苦藤水萃物於體外及動物模式之降尿酸效應評估

Evaluation of the Hypouricemic Potential of Tinospora cordifolia Extract in Vitro and in an Animal Model

蕭慧美(Huey-Mei Shaw) ； 陳倪熏(Ni-Shiun Chen) ； 沈君柔(Jun-Rou Shen) ； 陳玟瑾(Wen-Chin Chen) ； 王明雄(Ming-Shyong Wang)

《臺灣營養學會雜誌》 42卷1期 (2018/03) Pp. 11-22

https://doi.org/10.6691/NSJ.201803_42(1).0002

摘要

苦藤（Tinospora cordifolia）乾燥莖為民間常用草藥。此實驗意欲探討苦藤水萃物是否兼具體內外的抗高尿酸作用。苦藤萃出物含有總多酚、類黃酮及抗氧化能力，且受萃取溶劑不同而有差異。取苦藤熱水萃取10分鐘之萃出物進行體外黃嘌呤氧化酶（xanthine oxidase, XO）活性之抑制能力，IC_(50)約為10.85 mg/mL。高尿酸血症動物模式為採用ICR雄性小鼠連續7天腹腔注射氧嗪酸鉀（potassium oxonate, PO）250 mg/kg BW/Day以誘導高尿酸血症。將小鼠隨機分組：負對照組（vehicle）、正對照組（PO）、治療對照組（allopurinol, AL）、T100與T500試驗組（分別給予苦藤水萃物100 mg跟500 mg/kg BW）。除了負對照組腹腔注射生理食鹽水外，其餘各組則注射PO藥物以誘導急性高尿酸血症；於PO注射一小時後即依組別分別管餵一次蒸餾水、AL或苦藤水萃物，連續進行七天。動物經AL之管餵治療後，可使血漿尿酸顯著下降達到62.7%之抑制率；低或高劑量之苦藤水萃物皆可使血漿尿酸下降達平均43%的抑制效果；苦藤水萃物可顯著抑制肝臟黃嘌呤去氫酶（xanthine dehydrogenase, XDH）活性達21%，但是不具劑量效應；高劑量苦藤水萃物則具有顯著提升肝臟還原態麩胱甘肽（reduced-glutathione, GSH）含量的作用。本實驗結果指出，連續管餵苦藤水萃物可抑制肝臟XDH活性進而顯著降低高尿酸誘導小鼠的血漿尿酸濃度。高劑量苦藤水萃物可增加動物肝臟的GSH含量，但是未見有顯著降低脂質過氧化之作用。

關鍵字

苦藤萃取物 ； 多酚 ； 抗氧化 ； 黃嘌呤氧化酶 ； 黃嘌呤去氫酶 ； 尿酸

並列摘要

Tinospora cordifolia (TC) is a folk medicine used in Taiwan. Inhibition of xanthine oxidase (XO) activity in vitro and the anti-hyperuricemic effect of TC extracts in mice were investigated. TC stems were respectively extracted with cold and hot water and ethanol. Total phenols and flavonoids, and the in vitro antioxidant potential were evaluated. The 50% inhibitory concentration (IC_(50)) of XO activity was measured in vitro. A hyperuricemic animal model was conducted with male ICR mice treated with potassium oxonate (PO, 250 mg/kg body weight (BW)/day, intraperitoneally). Animals were assigned to a vehicle group, therapy group (allopurinol, AL), and TC extract of 100 (TC100) or 500 mg/kg BW (TC500) groups for 7 consecutive days. Hot-water extraction for 10 min was defined as the optimal condition for further study. The TC extract displayed XO inhibitory activity at an IC_(50) 10.85 mg/mL. Compared to the PO group, the TC extract showed a significant inhibitory effect against plasma uric acid levels at 42% and hepatic xanthine dehydrogenase (XDH) activity at 21%. The thiobarbituric acid-reactive substance (TBARS) levels in the liver showed no significant difference among all groups. A high dose of the TC extract showed the highest amount of reduced glutathione (GSH) in the liver. The TC extract showed a weak inhibitory effect on XO activity in vitro. However, a hypouricemic effect of the TC extract was observed as plasma uric acid was reduced, and it inhibited hepatic XDH activity in mice.

並列關鍵字

Tinospora cordifolia extract ； polyphenol ； antioxidant ； xanthine oxidase ； xanthine dehydrogenase ； uric acid