Exploration of isoxazole analogs: Synthesis, COX inhibition, anticancer screening, 3D multicellular tumor spheroids, and molecular modeling.

In this study, a new series of Isoxazole-carboxamide derivatives were synthesized and characterized via HRMS, 1H-, 13CAPT-NMR, and MicroED. The findings revealed that nearly all of the synthesized derivatives exhibited potent inhibitory activities against both COX enzymes, with IC50 values ranging from 4.1 nM to 3.87 µM. Specifically, MYM1 demonstrated the highest efficacy among the compounds tested against the COX-1, displaying an IC50 value of 4.1 nM. The results showed that 5 compounds possess high COX-2 isozyme inhibitory effects with IC50 value in range 0.24-1.30 µM with COX-2 selectivity indexes (2.51-6.13), among these compounds MYM4 has the lowest IC50 value against COX-2, with selectivity index around 4. Intriguingly, this compound displayed significant antiproliferative effects against CaCo-2, Hep3B, and HeLa cancer cell lines, with IC50 values of 10.22, 4.84, and 1.57 µM, respectively, which was nearly comparable to that of doxorubicin. Compound MYM4 showed low cytotoxic activities on normal cell lines LX-2 and Hek293t with IC50 values 20.01 and 216.97 µM respectively, with safer values than doxorubicin. Furthermore, compound MYM4 was able to induce the apoptosis, suppress the colonization of both HeLa and HepG2 cells. Additionally, the induction of Reactive oxygen species (ROS) production could be the mechanism underlying the apoptotic effect and the cytotoxic activity of the compound. In the 3D multicellular tumor spheroid model, results revealed that MYM4 compound hampered the spheroid formation capacity of Hep3B and HeLa cancer cells. Moreover, the molecular docking of MYM4 compound revealed a high affinity for the COX2 enzyme, with energy scores (S) -7.45 kcal/mol, which were comparable to celecoxib (S) -8.40 kcal/mol. Collectively, these findings position MYM4 as a promising pharmacological candidate as COX inhibitor and anticancer agent.

Cyclooxygenase products contribute to the exaggerated exercise pressor reflex evoked by static muscle contraction in male UCD-type 2 diabetes mellitus rats.

Cyclooxygenase (COX) products of arachidonic acid metabolism, specifically prostaglandins, play a role in evoking and transmitting the exercise pressor reflex in health and disease. Individuals with type 2 diabetes mellitus (T2DM) have an exaggerated exercise pressor reflex; however, the mechanisms for this exaggerated reflex are not fully understood. We aimed to determine the role played by COX products in the exaggerated exercise pressor reflex in T2DM rats. The exercise pressor reflex was evoked by static muscle contraction in unanesthetized, decerebrate, male, adult University of California Davis (UCD)-T2DM (n = 8) and healthy Sprague-Dawley (n = 8) rats. Changes (Δ) in peak mean arterial pressure (MAP) and heart rate (HR) during muscle contraction were compared before and after intra-arterial injection of indomethacin (1 mg/kg) into the contracting hindlimb. Data are presented as means ± SD. Inhibition of COX activity attenuated the exaggerated peak MAP (Before: Δ32 ± 13 mmHg and After: Δ18 ± 8 mmHg; P = 0.004) and blood pressor index (BPi) (Before: Δ683 ± 324 mmHg·s and After: Δ361 ± 222 mmHg·s; P = 0.006), but not HR (Before: Δ23 ± 8 beats/min and After Δ19 ± 10 beats/min; P = 0.452) responses to muscle contraction in T2DM rats. In healthy rats, COX activity inhibition did not affect MAP, HR, or BPi responses to muscle contraction. Inhibition of COX activity significantly reduced local production of prostaglandin E2 in T2DM and healthy rats. We conclude that peripheral inhibition of COX activity attenuates the pressor response to muscle contraction in T2DM rats, suggesting that COX products partially contribute to the exaggerated exercise pressor reflex in those with T2DM.NEW & NOTEWORTHY We compared the pressor and cardioaccelerator responses to static muscle contraction before and after inhibition of cyclooxygenase (COX) activity within the contracting hindlimb in decerebrate, unanesthetized type 2 diabetic mellitus (T2DM) and healthy rats. The pressor responses to muscle contraction were attenuated after peripheral inhibition of COX activity in T2DM but not in healthy rats. We concluded that COX products partially contribute to the exaggerated pressor reflex in those with T2DM.

Dihydroartemisinin, a potential PTGS1 inhibitor, potentiated cisplatin-induced cell death in non-small cell lung cancer through activating ROS-mediated multiple signaling pathways.

Dihydroartemisinin (DHA) exerts an anti-tumor effect in multiple cancers, however, the molecular mechanism of DHA and whether DHA facilitates the anti-tumor efficacy of cisplatin in non-small cell lung cancer (NSCLC) are unclear. Here, we found that DHA potentiated the anti-tumor effects of cisplatin in NSCLC cells by stimulating reactive oxygen species (ROS)-mediated endoplasmic reticulum (ER) stress, C-Jun-amino-terminal kinase (JNK) and p38 MAPK signaling pathways both in vitro and in vivo. Of note, we demonstrated for the first time that DHA inhibits prostaglandin G/H synthase 1 (PTGS1) expression, resulting in enhanced ROS production. Importantly, silencing PTGS1 sensitized DHA-induced cell death by increasing ROS production and activating ER-stress, JNK and p38 MAPK signaling pathways. In summary, our findings provided new experimental basis and therapeutic prospect for the combined therapy with DHA and cisplatin in some NSCLC patients.

Differential roles of cyclooxygenase enzymes in the regulation of murine juvenile undifferentiated spermatogonia.

BACKGROUND: Acetaminophen and ibuprofen are widely administered to babies due to their presumed safety as over-the-counter drugs. However, no reports exist on the effects of cyclooxygenase inhibitors on undifferentiated spermatogonia and spermatogonial stem cells. Infancy represents a critical period for spermatogonial stem cell formation and disrupting spermatogonial stem cells or their precursors may be associated with infertility and testicular cancer formation. OBJECTIVES: The goal of this study was to examine the molecular and functional impact of cyclooxygenase inhibition and silencing on early steps of undifferentiated spermatogonia (u spg) and spermatogonial stem cell development, to assess the potential reproductive risk of pharmaceutical cyclooxygenase inhibitors. METHODS: The effects of cyclooxygenase inhibition were assessed using the mouse C18-4 undifferentiated juvenile spermatogonial cell line model, previously shown to include cells with spermatogonial stem cell features, by measuring prostaglandins, cell proliferation, and differentiation, using cyclooxygenase 1- and cyclooxygenase 2-selective inhibitors NS398, celecoxib, and FR122047, acetaminophen, and ibuprofen. Cyclooxygenase 1 gene silencing was achieved using a stable short-hairpin RNA approach and clone selection, then assessing gene and protein expression in RNA sequencing, quantitative real-time polymerase chain reaction, and immunofluorescence studies. RESULTS: Cyclooxygenase 2 inhibitors NS398 and celecoxib, as well as acetaminophen, but not ibuprofen, dose-dependently decreased retinoic acid-induced expression of the spg differentiation gene Stra8, while NS398 decreased the spg differentiation marker Kit, suggesting that cyclooxygenase 2 is positively associated with spg differentiation. In contrast, short-hairpin RNA-based cyclooxygenase 1 silencing in C18-4 cells altered cellular morphology and upregulated Stra8 and Kit, implying that cyclooxygenase 1 prevented spg differentiation. Furthermore, RNA sequencing analysis of cyclooxygenase 1 knockdown cells indicated the activation of several signaling pathways including the TGFb, Wnt, and Notch pathways, compared to control C18-4 cells. Notch pathway genes were upregulated by selective cyclooxygenase inhibitors, acetaminophen and ibuprofen. CONCLUSION: We report that cyclooxygenase 1 and 2 differentially regulate undifferentiated spermatogonia/spermatogonial stem cell differentiation. Cyclooxygenases regulate Notch3 expression, with the Notch pathway targeted by PGD2. These data suggest an interaction between the eicosanoid and Notch signaling pathways that may be critical for the development of spermatogonial stem cells and subsequent spermatogenesis, cautioning about using cyclooxygenase inhibitors in infants.

An in vivo drug screen in zebrafish reveals that cyclooxygenase 2-derived prostaglandin D2 promotes spinal cord neurogenesis.

The study of neurogenesis is essential to understanding fundamental developmental processes and for the development of cell replacement therapies for central nervous system disorders. Here, we designed an in vivo drug screening protocol in developing zebrafish to find new molecules and signalling pathways regulating neurogenesis in the ventral spinal cord. This unbiased drug screen revealed that 4 cyclooxygenase (COX) inhibitors reduced the generation of serotonergic interneurons in the developing spinal cord. These results fitted very nicely with available single-cell RNAseq data revealing that floor plate cells show differential expression of 1 of the 2 COX2 zebrafish genes (ptgs2a). Indeed, several selective COX2 inhibitors and two different morpholinos against ptgs2a reduced the number of serotonergic neurons in the ventral spinal cord and led to locomotor deficits. Single-cell RNAseq data and different pharmacological manipulations further revealed that COX2-floor plate-derived prostaglandin D2 promotes neurogenesis in the developing spinal cord by promoting mitotic activity in progenitor cells. Rescue experiments using a phosphodiesterase-4 inhibitor suggest that intracellular changes in cAMP levels underlie the effects of COX inhibitors on neurogenesis and locomotion. Our study provides compelling in vivo evidence showing that prostaglandin signalling promotes neurogenesis in the ventral spinal cord.

Preparation and characterization of a curcumin nanoemulsion gel for the effective treatment of mycoses.

Fungal infections of skin including mycoses are one of the most common infections in skin or skins. Mycosis is caused by dermatophytes, non-dermatophyte moulds and yeasts. Various studies show different drugs to treat mycoses, yet there is need to treat it with applied drugs delivery. This study was designed to prepare a bio curcumin (CMN) nanoemulsion (CMN-NEs) for transdermal administration to treat mycoses. The self-nanoemulsification approach was used to prepare a nanoemulsion (NE), utilizing an oil phase consisting of Cremophor EL 100 (Cre EL), glyceryl monooleate (GMO), and polyethylene glycol 5000 (PEG 5000). Particle size (PS), polydispersity index (PDI), zeta potential (ZP), Fourier transform infrared (FTIR) spectrophotometric analysis, and morphological analyses were performed to evaluate the nanoemulsion (NE). The in vitro permeation of CMN was investigated using a modified vertical diffusion cell with an activated dialysis membrane bag. Among all the formulations, a stable, spontaneously produced nanoemulsion was determined with 250 mg of CMN loaded with 10 g of the oil phase. The average droplet size, ZP, and PDI of CMN-NEs were 90.0 ± 2.1 nm, - 7.4 ± 0.4, and 0.171 ± 0.03 mV, respectively. The release kinetics of CMN differed from zero order with a Higuchi release profile as a result of nanoemulsification, which also significantly increased the flux of CMN permeating from the hydrophilic matrix gel. Overall, the prepared nanoemulsion system not only increased the permeability of CMN but also protected it against chemical deterioration. Both CMN-ME (24.0 ± 0.31 mm) and CMN-NE gel (29.6 ± 0.25 mm) had zones of inhibition against Candida albicans that were significantly larger than those of marketed Itrostred gel (21.5 ± 0.34 mm). The prepared CMN-NE improved the bioavailability, better skin penetration, and the CMN-NE gel enhanced the release of CMN from the gel matrix on mycotic patients.

Discovery of (S)-flurbiprofen-based novel azine derivatives as prostaglandin endoperoxide synthase-II inhibitors: Synthesis, in-vivo analgesic, anti-inflammatory activities, and their molecular docking.

The anti-inflammatory and analgesic drugs currently used are associated with several adverse effects and found to be highly unsafe for long-term use. Currently, nineteen novel bis-Schiff base derivatives (1-19) of flurbiprofen have been designed, prepared and assessed for in-vivo analgesic, anti-inflammatory and in vivo acute toxicity evaluation. The structures of the acquired compounds were deduced through modern spectroscopic techniques including HR-ESI-MS, 13C-, and 1H NMR. Amongst the series, compounds 7, 9, and 10 attributed potent activities with 93.89, 92.50, and 90.47% decreased edema, respectively compared to flurbiprofen (90.01%), however, compounds 11 and 15 exhibited significant activity of 90.00% decrease. Out of them, fourteen compounds (1-6, 8, 12-14, and 16-19) displayed good activity in the range of 68.96-86.95%. In case of an analgesic study, all the derivatives significantly (p 0.001) increased the pain threshold time particularly compound 7 had the best analgesic effect (24 ± 2.08 s) in comparison with flurbiprofen (21.66 ± 2.02 s) using hot plate test. Similarly, in the acetic acid-induced writhing test, compound 7 determined a potent inhibitory effect (60.47 %) close to flurbiprofen (59.28%). All the synthesized derivatives were found safe up to the dose of 30 mg/kg, in acute toxicity study. On a molecular scale, the synthesized compounds were modeled through a ligand-based pharmacophore study and molecular docking to have insight into the different possible interactions leading to high inhibition levels against the COX-2 enzyme.

m-Terphenylamines, Acting as Selective COX-1 Inhibitors, Block Microglia Inflammatory Response and Exert Neuroprotective Activity.

Inhibition of cyclooxygenase-2 (COX-2) has been extensively studied as an approach to reduce proinflammatory markers in acute brain diseases, but the anti-neuroinflammatory role of cyclooxygenase-1 (COX-1) inhibition has been rather neglected. We report that m-terphenylamine derivatives are selective COX-1 inhibitors, able to block microglia inflammatory response and elicit a neuroprotective effect. These compounds were synthesized via a three-component reaction of chalcones, ß-ketoesters, and primary amines, followed by hydrolysis/decarboxylation of the ester group. Together with their synthetic intermediates and some urea derivatives, they were studied as inhibitors of COX-1 and COX-2. The m-terphenylamine derivatives, which were selective COX-1 inhibitors, were also analyzed for their ability to block microglia inflammatory and oxidative response. Compound 3b presented an interesting anti-inflammatory and neuroprotective profile by reducing nitrite release, ROS overproduction, and cell death in organotypic hippocampal cultures subjected to LPS. We thus show that COX-1 inhibition is a promising approach to provide enhanced neuroprotection against acute inflammatory processes, which are crucial in the development of a plethora of acute neurodegenerative injuries.

Synthesis, Biological, Spectroscopic and Computational Investigations of Novel N-Acylhydrazone Derivatives of Pyrrolo[3,4-d]pyridazinone as Dual COX/LOX Inhibitors.

Secure and efficient treatment of diverse pain and inflammatory disorders is continually challenging. Although NSAIDs and other painkillers are well-known and commonly available, they are sometimes insufficient and can cause dangerous adverse effects. As yet reported, derivatives of pyrrolo[3,4-d]pyridazinone are potent COX-2 inhibitors with a COX-2/COX-1 selectivity index better than meloxicam. Considering that N-acylhydrazone (NAH) moiety is a privileged structure occurring in many promising drug candidates, we decided to introduce this pharmacophore into new series of pyrrolo[3,4-d]pyridazinone derivatives. The current paper presents the synthesis and in vitro, spectroscopic, and in silico studies evaluating the biological and physicochemical properties of NAH derivatives of pyrrolo[3,4-d]pyridazinone. Novel compounds 5a-c-7a-c were received with high purity and good yields and did not show cytotoxicity in the MTT assay. Their COX-1, COX-2, and 15-LOX inhibitory activities were estimated using enzymatic tests and molecular docking studies. The title N-acylhydrazones appeared to be promising dual COX/LOX inhibitors. Moreover, spectroscopic and computational methods revealed that new compounds form stable complexes with the most abundant plasma proteins-AAG and HSA, but do not destabilize their secondary structure. Additionally, predicted pharmacokinetic and drug-likeness properties of investigated molecules suggest their potentially good membrane permeability and satisfactory bioavailability.

Comparative study of piroxicam and nitroglycerin on prostaglandin-modulated blood and electrolyte indices during di-estrous in female Wistar Rats.

OBJECTIVE: Endogenous prostaglandins are involved in hemostasis, renal excretion of electrolytes, and implicated in dysmenorrhea. Piroxicam and Nitroglycerin are common drugs used in treating dysmenorrhea by inhibiting the cyclooxygenase pathway involved in prostaglandin production. However, studies comparing the effects of these drugs on prostaglandin-modulated hemostasis and renal function are lacking. METHODS: Fifteen female rats (120-160g) were divided into 3 groups (20 per group), namely Control (distilled water, 0.3 mL), Piroxicam treated (3mg/kg) and Nitroglycerin treated (1 mg/kg). Di-estrous phase was confirmed in animals in each group using the Pipette smear method. Treatment was administered for 4 days covering the estrous cycle. Bleeding and clotting time were assessed and blood concentrations of sodium, potassium, urea and platelet counts were evaluated in all phases. Data were analyzed using one-way ANOVA and Newman-Keuls post-hoc test. Statistical significance was considered at p<0.0. RESULTS: The nitroglycerin-treated group showed significant increases in blood potassium during di-estrous while the piroxicam-treated group showed significant increases in blood potassium, urea and clotting time with a significant decrease in sodium levels during di-estrous compared to controls. Results obtained in other phases were not significant compared to controls. CONCLUSIONS: The study showed that Nitroglycerin produces minimum alteration of blood and electrolyte indices compared to piroxicam during di-estrous.

Influence of aspirin on aging skeletal muscle: Insights from a cross-sectional cohort of septuagenarians.

Aspirin is one of the most commonly consumed cyclooxygenase (COX)-inhibitors and anti-inflammatory drugs and has been shown to block COX-produced regulators of inflammation and aging skeletal muscle size. We used propensity score matching to compare skeletal muscle characteristics of individuals from the Health ABC study that did not consume aspirin or any other COX-inhibiting drugs (non-consumers, n = 497, 74 ± 3 year, 168 ± 9 cm, 75.1 ± 13.8 kg, 33.1 ± 7.4% body fat, 37% women, 34% black) to those that consumed aspirin daily (and not any other COX-inhibiting drugs) and for at least 1 year (aspirin consumers, n = 515, 74 ± 3 year, 168 ± 9 cm, 76.2 ± 13.6 kg, 33.8 ± 7.1% body fat, 39% women, 30% black, average aspirin consumption: 6 year). Subjects were matched (p > 0.05) based on age, height, weight, % body fat, sex, and race (propensity scores: 0.33 ± 0.09 vs. 0.33 ± 0.09, p > 0.05). There was no difference between non-consumers and aspirin consumers for computed tomography-determined muscle size of the quadriceps (103.5 ± 0.9 vs. 104.9 ± 0.8 cm2 , p > 0.05) or hamstrings (54.6 ± 0.5 vs. 54.9 ± 0.5 cm2 , p > 0.05), or quadriceps muscle strength (111.1 ± 2.0 vs. 111.7 ± 2.0 Nm, p > 0.05). However, muscle attenuation (i.e., density) was higher in the aspirin consumers in the quadriceps (40.9 ± 0.3 vs. 44.4 ± 0.3 Hounsfield unit [HU], p < 0.05) and hamstrings (27.7 ± 0.4 vs. 33.2 ± 0.4 HU, p < 0.05). These cross sectional data suggest that chronic aspirin consumption does not influence age-related skeletal muscle atrophy, but does influence skeletal muscle composition in septuagenarians. Prospective longitudinal investigations remain necessary to better understand the influence of chronic COX regulation on aging skeletal muscle health.

Hybrids of carbonic anhydrase and cyclooxygenase inhibitors attenuate cardiac hypoxic inflammatory injuries.

Cardiac inflammation is easily accompanied by hypoxia, while hypoxia-induced injury and microenvironmental variations limit the efficacy of common anti-inflammatory drugs. In order to effectively attenuate myocardial injury caused by hypoxic and inflammatory injury, we designed and synthesized a kind of anti-inflammatory compounds by coupling cyclooxygenase (COX) and carbonic anhydrase (CA) inhibitors, and evaluated the activity and their mechanism in vitro and in vivo. It was found that these compounds were structurally stable and had two enzymatic inhibition activities. By inhibiting the activity of overexpressed CA under hypoxia, the acidic microenvironment can be regulated to inhibit the hypoxic injury, in which the pH-dependent primary drug resistance can be overcome to improve the anti-inflammatory effect of the COX inhibitor. Consequently, this study provides a new strategy for the treatment of cardiac inflammation accompanied by hypoxia.

Synthesis and in silico studies of some new pyrrolidine derivatives and their biological evaluation for analgesic and anti-inflammatory activity.

BACKGROUND: An array of commercially viable intermediate molecules necessary for the synthesis of a variety of bioactive molecules are chemically synthesized by pyrrolidine and its derivatives, which play a significant role in drug design and development process. AIM: The aim of the present research work was to explore the synthesis of some new pyrrolidine derivatives and to perform their in silico studies and finally evaluation of analgesic and anti-inflammatory activity. OBJECTIVE: The purpose of this study was to synthesis new pyrrolidine derivatives, examine how they affected the COX-1 and COX-2 enzymes computationally, and to screen their in vivo analgesic and anti-inflammatory activity on laboratory animals. METHOD: The new pyrrolidine derivatives were synthesized by condensing N-(3-acetylphenyl)-2-(pyrrolidin-1-yl)acetamide with substituted aniline in ethanol in the presence of catalytic amounts of glacial acetic acid. The structures of novel pyrrolidine derivatives were characterised using IR, NMR, and mass spectroscopy. Several molecular properties of the newly synthesized derivatives were calculated in order to evaluate the nature of the drug-like candidate. A specific reference cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzyme was used to dock the newly synthesized pyrrolidine derivatives. RESULTS: From the observed data, it was noted that amongst all newly synthesized compounds, A-1 and A-4 exhibited the highest anti-inflammatory and analgesic effects, respectively. CONCLUSION: On the basis of findings of present research, it was concluded that A-1 and A-4 might be utilized as a promising new lead compound for Non-Steroidal Anti-Inflammatory Drug (NSAIDs) development.

Solid-Phase Parallel Synthesis of Dual Histone Deacetylase-Cyclooxygenase Inhibitors.

Multi-target drugs (MTDs) are emerging alternatives to combination therapies. Since both histone deacetylases (HDACs) and cyclooxygenase-2 (COX-2) are known to be overexpressed in several cancer types, we herein report the design, synthesis, and biological evaluation of a library of dual HDAC-COX inhibitors. The designed compounds were synthesized via an efficient parallel synthesis approach using preloaded solid-phase resins. Biological in vitro assays demonstrated that several of the synthesized compounds possess pronounced inhibitory activities against HDAC and COX isoforms. The membrane permeability and inhibition of cellular HDAC activity of selected compounds were confirmed by whole-cell HDAC inhibition assays and immunoblot experiments. The most promising dual inhibitors, C3 and C4, evoked antiproliferative effects in the low micromolar concentration range and caused a significant increase in apoptotic cells. In contrast to previous reports, the simultaneous inhibition of HDAC and COX activity by dual HDAC-COX inhibitors or combination treatments with vorinostat and celecoxib did not result in additive or synergistic anticancer activities.

The influence of cyclooxygenase inhibitors on kynurenic acid production in rat kidney: a novel path for kidney protection?

BACKGROUND: Kidney diseases have become a global health problem, affecting about 15% of adults and being often under-recognized. Immunological system activation was shown to accelerate kidney damage even in inherited disorders. The kynurenine pathway is the main route of tryptophan degradation. A metabolite of kynurenine (KYN), kynurenic acid (KYNA), produced by kynurenine aminotransferases (KATs), was reported to affect fluid and electrolyte balance as a result of natriuresis induction. The accumulation of KYNA was shown in patients with impaired kidney function and its level was related to the degree of kidney damage. Cyclooxygenase (COX) inhibitors are well-known analgesics and most of them demonstrate an anti-inflammatory effect. Their main mechanism of action is prostaglandin synthesis blockade, which is also responsible for their nephrotoxic potential. Since the KYN pathway is known to remain under immunological system control, the purpose of this study was to analyze the effect of 9 COX inhibitors on KYNA production together with KATs' activity in rat kidneys in vitro. METHODS: Experiments were carried out on kidney homogenates in the presence of L-KYN and the selected compound in 6 various concentrations. RESULTS: Among the examined COX inhibitors only acetaminophen did not change KYNA production in rat kidneys in vitro. Additionally, acetaminophen did not affect the activity of KAT I and KAT II, whereas acetylsalicylic acid and ibuprofen inhibited only KAT II. The remaining COX inhibitors decreased the activity of both KATs in rat kidneys in vitro. CONCLUSION: Our study provides novel mechanisms of COX inhibitors action in the kidney, with possible implications for the treatment of kidney diseases.

Single or Daily Application of Topical Curcumin Prevents Ultraviolet B-Induced Apoptosis in Mice.

Curcumin is a natural ingredient with antioxidant effects, widely studied as a treatment for various types of cancer. However, its effects on ultraviolet radiation have not been fully explored. The effects of single or daily application of 0.1-100 µM curcumin on cell apoptosis in ultraviolet B (UVB)-induced mice were tested using an experimental double-blind posttest design with a control group and two research models: a single application of curcumin before a single UVB exposure and daily application of curcumin for 7 days before a single UVB exposure on the seventh day. Apoptotic cells were counted using a tunnel system kit. The number of apoptotic cells under a single or daily application of curcumin for 7 days was significantly lower than that of the UVB controls (p ≤ 0.05). The number of apoptotic cells decreased with the increasing concentration of curcumin, and the maximum effect was observed at 100 µM. Daily application of topical curcumin was superior in preventing apoptosis (mean apoptotic cell count of 14.86 ± 1.68) compared with a single application (17.46 ± 0.60; p = 0.011). Topical curcumin can act as a potential photoprotective agent in preventing cutaneous malignancies due to UVB radiation. Further studies are warranted, especially in humans.

Synthesis and characterization of biologically active flurbiprofen amide derivatives as selective prostaglandin-endoperoxide synthase II inhibitors: In vivo anti-inflammatory activity and molecular docking.

A novel series of twenty two flurbiprofen amides (1-22) were designed and synthesized in good to excellent yields by reacting flurbiprofen acid with various aromatic/aliphatic primary amines in the presence of 1,1­carbonyldiimidazole (CDI) in basic medium using acetonitrile as solvent. Structures of the synthesized derivatives were elucidated with the help of HR-ESI-MS, 1H-, and 13C NMR spectroscopy and finally screened them for their in-vivo anti-inflammatory potential using carrageenan induced mice paw oedema assay. Among the series, four compounds (8, 14, 15, and 20) displayed excellent activity ranging from 59.0 to 77.7 % decrease, while eight compounds (1, 3, 7, 10, 12, 13, 17, and 18) exhibited good activity in the decrease range of 37.0-50.0 %. Additionally, four compounds (2, 6, 16, and 22) attributed less activity, while the remaining six compounds (4, 5, 9, 11, 19, and 21) were found to be inactive. Furthermore, the In-silico studies were executed on the synthesized derivatives in order to explain the binding interface of compounds with the active sites of prostaglandin endoperoxide-synthase II enzyme.

Discovery of novel pyrazole and pyrazolo[1,5-a]pyrimidine derivatives as cyclooxygenase inhibitors (COX-1 and COX-2) using molecular modeling simulation.

Searching for effective and selective anti-inflammatory agents, our study involved designing and synthesizing new pyrazole and pyrazolo[1,5-a]pyrimidine derivatives 4-11. The structures of the synthesized derivatives were confirmed using different spectroscopic techniques. Virtual screening was achieved for the newly designed derivatives using in silico docking simulation inside the active sites of four proteins classified as two cyclooxygenases (COX)-1 (PDB: 3KK6 and 4OIZ) and two COX-2 (PBD: 1CX2 and 3LN1). Among them, six derivatives 4c, 5b, 6a, 7a, 7b, and 10b displayed the highest binding energy. These derivatives were evaluated for their in vitro COX-1 and COX-2 inhibitory activities and their selectivity indexes were calculated. Additionally, these derivatives displayed IC50 values ranging between 4.909 ± 0.25 and 57.53 ± 2.91 µM, and 3.289 ± 0.14 and 124 ± 5.32 µM, against COX-1 and COX-2, respectively. Furthermore, the tested derivatives were found to have selective inhibitory activity on the COX-2 enzyme. Surprisingly, the two pyrazole derivatives 4c and 5b were found to be the most active, with IC50 values of 9.835 ± 0.50 and 4.909 ± 0.25 µM and 4.597 ± 0.20 and 3.289 ± 0.14 µM compared with meloxicam (1.879 ± 0.1 and 5.409 ± 0.23 µM) and celecoxib (5.439 ± 0.28 and 2.164 ± 0.09 µM) against COX-1/-2, respectively. Besides, two pyrazole derivatives, 4c and 5b, displayed a COX-1/COX-2 SI of 2.14 and 1.49. Computational techniques such as molecular docking, density function theory (DFT) calculation, and chemical absorption, distribution, metabolism, excretion, and toxicity evaluation were applied to explain the molecules' binding mode, chemical nature, drug likeness, and toxicity prediction.

Aspirin Protects against UVB-Induced DNA Damage through Activation of AMP Kinase.

The anti-inflammatory and chemopreventive activities of aspirin (ASA) may be mediated through its cyclooxygenase inhibitor function. We have previously shown that ASA can protect against UVR-induced skin inflammation and DNA damage; however, the role of inflammation in UV-induced DNA damage and the mechanism underlying ASA protection are poorly characterized. Using immunodeficient NOD scid gamma mice and immunocompetent C57BL/6 mice treated with immune cell‒depleting antibodies, we found that inflammation was not required for UVB-induced 8-oxoguanine and cyclobutane pyrimidine dimers in vivo. Unlike ASA, neither its immediate metabolite salicylate nor the cyclooxygenase inhibitor indomethacin reduced UVB-induced 8-oxoguanine or cyclobutane pyrimidine dimers in melanocyte Melan-a or keratinocyte HaCat cells in vitro. Moreover, addition of prostaglandin E2 did not reverse the protective effect of ASA on UVB-treated cells. Phosphorylation of the 5' AMP protein kinase, observed in ASA-treated cells, could be blocked by the 5' AMP protein kinase inhibitor compound C. Compound C or 5' AMP protein kinase knockdown partially reduced ASA-mediated protection against UVB-induced DNA damage. Finally, injection of compound C partially reversed the protective effect of ASA on UVB-treated mouse skin in vivo. These studies suggest that ASA confers protection against UVB-induced DNA damage through the activation of 5' AMP protein kinase rather than through cyclooxygenase inhibition.

Fifty years with aspirin and platelets.

In 2021, we reached the 50th anniversary of the publication of Sir John Vane's seminal paper in Nature New Biology describing the experiments supporting his mechanistic hypothesis that inhibition of prostaglandin synthesis might explain the main pharmacological effects of aspirin and aspirin-like drugs, that is, reduction in pain, fever and inflammation. Bengt Samuelsson's subsequent discoveries elucidating the cyclooxygenase pathway of platelet arachidonic acid metabolism motivated my research interest towards measuring platelet thromboxane A2 biosynthesis as a tool to investigate the clinical pharmacology of cyclooxygenase inhibition by aspirin in health and disease. What followed was a long, winding road of clinical research leading to the characterization of low-dose aspirin as a life-saving antiplatelet drug that still represents the cornerstone of antithrombotic therapy. Having witnessed and participated in these 50 years of aspirin research, I thought of providing a personal testimony of how things developed and eventually led to a remarkable success story of independent research.