Table 1.
A series of human clinical trials that investigated changes, after l-citrulline or watermelon extract supplementation, in blood pressure and associated indices of blood vessel function under resting and physiologically stressful conditions.
| Reference | Population | BP Status | Formulation | Dose | Duration | Resting Function | Results | ||
|---|---|---|---|---|---|---|---|---|---|
| Cardiovascular Reactivity | |||||||||
| Figueroa et al. (2010) [91] | 17 M | Normotensive | l-Citrulline | 6 g/day | 4 weeks | ↓ bSBP, aSBP, aPP | |||
| Orozco-Gutierrez et al. (2010) [92] | 9 M 6 F |
Heart failure w/ preserved EF |
l-Citrulline- Malate |
3 g/day | 8 weeks | ↓bSPB, bDBP, | ↑ RVEF during exercise | ||
| Figueroa et al. (2011) [90] | 4 M 5 W |
Pre-hypertensive | Watermelon Extract |
2.7 g/day | 6 weeks | ↓bPP, aSBP, aPP, AIx | |||
| Figueroa et al. (2012) [86] | 3 M 11 W |
Pre-hypertensive | Watermelon Extract |
2.7 g/day | 6 weeks | ↓ ankle SBP, DBP, MAP, ↓ bSBP, bDBP, bMAP ↓ carotid AIx |
|||
| Figueroa et al. (2013) [89] | 12 W | Hypertensive Post-menopausal |
Watermelon Extract |
6 g/day | 6 weeks | ↓b-aPWV, aSBP, aDBP, aSBP2 ↔ AIx |
|||
| Sanchez-Gonzalez et al. (2013) [88] | 16 M | Normotensive | l-Citrulline | 100 mg/kg | 2 weeks | ↓ CI and IHG increases in bSBP, aSBP and AIx | |||
| Alsop et al. (2016) [93] | 4 M 8 F |
Normotensive | l-Citrulline | 3 d/day | 1 week | ↓ bSBP, bDBP, MAP, pulse interval | ↓ Pulse interval, Pulse Amplitude Ratio, ↑ HRV post 30% MVC exercise |
||
| Figueroa et al. (2016) [94] | 16 M | Normotensive Overweight/obese |
l-Citrulline | 6 d/day | 2 weeks | Attenuated the increase in aSBP and AIx during IHG and reduced MAP aDBP | ↓ aSBP, aPP, AIx during IHG ↓ aDBP, MAP, AIx during PEMI ↓ aSBP, DBP, aPP, an baPWV during PEMI + CPT |
||
| Bailey et al. (2016) [81] | 8 M | Normotensive | Watermelon Juice |
~3.4 g/day | 2 weeks | ↑ aSBP and MAP | |||
| Massa et al. (2016) [95] | 10 M 10 W |
Pre-hypertensive | Watermelon Extract |
6 g/day | 6 weeks | ↓ bSBP and bDBP ↔ cardiac autonomic function |
|||
| Wong et al. (2016) [96] |
25 F * | Normotensive/ Pre-hypertensive |
l-Citrulline | 6 g/day | 8 weeks | ↓bSBP, bDBP, and nLF (SNS activity), LnLF/LnHF (sympathovagal balance) | |||
| Gonzales et al. (2017) [97] | 12M 13W |
Normotensive/ Pre-hypertensive |
l-Citrulline | 6 g/day | 2 weeks | ↓ seated bSBP | ↑muscle blood flow during submaximal exercise in men | ||
Abbreviations: M: male, F: female, bSBP: brachial systolic blood pressure, aSBP: aortic systolic blood pressure, aPP: aortic pulse pressure, AIx: augmentation index, DBP: diastolic blood pressure, cAIx: carotid augmentation index, CI: cold induced, CPT: cold pressor test, EF: ejection fraction IHG: intermittent hand grip exercise, MAP: mean arterial pressure, aDBP: aortic diastolic blood pressure, MVC: maximal voluntary contraction, LnLF: natural log low frequency from heart rate variability test and LnHF: natural log high frequency from heart rate variability test, ↓ decrease, ↑ increase, ↔ no significant change. * Post-menopausal women 50–65 years of age.