Discovery and biological evaluation of novel 1,4-benzoquinone and related resorcinol derivatives that inhibit 5-lipoxygenase

• The synthesis of 22 novel 1,4-benzoquinone/resorcinol derivatives is provided.
• SARs are obvious for inhibition of 5-lipoxygenase.
• The 1,4-benzoquinone Ig is a potent 5-lipoxygenase inhibitor (IC50 = 0.78 μM).
• Docking studies reveal concrete binding poses of active compounds to 5-lipoxygenase.

5-Lipoxygenase (5-LO), an enzyme that catalyzes the initial steps in the biosynthesis of pro-inflammatory leukotrienes, is an attractive drug target for the pharmacotherapy of inflammatory and allergic diseases. Here, we present the discovery and biological evaluation of novel series of 1,4-benzoquinones and respective resorcinol derivatives that efficiently inhibit human 5-LO, with little effects on other human lipoxygenases. SAR analysis revealed that the potency of the compounds strongly depends on structural features of the lipophilic residues, where bulky naphthyl or dibenzofuran moieties favor 5-LO inhibition. Among the 1,4-benzoquinones, compound Ig 5-[(2-naphthyl)methyl]-2-hydroxy-2,5-cyclohexadiene-1,4-dione potently blocked 5-LO activity in cell-free assays with IC50 = 0.78 μM, and suppressed 5-LO product synthesis in polymorphonuclear leukocytes with IC50 = 2.3 μM. Molecular docking studies suggest a concrete binding site for Ig in 5-LO where select π–π interactions along with hydrogen bond interactions accomplish binding to the active site of the enzyme. Together, our study reveals novel valuable 5-LO inhibitors with potential for further preclinical assessment as anti-inflammatory compounds.

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