Identification of new 4-(6-oxopyridazin-1-yl)benzenesulfonamides as multi-target anti-inflammatory agents targeting carbonic anhydrase, COX-2 and 5-LOX enzymes: synthesis, biological evaluations and modelling insights

Multiple inhibitions of CA, COX-2 and 5-LOX enzymes has been recognised as a useful strategy for the development of anti-inflammatory drugs that can avoid the disadvantages of using NSAIDs alone. Here, we report new pyridazine-based sulphonamides (5a-c and 7a-f) as potential multi-target anti-inflammatory candidates. First, the furanone heterocycle in the dual CA/COX-2 inhibitor Polmacoxib was replaced with the pyridazinone one. Then, a hydrophobic tail was appended through benzylation of the 3-hydroxyl group of the pyridazinone scaffold to afford benzyloxy pyridazines 5a-c. Furthermore, the structures were adorned with the polar sulphonate functionality, in pyridazine sulphonates 7a-f, that are expected to be engaged in interactions with the hydrophilic half of the CA binding sites. All of the disclosed pyridazinones were tested for inhibitory activities against 4 hCA isoforms (I, II, IX, and XII), as well as against COX-1/2, and 5-LOX. Furthermore, in vivo anti-inflammatory and analgesic effects of pyridazinones 7a and 7b were examined.</p

Antiviral effect of compounds on bunyavirus replication.

Vero cells were infected with either RVFV ZH501 (A) or LACV (B) then treated with decreasing concentrations of antiviral compound. Viral growth was measured by FFA. Data represents three independent experiments completed with biological replicates. Error bars represent standard deviation.</p

EC₅₀ against RVFV replication.

EC50 against RVFV replication.</p

Top antiviral hits.

Top antiviral hits.</p

Experimental methods for compound generation and validation of compounds.

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Development and validation of RVFV antiviral screen.

A. Identification of optimal mAb for the detection of RVFV by mAb staining of a serial dilution of RVFV strain MP-12 in an FFA. B. Impact of cell number on the sensitivity of antiviral compound screen. C. Evaluation of the sensitivity of the antiviral compound screen based upon the evaluation of ribavirin and β-D-N4-Hydroxycytidine N4-Hydroxycytidine (NHC/EIDD-1931), a known antiviral for RVFV. Data is presented as focus forming units. These data are the cumulation of three independent experiments with technical duplicates.</p

Primary screening data.

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EC₅₀ against LACV and ZIKV replication.

EC50 against LACV and ZIKV replication.</p

Representative structures of RFVF inhibitors.

(A) Inactive and active troponoid natural products, illustrating preference for oxygen triad, along with common nuclease inhibition mode for αHTs. (B) Synthetic αHTs with activity under 10 μM against RVFV, demonstrating broad substitution tolerance. (C) Representative examples of alternative scaffolds with activity against RFVF.</p

EC₅₀ value against RVFV.

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