Tongkat Ali (Eurycoma longifolia)降低PDE5A基因表現及增加血漿中NO和cGMP濃度的探討

Tongkat Ali (Eurycoma longifolia)為苦木科(Simaroubaceae) Eurycoma屬之植物，主要分布於東南亞地區，如印尼、馬來半島、泰國、越南等地。此植物在馬來西亞當地被廣泛的應用在藥用及食用中，主要有消除疲勞、恢復體力、抗氧化、增強性功能、促血液循環、治療皮膚病、糖尿病、潰瘍等功能，於東南亞各地被視為萬應仙丹，此外此植物更有“馬來西亞人蔘”之稱；由此可知此植物的重要性。於馬來西亞當地研究曾指出E.longifolia的根部萃取物，具有抗高血壓、抗痢疾、減輕疲勞、促進食慾和消化能力、調節膚質和肌肉、增強免疫力等功效。 本研究目的是在探討小鼠餵食Tongkat Ali (Eurycoma longifolia)後對於體內一氧化氮和環狀單磷酸鳥糞嘌呤濃度之影響，是否與sildenafil 抑制第五型磷酸二脂解酶作用途徑相似，並評估其安全性。飼料添加人體服用劑量的Tongkat Ali、sildenafil、arginine、Tongkat Ali plus ginseng、山藥五種飼料餵食雄性Balb/c小鼠，並在兩週、四週斷頸犧牲，採取血液、肝臟、腎臟、海綿體進行分析。研究結果顯示，兩週、四週小鼠血漿中一氧化氮及環狀單磷酸鳥糞嘌呤濃度各組皆有增加，並降低海綿體中第五型磷酸二脂解酶mRNA表現，至於相關藥物代謝酵素CYP3A11之mRNA變化，又以四週Tongkat Ali處理組及Tongkat Ali plus ginseng組有顯著激活表現；另外在肝臟及腎臟脂質過氧化分析中，處理組和對照組無顯著差異，臟器麩胱苷肽(GSH)相關酵素活性也無顯著激活情形。 因此本實驗證實，Tongkat Ali可透過降低第五型磷酸二脂解酶活性，增加血漿中一氧化氮及環狀單磷酸鳥糞嘌呤濃度，此外並不會造成肝、腎臟器的傷害。

Eurycoma longifolia (Tongkat Ali) is a plant with folk medicine in Indonesia, Malaysia, Thailand and Vietnam. The residences in Malaysia usually treat it as “ginseng of Malaysia”, and think it possesses multiple medical functions such as anti-hypertension and appetite stimulation. The purpose of this project was to examine the effect of E. longifolia extract on plasma NO and cGMP concentration in mice. Viagra was also used for comparison. Mice were treated by E. longifolia, Viagra, L-Arginine, Tongkat Ali plus ginseng, Dioscorea for 2 and 4 weeks. Plasma NO, cGMP level and the activity of type 5 phophodiesterase and cytochrome P450 were analyzed. Results showed that 5 treatments increased the NO and cGMP levels, and inhibited the activity of type 5 phophodiesterase. Tongkat Ali and Tongkat Ali plus ginseng treated mice at 4 weeks has significantly higher cytochrome P450 mRNA expression. These treatments did not affect the anti-oxidative defense in liver and kidney. These findings implied that Tongkat Ali could provide protective or medical functions via elevating plasma NO and cGMP concentration and decreasing PDE5 enzyme activity.