠藻飼料使血漿中總抗氧化狀態提高1倍。綜合評估結果,綠藻可增加大白鼠體內抗氧化力,而以1% 與 5% 綠藻提高抗氧化力的效果較10% 綠藻為佳,又以0.5% 與 4% 綠藻提高抗氧化力的效果較0.1% 綠藻為佳。實驗三結果顯示:在四氯化碳誘發氧化壓力下,0.5%綠藻的添加,並不會提高體內的抗氧化狀態及抗氧化力。
This study was to evaluate the antioxidant effect of chlorella on the concentrations of the antioxidants, the activities of the antioxidative enzymes, the antioxidative capacity, and the total antioxidant status in Sprague-Dawley rats after six-week oral feeding. The first experimental results showed that 0, 1,5, or 10% chlorella diet did not affect normal growth of the rats. Different dosages of chlorella diets didn’t affect levels of ferrous ion, ferric ion, and the ratio of ferrous to ferric ions, but significantly elevated the activity of glutathione peroxidase in the erythrocytes and liver. The activities of erythrocyte glutathione reductase and superoxide dismutase were significantly elevated by 1% and 5% chlorella diets. Addtionally, the concentrations of lipid peroxidation products in the low density lipoproteins were reduced in the rats fed 10% chlorella diet, but were elevated by 10% chlorella diet in the liver. The second experimental results showed that the levels of plasma ferrous ion were reduced by 50~70% in the rats fed 0.5 or 4% chlorella diet. All of the chlorella diets (0.1, 0.5, and 4%) significantly elevated the levels of plasma ferric ion and total iron, and decreased the ratio of ferrous to ferric ions in the plasma. The activities of erythrocyte glutathione reductase were increased and those of hepatocyte superoxide dismutase were decreased by all of the chlorella diets. The activities of erythrocyte superoxide dismutase were significantly elevated to 1.5-fold by 0.5 and 4% chlorella diets. However, different dosages of chlorella diets did not affect the activities of erythrocyte glutathione peroxidase and catalase, and those of hepatocyte glutathione reductase and catalase as well. The concentrations of lipid peroxidation products in the low density lipoproteins were reduced by 13, 68, and 57% in the rats fed 0.1, 0.5, or 4% chlorella diet, respectively. However, the concentrations of lipid peroxidation products in the liver were not affected by the chlorella diet. The total antioxidant status in the plasma was one-fold greater in the rats fed the chlorella diet than the control group. In summary, the chlorella diet increases antioxidative capacity in the rats, especially 1 and 5% chlorella diets improve antioxidative capacity more efficiently than 10% chlorella diet, and 0.5 and 4% chlorella diets improve antioxidative capacity more efficiently than 0.1% chlorella diet. The third experimental results showed that 0.5% chlorella diets can not improve antioxidative capacity in the rats treated with CCl4 under oxidative stress.