Nkosi C Z, Opoku A R, Terblanche S E
Department of Biochemistry and Microbiology, University of Zululand, Private Bag X1001, KwaDlangezwa, South Africa.
Phytother Res. 2006 Sep;20(9):780-3. doi: 10.1002/ptr.1958.
The antioxidative effects of pumpkin seed protein isolate (Cucurbita pepo) were investigated in vitro. The isolate exhibited about 80% radical scavenging activity, chelating activity of approximately 64% on Fe2+ ions and an inhibition of approximately 10% of xanthine oxidase. Subsequently the effects of the isolate on the plasma activity levels of alanine transaminase and aspartate transaminase against acetaminophen induced acute liver injury in low-protein fed male Sprague-Dawley rats were ascertained. The rats were maintained on a low-protein diet for 5 days and divided into three subgroups. Two subgroups were injected with acetaminophen and the other with an equivalent amount of polyethylene glycol 400. Two hours after intoxication one of the two subgroups was administered with the protein isolate. Rats from the different subgroups were killed at 24, 48 and 72 h after treatment. After 5 days on the low-protein diet the activity levels of the enzymes were significantly higher than their counterparts on a normal balanced diet. The administration of protein isolate after acetaminophen intoxication resulted in significantly reduced activity levels. It is concluded that the protein isolate has promising antioxidative properties. Furthermore, the isolate administration was effective in alleviating the detrimental effects associated with protein malnutrition and acetaminophen intoxication.
对南瓜籽分离蛋白（西葫芦）的抗氧化作用进行了体外研究。该分离蛋白表现出约80%的自由基清除活性、对Fe2+离子约64%的螯合活性以及对黄嘌呤氧化酶约10%的抑制作用。随后，确定了该分离蛋白对低蛋白喂养的雄性Sprague-Dawley大鼠中对乙酰氨基酚诱导的急性肝损伤时丙氨酸转氨酶和天冬氨酸转氨酶血浆活性水平的影响。将大鼠维持低蛋白饮食5天，然后分为三个亚组。两个亚组注射对乙酰氨基酚，另一个亚组注射等量的聚乙二醇400。中毒两小时后，两个亚组中的一个给予分离蛋白。在治疗后24、48和72小时处死来自不同亚组的大鼠。在低蛋白饮食5天后，酶的活性水平显著高于正常均衡饮食组的大鼠。对乙酰氨基酚中毒后给予分离蛋白导致活性水平显著降低。得出的结论是，该分离蛋白具有良好的抗氧化特性。此外，给予该分离蛋白可有效减轻与蛋白质营养不良和对乙酰氨基酚中毒相关的有害影响。
