Background:

2-(4-(biphenyl-4-ylamino)-6-chloropyrimidin-2- ylthio)octanoic acid (HZ52) is an inhibitor for 5-Lipoxygenase (5-LO) [1]. 5-Lipoxygenase (5-LO), the key enzyme involved in the biosynthesis of pro-inflammatory leukotrienes (LTs), is a potential target for pharmacological intervention with inflammation and allergic disorders [1].

In vitro: In cell-free assays using partially purified recombinant 5-LO enzyme, HZ52 inhibited 5-LO with an IC50 of 1.5 μM. In PMNL homogenates, HZ52 inhibited 5-LO with an IC50 of 9 μM [1]. HZ52 (10 or 30 μM) promoted 5-LO translocation to the nuclear membrane in PMNL [1]. The cell-based and cell-free assays revealed that inhibition of 5-LO by HZ52 did not depend on radical scavenging properties and was reversible [1].

In vivo: In rats with carrageenan-induced pleurisy and in mice bearing platelet-activating factor (PAF)-induced lethal shock, HZ52 (1.5 mg/kg, i.p) prevented carrageenan-induced pleurisy accompanied by reducing LTB4 levels. HZ52 protected mice (10 mg/kg, i.p) against PAF-induced shock. [1].

Reference:
[1] Greiner C, Hrnig C, Rossi A, et al.  2‐(4‐(Biphenyl‐4‐ylamino)‐6‐chloropyrimidin‐2‐ylthio) octanoic acid (HZ52)–a novel type of 5‐lipoxygenase inhibitor with favourable molecular pharmacology and efficacy in vivo[J]. British journal of pharmacology, 2011, 164(2b): 781-793.