New phenolic cinnamic acid derivatives as selective COX-2 inhibitors. Design, synthesis, biological activity and structure-activity relationships

Novel Cinnamic Acid Derivatives Containing Naproxen as NLRP3 Inhibitors: Synthesis and Evaluation of Their Biological Activity

Long-term use of naproxen can lead to serious side effects. Inspired by the biological activity of cinnamic acid, a series of cinnamic acid derivatives containing naproxen were designed and synthesized, and their anti-inflammatory activities and mechanisms were explored in vitro. Our results indicated that all of naproxen derivatives showed more significant inhibition against lipopolysaccharide (LPS)-induced nitric oxide (NO) production and had a lower degree of cytotoxicity than that of naproxen. The present studies revealed that compound 23 (IC50 = 5.66 ± 1.66 µM) markedly inhibited the LPS-induced NO production and the over-expression of pro-inflammatory cytokines, including interleukin (IL)-1β, inducible NO synthase (iNOS), and cyclooxygenase-2 (COX-2). Furthermore, it blocked the activation of NF-κB signaling pathway and pyrin domain-containing protein 3 (NLRP-3) inflammasome in a concentration-dependent manner. Additionally, docking studies confirmed that compound 23 exhibited a well-fitting into the NLRP3 active site. Considering these results, compound 23 might be a novel NLRP3 inhibitor to treat inflammatory diseases.

Plant-derived and dietary phenolic cinnamic acid derivatives: Anti-inflammatory properties

Cinnamic acids are aromatic acids primarily found in plants and plant-derived food. Phenolic cinnamic acids, with one or more hydroxyl groups in the aromatic ring, often contribute to the biological activities attributed to these compounds. The presence of hydroxyl groups and a carboxyl group makes cinnamic acids very hydrophilic, preventing them from crossing biological membranes and exerting their biological activities. To alleviate this condition, a panel of synthetic modifications have been made leading to a diverse set of phenolic cinnamic structures. In this review, an overview of the natural phenolic cinnamic acid derivatives and their plant sources (more than 200) is described. The synthetic approaches to obtain the referred derivatives (more than 200) namely esters and amides are reviewed. Further, their anti-inflammatory activity (more than 70 compounds) is scrutinized. Finally, future directions will be indicated to translate the research on phenolic cinnamic derivatives into potentially effective anti-inflammatory drugs.

Selective COX-2 inhibitors as anticancer agents: a patent review (2018-2023)

INTRODUCTION

COX-2 is a crucial enzyme in the manufacture of prostaglandins. The enzyme's metabolites might have an important function as regulators of the inflammatory response and other medical conditions such as cancer. Selective COX-2 inhibitors are believed to enhance or reverse the response of cancer chemotherapeutics.

AREAS COVERED

This study addresses the chemical structures as well as the antitumor activity of new COX-2 inhibitors produced in the recent five years, aiming to provide an insight into the mechanism of COX-2 induced PGE2 powerful signal in cancer development.

EXPERT OPINION

The significance of selective COX-2 inhibitors as an efficient superfamily of compounds with anti-inflammatory, anti-Alzheimer's, anti-Parkinson's disease, and anticancer properties has piqued the passion of academics in the field of drug development. Long-term usage of selective COX-2 inhibitors, such as celecoxib has been proven in clinical trials to lower the incidence of several human malignancies. Furthermore, celecoxib has the potential to greatly increase the effectiveness of chemotherapy. Our extensive understanding of selective COX-2 inhibitor SAR may aid in the development of safer and more effective selective COX-2 inhibitors as cancer chemopreventive agents. This review focuses on the different structural classes of selective COX-2 inhibitors, with a particular emphasis on their SAR.

A Review of Cinnamic Acid's Skeleton Modification: Features for Antibacterial-Agent-Guided Derivatives

Antimicrobial resistance has emerged as a significant danger to global health, and the need for more effective antimicrobial resistance (AMR) control has been highlighted. Cinnamic acid is abundant in plant products and is a potential starting material for further modification, focusing on the development of new antimicrobial compounds. In the following review, we describe the classification of critical antibacterial-guided reactions applied to the main skeleton structure of cinnamic acid derivatives over the last decade. Of all of the main parts of cinnamic acids, the phenyl ring and the carboxylic group significantly affect antibacterial activity. The results presented in the following review can provide valuable insights into considerable features in the organic modification of cinnamic acids related to antibacterial medication development and the food industry.

Liposomal quercetin: A promising strategy to combat hepatic insulin resistance and inflammation in type 2 diabetes mellitus

In type 2 diabetes mellitus, hepatic insulin resistance is intricately associated with oxidative stress and inflammation. Nonetheless, the lack of therapeutic interventions directly targeting hepatic dysfunction represents a notable gap in current treatment options. Flavonoids have been explored due to their potential antidiabetic effects. However, these compounds are associated with low bioavailability and high metabolization. In the present study, four flavonoids, kaempferol, quercetin, kaempferol-7-O-glucoside and quercetin-7-O-glucoside, were studied in a cellular model of hepatic insulin resistance using HepG2 cells. Quercetin was selected as the most promising flavonoid and incorporated into liposomes to enhance its therapeutic effect. Quercetin liposomes had a mean size of 0.12 µm, with an incorporation efficiency of 93 %. Quercetin liposomes exhibited increased efficacy in modulating insulin resistance. This was achieved through the modulation of Akt expression and the attenuation of inflammation, particularly via the NF-κB pathway, as well as the regulation of PGE2 and COX-2 expression. Furthermore, quercetin liposomes displayed a significant advantage over free quercetin in attenuating the production of reactive pro-oxidant species. These findings open new avenues for developing innovative therapeutic strategies to manage diabetes, emphasizing the potential of quercetin liposomes as a promising approach for targeting both hepatic insulin resistance and associated inflammation.

Investigation of the Anti-Inflammatory Properties of Bioactive Compounds from Olea europaea: In Silico Evaluation of Cyclooxygenase Enzyme Inhibition and Pharmacokinetic Profiling

In a landmark study, oleocanthal (OLC), a major phenolic in extra virgin olive oil (EVOO), was found to possess anti-inflammatory activity similar to ibuprofen, involving inhibition of cyclooxygenase (COX) enzymes. EVOO is a rich source of bioactive compounds including fatty acids and phenolics; however, the biological activities of only a small subset of compounds associated with Olea europaea have been explored. Here, the OliveNetTM library (consisting of over 600 compounds) was utilized to investigate olive-derived compounds as potential modulators of the arachidonic acid pathway. Our first aim was to perform enzymatic assays to evaluate the inhibitory activity of a selection of phenolic compounds and fatty acids against COX isoforms (COX-1 and COX-2) and 15-lipoxygenase (15-LOX). Olive compounds were found to inhibit COX isoforms, with minimal activity against 15-LOX. Subsequent molecular docking indicated that the olive compounds possess strong binding affinities for the active site of COX isoforms, and molecular dynamics (MD) simulations confirmed the stability of binding. Moreover, olive compounds were predicted to have favorable pharmacokinetic properties, including a readiness to cross biological membranes as highlighted by steered MD simulations and umbrella sampling. Importantly, olive compounds including OLC were identified as non-inhibitors of the human ether-à-go-go-related gene (hERG) channel based on patch clamp assays. Overall, this study extends our understanding of the bioactivity of Olea-europaea-derived compounds, many of which are now known to be, at least in part, accountable for the beneficial health effects of the Mediterranean diet.

Pyrazoles have a multifaceted anti-inflammatory effect targeting prostaglandin E2, cyclooxygenases and leukocytes' oxidative burst

Elevated levels of prostaglandin E2 have been implicated in the pathophysiology of various diseases. Anti-inflammatory drugs that act through the inhibition of cyclooxygenase enzymatic activity, thereby leading to the suppression of prostaglandin E2, are often associated with several side effects due to their non-specific inhibition of cyclooxygenase enzymes. Consequently, the targeted suppression of prostaglandin E2 production with innovative molecules and/or mechanisms emerges as a compelling therapeutic strategy for the treatment of inflammatory-related diseases. Therefore, in this study, a systematic analysis of 28 pyrazole derivatives was conducted to explore their potential mechanisms for reducing prostaglandin E2 levels. In this context, the evaluation of these derivatives extended to examining their capacity to reduce prostaglandin E2in vitro in human whole blood, inhibit cyclooxygenase-1 and cyclooxygenase-2 enzymes, modulate cyclooxygenase-2 expression, and suppress oxidative burst in human leukocytes. The results enabled the establishment of significant structure-activity relationships, elucidating key determinants for their activities. In particular, the 4-styryl group on the pyrazole moiety and the presence of chloro substitutions were identified as key determinants. Pyrazole 8 demonstrated the capacity to reduce prostaglandin E2 levels by downregulating cyclooxygenase-2 expression, and pyrazole-1,2,3-triazole 18 emerged as a dual-acting agent, inhibiting human leukocytes' oxidative burst and cyclooxygenase-2 activity. Furthermore, pyrazole 26 demonstrated effective reduction of prostaglandin E2 levels through selective cyclooxygenase-1 inhibition. These results underscore the multifaceted anti-inflammatory potential of pyrazoles, providing new insights into the substitutions and structural frameworks that are beneficial for the studied activity.

Exploring the broad-spectrum pharmacological activity of two less studied Australian native fruits: chemical characterisation using LCMS-driven metabolomics

Australian fruits such as native currant (Acrotriche depressa) and lemon aspen (Acronychia acidula) are under-examined in terms of their therapeutic potential. In this study, the in vitro antiproliferative activity of native currant and lemon aspen extracts (water and ethanol) against MCF7 breast adenocarcinoma cells was determined using the Alamar blue assay. The most potent extracts (native currant water, NC-W; native currant ethanol, NC-Et; lemon aspen ethanol, LA-Et) were further evaluated using flow cytometry to detect the potential induction of apoptosis in MCF7 cells whereas 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) assay was implemented to understand the impact of the extracts on the intracellular reactive oxygen species (ROS) levels in MCF7 cells. Furthermore, the antioxidant activity of the extracts was assessed using ABTS [2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate)], and CUPRAC (cupric reducing antioxidant capacity) assays. The antimicrobial susceptibility testing of NC-W, NC-Et, and LA-Et was carried out against Gram-positive (Staphylococcus aureus), Gram-negative (Escherichia coli), and yeast (Candida albicans) strains using a resazurin-based assay. Additionally, potential metabolites in the NC-W and NC-Et extracts were analysed with liquid chromatography-mass spectrometry (LC-MS) driven metabolomics and chemometrics to spot differential and major metabolites. A dose-dependent antiproliferative activity was conferred by the NC extracts against MCF7 cells. Of the two LA extracts, only LA-Et showed a dose-dependent antiproliferative activity at higher concentrations. Both NC extracts and LA-Et induced apoptosis in MCF7 cells. None of the extracts increased the production of ROS significantly in MCF7 cells compared to the untreated control. A dose-dependent antioxidant activity was observed in both antioxidant assays. Both NC and LA extracts showed a similar minimum inhibitory concentration (MIC) value against S. aureus. Only LA-Et showed activity against E. coli, while NC-W and NC-Et were less active. All extracts showed MIC values of >1500 μg mL-1 against C. albicans. The metabolomics analysis revealed an abundance of flavonoids, fatty acyl derivatives, carbohydrates, carboxylic acids and their derivatives, and alkaloid compounds as potential bioactive metabolites in the NC extracts. In conclusion, both NC and LA showed antiproliferative (against MCF7 breast adenocarcinoma cells through the induction of apoptosis), strong antioxidant and minimal antimicrobial properties.

New neuroprotective derivatives of cinnamic acid by biotransformation

Microbial transformation is extensively utilized to generate new metabolites in bulk amounts with more specificity and improved activity. As cinnamic acid was reported to exhibit several important pharmacological properties, microbial transformation was used to obtain its new derivatives with enhanced biological activities. By manipulating the 2-stage fermentation protocol of biotransformation, five metabolites were produced from cinnamic acid. Two of them were new derivatives; N-propyl cinnamamide 2̲ and 2-methyl heptyl benzoate 3̲ produced by Alternaria alternata. The other 3 metabolites, p-hydroxy benzoic acid 4̲, cinnamyl alcohol 5̲ and methyl cinnamate 6̲, were produced by Rhodotorula rubra, Rhizopus species and Penicillium chrysogeneum, respectively. Cinnamic acid and its metabolites were evaluated for their cyclooxygenase (COX) and acetylcholinesterase (AChE) inhibitory activities. Protection against H2O2 and Aβ1-42 induced-neurotoxicity in human neuroblastoma (SH-SY5Y) cells was also monitored. Metabolite 4̲ was more potent as a COX-2 inhibitor than the parent compound with an IC50 value of 1.85 ± 0.07 μM. Out of the tested compounds, only metabolite 2̲ showed AChE inhibitory activity with an IC50 value of 8.27 μM. These results were further correlated with an in silico study of the binding interactions of the active metabolites with the active sites of the studied enzymes. Metabolite 3̲ was more potent as a neuroprotective agent against H2O2 and Aβ1-42 induced-neurotoxicity than catechin and epigallocatechin-3-gallate as positive controls. This study suggested the two new metabolites 2̲ and 3̲ along with metabolite 4̲ as potential leads for neurodegenerative diseases associated with cholinergic deficiency, neurotoxicity or neuroinflammation.

Derivative of cinnamic acid inhibits T3SS of Xanthomonas oryzae pv. oryzae through the HrpG-HrpX regulatory cascade

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) has a significant impact on rice yield and quality worldwide. Traditionally, bactericide application has been commonly used to control this devastating disease. However, the overuse of fungicides has led to a number of problems such as the development of resistance and environmental pollution. Therefore, the development of new methods and approaches for disease control are still urgent. In this paper, a series of cinnamic acid derivatives were designed and synthesized, and three novel T3SS inhibitors A10, A12 and A20 were discovered. Novel T3SS inhibitors A10, A12 and A20 significantly inhibited the hpa1 promoter activity without affecting Xoo growth. Further studies revealed that the title compounds A10, A12 and A20 significantly impaired hypersensitivity in non-host plant tobacco leaves, while applications on rice significantly reduced symptoms of bacterial leaf blight. RT-PCR showed that compound A20 inhibited the expression of T3SS-related genes. In summary, this work exemplifies the potential of the title compound as an inhibitor of T3SS and its efficacy in the control of bacterial leaf blight.

Design and Development of COX-II Inhibitors: Current Scenario and Future Perspective

Innate inflammation beyond a threshold is a significant problem involved in cardiovascular diseases, cancer, and many other chronic conditions. Cyclooxygenase (COX) enzymes are key inflammatory markers as they catalyze prostaglandins production and are crucial for inflammation processes. While COX-I is constitutively expressed and is generally involved in "housekeeping" roles, the expression of the COX-II isoform is induced by the stimulation of different inflammatory cytokines and also promotes the further generation of pro-inflammatory cytokines and chemokines, which affect the prognosis of various diseases. Hence, COX-II is considered an important therapeutic target for drug development against inflammation-related illnesses. Several selective COX-II inhibitors with safe gastric safety profiles features that do not cause gastrointestinal complications associated with classic anti-inflammatory drugs have been developed. Nevertheless, there is mounting evidence of cardiovascular side effects from COX-II inhibitors that resulted in the withdrawal of market-approved anti-COX-II drugs. This necessitates the development of COX-II inhibitors that not only exhibit inhibit potency but also are free of side effects. Probing the scaffold diversity of known inhibitors is vital to achieving this goal. A systematic review and discussion on the scaffold diversity of COX inhibitors are still limited. To address this gap, herein we present an overview of chemical structures and inhibitory activity of different scaffolds of known COX-II inhibitors. The insights from this article could be helpful in seeding the development of next-generation COX-II inhibitors.

Natural-Derived COX-2 Inhibitors as Anticancer Drugs: A Review of their Structural Diversity and Mechanism of Action

Cyclooxygenase-2 (COX-2) is a key-type enzyme playing a crucial role in cancer development, making it a target of high interest for drug designers. In the last two decades, numerous selective COX-2 inhibitors have been approved for various clinical conditions. However, data from clinical trials propose that the prolonged use of COX-2 inhibitors is associated with life-threatening cardiovascular side effects. The data indicate that a slight structural modification can help develop COX-2 selective inhibitors with comparative efficacy and limited side effects. In this regard, secondary metabolites from natural sources offer great hope for developing novel COX-2 inhibitors with potential anticancer activity. In recent years, various nature-derived organic scaffolds are being explored as leads for developing new COX-2 inhibitors. The current review attempts to highlight the COX-2 inhibition activity of some naturally occurring secondary metabolites, concerning their capacity to inhibit COX-1 and COX-2 enzymes and inhibit cancer development, aiming to establish a structure-activity relationship.

Polyphenols: Chemoprevention and therapeutic potentials in hematological malignancies

Polyphenols are one of the largest plant-derived natural product and they play an important role in plants' defense as well as in human health and disease. A number of them are pleiotropic molecules and have been shown to regulate signaling pathways, immune response and cell growth and proliferation which all play a role in cancer development. Hematological malignancies on the other hand, are cancers of the blood. While current therapies are efficacious, they are usually expensive and with unwanted side effects. Thus, the search for newer less toxic agents. Polyphenols have been reported to possess antineoplastic properties which include cell cycle arrest, and apoptosis via multiple mechanisms. They also have immunomodulatory activities where they enhance T cell activation and suppress regulatory T cells. They carry out these actions through such pathways as PI3K/Akt/mTOR and the kynurenine. They can also reverse cancer resistance to chemotherapy agents. In this review, i look at some of the molecular mechanism of action of polyphenols and their potential roles as therapeutic agents in hematological malignancies. Here i discuss their anti-proliferative and anti-neoplastic activities especially their abilities modulate signaling pathways as well as immune response in hematological malignancies. I also looked at clinical studies done mainly in the last 10-15 years on various polyphenol combination and how they enhance synergism. I recommend that further preclinical and clinical studies be carried out to ensure safety and efficacy before polyphenol therapies be officially moved to the clinics.

Synthesis of mitochondria-targeted ferulic acid amide derivatives with antioxidant, anti-inflammatory activities and inducing mitophagy

The seventeen ferulic acid amide derivatives were synthesized by coupling mitochondrial carrier coumarin-3-carboxamide with acrylic acids. The results of cellular antioxidant activity and inhibitory effects on NO production against LPS-stimulated RAW264.7 macrophages indicated four compounds (8c, 8d, 9c, 9d) showed the higher dual-activities of antioxidant and anti-inflammatory. The structure-activity relationship was deduced. In regard to mechanism research, the most potent compound 8d which mainly distributed in mitochondria suppressed the secretion of inflammatory cytokines IL-6 and TNF-α, enhancing mitophagy to alleviate inflammatory response. Besides, the dual-activities were diminished by removal of coumarin carrier in 8d, suggesting the enrichment in mitochondria might be important for activities. This study showed that development of mitochondria-targeted antioxidants could be a feasible strategy to resist inflammation.

Design, Synthesis and Anti-Tumor Activity Evaluation of Novel 3,4-(Methylenedioxy)cinnamic Acid Amide-Dithiocarbamate Derivatives

The fragments, 3,4-(methylenedioxy)cinnamic acid amide and dithiocarbamates, have received increasing attention because of their multiple pharmacological activities in recent years, especially in anti-tumor. We synthesized 17 novel 3,4-(methylenedioxy)cinnamic acid amide-dithiocarbamate derivatives based on the principle of pharmacophore assembly and discovered that compound 4a₇ displayed the most potent antiproliferative activity against HeLa cells with IC₅₀ value of 1.01 μM. Further mechanistic studies revealed that 4a₇ triggered apoptosis in HeLa cells via activating mitochondria-mediated intrinsic pathways and effectively inhibited colony formation. Also, 4a₇ had the ability to arrest cell cycle in the G2/M phase as well as to inhibit the migration in HeLa cells. More importantly, acute toxicity experiments showed that 4a₇ had good safety in vivo. All the results suggested that compound 4a₇ might serve as a promising lead compound that merited further attention in future anti-tumor drug discovery.

Immunomodulatory effect of metabolites from digested and fermented fractions from irradiated pineapple (Annanas comosus L.) snack-bars

Phenolic compounds (PC), can modulate the immune response. UV-C irradiation, commonly used as a minimal processing method in fresh-foods to reduce the microbial load, increase shelf-life, provide a minimal processing and facilitate the release of PC. This study aimed to evaluate the effect of intestinal (IF) and fermented (FF) fractions of non-irradiated (NIPB) and irradiated (IPB) pineapple snack-bars on the production of nitric oxide (NO), interleukin 6 (IL-6), cyclooxygenase 2 (COX-2), and tumor necrosis factor-alpha (TNF-α) in mice macrophages. IF of NIPB and IPB exerted an immunomodulatory effect by promoting the production of NO (26 pg/mL) in both treatments, COX-2 (438 and 399 pg/mL), and TNF-α (778 and 802 pg/mL) for NIPB and IPB respectively. The TNF-α increased in IF of NIPB and IPB approximately 371 %, and in FF, only increased 132 %. The NO production was not different between IF and FF. COX-2 production was higher in FF.

Potential of Caffeic Acid Derivatives as Antimalarial Leads

Background:

Background Malaria remained one of the deadliest infectious diseases in 2021. Indeed, this infection, mostly caused by a protozoan called Plasmodium falciparum, is responsible for more than 200 million cases and around 400 000 related deaths annually, mainly in Africa. Despite the availability of efficient drugs, an increase of patients has occurred since 2015, which could be due to the development of resistances from the parasite, but also from its vectors, Anopheles mosquitoes. Consequently, it is necessary to search for new alternative treatments.

Methods:

Methods Polyphenols, and more precisely small phenolic acids, could represent a good starting point for new antimalarials. Indeed, these molecules, including caffeic acid (1), possess several pharmacological activities and an interesting pharmacokinetic profile. Therefore, we have developed several small derivatives of this scaffold to define the potential pharmacophore responsible for the antiplasmodial properties

Results:

Results A good to low activity on Plasmodium falciparum (IC50 = 16-241 µM) was observed, especially for the small ester derivatives (2-6). These molecules were good antiplasmodials compared to their mother compound (IC50 = 80 µM) and showed selectivity against human cells. These structures have also highlighted the need for catechol and carboxyl moieties in the anti-Plasmodium effect.

Conclusion:

Conclusion None of the synthetic caffeate derivatives reported here seemed sufficiently effective to become a potential antimalarial (IC50 < 1 µM). However, the significant increase of their efficacy on the malarial agent and the selectivity to human cells, highlighted their potential as new leads for future developments

Synthesis and Evaluation of Bakuchiol Derivatives as Potent Anti-inflammatory Agents in Vitro and in Vivo

Bakuchiol, a prenylated phenolic monoterpene derived from the fruit of Psoralen corylifolia L. (Buguzhi), is widely used to treat tumors, viruses, inflammation, and bacterial infections. In this study, we designed and synthesized 30 bakuchiol derivatives to identify new anti-inflammatory drugs. The anti-inflammatory activities of the derivatives were screened using lipopolysaccharide-induced RAW264.7 cells. To evaluate the anti-inflammatory activity of the compounds, we measured nitric oxide (NO), interleukin-6, and tumor necrosis factor-α production. Based on the screening results, compound 7a displayed more pronounced activity than bakuchiol and celecoxib. Furthermore, the mechanistic studies indicated that 7a inhibited pro-inflammatory cytokine release, which was correlated with activation of the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 signaling pathway and blockade of the nuclear factor-κB/mitogen-activated protein kinase signaling pathway. The in vivo anti-inflammatory activity in zebrafish indicated that 7a inhibited NO and reactive oxygen species production in a dose-dependent manner. These results indicate that 7a is a potential candidate for development as an anti-inflammatory agent.

Recent development on COX-2 inhibitors as promising anti-inflammatory agents: The past 10 years

Cyclooxygenases play a vital role in inflammation and are responsible for the production of prostaglandins. Two cyclooxygenases are described, the constitutive cyclooxygenase-1 and the inducible cyclooxygenase-2, for which the target inhibitors are the non-steroidal anti-inflammatory drugs (NSAIDs). Prostaglandins are a class of lipid compounds that mediate acute and chronic inflammation. NSAIDs are the most frequent choices for treatment of inflammation. Nevertheless, currently used anti-inflammatory drugs have become associated with a variety of adverse effects which lead to diminished output even market withdrawal. Recently, more studies have been carried out on searching novel selective COX-2 inhibitors with safety profiles. In this review, we highlight the various structural classes of organic and natural scaffolds with efficient COX-2 inhibitory activity reported during 2011–2021. It will be valuable for pharmaceutical scientists to read up on the current chemicals to pave the way for subsequent research.

Design, Synthesis, and In Vitro and In Vivo Biological Evaluation of Limonin Derivatives for Anti-Inflammation Therapy

In this study, limonin derivatives were used to design new anti-inflammatory compounds with high pharmacological activity and low toxicity. A total of 23 new limonin derivatives were discovered, synthesized, and screened for their anti-inflammatory activity against lipopolysaccharide (LPS)-treated RAW 264.7 cells. Of them, compound f4 was found to be the most active, with a higher efficiency compared with limonin and celecoxib. Subsequently, we studied the mechanism underlying the activity of f4 and found that it inhibited proinflammatory cytokines by blocking the NF-κB/MAPK signaling pathway in LPS-treated RAW 264.7 cells as well as mice. In conclusion, f4 may be a promising anti-inflammatory lead compound.

Preliminary Assessment of the Anti-inflammatory Activity of New Structural Honokiol Analogs with a 4'-O-(2-Fluoroethyl) Moiety and the Potential of Their 18F-Labeled Derivatives for Neuroinflammation Imaging

Neolignans honokiol and 4′-O-methylhonokiol (MH) and their derivatives have pronounced anti-inflammatory activity, as evidenced by numerous pharmacological studies. Literature data suggested that cyclooxygenase type 2 (COX-2) may be a target for these compounds in vitro and in vivo. Recent studies of [¹¹C]MPbP (4′-[¹¹C]methoxy-5-propyl-1,1′-biphenyl-2-ol) biodistribution in LPS (lipopolysaccharide)-treated rats have confirmed the high potential of MH derivatives for imaging neuroinflammation. Here, we report the synthesis of four structural analogs of honokiol, of which 4′-(2-fluoroethoxy)-2-hydroxy-5-propyl-1, 1′-biphenyl (F-IV) was selected for labeling with fluorine-18 (T_1/2 = 109.8 min) due to its high anti-inflammatory activity confirmed by enzyme immunoassays (EIA) and neuromorphological studies. The high inhibitory potency of F-IV to COX-2 and its moderate lipophilicity and chemical stability are favorable factors for the preliminary evaluation of the radioligand [¹⁸F]F-IV in a rodent model of neuroinflammation. [¹⁸F]F-IV was prepared with good radiochemical yield and high molar activity and radiochemical purity by ¹⁸F-fluoroethylation of the precursor with Boc-protecting group (15) with [¹⁸F]2-fluoro-1-bromoethane ([¹⁸F]FEB). Ex vivo biodistribution studies revealed a small to moderate increase in radioligand uptake in the brain and peripheral organs of LPS-induced rats compared to control animals. Pretreatment with celecoxib resulted in significant blocking of radioactivity uptake in the brain (pons and medulla), heart, lungs, and kidneys, indicating that [¹⁸F]F-IV is likely to specifically bind to COX-2 in a rat model of neuroinflammation. However, in comparison with [¹¹C]MPbP, the new radioligand showed decreased brain uptake in LPS rats and high retention in the blood pool, which apparently could be explained by its high plasma protein binding. We believe that the structure of [¹⁸F]F-IV can be optimized by replacing the substituents in the biphenyl core to eliminate these disadvantages and develop new radioligands for imaging activated microglia.

Small molecule compounds with good anti-inflammatory activity reported in the literature from 01/2009 to 05/2021: a review

Inflammation and disease are closely related. Inflammation can induce various diseases, and diseases can promote inflammatory response, and two possibly induces each other in a bidirectional loop. Inflammation is usually treated using synthetic anti-inflammatory drugs which are associated with several adverse effects hence are not safe for long-term use. Therefore, there is need for anti-inflammatory drugs which are not only effective but also safe. Several researchers have devoted to the research and development of effective anti-inflammatory drugs with little or no side effects. In this review, we studied some small molecules with reported anti-inflammatory activities and hence potential sources of anti-inflammatory agents. The information was retrieved from relevant studies published between January 2019 and May, 2021 for review. This review study was aimed to provide relevant information towards the design and development of effective and safe anti-inflammation agents.

Determination of phenolic profiles of Herniaria polygama and Herniaria incana fractions and their in vitro antioxidant and anti-inflammatory effects

The study is based on phytochemical profiling and in vitro evaluation of biological effects of phenolic acid derivatives-rich Herniaria fractions, isolated from two rupturewort (Herniaria L.) species, i.e. Herniaria incana Lam. (syn. H. besseri Fisch. ex Hornem) and H. polygama J. Gay (syn. H. odorata). For the first time, the composition of phenolic compounds of these species was extensively evaluated by both LC-HR-QTOF-ESI-MS and Nuclear Magnetic Resonance spectroscopy (NMR). LC-MS analyses of H. polygama revealed 72 tentatively identified compounds, while H. incana - 63. Only 8% of the metabolites reported in this work have been previously described for Herniaria spp. Most of the identified specialized metabolites were cinnamic and benzoic acid derivatives. Phenolic fraction of H. incana herb contained flavonoids as well. A multi-step chromatographic separation of phenolic fractions from H. polygama yielded three known cinnamic and one benzoic acid derivates, and from H. incana - 4 known flavonoids and one previously undescribed, i.e. rhamnocitrin-3-O-[3-hydroxy-3-methylglutaryl-(1 → 6'')]-[α-rhamnopyranosyl-(1 → 2'')]-β-glucopyranoside. Antioxidant properties of the examined fractions (1-50 μg/ml) were assessed in human blood plasma under the conditions of peroxynitrite-induced oxidative stress. Measurements of well-known biomarkers such as 3-nitrotyrosine, protein thiol groups, thiobarbituric acid-reactive substances and the ferric reducing ability of blood plasma revealed the protective effect of Herniaria fractions against oxidative damage to blood plasma components. Furthermore, the examined fractions effectively ameliorated the inflammatory response of the concanavalin A-stimulated human peripheral blood mononuclear cells (PBMCs). Additionally, cellular safety of the fractions was confirmed in PBMCs.

Pyridine Scaffolds, Phenols and Derivatives of Azo Moiety: Current Therapeutic Perspectives

Synthetic heterocyclic compounds have incredible potential against different diseases; pyridines, phenolic compounds and the derivatives of azo moiety have shown excellent antimicrobial, antiviral, antidiabetic, anti-melanogenic, anti-ulcer, anticancer, anti-mycobacterial, anti-inflammatory, DNA binding and chemosensing activities. In the present review, the above-mentioned activities of the nitrogen-containing heterocyclic compounds (pyridines), hydroxyl (phenols) and azo derivatives are discussed with reference to the minimum inhibitory concentration and structure–activity relationship, which clearly indicate that the presence of nitrogen in the phenyl ring; in addition, the hydroxyl substituent and the incorporation of a diazo group is crucial for the improved efficacies of the compounds in probing different diseases. The comparison was made with the reported drugs and new synthetic derivatives that showed recent therapeutic perspectives made in the last five years.

Diaryl azo derivatives as anti-diabetic and antimicrobial agents: synthesis, in vitro, kinetic and docking studies

In the present study, a series of azo derivatives (TR-1 to TR-9) have been synthesised via the diazo-coupling approach between substituted aromatic amines with phenol or naphthol derivatives. The compounds were evaluated for their therapeutic applications against alpha-glucosidase (anti-diabetic) and pathogenic bacterial strains E. coli (gram-negative), S. aureus (gram-positive), S. aureus (gram-positive) drug-resistant strain, P. aeruginosa (gram-negative), P. aeruginosa (gram-negative) drug-resistant strain and P. vulgaris (gram-negative). The IC₅₀ (µg/mL) of TR-1 was found to be most effective (15.70 ± 1.3 µg/mL) compared to the reference drug acarbose (21.59 ± 1.5 µg/mL), hence, it was further selected for the kinetic studies in order to illustrate the mechanism of inhibition. The enzyme inhibitory kinetics and mode of binding for the most active inhibitor (TR-1) was performed which showed that the compound is a non-competitive inhibitor and effectively inhibits the target enzyme by binding to its binuclear active site reversibly.

New benzamide derivatives and their nicotinamide/cinnamamide analogs as cholinesterase inhibitors

In this study, a total of 18 new benzamide/ nicotinamide/ cinnamamide derivative compounds were designed and synthesized for the first time (except B1 and B5) by conventional and microwave irradiation methods. The chemical structures of the synthesized compounds were characterized by ¹H NMR, ¹³C NMR, and HRMS spectra. In vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibition effects of the compounds were evaluated to find out new possible drug candidate molecule/s. According to the inhibition results, the IC50 values of the compounds synthesized were in the range of 10.66-83.03 nM towards AChE, while they were in the range of 32.74-66.68 nM towards BuChE. Tacrine was used as the reference drug and its IC50 values were 20.85 nM and 15.66 nM towards AChE and BuChE, respectively. The most active compounds B4 (IC50: 15.42 nM), N4 (IC50: 12.14 nM), and C4 (IC50: 10.67 nM) in each series towards AChE were docked at the binding site of AChE enzyme to explain the inhibitory activities of each series. On the other hand, the compounds B4, N4, and C4 showed satisfactory pharmacokinetic properties via the prediction of ADME profiles.

Cinnamic Acid Derivatives and Their Biological Efficacy

The role played by cinnamic acid derivatives in treating cancer, bacterial infections, diabetes and neurological disorders, among many, has been reported. Cinnamic acid is obtained from cinnamon bark. Its structure is composed of a benzene ring, an alkene double bond and an acrylic acid functional group making it possible to modify the aforementioned functionalities with a variety of compounds resulting in bioactive agents with enhanced efficacy. The nature of the substituents incorporated into cinnamic acid has been found to play a huge role in either enhancing or decreasing the biological efficacy of the synthesized cinnamic acid derivatives. Some of the derivatives have been reported to be more effective when compared to the standard drugs used to treat chronic or infectious diseases in vitro, thus making them very promising therapeutic agents. Compound 20 displayed potent anti-TB activity, compound 27 exhibited significant antibacterial activity on S. aureus strain of bacteria and compounds with potent antimalarial activity are 35a, 35g, 35i, 36i, and 36b. Furthermore, compounds 43d, 44o, 55g–55p, 59e, 59g displayed potent anticancer activity and compounds 86f–h were active against both hAChE and hBuChE. This review will expound on the recent advances on cinnamic acid derivatives and their biological efficacy.