Catalog No.S9678

For research use only.

AT-56 is an orally active and selective inhibitor of lipocalin-type prostaglandin (PG) D synthase (L-PGDS) with Ki of 75 μM and IC50 of 95 μM.

AT-56 Chemical Structure

CAS No. 162640-98-4

Purity & Quality Control

Choose Selective PGDS Inhibitors

Biological Activity

Description AT-56 is an orally active and selective inhibitor of lipocalin-type prostaglandin (PG) D synthase (L-PGDS) with Ki of 75 μM and IC50 of 95 μM.
L-PGDS [1]
(Cell-free assay)
L-PGDS [1]
(Cell-free assay)
75 μM(Ki) 95 μM
In vitro

AT-56 inhibits human and mouse L-PGDSs in a concentration (3–250 μm)-dependent manner. AT-56 inhibits the L-PGDS activity in a competitive manner against the substrate PGH2 (Km = 14 μm) with a Ki value of 75 μm. AT-56 inhibits the production of PGD2 by L-PGDS-expressing human TE-671 cells after stimulation with Ca2+ ionophore (5 μm A23187) with an IC50 value of about 3 μm without affecting their production of PGE2 and PGF2α.[1]

In vivo

Orally administered AT-56 (<30 mg/kg body weight) decreases the PGD2 production to 40% in the brain of H-PGDS-deficient mice after a stab wound injury in a dose-dependent manner without affecting the production of PGE2 and PGF2α and also suppresses the accumulation of eosinophils and monocytes in the bronco-alveolar lavage fluid from the antigen-induced lung inflammation model of human L-PGDS-transgenic mice.[1]

Protocol (from reference)

Cell Research:


  • Cell lines: TE-671 cells, MEG-01S cells
  • Concentrations: 0 - 100 μM
  • Incubation Time: 10 min
  • Method:

    TE-671 (1×106 cells/well) and MEG-01S (5×105 cells/well) are seeded into multiplates and cultured in Dulbecco's modified Eagle's medium supplemented with 10% heat-inactivated fetal bovine serum, 4 mM L-glutamine, 4.5 g/liter glucose, 100 units/ml penicillin, and 100 μg/ml streptomycin sulfate under a 5% CO2 atmosphere at 37 ℃. MEG-01S cells are caused to differentiate by treatment with 12-O-tetradecanoylphorbol-13-acetate to express H-PGDS and COX-1. After the cells have been cultured for 1 day, AT-56 is added to them at different doses ranging from 0 to 100 μM, and the cells are then incubated at 37 ℃ for 10 min. Thereafter, they are stimulated with a calcium ionophore, A23187 (5 μM), at 37 ℃ for 15 min. The culture media were harvested and centrifuged at 10,000 × g for 5 min to remove the cells, and the supernatant is removed and stored at 80 ℃ until the measurements of PGs can be made.

Animal Research:


  • Animal Models: H-PGDS KO mice (14–16-week-old males or females weighing 25–30 g, C57BL/6 strain)
  • Dosages: 1 mg/kg, 3 mg/kg, 10 mg/kg, 30 mg/kg
  • Administration: Oral gavage

Solubility (25°C)

In vitro

Chemical Information

Molecular Weight 397.52


CAS No. 162640-98-4
Storage 3 years -20°C powder
2 years -80°C in solvent

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Clinical Trial Information

NCT Number Recruitment Interventions Conditions Sponsor/Collaborators Start Date Phases
NCT04102800 Recruiting Drug: Benralizumab Asthma NHS Greater Glasgow and Clyde|University of Glasgow|AstraZeneca|Queen''s University Belfast|Bosch Healthcare Solutions GmbH|InHealthcare|University of Leicester|University of Plymouth|Vitalograph September 30 2019 Phase 4
NCT02494479 Completed Drug: Prurisol|Drug: Placebo Plaque Psoriasis Cellceutix Corporation August 2015 Phase 2
NCT02195232 Completed Drug: Isoquercetin Thromboembolism of Vein VTE in Colorectal Cancer|Thromboembolism of Vein in Pancreatic Cancer|Thromboembolism of Vein in Non-small Cell Lung Cancer Jeffrey Zwicker MD|Quercegen Pharmaceuticals|National Heart Lung and Blood Institute (NHLBI)|Dana-Farber Cancer Institute January 2015 Phase 2|Phase 3
NCT01925417 Completed Biological: RBX2660 (microbiota suspension) Recurrent Clostridium Difficile Infection Rebiotix Inc. August 2013 Phase 2

(data from, updated on 2022-08-01)

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