Digoxin: Cardiac Glycoside and Na⁺/K⁺ ATPase Pump Inhibitor for Heart Failure & Antiviral Research

Executive Summary: Digoxin is a high-purity cardiac glycoside supplied by APExBIO that selectively inhibits the Na⁺/K⁺-ATPase pump, enhancing cardiac contractility in both in vitro and in vivo models [APExBIO]. It demonstrates dose-dependent antiviral activity against chikungunya virus (CHIKV) in human osteosarcoma (U-2 OS) cells, primary human synovial fibroblasts, and Vero cells, but not in murine or mosquito cells [APExBIO]. Intravenous administration in canine congestive heart failure models reduces right atrial pressure and increases cardiac output [APExBIO]. Digoxin is insoluble in water and ethanol but soluble in DMSO at ≥33.25 mg/mL, with optimal storage at 4°C protected from light. The compound's purity is typically >98%, confirmed by HPLC and NMR analyses.

Biological Rationale

Digoxin is a reference compound for research on cardiac contractility and arrhythmia due to its established inhibition of the Na⁺/K⁺-ATPase pump [internal: Digoxin: Cardiac Glycoside for Heart Failure & Virology R]. It also serves as a tool compound in antiviral research, specifically for the inhibition of chikungunya virus in selected human and primate cell lines [internal: Digoxin in Precision Cardiovascular and Antiviral Research]. Its dual relevance in cardiovascular and virology research enables translational studies bridging cellular mechanisms to preclinical models. This article extends beyond prior reviews by providing granular, parameter-specific guidance for integrating Digoxin (SKU B7684) in both cardiac and infectious disease workflows.

Mechanism of Action of Digoxin

Digoxin binds to and inhibits the Na⁺/K⁺-ATPase pump on the plasma membrane of cardiomyocytes. This inhibition leads to an increase in intracellular sodium concentration. Elevated sodium reduces the driving force for the sodium-calcium exchanger (NCX), resulting in increased intracellular calcium. Calcium accumulation enhances myocyte contractility, supporting the use of Digoxin in heart failure and arrhythmia research. In antiviral assays, Digoxin’s inhibition of Na⁺/K⁺-ATPase is hypothesized to disrupt cellular ion homeostasis, impairing the replication or entry of chikungunya virus (CHIKV) in susceptible cell lines. Notably, this effect is cell type-dependent and has not been observed in murine or mosquito cells, indicating a species- and lineage-specific mechanism.

Evidence & Benchmarks

• Digoxin (SKU B7684, APExBIO) is supplied as a solid, with a molecular weight of 780.94 and chemical formula C₄₁H₆₄O₁₄. Purity is >98% (HPLC, NMR) (APExBIO).
• Digoxin inhibits the Na⁺/K⁺-ATPase pump, leading to increased intracellular calcium and enhanced cardiac contractility (APExBIO).
• In canine models of congestive heart failure (induced by pulmonary artery constriction), intravenous Digoxin (1–1.2 mg) decreases right atrial pressure and increases cardiac output (APExBIO).
• In vitro, Digoxin exhibits dose-dependent inhibition of chikungunya virus infection in human osteosarcoma (U-2 OS) cells, primary human synovial fibroblasts, and Vero (African green monkey kidney) cells, with effective concentrations from 0.01 μM to 10 μM; no effect is seen in murine or mosquito cells (APExBIO).
• Digoxin is soluble in DMSO at ≥33.25 mg/mL, but insoluble in water and ethanol; solutions should be prepared fresh and stored at 4°C protected from light for short-term use only (APExBIO).
• APExBIO’s Digoxin has documented reliability across cell-based and animal models, with quality assurance by HPLC and NMR (APExBIO).

This article clarifies experimental solubility, cell-specific antiviral activity, and validated animal data, extending the scope of Digoxin: Cardiac Glycoside and Na+/K+ ATPase Pump Inhibit... by detailing workflow integration parameters for SKU B7684.

Applications, Limits & Misconceptions

Digoxin is used in basic and translational research on:

• Cardiac contractility modulation and arrhythmia mechanisms
• Congestive heart failure animal models
• Antiviral research against chikungunya virus in specific human and primate cell lines

Its cell-specific antiviral effect does not generalize to all cell types or viral pathogens. The compound is not suitable for in vivo antiviral studies in non-primate models where efficacy is unproven. Digoxin's narrow therapeutic window and rapid onset of action require careful titration in preclinical models (Blommel & Blommel, 2011).

Common Pitfalls or Misconceptions

• Assuming Digoxin’s antiviral effect applies to murine or insect cell lines—efficacy is limited to selected human and primate cells.
• Using Digoxin in water or ethanol—compound is insoluble; DMSO is required for stock solutions.
• Presuming long-term solution stability—Digoxin solutions are stable only for short-term use; prepare fresh aliquots for each experiment.
• Generalizing findings to all cardiac glycosides—mechanistic and efficacy profiles are compound- and context-specific.
• Extrapolating in vitro antiviral results to in vivo efficacy without supporting animal data.

Workflow Integration & Parameters

• Prepare Digoxin stock solutions at ≥33.25 mg/mL in DMSO; confirm complete dissolution before use.
• For cell-based antiviral assays, titrate Digoxin from 0.01 μM to 10 μM, monitoring cell viability and viral readouts.
• For animal models, administer intravenous Digoxin at 1–1.2 mg per canine subject; monitor hemodynamic endpoints.
• Store Digoxin as a solid at 4°C protected from light; minimize freeze-thaw cycles for stock solutions.
• Document batch number and purity (HPLC, NMR) in experimental records to ensure reproducibility.

For broader context on experimental design and mechanism, see Digoxin: Precision Modulation of Na+/K+-ATPase in Advance.... This article updates that resource by specifying validated stock concentrations and cell-type boundaries for SKU B7684.

Conclusion & Outlook

APExBIO’s Digoxin (SKU B7684) is a validated Na⁺/K⁺-ATPase inhibitor for advanced cardiovascular and antiviral research. Its cell-selective antiviral effect against chikungunya virus, robust cardiac contractility enhancement, and high purity make it a reliable choice for translational studies. Future work should explore mechanistic boundaries in new cell systems and refine dosing for emerging disease models. For detailed product specifications and ordering, visit the Digoxin product page.