水丁香在台灣已被廣泛用作為香料和中草藥。目前已經被證實擁有許多生物活性，例如抗氧化、抗肝毒性、抗菌及抗癌等。在本研究中，我們利用兩種不同果蠅株w1118和Canton-S(CS)餵食兩種不同的飲食條件，分別為標準食物配方(15% yeast和15% dextrose)及卡路里節制(calorie restriction, CR)食物配方(5% yeast和5% dextrose)，來評估水丁香水萃取物對果蠅老化的影響。我們測試不同水丁香水萃取物濃度(0.1% 及0.5％)的食物對於果蠅的壽命、食物攝取量、下蛋率、活動能力、學習記憶、氧化壓力和基因表現等影響。我們發現水丁香水萃取物在標準食物配方下對於兩種品系的母果蠅均有延長壽命的表現，但並不影響果蠅的下蛋率及活動能力，另外水丁香水萃取物明顯的延緩了老化過程中學習能力退化的情況。然而於CR食物中添加水丁香水萃取物，其延長果蠅壽命的現象則消失，顯示水丁香水萃取物延長果蠅壽命的現象可能透過卡路里節制相關路徑。水丁香水萃取物可增加果蠅抵抗paraquat所引發的氧化壓力，並且降低抗氧化基因如superoxide dismutase(sod1及sod2)、catalase以及果蠅類胰島素胜肽(Drosophila insulin-like peptide, dilp2及dilp3) mRNA的表現。 綜合以上實驗結果我們推測，水丁香水萃取物延長壽命可能的作用機制為：(1)透過卡路里節制的路徑。 (2)影響類胰島素生長因子的訊號傳導(Insulin/IGF-1 signaling)。(3)增加抗氧化壓力的能力。 / Ludwigia octovalvis (Jacq.) P. H. Raven has been widely used as a spice and herbal medicine in Taiwan. It has been proved to possess many biological activities, antioxidative, anti-hepatotoxic, anti-bacterial and anticancer properties, for example. In this research, Ludwigia octovalvis extract (LOE) was used in two different diet conditions, one is standard diet (15% yeast and 15% dextrose), and the other is calorie restriction (5% yeast and 5% dextrose). The effect of LOE on the lifespan of the flies was estimated using w1118 and Canton-S strains of Drosophila melanogaster. We also evaluated the effects of 0.1% or 0.5% of LOE on food intake, fecundity, locomotor activity, cognitive performance, anti-oxidative stress and age-related gene expression in flies under standard diet. Our results showed that LOE could extend the lifespan of female flies on both species without affecting the fecundity and locomotor activity. Intriguingly, LOE attenuated the cognitive decline in both male and female flies. The longevity effect of LOE, however, was vanished when the lifespan of the flies was examined under CR diet, suggesting that LOE may extend lifespan through a CR-related pathway. LOE also increased resistance of paraquat-induced oxidative stress and down regulated the mRNA expression of sod1, sod2, cat, dilp2 and dilp3 in the flies. In summary, our results indicated that LOE may extend lifespan through: (1) a CR-related pathway. (2) regulation of Insulin/IGF-1 signaling. (3) increase of anti-oxidative stress.