Potential antioxidant activity of celecoxib and amtolmetin guacyl: in vitro studies

Anti-arthritic effects of geranium essential oil loaded chitosan nanoparticles in Freund's complete adjuvant induced arthritic rats through down-regulation of inflammatory cytokines

Geranium essential oil (GEO) has been widely used in aromatherapy and traditional medicines. Nanoencapsulation, a novel technique has emerged to overcome the environmental degradation and less oral bioavailability of essential oils. This work was undertaken to encapsulate geranium essential oil in chitosan nanoparticles (GEO-CNPs) by ionic gelation technique and to explore anti-arthritic and anti-inflammatory potential in FCA-induced arthritic model in rats. The GEO was characterized by gas chromatography flame ionization detector (GCFID) and the nanosuspension was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-rays diffraction (XRD). The Wistar albino rats (n = 32) were separated into four groups; Group 1 and 2 were considered as normal and arthritic controls. Group 3 was positive control that received oral celecoxib for 21 days while Group 4 was treated with oral GEO-CNPs after the induction of arthritis. Hind paw ankle joints diameters were weekly measured throughout the study and significant decrease (5.5 ± 0.5 mm) was observed in GEO-CNPs treatment group in comparison to arthritic group (9.17 ± 0.52 mm). Blood samples were drawn at end for evaluation of hematological, biochemical and inflammatory biomarkers. A significant upregulation of red blood cells and hemoglobin while downregulation of white blood cells, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP) and rheumatoid factor (RF) was observed. Ankles were transected for the histopathological and radiographic examination after animals were sacrificed which confirmed the alleviation of necrosis along cellular infiltration. It was concluded that GEO-CNPs were found to possess excellent therapeutic potential and promising candidates to reduce FCA-induced arthritis.

Photo-Protective and Anti-Inflammatory Effects of Antidesma thwaitesianum Müll. Arg. Fruit Extract against UVB-Induced Keratinocyte Cell Damage

The main cause of most skin cancers is damage from UVB from sunlight, which penetrate the skin surface and induce inflammation. For this reason, this study aims to identify natural products with photo-protection properties and their mode of action by using the UVB-irradiated HaCaT keratinocyte model. Antidesma thwaitesianum fruit extracts at 25, 50, and 100 µg/mL recovered cell viability following UVB exposure in a dose-dependent manner. Cell survival was associated with the reduction in intracellular ROS and NO. In addition, we showed that the pre-treatment with the fruit extract lowered the phosphorylation level of two MAPK-signaling pathways: p38 MAPKs and JNKs. The resulting lower MAPK activation decreased their downstream pro-inflammatory cascade through COX-2 expression and subsequently reduced the PGE₂ proinflammatory mediator level. The photoprotective effects of the fruit extract were correlated with the presence of polyphenolic compounds, including cyanidin, ferulic acid, caffeic acid, vanillic acid, and protocatechuic acid, which have been previously described as antioxidant and anti-inflammation. Together, we demonstrated that the pre-treatment with the fruit extract had photo-protection by inhibiting oxidative stress and subsequently lowered stress-induced MAPK responses. Therefore, this fresh fruit is worthy of investigation to be utilized as a skincare ingredient for preventing UVB-induced skin damage.

High ROS Production by Celecoxib and Enhanced Sensitivity for Death Ligand-Induced Apoptosis in Cutaneous SCC Cell Lines

Incidence of cutaneous squamous cell carcinoma (cSCC) and actinic keratosis has increased worldwide, and non-steroidal anti-inflammatory drugs as celecoxib are considered for treatment. We show here strong anti-proliferative effects of celecoxib in four cSCC cell lines, while apoptosis and cell viability largely remained unaffected. Impeded apoptosis was overcome in combinations with agonistic CD95 antibody or TNF-related apoptosis-inducing ligand (TRAIL), resulting in up to 60% apoptosis and almost complete loss of cell viability. Proapoptotic caspase cascades were activated, and apoptosis was suppressed by caspase inhibition. TRAIL receptor (DR5) and proapoptotic Bcl-2 proteins (Puma and Bad) were upregulated, while anti-apoptotic factors (survivin, XIAP, cFLIP, Mcl-1, and Bcl-w) were downregulated. Strongly elevated levels of reactive oxygen species (ROS) turned out as particularly characteristic for celecoxib, appearing already after 2 h. ROS production alone was not sufficient for apoptosis induction but may play a critical role in sensitizing cancer cells for apoptosis and therapy. Thus, the full therapeutic potential of celecoxib may be better used in combinations with death ligands. Furthermore, the immune response against cSCC/AK may be improved by celecoxib, and combinations with checkpoint inhibitors, recently approved for the treatment of cSCC, may be considered.

Current progress on antioxidants incorporating the pyrazole core

The search of new antioxidants, as drugs candidates, is an active field of medicinal chemistry. The synthesis of compounds with antioxidant potential has increased in recent years and a high number of structurally diverse compounds have been published. This review aims to show the current state-of-the-art on the development of antioxidant compounds incorporating the pyrazole pharmacophore. It is a well-timed review driven by the increasing number of papers, on this issue, that have been published since the beginning of the 21st century (from 2000 to 2017). The aim is to look deeper into the structures already published in the literature containing the pyrazole core as the unique pharmacophore or combined with other pharmacophores and see the relationship between the presence of this five-membered nitrogen heterocycle and the behaviour of the compounds as potential antioxidant agents. An attempt was made to whenever possible establish structure-activity relationships that could help the design of new and more potent antioxidant agents containing this important pharmacophore.

Histopathology and oxidative stress analysis of concomitant misoprostol and celecoxib administration

Nonsteroidal anti-inflammatory drugs (NSAIDs), non-selective or selective inhibitors of cyclooxygenase (COX-1 and -2), reduce pain and inflammation associated with arthritic diseases. Celecoxib, a COX-2-selective inhibitor providing decreased gastric injury relative to non-selective NSAIDs, is commonly prescribed. Misoprostol, a prostaglandin analog, supplements NSAID-inhibited prostaglandin levels. As concomitant celecoxib and misoprostol administration has been shown to intensify renal adverse effects, this article examined the influence of concomitant administration on hepatic histopathology, oxidative stress, and celecoxib concentration. On days 1 and 2, rat groups (n = 6) were gavaged twice daily (two groups with vehicle and two groups with 100 μg/kg misoprostol). From day 3 to day 9, one celecoxib dose (40 mg/kg) replaced a vehicle dose of one group and one group received celecoxib in addition to misoprostol. Livers were harvested on day 10. No hepatic abnormalities were observed denoting a lack of influence by either drug. Also no change in mean biomarker levels was detected. The changes in hepatic celecoxib concentration in the misoprostol-receiving group compared to control were not significant. Thus misoprostol does not influence hepatic celecoxib effects in terms of histopathology, oxidative stress, or celecoxib concentration level at the dosage and duration examined.

Chronic pretreatment with celecoxib reduces infarct size

This study was designed to evaluate the effect of long-term pretreatment with celecoxib, a cyclooxygenase-2 inhibitor, on myocardial infarct size. Celecoxib (3 mg/kg/day i.p; n = 16) or vehicle (DMSO 50%; EtOH 15%; distilled water, n = 16) was administered chronically to male Sprague-Dawley rats through ALZET osmotic pumps for 28 days. Under anaesthesia, the animals were then subjected to left anterior descending coronary artery occlusion for 40 minutes, followed by 24-hour reperfusion. The results show that myocardial infarct size in celecoxib-treated rats was significantly reduced compared to the control group (37.5 +/- 2.5% versus 48.0 +/- 2.6% of the area at risk, P < 0.05, n = 10 per group). Accumulation of neutrophils, estimated by myeloperoxidase levels, indicated an increase in the ischemic area without any significant difference between groups. No significant difference was observed between the treated and vehicle groups in terms of plasma prostaglandin E2 and tumour necrosis factor-alpha. Apoptosis, evaluated by Bax/Bcl-2 and terminal dUTP nick-end labelled-positive cells, was significantly decreased in the subendocardial layer of the ischemic area in celecoxib-treated rats. This study indicates that pretreatment with celecoxib can reduce infarct size by a mechanism, which may involve apoptosis inhibition.

Cytometric assessment of DNA damage by exogenous and endogenous oxidants reports aging-related processes

The ongoing DNA damage caused by reactive oxygen species generated during oxidative metabolism is considered a key factor contributing to cell aging as well as preconditioning cells to neoplastic transformation. We postulated before that a significant fraction of constitutive histone H2AX phosphorylation (CHP) and constitutive activation of ATM (CAA) seen in untreated normal and tumor cells occurs in response to such DNA damage. In the present study, we provide further evidence in support of this postulate. The level of ATM activation and H2AX phosphorylation, detected immunocytochemically, has been monitored in WI-38, A549, and TK6 cells treated with H2O2 as well as growing under conditions known or suspected to affect the level of endogenous oxidants. Thirty- to 60-min exposure of cells to 100 or 200 microM H2O2 led to an increase in the level of H2AX phosphorylation and ATM activation, particularly pronounced (nearly fivefold) in S-phase cells. Cell growth for 24-48 h under hypoxic conditions (3% O2) distinctly lowered the level of CHP and CAA while it had minor effect on cell cycle progression. Treatment (4 h) with 0.1 or 0.3 mM 3-bromopyruvate, an inhibitor of glycolysis and mitochondrial oxidative phosphorylation, reduced the level of CHP (up to fourfold) and also decreased the level of CAA. Growth of WI-38 cells in 2% serum concentration for 48 h led to a 25 and 30% reduction in CHP and CHA, respectively, compared with cells growing in 10% serum. The antioxidant vitamin C (2 mM) reduced CHP and CAA by 20-30% after 24 h of treatment, while the COX-2 inhibitor celecoxib (5 microM) had a minor effect on CHP and CAA, though it decreased the level of H2O2-induced H2AX phosphorylation and ATM activation. In contrast, dichloroacetate known to shift metabolism from anaerobic to oxidative glycolysis through its effect on pyruvate dehydrogenase kinase enhanced the level of CHP and CAA. Our present data and earlier observations strongly support the postulate that a large fraction of CHP and CAA occurs in response to DNA damage caused by metabolically generated oxidants. Cytometric analysis of CHP and CAA provides the means to measure the effectiveness of exogenous factors, which either through lowering aerobic metabolism or neutralizing radicals may protect DNA from such damage.