Nitric Oxide / cGMP Pathway

Chiou et al. (1996) reported nitric oxide-dependent vasodilatation (full, 100% endothelium-dependent) in isolated rat aorta. Sheu et al. (2000) reported antithrombotic activity in a murine model, with prolongation of platelet plug occlusion time compared with aspirin on a molar basis.

Chiou et al. (1996) reported partial (~50%) endothelium-dependent vasodilatation with possible α1-adrenoceptor blocking and 5-HT antagonising actions in vitro.

Chiou et al. (1996) reported ~10% endothelium-dependent vasodilatation with possible α1-adrenoceptor blocking contribution in vitro.

Reduced by oral commensal bacteria to nitrite, then to nitric oxide — endothelial-independent NO supply. Mouthwash use blocks this conversion.

Phenolic acids identified in A. lappa extracts; preclinical reviews note antioxidant and anti-inflammatory properties including potential modulation of NO pathways.

Reduces venous capillary permeability and promotes venous tone via partial inhibition of hyaluronidase and lysosomal enzyme release; modulates endothelial NO signaling.

Studies report multi-target activity: inhibition of NF-κB–mediated neuroinflammation, modulation of thromboxane A2 and arachidonic acid pathways to attenuate platelet aggregation, nitric oxide/cGMP pathway modulation, NMDA receptor involvement in neuroprotection, and L-type calcium channel effects relevant to cardiovascular research contexts.

In vitro studies report inhibition of LPS-stimulated macrophage NO production and COX-2-mediated prostaglandin synthesis.

Studies report that amaranth-derived dietary nitrates may serve as a nitric oxide (NO) precursor via the nitrate–nitrite–NO pathway, investigated in relation to muscle oxygen efficiency and aerobic performance (Liubertas et al., 2020).

Stabilizes capillary endothelium, modulates nitric-oxide signaling, and reduces vascular permeability — the mechanistic basis for the venous-tone and ophthalmic-microcirculation uses.

Studies report inhibition of platelet activation, modulation of eicosanoid pathways, and upregulation of nitric oxide bioavailability. Murphy et al. (2003) reported inhibition of platelet function in healthy volunteers following cocoa flavanol supplementation.

Proposed mechanisms include vasodilatory activity via calcium channel modulation, nitric oxide/cGMP pathway enhancement, and ACE inhibition; anxiolytic and antidepressant-related activity investigated in preclinical models via GABAergic and serotonergic pathways. Clinical data from Shayani Rad et al. (2022, 2023) investigated these effects in hypertensive patients.

Antiplatelet (interferes with ADP and TXA2 platelet activation pathways), endothelium-protective via NO signaling, and modestly fibrinolytic — the principal mechanism for Danshen's well-documented warfarin interaction.

Preclinical and review-level data suggest OPCs may promote nitric oxide–mediated vasodilation, modulate calcium influx in vascular smooth muscle, and inhibit ACE activity; proposed mechanisms for reported coronary vasodilatory and mild antihypertensive effects.

Ginsenosides are documented to enhance endothelial/penile nitric oxide synthase activity and NO/cGMP signaling, the mechanistic basis for red ginseng's effect on erectile function (the best-evidenced indication, Jang 2008). Compound-specific eNOS/NO induction by ginsenosides is well studied.

L-citrulline is a precursor to L-arginine, which serves as substrate for nitric oxide synthase (NOS), thereby supporting nitric oxide (NO) biosynthesis and downstream cGMP-mediated vasodilation. Watermelon rind is a particularly concentrated dietary source. Studies report increases in plasma L-arginine and L-citrulline following ingestion of microencapsulated watermelon rind preparations.

Protodioscin, the principal steroidal saponin, has been reported in preclinical studies to enhance nitric oxide release in cavernosal tissue — the mechanism investigated for its pro-erectile activity.