HQL 79

HQL 79 is an orally active anti-allergic agent that acts as an antagonist for histamine H1 receptors (H1R), eliciting anti-asthmatic effects. It interacts with prostaglandin (PG) D synthase (H-PGDS) in the catalytic region. It may be potential lead due to its H-PGDS inhibition to treat allergies.

HQL-79 is a selective inhibtor of hematopoietic prostaglandin D (PGD) synthase, one of two synthases involved in the production of Prostaglandin D2 (PGD2) from arachidonic acid. PGD2 is a lipid signaling molecule, which activates two receptors, DP1 involved in centrally mediated processes such as sleep and pain and DP2 involved and inflammation. The two PGD synthases involved in its synthesis are lipocalin-type (L-PGDS) and hematopoietic (H-PDGS), which acts to form PGD2 in mast cells, Th2 cells, microglia, and other inflammatory cells/tissues. HQL-79 selectively inhibited the activity of recombinant H-PGDS with an IC₅₀ of 6 μM and had almost no effect on COX-1, COX-2, m-PGES, or L-PGDS up to 300 μM. HQL-79 has anti-inflammatory activity in vitro and in vivo.

HQL-79 is a selective inhibtor of hematopoietic prostaglandin D (PGD) synthase.