香瓜茄葉水萃物之體內及體外試驗對於高血壓之影響

高血壓是中風、心血管疾病和腎臟病等疾病之重大危險因子。控制血壓於標準內，能有效降低嚴重併發症產生。香瓜茄Pepino (Solanum muricatum Ait)是台灣澎湖地區特有的水果，當地相傳香瓜茄具有降低血壓以及控制血糖的效果，但目前相關文獻有限。本實驗室先前研究發現香瓜茄果實具有控制血壓的效果，故本實驗想進一步了解香瓜茄葉對於血壓的影響。本實驗以正常血壓鼠(Wistar Kyoto rats, WKY)及自發性高血壓鼠(Spontaneously hypertensive rats, SHR)做為高血壓動物實驗模式，觀察每日餵食30 mg/kg和60 mg/kg香瓜茄葉萃取物(Pepino leaf extract, PLE)，連續22週，是否能降低SHR鼠的血壓。結果證實，SHR鼠經過餵食PLE後發現，不論是收縮壓還是舒張壓均有顯著下降。進一步組織病理切片染色觀察到SHR鼠有主動脈管壁擴張、心肌肥厚以及腎臟纖維化的現象，餵食PLE後均可顯著改善這些病癥，且餵食PLE組可提升SHR鼠腎臟的抗氧化能力及抑制脂質過氧化現象。分析腎臟組之中發炎相關蛋白(NF-κB、COX-2和iNOS)的表現量上也顯著地降低。體外實驗中，以大鼠腎小管上皮細胞NRK-52E cell加入2 μM angiotensin II誘發24小時，同時添加50 µg/ml、100 µg/ml的PLE，結果發現PLE能夠抑制angiotensin II所誘導的氧化壓力。根據上述結果推論，PLE可提升體內抗氧化能力、降低體內發炎程度，並且能夠改善血壓，減緩高血壓所造成的心血管、腎臟損傷，達到抑制高血壓及其併發症的效果。

Hypertension is one of the major risk factors for cardiovascular disease and chronic renal disease. Pepino (Solanum muricatum Ait) has been shown to improve glycemic control and mitigated oxidative and inflammatory stress in the kidney of type 1 diabetic mice. The present study was designed to examine the effects of pepino leaf extracts (PLE), rich in flavonoids, upon hypertensive stress in spontaneously hypertensive rats (SHR). PLE at 30 mg/kg or 60 mg/kg was supplied to SHR. PLE significantly improved the systolic blood pressure (SBP) and diastolic blood pressure (DBP) in SHR. In histological studies, the lesions of myocardium and aorta, and renal fibrosis in SHR were caused when compared with the control Wistar Kyoto rats (WKY) group. PLE treatments improved these alterations. For in vitro experiments, NRK-52E renal tubular epithelial cells were stimulated with 2 μM angiotensin II for 24hr with 50 µg/ml or 100 µg/ml. PLE supplement improves angiotensin II-induced mitochondrial membrane depolarization and the production of ROS in NRK-52E cells. Based on these findings, it can be concluded that PLE could evaluate the anti-oxidative status and mitigate the inflammatory response, which in turn improve the blood pressure of SHR, and protect cardiovascular and kidney from hypertensive stress, implying that PLE potentially could be developed as an anti-hypertensive agent.