Bq-123
From PeptidePlaza, the free peptide reference · Entry #1014 · Recovery · Sources fetched 2026-09-10 · Editorial standards
Bq-123 (also known as Cyclo(D-trp-D-asp-pro-D-val-leu), cyclo(Trp-Asp-Pro-Val-Leu), cyclo[D-Trp-D-Asp-Pro-D-Val-Leu], cyclo(L-Leu-D-Trp-D-Asp-L-Pro-D-Val)) is a recovery research peptide. BQ-123 is a cyclic pentapeptide and a selective antagonist of the endothelin A (ETA) receptor.
BQ-123 is a cyclic pentapeptide that acts as a selective antagonist for the endothelin A (ETA) receptor. It has been investigated for its potential in various cardiovascular conditions, including ST elevation myocardial infarction, pulmonary hypertension, coronary disease, and reperfusion injury, reaching Phase 2 clinical trials. Research also explores its role in modulating endothelin-dependent blood pressure and its potential to prevent LPS-induced preterm birth by inducing uterine and placental IL-10. Studies have also examined its transport mechanisms into rat hepatocytes.
1 Mechanism of action
Endothelin receptor ET-A antagonist (antagonist)
Primary targets: Endothelin receptor ET-A
2 Reported effects
Effects below are those reported in the published literature cited on this page. They are not claims of clinical benefit and not medical advice.
2.1 Indicated / studied for
- ST Elevation Myocardial Infarction
- Pulmonary Hypertension
- Coronary Disease
- Reperfusion Injury
- Cardiovascular Diseases
- Heart Failure
3 Chemical and physical properties
| CAS number | 136553-81-6 |
|---|---|
| Molar mass | 610.7 g/mol |
| Purity (typical) | Not independently verified |
| Storage | −20 °C, lyophilised powder, desiccated |
| Solubility | Sterile water / bacteriostatic water |
| Receptors / targets | Endothelin receptor ET-A |
4 Research studies (8)
- Extracellular Vesicles Link Cerebral Ischemia to Coronary Microvascular Dysfunction - Role for RGD Motif-Activated Endothelin Signaling
Journal of cardiovascular translational research (2026) - Synergistic inhibition by BQ-123 and BQ-788 of endothelin-1-induced contractions of the rabbit pulmonary artery
British journal of pharmacology (1994) - Carrier-mediated active transport of BQ-123, a peptidic endothelin antagonist, into rat hepatocytes
The Journal of pharmacology and experimental therapeutics (1996) - Epigenetic alteration of smooth muscle cells regulates endothelin-dependent blood pressure and hypertensive arterial remodeling
The Journal of clinical investigation (2025) - BQ-123 prevents LPS-induced preterm birth in mice via the induction of uterine and placental IL-10
Toxicology and applied pharmacology (2015) - Effects of endothelin receptor selective antagonists, BQ-123 and BQ-788, on IRL 1620 and endothelin-1 responses of airway and vascular preparations from rats
Pulmonary pharmacology (1995) - BQ-123, a peptidic endothelin ETA receptor antagonist, prevents the early cerebral vasospasm following subarachnoid hemorrhage after intracisternal but not intravenous injection
Life sciences (1993) - [3H]BQ-123, a highly specific and reversible radioligand for the endothelin ETA receptor subtype
European journal of pharmacology (1995)
5 Safety and risk profile
5.1 Regulatory status
Bq-123 is currently classified as Phase 2 clinical trials. It has no approved human indication in the United States; availability elsewhere does not imply demonstrated safety or efficacy.
6 Frequently asked questions
- What is BQ-123 used for?
- BQ-123 has been studied for its potential therapeutic applications in several cardiovascular conditions. These include ST elevation myocardial infarction, pulmonary hypertension, coronary disease, reperfusion injury, and heart failure. It has progressed to Phase 2 clinical trials for some of these indications.
- How does BQ-123 work?
- BQ-123 functions as a selective antagonist of the endothelin A (ETA) receptor. By blocking this receptor, it interferes with the actions of endothelin-1, a potent vasoconstrictor, which can influence blood pressure and vascular remodeling.
- What class of compound is BQ-123?
- BQ-123 is classified as a cyclic pentapeptide. Its structure allows it to specifically interact with and block the endothelin A receptor, making it an endothelin receptor antagonist.
- What is the regulatory status of BQ-123?
- BQ-123 is currently in Phase 2 clinical trials for several indications, including ST elevation myocardial infarction, pulmonary hypertension, coronary disease, and reperfusion injury. It has also been studied in Phase 1 for cardiovascular diseases and Phase 0.5 for heart failure.
7 References
- Bq-123 — compound summary PubChem. View source
- Bq-123 — molecule record ChEMBL. View source
- Bq-123 — published literature (1,384 records) PubMed. View source
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