洛神花萃取物降低鼠體血中尿酸之作用

隨著社會經濟的發達，食物豐盛，罹患高尿酸血症的人口逐漸增加，且有越來越年輕化的趨勢。高尿酸血症除了會導致大家耳熟能詳的痛風性關節炎外，也與高血壓、心血管疾病等慢性疾病息息相關。近年來研究洛神花萃取物的成分，發現具有捕捉體內自由基、抑制低密度脂蛋白的氧化、減少血栓的產生、降低血脂肪作用,達到減少罹患心血管疾病的機率，對於預防癌症、粥狀動脈硬化、降血壓、幫助消化以及抗老化也有相當的功效。本實驗計畫以老鼠為實驗材料，利用Oxonic acid 誘發輕度的高尿酸血症，探討洛神花萃取物是否會降低人體內尿酸的形成，進而減少高尿酸血症發生及其所引起的相關慢性疾病之發生。由實驗結果得知，洛神花萃取物會抑制由Oxonic acid誘發老鼠所產生的輕度高尿酸血症，並且與臨床上所使用的降尿酸藥物Allopurinol抑制尿酸合成的黃嘌呤氧化酶(Xanthine oxidase)作用機轉是不同的；洛神花萃取物是經由誘導尿素酶（Uricase）增加，進而將尿酸分解成尿囊素（Ａllantoin）後，由腎臟排出而達到降低血液中尿酸的濃度。

Elevated serum levels of uric acid have been associated with an increased risk for hyperuricemia, gout, hypertension, cardiovascular disease, and renal failure. In recent years, attention has been focused on the bioactive properties of edible plants, an important role in the prevention of disease. Hibiscus sabdariffa L., a local soft drink material and medicinal herb in Taiwan, is usually used effectively in native medicines against hypertension, pyrexia and liver disorders. Here, we report an extract, HSE (Hibiscus sabdariffa extract), designed to determine whether the effects of it on oxonic acid-induced hyperuricemia could be associated with altered urate enzymes containing uricase and xanthine oxidase. SD rats were treated ip with normal saline and oxonate solution (250 mg/kg) with or without feeding 1 %, 2 % or 5 % HSE for 5 weeks. The xanthine oxidase inhibitory activity of allopurinol, a clinical drug, was negative control. During the five-week study period, the rats were measured plasma uric acid values once every week. Further investigation showed that HSE effectively inhibited oxonic acid-induced hyperuricemia via increasing the activity of uricase, but not affecting xanthine oxidase. Finally, oral HSE had a hypouricemic effect 1 h after its administration to oxonate-pretreated rats. These results suggested that a continuous intake of Hibiscus sabdariffa L. may be effective for the prevention and the treatment of gout and hyperuricemia.