Notoginsenoside R1

Notoginsenoside R1 is a steroidal saponin isolated from Panax notoginseng that exerts cardiovascular and neuroprotective effects primarily by modulating ROCK1 expression, ERK1/2 signaling, and PI3K/PKB pathways. Its multi-target mechanism makes it a subject of active preclinical research for inflammation, cardiac protection, and neurological applications.

Origin & History

Notoginsenoside R1 (NGR1) is a dammarane-type tetracyclic triterpenoid saponin with molecular formula C₄₇H₈₀O₁₈, found as a major and unique constituent in Panax notoginseng (Burk.) F.H.Chen roots and rhizomes. It is typically isolated through solvent extraction methods, with commercial sources providing ≥98% purity in white powder form.

Historical & Cultural Context

NGR1 is a major active ingredient in Panax notoginseng (Tienchi ginseng), which has been used in traditional Chinese medicine for centuries, particularly for cardiovascular health, hemostasis, and trauma-related injuries. The compound is recognized for its cardiovascular activity as a key bioactive component in traditional formulations.

Health Benefits

• Cardiovascular protection through inhibition of ROCK1 expression and enhancement of mitochondrial ATP synthase δ-subunits (animal studies only)
• Anti-inflammatory effects via inhibition of TNF-α-induced PAI-1 overexpression through ERK1/2 and PI3K/PKB signaling pathways (in vitro evidence)
• Neuroprotective properties by attenuating amyloid-β-induced neuronal damage and inhibiting ROS production (cell culture studies)
• Antiapoptotic effects in cardiomyocytes under oxygen-glucose deprivation/reoxygenation conditions (in vitro evidence)
• Antioxidant and immune-stimulatory properties with endotoxin-protective effects (animal model evidence)

How It Works

Notoginsenoside R1 inhibits Rho-associated protein kinase 1 (ROCK1) expression while upregulating mitochondrial ATP synthase δ-subunits, improving cellular energy efficiency in cardiac tissue. It also suppresses TNF-α-induced plasminogen activator inhibitor-1 (PAI-1) overexpression by blocking ERK1/2 and PI3K/PKB phosphorylation cascades, reducing pro-thrombotic and pro-inflammatory signaling. Additionally, it modulates NF-κB activation and oxidative stress pathways, contributing to its observed neuroprotective effects in cell culture models.

Scientific Research

The available research consists primarily of in vitro cell culture studies and in vivo animal models demonstrating NGR1's effects on ischemia-reperfusion injury, with no human clinical trials or RCTs provided in the research dossier. The literature references multiple complex mechanisms of action but lacks human trial data with PMIDs or clinical outcomes.

Clinical Summary

The current body of evidence for notoginsenoside R1 is limited almost entirely to in vitro cell studies and rodent animal models, with no robust randomized controlled trials in humans published to date. Animal studies using doses typically ranging from 10–100 mg/kg have demonstrated reductions in myocardial ischemia-reperfusion injury, decreased inflammatory cytokine levels, and improved neurological outcomes after stroke models. In vitro data from human endothelial and neuronal cell lines show statistically significant reductions in PAI-1 expression and oxidative stress markers at concentrations of 1–50 μM. Until well-designed human clinical trials are completed, efficacy claims remain preliminary and should be interpreted with caution.

Nutritional Profile

Notoginsenoside R1 is a saponin glycoside (molecular formula C47H80O18, MW ~932.12 Da) uniquely found in Panax notoginseng root, comprising approximately 0.3–0.9% of the dried root by weight. It is not a macronutrient or micronutrient source but rather a bioactive phytochemical characterized by a dammarane-type tetracyclic triterpenoid aglycone backbone with two sugar moieties (glucose and xylose) attached at C-20. It contains no appreciable protein, fiber, fat, or conventional vitamins or minerals in isolated form. Bioavailability is notably limited by poor oral absorption due to its high molecular weight and hydrophilic glycoside structure; studies suggest intestinal bacterial deglycosylation partially converts it to more absorbable aglycone forms. Plasma Cmax following oral dosing in rodent models ranges approximately 50–200 ng/mL at doses of 10–50 mg/kg, with a reported half-life of roughly 2–4 hours. Intestinal permeability is low (Papp ~1–3 × 10⁻⁶ cm/s in Caco-2 models), and co-administration with P-glycoprotein inhibitors has been shown to modestly enhance absorption.

Preparation & Dosage

No clinically studied dosage ranges for human use are provided in the available research. While NGR1 is described as a major active component in traditional Chinese medicine preparations like Naodesheng injection, specific dosing recommendations are not detailed. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Notoginsenoside R1 pairs strongly with Ginsenoside Rg1 and Ginsenoside Rb1 (co-occurring saponins in Panax notoginseng), as these three compounds collectively act on overlapping cardiovascular and neuroprotective pathways — Rg1 enhances eNOS-mediated vasodilation while R1 suppresses ROCK1, producing additive anti-thrombotic and vascular-relaxing effects. Pairing with Astragaloside IV (from Astragalus membranaceus) creates complementary neuroprotection, as Astragaloside IV activates the Nrf2/HO-1 antioxidant pathway while R1 suppresses ROS production through mitochondrial mechanisms, together providing broader oxidative stress coverage than either alone. Additionally, co-administration with Piperine (from Piper nigrum, ~5–20 mg dose) is a practical bioavailability enhancer, as piperine inhibits P-glycoprotein efflux and CYP3A4-mediated first-pass metabolism, which has been demonstrated to increase plasma concentrations of structurally similar large saponin glycosides by 30–60% in rodent pharmacokinetic studies.

Safety & Interactions

No formal human safety or toxicology trials specific to isolated notoginsenoside R1 have been published, making a definitive side effect profile impossible to establish at this time. Because notoginsenoside R1 inhibits PI3K/PKB and ERK1/2 pathways, it may theoretically potentiate or interfere with anticoagulant medications such as warfarin and antiplatelet drugs like aspirin or clopidogrel, as Panax notoginseng preparations have established antiplatelet activity. Pregnant and breastfeeding individuals should avoid supplementation given the complete absence of safety data in these populations. Individuals on blood pressure medications or immunosuppressants should consult a physician before use due to potential additive or antagonistic pharmacodynamic interactions.