| 摘要: | 高尿酸血症的盛行率逐漸增加，近來研究更指出高尿酸血症之發生除了與痛風有關之外與肥胖、心臟病、糖尿病、腦血管疾病等慢性疾病皆有密切相關。本研究目的：一、欲探討白鳳菜與七層塔冷水萃取物之體外抗氧化分析。分析項目如下：總類黃酮含量、總多酚含量、總抗氧化分析、清除DPPH自由基、亞鐵螯合力、還原力等。二、欲探討白鳳菜及七層塔水萃物對於高尿酸誘導小鼠之影響。本研究使用42隻ICR雄性小鼠三週齡適應兩週後，除了一組為Vehicle組(正常控制組)外其餘動物連續7天腹腔注射氧嗪酸鉀 (Potassium oxonate) 250 mg /kg以誘導高尿酸血症。高尿酸血症組再依試驗樣品濃度不同分為六組：分別為PO組(尿酸誘導組)、AL組(Allopurinol藥物治療組)、GF1與GF5組分別為白鳳菜水萃物100mg/kg、500mg/kg；OG1與 OG5組為七層塔水萃物100mg/kg、500mg/kg，每日管餵一次，連續7天。分析項目如下：血漿尿酸(Urea acid)濃度、尿素氮(BUN) 、肌酸酐(Creatinine)，肝臟黃嘌呤氧化酶 (Xanthin Oxidase, XO)與黃嘌呤去氫酶 (Xanthin Dehydrogense, XDH ) 酵素活性、脂質過氧化指標(TBARS)含量以及腎臟尿酸鹽轉運蛋白(URAT1、OAT1)等。體外抗氧化分析部分，總抗氧化能力以七層塔總抗氧化力最高，總多酚則是以白鳳菜總多酚含量較高。動物實驗部分血漿尿酸濃度以PO組顯著最高，給予藥物治療之AL組則顯著下降，在試驗樣品組中無論是GF1、GF5或OG1、OG5組其血漿尿酸濃度都顯著低於PO組( p<0.05 )，且下降情形與AL組效果相當。肝臟XO活性於各組間雖無顯著差異，但是XDH活性亦以PO組顯著上升，除了OG5組外，其餘各組的XDH活性皆顯著低於PO組。肝臟TBARS含量於各組間並無顯著差異。GF組與OG組的URAT1、OAT1蛋白質表現量雖然有低於PO組的趨勢，但是於各組之間未見有顯著差異。本實驗結果指出，連續管餵白鳳菜與七層塔水萃物具有體外抗氧化能力，而且可顯著降低高尿酸誘導小鼠的血漿尿酸濃度，其降尿酸機制應與肝臟XDH酵素活性之抑制有關。
Background and Purpose: Hyperuricemia and metabolic syndroms, including obesity, heart disease, hypertension and kidney disease, have been reported to be highly prevalent in many countries. The purpose of this study was to investigate the antioxidant ability and the hypouricemic effect of the water extracts of Gynura formosana and Ocimum gratissimum in mice treated with potassium-oxonate. Methods: The in vitro antioxidant ability of the water extracts of the vegetables were measured, including Trolox equivalent antioxidant capacity, (TEAC), DPPH scavenging effect, reducing power, the ferrous iron-chelating effect. The hypouricemic effect was conducted with animals. 42 three-week-old ICR male mice were divided into 7 groups, all animals except the Vehicle group (normal control group) were treated with potassium oxonate (PO, 250mg/kg BW, i.p.) to induce hyperuricemia for 7 days. The animals were tube fed with the following test samples: saline (vehicle and PO groups), Allopurinol drug (AL group, as the curring group) , water extract of Gynura formosana 100mg/kg BW or 500mg/kg BW (GF1 or GF5 group) , water extract of Ocimum gratissimum 100mg/kg BW or 500mg/kg BW (OG1 or OG5 group) for seven consecutive days. The concentration of plasma uric acid, BUN and creatinine, the enzyme activities of xanthine oxidase(XO) and xanthine dehydrogenase (XDH) in liver, thiobarbituric acid-reactive substances (TBARS) levels in tissues were measured. The renal uric acid salt transporter protein(URAT1) and organic anion transporter (OAT) were aslo measured with Western blot. Result: The PO group showed significantly the highest levels of plasma uric acid, the AL group reduced the plasma uric acid levels significantly. The plasma uric acid concentrations in all the test groups, (GF1, GF5 or OG1, OG5) were significantly lower than the PO group (p <0.05). There is no significant difference among the 7 groups in liver XO activity. However, the XDH activity showed significantly higher in PO group than that in the remaining groups (GF1, GF5, OG1, OG5 and vehicle groups). Liver TBARS content showed no significantly difference among the 7 groups. The protein levels of URAT1 and OAT1 also showed no significant differences among the 7 groups. Conclusion: The water extracts of Gynura formosana and Ocimum gratissimum showed the in vitro antioxidant ability and also showed the hypouricemic effect in mice treated with potassium-oxonate. The hypoucricemic mechanism of the water extracts of Gynura formosana and Ocimum gratissimum could be due to their inhibition effect of liver XDH activity. |
