Elsevier

Bioorganic Chemistry

Volume 101, August 2020, 104044
Bioorganic Chemistry

Neuroprotective effect of novel celecoxib derivatives against spinal cord injury via attenuation of COX-2, oxidative stress, apoptosis and inflammation

https://doi.org/10.1016/j.bioorg.2020.104044Get rights and content

Highlights

  • Novel celecoxib derivatives developed as COX-2 inhibitor.

  • Compound 7m showed most potent COX-2 activity.

  • Compound 7m protects rats after spinal cord injury.

Abstract

A novel series of celecoxib derivatives were synthesized and evaluated for cyclooxygenase (COX-1/COX-2) inhibitory activities for benefit in spinal cord injury (SCI). The title compounds were synthesized by conventional methods in good yields and subsequently tested for inhibitory activity against COX-1/COX-2. The most potent COX-2 inhibitor among the tested derivatives was further assayed for protective effect against experimental SCI of Sprague-Dawley rats. The designed compounds showed considerable inhibition of COX-2 as compared to COX-1 revealing compound 7m as most potent inhibitor of COX-2 isoenzyme (IC50 = 0.04 µM). The expression of mitochondrial apoptotic genes (Bcl-2 and Bax) together with COX-2 and iNOS was restored near to normal as evidenced by western blot analysis in SCI rats. Taken altogether, compound 7m was identified as most potent inhibitor of COX-2. It also showed protective action against SCI via attenuation of COX-2, oxidative stress and apoptosis and inflammation in Male Sprague-Dawley rats.

Graphical abstract

Effect of compound 7m on COX-2 and iNOS expression in spinal cord of SCI rats.

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Introduction

The loss of motor and sensory function in a person due to spinal cord injury (SCI) is major cause of disability and mortality across the world. The physiological, biochemical and structural alterations cause irreversible damage to the spinal cord followed by SCI [1]. According to estimates, around more than 2 million people live with SCI and more than million new cases reported each year in the worldwide. This large community affected by SCI have huge, life-changing impacts and financial implication on the associated families. The studies have confirmed that, the etiology of SCI is multi-factorial in nature involving multiple mechanisms [2], [3]. Moreover, the damage caused by SCI to the spine categorised specifically in two distinct forms, which are interrelated to each other, such as, primary and secondary. The primary SCI describes immediate damage by mechanical trauma causing alteration of cellular membrane, micro-vasculature system which enhances cellular permeability and loss of integrity of myelin and axons. This milieu initiates secondary injury concomitantly which are multi-faceted and can last for years. The secondary injuries consist of numerous sub-phases which causing loss of neuronal activity due oxidative stress, inflammation, apoptosis including other physiological changes [4], [5], [6], [7]. Therefore, many of the therapeutic modalities against SCI are targeting complication arises due to secondary injuries, However, none of the agent/drugs proved effective till now against SCI which has put selective pressure to discover novel agents/molecules which can mitigate the consequences of SCI via multiple mechanisms (see Scheme 1).

Inflammation is the characteristic hallmark of SCI. It induces secretion of cytokines released by CNS or inflammatory cells [tumour necrosis factor (TNF)-α, Interleukin (IL)-1β and IL-6] and play key role in the regulation of the various steps of inflammatory reactions, i.e., recruitment and activation, but also in the downregulation of inflammatory cells [8], [9]. This increase in inflammation in SCI is frequently coupled with oxidative stress due to loss of antioxidant capacity. Oxidative stress is defined as imbalance between oxidants and antioxidants, ultimately resulting in necrosis and lipid peroxidation. Malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD) are important biomarkers of oxidative stress after SCI [10], [11], [12]. Apoptosis is another prominent clinical feature in the spinal cord post SCI after inflammation. It is known as programmed cell death and mainly controlled by the genes of Bcl-2 family (Bcl2 and Bax). The proportion of Bcl-2/Bax determines whether cells undergoing apoptosis or not. Besides, caspase associated cascade reaction is the important pathway for apoptosis, and caspase-3 is the key protease in the process of apoptosis [13]. The cyclooxygenase-2 (COX-2) is an inducible enzyme which produces leukotrienes and thromboxanes and reported to induce inflammatory cascade. Experimental evidences suggests that following to SCI, the level of COX-2 was found overexpressed primarily in brain and activated macrophages in response to inflammatory stimuli or lipopolysaccharides [14]. It has been found that improving antioxidative capacity and inhibiting inflammation and apoptosis could ameliorate neurological impairment in SCI. Therefore, present study discusses the development of novel COX-2 inhibitors against SCI.

Pyrazole is well know heterocyclic molecule endowed with limitless therapeutic roles such, as anti-cancer [15], [16], [17], anti-viral [18], [19], [20], [21], anti-bacterial [22], [23], [24], [25], anti-fungal [26], [27], anti-diabetic [28], [29] and many more [30]. Celecoxib, a well known pyrazole based NSAID (Non-steroidal anti-inflammatory drug) and selective COX-2 inhibitor used to treat arthritis, acute pain, menstrual cramps and in familial adenomatous polyposis [31], [32]. Moreover, lot of NSAIDS are derived from pyrazole nucleus as shown in Fig. 1. The potent activity of Celecoxib led to the discovery of various derivatives and pro-drugs in search of novel anti-inflammatory agents [33]. Moreover, Celecoxib has shown to ameliorate after effects of SCI alone or in combination of agents [34]. Thus, prompted by the above, the present study deals with the discovery and development of novel derivatives of Celecoxib as potent COX-2 inhibitor and their protective effect against experimentally induced spinal cord injury in rats.

Section snippets

Chemistry

The compounds were synthesized by claisen condensation of the commercially available p-methyl-acetophenone (1) and trifluoroacetic acid ethyl ester gave diketone (2) in good yield. Compound 2 was then reacted with the commercially available p-hydrazino-benzenesulfonic acid (3) in refluxing ethanol to afford sulfonic acid derivative 4 (yield over 90%). This reaction is a regioselective transformation and the 1,5-diarylpyrazole could be generated almost exclusively by carrying out the

Synthesis of target molecules

The chemicals used in the current work were obtained from Sigma Aldrich (USA). 1H NMR spectra were recorded in d6-DMSO on a Bruker Avance-400 NMR spectrometer with TMS as the internal reference. 13C NMR spectra were recorded on a Bruker Avance-100 NMR spectrometer in d6-DMSO on the same spectrometers with TMS as the internal reference. The multiplicity of a signal is indicated as: s – singlet, d – doublet, t – triplet, q – quartet, m – multiplet, br – broad, dd – doublet of doublets, etc.

Conclusion

Our study has shown the development of novel celecoxib derivatives via facile synthetic route as COX-2 inhibitor. Among the synthesized derivatives, compound 7m, a highly potent COX-2 inhibitor showed protective action against SCI via attenuation of COX-2, oxidative stress, apoptosis and inflammation in Male Sprague-Dawley rats.

Ethics approval and consent to participate

The animal use protocol listed below has been reviewed and approved by the Animal Ethical and Welfare Committee of Beijing Jishuitan Hospital, Beijing, China.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References (44)

  • T. Nasr et al.

    Design, synthesis, antimicrobial evaluation and molecular docking studies of some new thiophene, pyrazole and pyridone derivatives bearing sulfisoxazole moiety

    Eur. J. Med. Chem.

    (2014)
  • S. Mert et al.

    Synthesis, structure-activity relationships, and in vitro antibacterial and antifungal activity evaluations of novel pyrazole carboxylic and dicarboxylic acid derivatives

    Eur. J. Med. Chem.

    (2014)
  • J.Y.L. Chung et al.

    Evolution of a manufacturing route to omarigliptin, a long-acting DPP-4 inhibitor for the treatment of Type 2 diabetes

    Org. Process Res. Dev.

    (2015)
  • E. Hernández-Vázquez et al.

    Synthesis, hypoglycemic activity and molecular modeling studies of pyrazole-3-carbohydrazides designed by a CoMFA model

    Eur. J. Med. Chem.

    (2013)
  • A.A. Webb et al.

    Sensorimotor behaviour following incomplete cervical spinal cord injury in the rat

    Behav. Brain Res.

    (2005)
  • C. Sadowsky et al.

    Spinal cord injury

    Disabil. Rehabil.

    (2002)
  • M.J. Devivo

    Epidemiology of traumatic spinal cord injury: trends and future implications

    Spinal Cord

    (2012)
  • M.M. Adams et al.

    Spasticity after spinal cord injury

    Spinal Cord.

    (2005)
  • N. Sezer et al.

    Chronic complications of spinal cord injury

    World J. Orthop.

    (2015)
  • A.A. Rabinstein

    Traumatic spinal cord injury

    Contin. Lifelong Learn. Neurol.

    (2018)
  • D.J. Allison et al.

    Immune dysfunction and chronic inflammation following spinal cord injury

    Spinal Cord.

    (2015)
  • Z. Jia et al.

    Oxidative stress in spinal cord injury and antioxidant-based intervention

    Spinal Cord.

    (2012)
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