Design, Synthesis of Novel Pyrazole Derivatives Bearing P-Amino benzene Sulfonyl Chloride Moiety with Anti-Inflammatory Activity and Exhibit Inhibitory effects against p38α MAP Kinase

Avanish Maurya¹, Bhavana Dubey²*, Neha Mishra³

¹Assistant Professor, Department of Pharmacy,

Avadh Institute of Medical Technology and Hospital, Lucknow, Uttar Pradesh 206026.

²Associate Professor, Department of Pharmacy,

Saroj Institute of Technology and management, Lucknow, Uttar Pradesh 206002.

³Associate Professor, Department of Pharmacy,

Saroj Institute of Technology and Management, Lucknow, Uttar Pradesh 206002.

*Corresponding Author E-mail: bhavanadubey91@gmail.com

ABSTRACT:

In recent years, numerous pyrazole derivatives have been identified in scientific literature as potent anti-inflammatory agents. Among these, pyrazolyl sulfonamides and pyrazolyl derivatives of urea have demonstrated significant anti-inflammatory properties and the ability to inhibit p38α MAP kinase. This study aimed to determine the structures of these compounds using spectral data and evaluate their anti-inflammatory activity through in vitro assays. The anti-denaturation assay using bovine serum albumin (BSA) and the p38α MAP kinase assay were employed to screen the compounds for anti-inflammatory potential. Compounds that exhibited promising results in these initial assessments were further evaluated for their ability to reduce inflammation, induce ulcers, cause lipid damage, and suppress TNF-α. The findings highlight the therapeutic potential of these pyrazole derivatives in the treatment of inflammatory diseases and provide a basis for further development of novel anti-inflammatory agents.

KEYWORDS: Pyrazole, Anti-inflammatory, Bovine Serum Albumin, Ulcers.

INTRODUCTION:

Experimental Approach (Methodology)

To achieve the objectives of the, series of compounds incorporating pyrazole and imidazole motifs have been synthesized. These compounds are designed with structural modifications aimed at enhancing their potency and selectivity towards inhibiting p38α MAP kinase and reducing inflammation. The research methodology includes:

Synthesis: The synthesis of novel compounds with varying substituents on the pyrazole by using p-acetamidobenzenesulfonyl chloride rings to explore structure-activity relationships.

Characterization: The synthesized compounds were characterized using IR, NMR, and MS spectroscopic methods.

Evaluation of Anti-inflammatory Activity: Testing the synthesized compounds for their ability to reduce inflammation using established in vitro and possibly in vivo models. This includes assessing their effects on pro-inflammatory cytokine production, enzyme inhibition (e.g., COX-2, MMPs), and cellular responses associated with inflammation.

Assessment of p38α MAP Kinase Inhibition: Evaluating the compounds for their capacity to inhibit p38α MAP kinase activity, potentially through enzymatic assays or cellular assays measuring phosphorylation levels of p38α.

General method for the synthesis of N-(4-(N-(4-(5-(4-(benzyloxy) pheny)-1-(substitutedphenyl)—1H-pyrazol-3yl) phenyl) sulfanoyl) phenyl) acetamide (4a-o)

Equal amounts of 4-[5-[4-(Benzyloxy) phenyl]-1-(4-methoxyphenyl)-1H-pyrazol-3-yl] aniline and p-acetamido benzene sulfonyl chloride (0.005mol each) was mixed together and agitated at ambient temperature for 6-9 hours in the presence of pyridine (0.005mol) in 30mL of THF1 Subsequently, the concoction was introduced into crushed ice, resulting in the formation of a solid substance. This solid was then separated from the liquid by filtration, and subsequently dried and purified by crystallization using ethanol as the solvent.^1,2

Evaluation of Activity:

Anti-inflammatory screening:

The efficacy of the synthesized compounds 4a-o was assessed in terms of their ability to mitigate inflammation, employing the albumin denaturation inhibition method. Compound 4a demonstrated superior anti-inflammatory^3,4effects, achieving an efficacy of 88.95%, surpassing the safety profile of the conventional diclofenac sodium, which had an efficacy of 83.60%. Compound 4c exhibited a notable anti-inflammatory efficacy of 87.52%, exceeding the potency of diclofenac sodium. Similarlycompound 4b revealed a large anti-inflammatory activity of 84.49%. The other compounds exhibited a diverse array of anti-inflammatory properties, with percentage ranging from 82.18%to 62.92% table 1

Table 1: BSA anti-denaturation assay results of pyrazolyl sulfonamide derivatives

Compound	% Inhibition ± SD
4a	88.95 ± 2.53
4b	84.49 ± 2.83
4c	87.52 ± 1.88
4d	78.08 ± 1.85
4e	82.18 ± 4.32
4f	73.80 ± 3.51
4g	80.03 ± 2.53
4h	78.79 ± 2.16
4i	66.13 ± 0.82
4j	64.35 ± 0.31
4k	68.27 ± 2.64
4l	70.77 ± 4.85
4m	63.28 ± 2.74
4n	62.92 ± 4.97
4o	70.05 ± 3.25
Control	-
Diclofenac sodium	83.60 ± 2.03

1.2 p38α MAP kinase assay:

Compound 4c, which has a 4-chlorophenyl group instead of a 2-chlorophenyl group, exhibited slightly reduced activity with an IC50 of 0.031 ± 1.27 µM. Compound 4b, containing a 3-chlorophenyl group, showed higher activity with a % inhibition of 48.39 compared to SB 203580's 51.79%. Compounds 4e and 4g demonstrated p38α MAPK inhibition with % inhibition values of 44.58 and 41.32, respectively,^5,6 which were comparable to SB 203580 (Table 2).

Table 2: p38αMAPK inhibition of pyrazolyl sulfonamide derivatives

Compound	%inhibition	^IC50^value(µM)
Solvent control	-
4a	59.31	0.028 ± 0.04
4b	48.39	-
4c	56.83	0.031 ± 1.27
4e	44.58	-
4g	41.32	-
SB 203580	51.79	0.043 ± 3.62

RESULT AND DISCUSSION:

The extended clinical use of these substances is linked to gastrointestinal damage. Several specific COX-2 inhibitors, including celecoxib, forecoxa, and this medication, demonstrated anti-inflammatory properties while causing minimal gastrointestinal side effects Regrettably, it was discovered that specific COX-2 medications induce cardiovascular adverse effects.^7,8Hence, it is imperative to create anti-inflammatory medications that provide an enhanced safety profile.⁹

CONCLUSION:

Pyrazolyl sulfonamide, including pyrazolyl derivatives of urea have demonstrated notable anti-inflammatory properties and the ability to inhibit p38α MAP kinase.^10,11The compounds underwent in vitro assessment for anti-inflammatory activity using the BSA anti-denaturation assay, p38α MAP kinase assay.^12,13Compounds that showed favorable outcomes in laboratory trials were chosen and assessed for their potential to reduce inflammation,¹⁴ induce ulcers, cause lipid damage, and suppress TNF-α.¹⁵

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