Colon (espástico)

This compound contains an organic nitrate (–ONO2) functional group that releases nitric oxide via enzymatic reduction pathways identical to those of classical organic nitrate vasodilators. The amino acid ester backbone may improve membrane permeability for intracellular NO delivery. Its NO-releasing mechanism is established from the well-characterized organic nitrate pharmacology class.

Agmatine is the decarboxylation product of L-arginine that acts as an endogenous NOS modulator. It stimulates eNOS by binding imidazoline receptors on endothelial cells while inhibiting iNOS and nNOS, providing isoform-selective NO regulation that distinguishes it from simple NO precursors.

Arginine alpha-ketoglutarate (AAKG) is a salt of L-arginine and alpha-ketoglutaric acid used to deliver arginine as a NO precursor. A 7-day RCT showed AAKG significantly raised plasma L-arginine by ~85% but did not produce greater post-exercise NO or blood flow increases than placebo, indicating the arginine component drives any NO effect while independent benefit of the salt form is limited.

Arginine aspartate is a salt of L-arginine and aspartic acid; aspartate participates directly in the argininosuccinate synthase reaction regenerating arginine for eNOS-mediated NO synthesis. Preclinical data show aspartate combined with malate elevates L-arginine and NO production in hypertension models, complementing the established arginine-to-NO mechanism.

Arginine malate combines L-arginine with malic acid; malate supports the argininosuccinate-mediated arginine regeneration pathway and L-arginine is the direct eNOS substrate. Preclinical data show malate elevates L-arginine levels and NO production in hypertension models, giving the compound both direct substrate and metabolic recycling support for NO synthesis.

Arginine nitrate combines L-arginine with inorganic nitrate, providing NO production via two parallel pathways: the enzymatic eNOS-mediated arginine citrullination route and the non-enzymatic nitrate-nitrite-NO reduction cascade. This dual mechanism gives faster vasodilation onset than L-arginine alone and is used in sports and cardiovascular supplements.

Arginine silicate (Nitrosigine) is a patented arginine-silicon chelate shown in human RCTs to produce superior plasma arginine AUC and NO biomarker elevation compared to equivalent doses of L-arginine HCl. It enhances eNOS substrate delivery and is clinically studied for endothelial function support in sports and cardiovascular contexts.

ATP is an endothelium-dependent vasodilator that partly acts via nitric oxide (NO) pathways in human vasculature. Intra-arterial infusion studies in humans show that ATP-induced limb vasodilation is partially (approximately 14–40%) mediated by nitric oxide synthase activation, with P2Y receptors on the endothelium activating eNOS. The relationship is mechanistically established in humans, though oral supplementation's effect on circulating NO levels is less directly documented.

Icariin enhances endothelial nitric oxide synthase (eNOS) expression and NO production in human endothelial cells in both short- and long-term studies. It also produces NO-dependent vasorelaxation in coronary arterial rings via eNOS/cGMP pathway activation. This NO-upregulating activity underpins many of Barrenwort's cardiovascular and erectogenic properties.

Beets are the most concentrated dietary source of inorganic nitrate (~250 mg/100 g), which is converted to NO via the nitrate-nitrite-NO pathway independent of NOS. Multiple RCTs show beetroot juice (300–500 mg nitrate) significantly raises plasma NO metabolites, lowers resting blood pressure by ~4–5 mmHg, and improves exercise performance.

Blueberry polyphenols increase nitric oxide bioavailability in human endothelial cells and in vivo by activating eNOS, reducing NADPH oxidase activity, and decreasing superoxide-mediated NO quenching. Plasma nitrite (NO2−) increases have been measured in human RCTs after blueberry consumption.

Cocoa flavanols (primarily epicatechin and procyanidins) activate eNOS via Akt/PI3K-dependent phosphorylation, raising NO production and improving flow-mediated dilation. Research in smokers shows 176–185 mg cocoa flavanols improve vascular dilation within 2 hours. Multiple RCTs and meta-analyses confirm cocoa flavanols reduce blood pressure and improve endothelial function through NO-mediated mechanisms.

CoQ10 supports nitric oxide (NO) bioavailability by protecting endothelial NO synthase (eNOS) from oxidative inactivation and reducing superoxide-mediated NO degradation. Clinical trials in type 2 diabetes and coronary artery disease patients show improved endothelium-dependent vasodilation (flow-mediated dilation) with CoQ10 supplementation. Evidence from NIH StatPearls lists improving endothelial function as a Level 2 clinical indication.

Cordyceps modulates nitric oxide (NO) signaling via stimulation of endothelial NOS (eNOS) activity. Cordycepin and adenosine in Cordyceps are reported to stimulate endothelial NO production, promoting vasodilation. This pathway is mechanistically linked to improvements in blood pressure and circulatory function observed in preclinical models.

EGCG, the primary catechin in green tea, increases eNOS phosphorylation, vascular cGMP, and BH4 levels while reducing oxidative stress in animal hypertension models. It is recognized among natural polyphenols that positively modulate eNOS activity and endothelial NO production in peer-reviewed literature.

Epicatechin, a flavan-3-ol in cocoa and tea, is among the dietary flavonoids most clearly shown to augment nitric oxide status in humans. A randomized crossover RCT found 200 mg epicatechin significantly raised plasma S-nitrosothiols, plasma nitrite, and urinary nitrate, and reduced endothelin-1 in healthy men, demonstrating enhanced endothelial NO production.

L-DOPA in fava beans is converted to dopamine, which stimulates endothelial nitric oxide synthase (eNOS) activity, increasing nitric oxide (NO) production. This mechanism contributes to vasodilation, blood pressure reduction, and improved vascular function. The dopaminergic pathway's influence on NO synthesis is documented in peer-reviewed cardiovascular literature.

Aged garlic extract activates constitutive NOS (eNOS) and temporarily raises plasma NO metabolites by 30–40% in vivo, independent of its arginine content. Garlic is recognized in peer-reviewed reviews among natural products that enhance endothelial NO production, with organosulfur compounds as the proposed active constituents.

Garlic's organosulfur compounds (DADS, DATS, SAC) stimulate endothelial nitric oxide synthase (eNOS), increasing NO bioavailability in vascular endothelium. This mechanism underlies garlic's antihypertensive and antiplatelet effects. Clinical trials using garlic with dietary nitrate have measured salivary NO increases in hypertensive subjects.

Panax ginseng ginsenosides stimulate eNOS in vascular endothelial cells via PI3K-Akt and AMPK signaling, increasing NO production. Systematic reviews of clinical trials confirm ginseng improves erectile function and vascular biomarkers through NO-mediated mechanisms, consistent with its multi-millennial cardiovascular use in Asian traditional medicine.

Ginsenosides are the primary bioactive triterpenoid saponins of Panax ginseng responsible for eNOS activation and increased endothelial NO production. Individual ginsenosides (Rg1, Re, Rb1) activate eNOS via PI3K-Akt, AMPK, and receptor-ligand pathways, with protopanaxatriol fractions showing the highest eNOS-activating potency in cell models.

Hawthorn extract (especially WS 1442) stimulates endothelial nitric oxide synthase (eNOS) to release NO from vascular endothelium, producing vasodilation and increasing coronary flow. This mechanism has been demonstrated in isolated arterial rings, rat heart preparations, and the human mammary artery. NO-mediated vasodilation is considered a primary mechanism behind hawthorn's cardiovascular and antihypertensive effects.

A 1999 peer-reviewed study (Tanner et al., Nitric Oxide journal) confirmed that gypenosides directly release nitric oxide in vitro. Multiple subsequent studies have linked jiaogulan's blood pressure and arterial effects to endothelial NO stimulation.

L-arginine is the direct endogenous substrate for nitric oxide synthase (NOS) enzymes, which convert it to NO and L-citrulline. Extensive peer-reviewed evidence confirms oral L-arginine supplementation increases NO synthesis and blood flow in tissues. Clinical studies demonstrate improvements in NO-dependent vasodilation, endothelial function, and blood pressure in populations with cardiovascular compromise.

L-citrulline is converted to L-arginine in the kidneys via the citrulline-NO cycle, making it a more bioavailable oral NO precursor than L-arginine itself. Clinical trials show it raises plasma arginine and NO metabolites more effectively than equivalent oral arginine doses. It is well-studied for endothelial function, blood pressure, and exercise performance.

L-ornithine is a urea cycle intermediate that supports NO production by feeding the ornithine-citrulline-arginine recycling pathway. Ornithine is converted to citrulline, which is then converted to arginine for eNOS-mediated NO synthesis, making it an indirect but metabolically established contributor to the arginine pool available for NO generation.

Diarginine malate delivers two molecules of L-arginine (the direct eNOS substrate) with malate (a Krebs cycle intermediate supporting arginine regeneration). Both components have established mechanistic relevance to NO synthesis: arginine as the NOS substrate and malate as a supporter of the argininosuccinate-mediated arginine recycling pathway.

Ornithine alpha-ketoglutarate (OKG) is metabolized to citrulline and arginine, supporting eNOS substrate availability and NO production. Clinically studied at 10–30 g/day in post-surgical and trauma patients, with arginine elevation and NO production proposed as contributing mechanisms to its documented wound healing and muscle metabolism benefits.

Peanuts are one of the richest dietary sources of L-arginine, the obligate substrate for endothelial nitric oxide synthase (eNOS). L-arginine supplementation in clinical studies increases NO production, improves flow-mediated dilation, and reduces arterial stiffness. This mechanistic pathway underlies peanuts' known cardiovascular and vascular benefits.

Pine bark extract (standardized as Pycnogenol from Pinus pinaster) stimulates eNOS transcription and activity, scavenges superoxide radicals that degrade NO, and has human clinical evidence for improved endothelial function and blood pressure, with documented synergy with L-arginine for NO-mediated improvements in erectile dysfunction.

Pomegranate polyphenols upregulate eNOS and protect nitric oxide from oxidative degradation, effectively increasing NO bioavailability. Human studies confirm improved arterial elasticity and blood pressure consistent with enhanced NO activity. Pomegranate is a dietary source of nitrates that feed the nitrate-nitrite-NO pathway.

Pycnogenol (French maritime pine bark extract) stimulates eNOS transcription and activity and scavenges superoxide that degrades NO, enhancing endothelial NO bioavailability. Human clinical studies show improved vascular function and blood pressure, and its combination with L-arginine has documented NO-mediated improvements in erectile dysfunction.

Quercetin is a plant flavonoid that augments nitric oxide status in humans by raising plasma S-nitrosothiols, plasma nitrite, and urinary nitrate while reducing endothelin-1 in a randomized crossover RCT. It is well characterized as a dietary polyphenol that activates eNOS and enhances endothelial NO production.

Resveratrol activates eNOS through AMPK/SIRT1-dependent phosphorylation and antioxidant superoxide scavenging, enhancing endothelial NO production and bioavailability. It is well documented in natural products and eNOS literature as a modulator of endothelial NO synthesis, with cardiovascular evidence consistent with NO-mediated vasodilation.

Spinach is among the most nitrate-dense vegetables, and dietary nitrate is the rate-limiting substrate for entero-salivary nitric oxide biosynthesis. RCTs confirm spinach intake significantly raises plasma nitrite and NO-related species, improving vascular function.

Taurine enhances endothelial nitric oxide bioavailability by stimulating endothelial nitric oxide synthase (eNOS), restoring redox balance, and increasing plasma hydrogen sulfide—an eNOS activator. This contributes to taurine's established vasodilatory and blood pressure-lowering effects demonstrated in clinical trials.

Preclinical and mechanistic studies demonstrate that tribulus saponins (protodioscin) promote endothelial nitric oxide release, causing vasodilation. This mechanism is proposed to underlie TT's pro-erectile and antihypertensive effects. In vitro confirmation of NO upregulation exists; direct human clinical measurement is lacking.

Ubiquinol increases nitric oxide (NO) bioavailability by enhancing superoxide dismutase (SOD) activity, thereby reducing superoxide-mediated NO degradation. A clinical RCT (n=51) found dose-dependent increases in serum NOx (nitric oxide metabolites) with 100–200 mg/day ubiquinol. This mechanism also underlies its blood pressure-lowering and arterial health effects.

Watermelon is among the richest natural sources of L-citrulline, which the body converts to L-arginine and then to NO via eNOS. Human studies show watermelon consumption and supplementation increase plasma arginine and NO bioavailability, improving blood pressure and endothelial function; concentrated extracts are needed to reliably achieve effective L-citrulline doses.