Elucidation of the molecular mechanism and the efficacy in vivo of a novel 1,4-benzoquinone that inhibits 5-lipoxygenase.
OBJECTIVE
1,4-Benzoquinones are well-known inhibitors of 5-lipoxygenase (5-LOX, the key enzyme in leukotriene biosynthesis), but the molecular mechanisms of 5-LOX inhibition are not completely understood. Here we investigated the molecular mode of action and the pharmacological profile of the novel 1,4-benzoquinone derivative 3-((decahydronaphthalen-6-yl)methyl)-2,5-dihydroxycyclohexa-2,5-diene-1,4-dione (RF-Id) in vitro and its effectiveness in vivo.


METHODS
Mechanistic investigations in cell-free assays using 5-LOX and other enzymes associated with eicosanoid biosynthesis were conducted, along with cell-based studies in human leukocytes and whole blood. Molecular docking of RF-Id into the 5-LOX structure was performed to illustrate molecular interference with 5-LOX. The effectiveness of RF-Id in vivo was also evaluated in two murine models of inflammation.


RESULTS
RF-Id consistently suppressed 5-LOX product synthesis in human leukocytes and human whole blood. RF-Id also blocked COX-2 activity but did not significantly inhibit COX-1, microsomal PGE2 synthase-1, cytosolic PLA2 or 12- and 15-LOX. Although RF-Id lacked radical scavenging activity, reducing conditions facilitated its inhibitory effect on 5-LOX whereas cell stress impaired its efficacy. The reduced hydroquinone form of RF-Id (RED-RF-Id) was a more potent inhibitor of 5-LOX as it had more bidirectional hydrogen bonds within the 5-LOX substrate binding site. Finally, RF-Id had marked anti-inflammatory effects in mice in vivo.


CONCLUSIONS
RF-Id represents a novel anti-inflammatory 1,4-benzoquinone that potently suppresses LT biosynthesis by direct inhibition of 5-LOX with effectiveness in vivo. Mechanistically, RF-Id inhibits 5-LOX in a non-redox manner by forming discrete molecular interactions within the active site of 5-LOX.
Institute of Pharmacy, University Jena, Jena, Germany.
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Schaible
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Filosa
V
V
Temml
V
V
Krauth
M
M
Matteis
A
A
Peduto
F
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Bruno
S
S
Luderer
F
F
Roviezzo
A
A
Di Mola
M
M
de Rosa
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B
D'Agostino
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C
Weinigel
D
D
Barz
A
A
Koeberle
C
C
Pergola
D
D
Schuster
O
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Werz
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000737:chemistry* / Q000378:metabolism / Q000627:therapeutic use; D016227:Benzoquinones / Q000737:chemistry* / Q000378:metabolism / Q000627:therapeutic use; D004487:Edema / Q000188:drug therapy / Q000378:metabolism; D006801:Humans; D016859:Lipoxygenase Inhibitors / Q000737:chemistry* / Q000378:metabolism / Q000627:therapeutic use; D008297:Male; D051379:Mice; D062105:Molecular Docking Simulation / Q000379:methods; D017433:Protein Structure, Secondary; D012756:Sheep; D016896:Treatment Outcome
D000893:Anti-Inflammatory Agents; D016227:Benzoquinones; D016859:Lipoxygenase Inhibitors; C004532:quinone
1,4-benzoquinone; 5-lipoxygenase; inflammation; leukocytes; leukotriene