Department of Nutrition, Food and Exercise Sciences, College of Human Sciences, Florida State University, Tallahassee, Florida, USA.
Am J Hypertens. 2012 Jun;25(6):640-3. doi: 10.1038/ajh.2012.20. Epub 2012 Mar 8.
Ankle-brachial index (ABI) and ankle blood pressure (BP) are associated with increased carotid wave reflection (augmentation index, AIx). Oral L-citrulline and L-arginine from synthetic or watermelon sources have reduced brachial BP, aortic BP, and aortic AIx. A directly measured carotid AIx (cAIx) rather than aortic AIx has been proposed as a better measurement of central AIx. We evaluated the effects of watermelon extract on ankle BP and cAIx in individuals with normal ABI and prehypertension or stage 1 hypertension.
Ankle and brachial systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), cAIx, ABI, and heart rate (HR) were evaluated in the supine position in 14 adults (11 women/3 men, age 58 ± 1 years) with prehypertension or stage 1 hypertension (153 ± 4 mm Hg). Subjects were randomly assigned to 6 weeks of watermelon extract supplementation (L-citrulline/L-arginine, 6 g daily) or placebo followed by a 2-week washout period and then crossover.
Ankle and brachial SBP (-11.5 ± 3.8 and -15.1 ± 2.8 mm Hg), DBP (-7.8 ± 2.3 and -7.6 ± 1.8 mm Hg), and MAP (-9.8 ± 2.6 and -7.3 ± 1.8 mm Hg), and cAIx (-8.8 ± 2.6 %) decreased significantly (P < 0.05) after watermelon supplementation compared to placebo. Watermelon supplementation had no significant effect (P > 0.05) on ABI and HR.
This study shows that watermelon extract supplementation reduces ankle BP, brachial BP, and carotid wave reflection in obese middle-aged adults with prehypertension or stage 1 hypertension and normal ABI, which may reflect improved arterial function.
踝臂指数（ABI）和踝部血压（BP）与颈动脉波反射（增强指数，AIx）增加有关。来自合成或西瓜源的口服 L-瓜氨酸和 L-精氨酸可降低肱动脉血压、主动脉血压和主动脉 AIx。直接测量的颈动脉 AIx（cAIx）而不是主动脉 AIx 被提议作为中央 AIx 的更好测量方法。我们评估了西瓜提取物对 ABI 正常的高血压前期或 1 期高血压个体的踝部血压和 cAIx 的影响。
在 14 名患有高血压前期或 1 期高血压（153 ± 4 mmHg）的成年人（11 名女性/3 名男性，年龄 58 ± 1 岁）的仰卧位评估踝部和肱动脉收缩压（SBP）、舒张压（DBP）、平均动脉压（MAP）、cAIx、ABI 和心率（HR）。受试者被随机分配到 6 周的西瓜提取物补充（L-瓜氨酸/L-精氨酸，每天 6 克）或安慰剂，然后进行 2 周的洗脱期，然后交叉。
与安慰剂相比，西瓜补充后踝部和肱部 SBP（-11.5 ± 3.8 和-15.1 ± 2.8 mmHg）、DBP（-7.8 ± 2.3 和-7.6 ± 1.8 mmHg）和 MAP（-9.8 ± 2.6 和-7.3 ± 1.8 mmHg）以及 cAIx（-8.8 ± 2.6%）均显著降低（P < 0.05）。西瓜补充对 ABI 和 HR 没有显著影响（P > 0.05）。
本研究表明，西瓜提取物补充可降低高血压前期或 1 期高血压且 ABI 正常的肥胖中年成年人的踝部血压、肱部血压和颈动脉波反射，这可能反映出动脉功能的改善。
