Chang Sue-Joan, Lee Yi-Chun, Liu Sin-Yie, Chang Tso-Wei
Department of Biology, National Cheng Kung University, Tainan, Taiwan.
J Agric Food Chem. 2004 Mar 24;52(6):1720-5. doi: 10.1021/jf0345954.
Antioxidative effects of Dioscorea alata (D. alata) were investigated in hyperhomocysteinemia (HHcy) induced by methionine (Met) oral feeding (1 (g/kg of BW)/day). HHcy rats were fed a standard laboratory chow supplemented without or with freeze-dried D. alata powder at 1, 2.5, and 5 (g/kg of BW)/day, assigned as Met, Met + D1, Met + D2, and Met + D3 groups, respectively. Twelve weeks after D. alata feeding, plasma homocysteine levels (16.3-24.2 microM) were significantly decreased compared to that of the Met group (34.1 +/- 9.9 microM) (p < 0.01), and similar to the basal level (15.0 +/- 1.9 microM). Thrombin-induced platelet aggregation (PA) of the Met + D2 and Met + D3 groups was significantly lower than that of the Met group. Plasma malondialdehyde levels, an indicator of lipid peroxidation, and hepatic reactive oxygen species, an indicator of oxidative stress, of HHcy with D. alata feeding were significantly lower than that without D. alata feeding. The hepatic catalase in the Met + D2 and Met + D3 groups was significantly elevated compared to that in the Met group. D. alata feeding did not significantly change hepatic superoxide dismutase, glutathione peroxidase, and glutathione reductase, which were adaptively enhanced by Met feeding. The decreased glutathione/glutathione disulfide ratio in the Met group was increased after D. alata feeding. These results indicated that HHcy induced by Met could be reversed by D. alata feeding. D. alata feeding exhibited its antioxidative effects in HHcy including alleviating PA, lipid peroxidation, and oxidative stress, but did not induce activity of antioxidant enzymes which had already adaptively increased by HHcy.
通过口服蛋氨酸（Met，1克/千克体重/天）诱导高同型半胱氨酸血症（HHcy），研究了大薯（D. alata）的抗氧化作用。给HHcy大鼠喂食添加或不添加冻干大薯粉（分别为1、2.5和5克/千克体重/天）的标准实验室饲料，分别设为Met、Met + D1、Met + D2和Met + D3组。喂食大薯12周后，与Met组（34.1±9.9微摩尔）相比，血浆同型半胱氨酸水平（16.3 - 24.2微摩尔）显著降低（p < 0.01），且与基础水平（15.0±1.9微摩尔）相似。Met + D2组和Met + D3组凝血酶诱导的血小板聚集（PA）显著低于Met组。喂食大薯的HHcy组中，作为脂质过氧化指标的血浆丙二醛水平和作为氧化应激指标的肝脏活性氧显著低于未喂食大薯的组。与Met组相比，Met + D2组和Met + D3组的肝脏过氧化氢酶显著升高。喂食大薯并未显著改变肝脏超氧化物歧化酶、谷胱甘肽过氧化物酶和谷胱甘肽还原酶，这些酶因Met喂食而适应性增强。Met组降低的谷胱甘肽/谷胱甘肽二硫化物比值在喂食大薯后升高。这些结果表明，Met诱导的HHcy可通过喂食大薯得到逆转。喂食大薯在HHcy中表现出抗氧化作用，包括减轻PA、脂质过氧化和氧化应激，但并未诱导已因HHcy而适应性增加的抗氧化酶活性。
