Thymoquinone Pretreatment Research Articles

Thymoquinone Effects on the Expression of p62 Gene in Cisplatin-Induced Testicular Damage in Mice

Background: Cisplatin (CPN) is widely used for the management of various malignant tumors. Objectives: This study investigated the effects of Thymoquinone (TQN) on the expression of the p62 gene in CPN-induced testicular damage in mice. Methods: Histomorphometry, testis injury scores, expression of p62, and protein levels of LC3-II were assessed. Results: Cisplatin induced histological changes, increased p62 expression (P < 0.01), and reduced LC3-II levels (P < 0.001). Thymoquinone pretreatment decreased p62 expression while increasing LC3-II protein levels. Thymoquinone significantly reversed the testicular injury scores and improved histomorphometric parameters. Conclusions: The results indicate that TQN enhances autophagy and improves testicular tissue in CPN-intoxicated mice.

Thymoquinone effects on autophagy, apoptosis, and oxidative stress in cisplatin-induced testicular damage in mice.

In this study, the effect of thymoquinone (TQ) on CP-induced spermatogenesis defects in mice has been investigated. Sperm parameters, serum testosterone concentration, histology, Bax/Bcl-2 ratio, and expression of autophagy-related biomarkers have been assessed. Total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) in testicular tissue were examined for the evaluation of oxidative stress levels. CPhas induced histological changes and significantlyincreased the Bax/Bcl-2 ratio, decreased testosterone concentration, testicular weight, and sperm quality. CP induced oxidative stress by elevating OSIin the testicular tissue(p < 0.05).Expression of theautophagy-inducer genes (ATG7, ATG5, and Beclin-1) andratio ofLC3B/LC3Aproteinswere significantly decreased, while mTOR expression was increased in the CP group.TQ pretreatment dose-dependently decreased the Bax/Bcl-2 ratio and mTOR gene expression while increasing the expression of ATG5 and ATG7 genes, LC3B/LC3A ratio, and Beclin-1 proteins.TQ could also dose-dependently reverse the histology, testosterone level, and sperm quality of the CP-intoxicated mice. These findings show that TQ pretreatment can enhance sperm production by inducing autophagy and reducing apoptosis and oxidative stress in the CP-intoxicated mouse testicles.

Thymoquinone enhanced the antitumor activity of cisplatin in human bladder cancer 5637 cells in vitro.

Cisplatin-based chemotherapy is a primary alternative for treating bladder cancer. But drug resistance and various side effects are the main unsightliness challenges. In search of a novel chemotherapeutic approach, this study was conducted to investigate whether thymoquinone (TQ) chemosensitize 5637 bladder cancer cells to cisplatin (CDDP). The IC50 for each drug was first determined. The cells were then pre-exposed to 40 µM of TQ for 24h before being treated with 6 µM of cisplatin. The viability and the sub-G1 population of the 5673 cells were respectively evaluated by alamar blue assay and propidium iodide staining. RT-qPCR was also applied to analyze the expression profile of the apoptosis-related genes (Bax, Bcl-2, p53). The viability of the cells treated with the combination of TQ and CDDP was significantly decreased compared to CDDP- or TQ-treated cells. TQ at the concentration of 40 µM increased the cytotoxicity of 6 µM CDDP by 35.5%. Moreover, flow cytometry analysis indicated that TQ pre-treatment of the cells resulted in a 55.5% increase in the population of 5637 cells in the sub-G1 phase compared to cells treated with CDDP alone. The results from RT-qPCR exhibited that the exposure of the cells to both TQ and CDDP significantly elevated Bax/Bcl-2 ratio by down-regulating Bcl-2 expression. TQ significantly increased the cytotoxicity of CDDP in 5637 cells and induced apoptosis by down-regulation of the Bcl-2. Therefore, TQ and CDDP might be an effective therapeutic combination for TCC bladder cancer treatment.

Thymoquinone Produces Cardioprotective Effect in β-Receptor Stimulated Myocardial Infarcted Rats via Subsiding Oxidative Stress and Inflammation

Earlier studies reported that long-term treatment with thymoquinone (TQ) at a high dose (20 mg/kg) exerts a cardioprotective effect against isoproterenol (ISO)-triggered myocardial infarction (MI) in rats. In the present study, we tested the hypothesis that TQ, as a potent molecule, can exhibit cardioprotective effects at the lower dose for a short-term regimen. The rats were administered with TQ (5 mg/kg, intraperitoneal) at the 4 h interval for 2 days. ISO (100 mg/kg/day, subcutaneous) was given for 2 days to produce MI. ISO challenge results in deformation in ECG wave front, elevated left ventricular (LV) end-diastolic pressure, and reduced LVdP/dtmax and LVdP/dtmin. The levels of the cardiac biomarker in serum, such as creatine kinase MB, alanine aminotransferase, and aspartate aminotransferase, were increased. In the myocardium, a rise in malonaldehyde and decreased superoxide dismutase, glutathione, and catalase contents were observed. Furthermore, increased levels of tumor necrotic factor-α, interleukin-6, and interleukin-1β were observed in the myocardium. TQ pretreatment significantly normalized alterations in hemodynamic parameters, strengthened the antioxidant defense system, and decreased the contents of pro-inflammatory cytokines and hepatic enzymes as compared to the ISO group. Based on the results, TQ appears to be cardioprotective at low doses, and effective even administered for a shorter duration.

Thymoquinone Attenuates Immune Mediated Liver Injury Induced by Concanavalin A in Mice

Autoimmune hepatitis is an inflammatory disease and its incidence has been increasing. The features of hepatitis are the release of inflammatory cytokines, the elevation of AST and ALT, and hepatocyte apoptosis and necrosis. Concanavalin A considered as essential model represents the acute immune-mediated liver damage in rodents. Thymoquinone is well known herbal compound that exert hepatoprotective, anti-inflammatory, and antioxidant activity. In this study, we focus on the immunoregulatory and liver protective effect of thymoquinone in a mouse model of concanavalin A-induced liver injury.&#x0D; Twenty-four male mice were randomly divided into four groups each containing six animals: Negative control group, concanavalin A model group, thymoquinone 15mg/kg group, and thymoquinone 30mg/kg group. Blood was collected to detect the activities of alanine transaminase (ALT) and aspartate transaminase (AST) as well as liver tissue for the detection of tumor necrosis factor &#x0D; levels, after 8 hours of concanavalin A injection.&#x0D; Injecting mice with concanavalin resulted in a dramatic increase in serum level of both ALT and AST which indicate severe liver tissue damage with a significant increase in inflammatory cytokines TNF alpha -&#x0D; and INF levels, with a notable increase in NF-kB gene expression in mice liver tissue homogenate. Thymoquinone pretreatment revealed a dose-dependent increase in liver tissue protection.&#x0D; Conclusion: Thymoquinone has hepatoprotective and immune modulatory effects in concanavalin A induced immune mediated liver damage. Thymoquinone exerted its effect through attenuating NF and its downstream effectors TNF and INF in a dose dependent manner.

Thymoquinone attenuates isoproterenol-induced myocardial infarction by inhibiting cytochrome C and matrix metalloproteinase-9 expression.

Thymoquinone (TQ) is the main active constituent of Nigella sativa. The present study aimed to investigate the effect of TQ on apoptotic parameters and MMP-9 expression in isoproterenol (ISP)-induced myocardial infarction (MI). TQ was given once daily for 7days at doses of 10 and 20mg/kg orally with ISP (86mg/kg; s.c.) administered on the sixth and seventh days. TQ pre-treatment protected against ISP-induced MI as approved by normalisation of electrocardiogram (ECG) and b (CK)-MB, minimal histopathological changes, and reduction of the infarction size. Effects of TQ could be supported by its antioxidant activity, evidenced by the increase of cardiac reduced glutathione and total serum antioxidant capacity, and the inhibition of ISO-induced lipid peroxidation. TQ anti-inflammatory activity was associated with reduced expression of NF-κB and TNF-α. TQ ameliorated cardiomyocytes, apoptotic pathways by inhibiting both the intrinsic pathway, via reducing cytoplasmic cytochrome C, and the extrinsic pathway, by inhibiting TNF-α and caspases, and the effect of TQ was dose-dependent. Moreover, TQ reduced the expression of metalloproteinase (MMP)-9, which is considered as a prognostic marker of ventricular remodelling, recommending that TQ can be used as a possible supplement to minimise post-MI changes. So, we conclude that TQ antiapoptotic activity and the inhibitory modulation of MMP-9 expression contribute to TQ protective effects in MI. To our knowledge, this is the first study reporting the effect of TQ on cytochrome c activity and MMP-9 expression in MI.

Thymoquinone dose-dependently attenuates myocardial injury induced by isoproterenol in rats via integrated modulations of oxidative stress, inflammation, apoptosis, autophagy, and fibrosis

As rats develop myocardial infarction (MI) like lesions when injected with large doses of isoproterenol (ISO), this investigation was designed to evaluate the dose-dependent effects of thymoquinone (TQ) on ISO-induced myocardial injury in rats. Adult male rats were divided into negative control, TQ20 (20mg/kg/day), TQ50 (50mg/kg/day), ISO positive control, TQ20 + ISO, and TQ50 + ISO groups. In these rats, biochemical, immunobiochemical, and histopathological studies were carried out to evaluate myocardial oxidative stress, inflammation, apoptosis, fibrosis, and autophagy, and the changes in serum cardiac biomarkers. The results showed that TQ pretreatment in ISO-administered rats produced a dose-dependent significant reduction of the myocardial infarct size, markedly reduced the ISO-induced elevation in serum cardiac markers and demonstrated several other important findings related to the cardioprotective efficacy of TQ. First, this study is the first reported research work showing that TQ treatment could increase the myocardial reduced glutathione baseline level, adding an indirect antioxidant effect to its known direct free radical scavenging effect. Second, pretreatment with TQ significantly reduced the markers of myocardial oxidative stress, inflammation, fibrosis, and apoptosis. Third, TQ acted as an autophagy enhancer ameliorating myocardial cell damage and dysfunction. Thus, the morphological and biochemical changes associated with ISO-induced myocardial injury were ameliorated with TQ pretreatment. The extent of this improvement was significantly greater in the TQ50 + ISO group than in the TQ20 + ISO group. The present study, for the first time, demonstrates these dose-dependent effects of TQ in experimentally induced myocardial injury. These findings raise the possibility that TQ may serve as a promising prophylactic cardioprotective therapy for patients who are at risk of developing myocardial injury and against the progression of existent myocardial injury as in cases of MI.

Thymoquinone reduces mitochondrial damage and death of cardiomyocytes induced by clozapine.

The generation of a reactive nitrenium ion by microsomal/mitochondrial cytochrome P450 (CYPs) from clozapine (CLZ) has been suggested as the main cause of cardiotoxicity by this drug. Previous studies indicated that thymoquinone (TQ) as an active constituent of Nigella sativa has pharmacological effects such as antioxidant, reactive oxygen species (ROS) scavenger, and inhibitory effect on CYPs enzymes. Therefore, we hypothesized that TQ with these pharmacological effects can reduce CLZ-induced toxicity in isolated cardiomyocytes and mitochondria. Rat left ventricular cardiomyocytes and mitochondria were isolated by collagenase perfusion and differential centrifugation respectively. Then, isolated cardiomyocytes and mitochondria were pretreated with different concentrations of TQ (1, 5, and 10μmol/l) for 30min and then followed by exposure to CLZ (50μmol/l) for 6h. After 6h of incubation, using biochemical evaluations and flow cytometric analysis, the parameters of cellular toxicity including cytotoxicity, the level of oxidized/reduced glutathione (GSH/GSSG), malondialdehyde (MDA), reactive oxygen species (ROS) formation, lysosomal membrane integrity, mitochondria membrane potential (ΔΨm) collapse, and mitochondrial toxicity including succinate dehydrogenase (SDH) activity and mitochondrial swelling were analyzed. We observed a significant toxicity in isolated cardiomyocytes and mitochondria after exposure with CLZ which was related to ROS formation, oxidative stress, GSH depletion, lysosomal and mitochondrial damages, and mitochondrial dysfunction and swelling, while TQ pretreatment reverted the above toxic effect of CLZ on isolated cardiomyocytes and mitochondria. Our results indicate that TQ prevents and reverses CLZ-induced cytotoxicity and mitochondrial damages in isolated cardiomyocytes and mitochondria, providing an experimental basis for clinical treatment on CLZ-induced cardiotoxicity.

Effect of Thymoquinone as Prophylactic Treatment Against CCl4-Induced Hepatotoxicity on Antioxidants Status

Objective: The present study aims to study the effect of thymoquinone as prophylactic treatment against CCl4-induced hepatotoxicity on antioxidants status.&#x0D; Methodology: Hepatotoxicity was induced in rats by intraperitoneal administration of 3 ml/kg, 1:1 (V/V) mixture of CCl4 and olive oil after treatment for 7 days with TQ, using two doses. The method consists of studying the antioxidant effect of thymoquinone pretreatment by measuring superoxide dismutase (SOD) and catalase (CAT) activities, with reduced glutathione level in both plasma and liver homogenate.&#x0D; Results: The results revealed that hepatotoxicity is accompanied by significant decrease (p ≤ 0.01) of SOD and CAT activities with GSH level, in both plasma and liver homogenate. While prophylactic treatment using TQ at doses of 02.5 and 05 mg/kg increase significantly the status of the antioxidants, as dose dependent manner, in both plasma and liver homogenate. &#x0D; Conclusion: The results of this study show that thymoquinone has an antioxidant effect when it used as prophylactic treatment against CCl4-induced hepatotoxicity.&#x0D; Keywords: Thymoquinone, hepatotoxicity, CCl4, prophylactic and antioxidant.

Neuroprotective effects of thymoquinone against ketamine -and MK-801-induced neurotoxicity in SH-SY5Y cells: From the perspective of glutamatergic dysfunction in schizophrenia

Objective: Schizophrenia is a chronic disorder with approximately 1% prevalence and related to disrupted neurodevelopment process. It has been known that N-methyl D-Aspartate (NMDA) receptor antagonists such as ketamine and MK-801 mimic schizophrenia-like behaviors in rodents and cellular changes in cell culture. There are certain preliminary reports showing the beneficial effects of Nigella sativa L. extracts or its main active ingredient, thymoquinone, on psychiatric disorders. In our study, we aimed to investigate the neuroprotective effects of thymoquinone against ketamine- and MK-801- induced neurotoxicites, which may be relevant to schizophrenia. Methods: The neurotoxic concentrations of ketamine and MK-801, and non-toxic concentrations of thymoquinone were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test at the 24th hour of administrations in SH-SY5Y cells. Seven different concentrations of thymoquinone (0.5 µM, 1 µM, 2.5 µM, 5 µM, 10 µM, 20 µM, 30 µM) were tested against two different concentrations of ketamine (250 µg/ml, 500 µg/ml) and one concentration of MK-801 (100 µM).Results: Ketamine (250 µg/ml and 500 µg/ml) and MK-801 (100 µM) decreased (P&amp;lt;0.05) the cellular viabilities at the 24 hour of administrations. Thymoquinone pretreatment prevented (P&amp;lt;0.05) the decrease of cell viabilities against ketamine (250 µg/ml) and ketamine (500 µg/ml) at 1 uM, 2.5 µM, 5 µM, 10 µM, 20 µM, and 2.5 µM concentrations, respectively. Thymoquinone pretreatment also increased (P&amp;lt;0.05) cell viability compared to MK-801. Conclusion: We suggested that thymoquinone had neuroprotective effects on the NMDA receptor antagonists induced neurotoxicity and encourage researchers for further in vivo studies for schizophrenia.

Thymoquinone reduces ischemia and reperfusion-induced intestinal injury in rats, through anti-oxidative and anti-inflammatory effects.

The aim of the present study was to investigate the effect of thymoquinone on ischemia/reperfusion (I/R) injury at 150 min or/and 24 h of reperfusion in male Wistar Rats. The therapeutic value of thymoquinone on cellular damage caused by reactive oxygene species or inflammatory processes during intestinal ischemia/reperfusion was investigated using pharmacological function studies on smooth muscle contractile responses of acetylcholine (Ach) and KCl, along with myeloperoxidase activity, malondialdehyhde, glutathione and cytokine levels such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β in serum and ileum tissue of rats. Thymoquinone was administered at a dose of 50 mg/kg orally for three times: 30 min, 24 h and 48 h prior to the surgical procedure. Soon after reperfusion timing (150 min or 24 h), the contractility traces to KCl and acetylcholine of the ileum smooth muscle were recorded through isolated organ bath. Pretreatment with thymoquinone reversed the disrupted contractility of the ileum smooth muscle at the 24 h reperfusion. Increased malondialdehyde and depleted glutathione levels and high myeloperoxidase activity determined in the ileum I/R tissue returned to reasonable amounts by pretreatment of Thymoquinone, which attenuated malondialdehyde quantity, restored glutathione level and inhibited myeloperoxidase activity. In addition, both serum and tissue TNF-α and IL-1β activities were modulated by thymoquinone at 24 h of intestinal I/R. The results indicate that thymoquinone may have therapeutic value due to its immunomodulating, radical scavenging and/or antioxidant effects in intestinal I/R injury including oxidant damage mechanisms.

Thymoquinone Attenuates Acetaminophen Overdose-Induced Acute Liver Injury and Inflammation Via Regulation of JNK and AMPK Signaling Pathway.

Thymoquinone (TQ) is a main aromatic component of Nigella sativa L. seeds or Agastache rugosa (Fisch. & C.A.Mey.) Kuntze. The protective mechanism of TQ against acute liver injury induced by acetaminophen (APAP), however, remains unclear. We aimed to investigated the hepato-protective mechanism of TQ on the development of APAP-induced acute liver injury. Male kunming mice were pretreated with TQ or N-acetylcysteine (NAC) before a single APAP injection. Human Chang liver cells were incubated with TQ, SP600125 or AICAR in presence of APAP for 24 h. TQ pretreatment reduced levels of serum aminotransferases and increased hepatic glutathione and glutathione peroxidase activities via inhibiting CYP2E1 expression. TQ inhibited JNK, ERK and P38 phosphorylation induced by APAP. Meanwhile, TQ inhibited PI3K/mTOR signaling activation and activated AMPK phosphorylation. Moreover, TQ prevented APAP-induced hepatocytes apoptosis regulated by Bcl-2 and Bax. Furthermore, TQ inhibited STAT3 phosphorylation on APAP-induced acute liver injury. In addition, TQ significantly inhibited P2X7R protein expression and IL-1 release. APAP-enhanced JNK phosphorylation and APAP-suppressed AMPK phosphorylation were also observed in Chang liver cells, and these changes were recovered by pretreatment with TQ, SP600125 and AICAR. Our findings suggest that TQ may actively prevent APAP-induced acute liver injury, and the effect may be mediated by JNK and AMPK signaling pathways.

Thymoquinone protects human retinal pigment epithelial cells against hydrogen peroxide induced oxidative stress and apoptosis.

Oxidative stress in retinal pigment epithelium (RPE) cells may contribute to the progression of age-related macular degeneration. Thymoquinone (TQ), an active component derived from Nigella sativa, possesses antioxidative effect. However, the role of TQ in RPE cells under oxidative stress condition remains unclear. The present study aimed to examine the protective effect of TQ against hydrogen peroxide (H2 O2 )-induced oxidative stress in human RPE cells. Our results showed that TQ improved the cell viability and apoptosis in H2 O2 -induced ARPE cells. We also found that the levels of reactive oxygen species and malondialdehyde induced by H2 O2 were reduced after the pretreatment of TQ. In addition, the inhibitory effect of H2 O2 on the glutathione (GSH) level and superoxide dismutase activity was markedly attenuated by TQ pretreatment. Moreover, TQ enhanced the activation of Nrf2/heme oxygenase 1 (HO-1) signaling pathway in H2 O2 -induced ARPE cells. Knockdown of Nrf2 abolished the protective effect of TQ on H2 O2 -induced oxidative damage. These results suggested that TQ protected ARPE cells from H2 O2 -induced oxidative stress and apoptosis via the Nrf2/HO-1 signaling pathway.

Evaluation of phyto-medicinal efficacy of thymoquinone against Arsenic induced mitochondrial dysfunction and cytotoxicity in SH-SY5Y cells

BackgroundIt is evaluated that a few million individuals worldwide are experiencing Arsenic (As) harmfulness coming about because of anthropogenic discharges. There is likewise proof to propose that As can affect the peripheral, as well as, the central nervous system (CNS). On the contrary, thymoquinone (TQ), a biologically active ingredient of Nigella sativa has exhibited numerous neuro-pharmacological traits since ancient times. Hypothesis/PurposeIn the present study, the neuroprotective efficacy of TQ was explored by primarily studying its antioxidant and anti-apoptotic potential against Arsenic trioxide (As2O3) induced toxicity in SH-SY5Y human neuroblastoma cell lines. Study designFor experimentation, cells were seeded in 96 well tissue culture plates and kept undisturbed for 24 h to attain proper adhesion. After 75–80% confluence, cells were pretreated with 10 µM and 20 µM thymoquinone (TQ) for 1 h After adding 2 µM As, cells were set aside for incubation for 24 h without changing the medium. MethodsThe mitigatory effects of TQ with particular reference to cell viability and cytotoxicity, the generation of reactive oxygen species, DNA damage, and mitochondrial dynamics were studied. ResultsPretreatment of SH-SY5Y cells with TQ (10 and 20 μM) for an hour and subsequent exposure to 2 μM As2O3 protected the SH-SY5Y cells against the neuro-damaging effects of the latter. Also, the SH-SY5Y cells were better preserved with increased viability, repaired DNA, less free radical generation and balanced transmembrane potential than those exposed to As2O3 alone. TQ pretreatment also inhibited As2O3-induced exacerbation in protein levels of BAX and PARP-1 and restored the loss of Bcl2 levels. ConclusionThe findings of this study suggest that TQ may prevent neurotoxicity and As2O3-induced apoptosis and cytotoxicity. It is, therefore, worth studying further for its potential to reduce the risks of arsenic-related neurological implications.

Enhancing conventional chemotherapy drug cisplatin-induced anti-tumor effects on human gastric cancer cells both in vitro and in vivo by Thymoquinone targeting PTEN gene.

Combination chemotherapy regimen with several anti-tumor drugs is a strategy to improve outcome. Thymoquinone (TQ) has been reported to exert biological activity on various types of human cancers without obvious toxicity. However, only few studies showed the anti-tumor effects of TQ combination with cisplatin on gastric cancer (GC). Here, we showed pretreatment with 5μM TQ significantly increased the apoptotic effects induced by cisplatin on GC cell lines. Combined treatment of cisplatin with TQ represented a significantly superior tumor suppression effect than either agent alone in a xenograft tumor mouse model. Interestingly, TQ pretreatment following cisplatin caused a significant increase in the levels of PTEN, an obvious decrease in p-AKT, CyclinD1, P-glycoprotein (P-gp), meanwhile, TQ and cisplatin also led to an increase in Bax, Cyt C, AIF, cleaved caspase 9, and cleaved caspase 3, and a decrease in Bcl-2, procaspase-9, procaspase-3. Moreover, results in vitro, showed that a combination of TQ and cisplatin represents a more effective anti-tumor agent than either agent alone in a xenograft tumor mouse model. In conclusion, TQ significantly augments cisplatin-induced anti-tumor effects on gastric cancer both in vitro and in vivo, through inhibiting PI3K/AKT signaling pathway, activating the mitochondrial pathway, and down-regulating P-glycoprotein by up-regulating PTEN gene. TQ might be as a promising candidate as a cancer chemopreventive or chemotherapeutic agent for antineoplastic combination therapy and merits further clinical investigation.

Thymoquinone inhibits TNF-α-induced inflammation and cell adhesion in rheumatoid arthritis synovial fibroblasts by ASK1 regulation

Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine produced by monocytes/macrophage that plays a pathological role in rheumatoid arthritis (RA). In this study, we investigate the effect of thymoquinone (TQ), a phytochemical found in Nigella sativa, in regulating TNF-α-induced RA synovial fibroblast (RA-FLS) activation. Treatment with TQ (1–5μM) had no marked effect on the viability of human RA-FLS. Pre-treatment of TQ inhibited TNF-α-induced interleukin-6 (IL-6) and IL-8 production and ICAM-1, VCAM-1, and cadherin-11 (Cad-11) expression in RA-FLS (p<0.01). Evaluation of the signaling events showed that TQ inhibited TNF-α-induced phospho-p38 and phospho-JNK expression, but had no inhibitory effect on NF-κB pathway, in RA-FLS (p<0.05; n=4). Interestingly, we observed that selective down-regulation of TNF-α-induced phospho-p38 and phospho-JNK activation by TQ is elicited through inhibition of apoptosis-regulated signaling kinase 1 (ASK1). Furthermore, TNF-α selectively induced phosphorylation of ASK1 at Thr845 residue in RA-FLS, which was inhibited by TQ pretreatment in a dose dependent manner (p<0.01). Pre-treatment of RA-FLS with ASK1 inhibitor (TC ASK10), blocked TNF-α induced expression of ICAM-1, VCAM-1, and Cad-11. Our results suggest that TNF-α-induced ASK1-p38/JNK pathway is an important mediator of cytokine synthesis and enhanced expression of adhesion molecule in RA-FLS and TQ, by selectively inhibiting this pathway, may have a potential therapeutic value in regulating tissue destruction observed in RA.

Thymoquinone inhibits TNF‐α‐induced pro‐inflammatory mediators in Rheumatoid arthritis synovial fibroblasts in vitro

Rheumatoid arthritis (RA) is an autoimmune disease in which cytokine such as tumor necrosis factor‐α (TNF‐α), activate synovial fibroblast (FLS) that results in inflammation and activate joint destruction. In this study using RA‐FLS, we investigate the efficacy of thymoquinone (TQ), a phytochemical found in Nigella sativa, in inhibiting TNF‐α induced proinflammatory mediators. RA‐FLS were pretreated with TQ (1–5 µM) for 2 hours followed by TNF‐α stimulation (30 mins or 24 hours). Conditioned medium was used for the quantification of IL‐6 and IL‐8 by ELISA and cell lysates were prepared for the analysis of adhesion molecule (ICAM‐1 and VCAM‐1) and mitogen‐activated protein kinases. Pretreatment of TQ inhibited the ability of TNF‐α to induce IL‐6 and IL‐8 production in RA synovial fibroblasts in a dose‐dependent manner (p&lt;0.01). We also observed a marked inhibition in TNF‐α induced ICAM‐1 and VCAM‐1 expression by TQ (p&lt;0.01). Evaluation of the signaling pathways using the inhibitors of p38(SB203580), JNK(SP600125),ERK(PD98059) and AKT (LY294001) showed that p38 and JNK played an important role in regulating TNF‐α induced IL‐6 and IL‐8 production, whereas p38 and AKT were involved in regulating ICAM‐1 and VCAM‐1 expression by TNF‐α stimulation in RA‐FLS (p&lt;0.05). TQ was found to selectively inhibit TNF‐induced phosphorylation of p38 and JNK in a dose‐dependent manner. The results of the study show that TQ interferes with TNF‐α signaling pathways to regulate IL‐6 and IL8 production, and ICAM‐1/VCAM‐1 expression in RA‐FLS. Thus,TQ may be of potential therapeutic value in regulating inflammation and synovial invasion in RA.

Thymoquinone Protects against Myocardial Ischemic Injury by Mitigating Oxidative Stress and Inflammation.

The present study was aimed at investigating the cardioprotective activity of thymoquinone (TMQ), an active principle of the herb, Nigella sativa, which is used for the management of various diseases. The present study examined the cardioprotective effect of TMQ in isoproterenol- (ISP-) induced myocardial infarction in rats. Myocardial infarction was induced by two subcutaneous injections of ISP (85 mg/kg) at an interval of 24 hr. TMQ (20 mg/kg) was administered orally for 21 days. ISP-treated rats showed depletion of antioxidants and marker enzymes from myocardium along with lipid peroxidation and enhanced levels of proinflammatory cytokines. ISP also induced histopathological alterations in myocardium. Treatment with TMQ prevented the depletion of endogenous antioxidants and myocyte injury marker enzymes and inhibited lipid peroxidation as well as reducing the levels of proinflammatory cytokines. TMQ pretreatment also reduced myonecrosis, edema, and infiltration of inflammatory cells and showed preservation of cardiomyocytes histoarchitecture. The present study results demonstrate that TMQ exerts cardioprotective effect by mitigating oxidative stress, augmenting endogenous antioxidants, and maintaining structural integrity. The results of the present study indicate that TMQ may serve as an excellent agent alone or as adjuvant to prevent the onset and progression of myocardial injury.

Thymoquinone Pretreatment Overcomes the Insensitivity and Potentiates the Antitumor Effect of Gemcitabine Through Abrogation of Notch1, PI3K/Akt/mTOR Regulated Signaling Pathways in Pancreatic Cancer.

The gemcitabine-insensitivity remains the main challenge for pancreatic cancer treatment. Thymoquinone, the predominant bioactive ingredient of Nigella sativa, has been shown to possess promising anti-cancer and chemo-sensitizing effects on pancreatic cancer, however, its meticulous mechanism is still indistinct. The objective of the present study was to investigate the potency of thymoquinone in combination with gemcitabine in inducing apoptosis and preventing the development of gemcitabine-insensitivity in pancreatic cancer cells. The anti-tumor effects of thymoquinone and gemcitabine were analyzed via evaluation of alterations of cell viability, tumor weight, apoptosis-related proteins, caspase-3, -9 activities and NF-κB DNA binding activity in pancreatic cancer cells in vitro and PANC-1 cells orthotopic xenograft in vivo. Thymoquinone pretreatment following gemcitabine treatment synergistically caused an increase in pancreatic cancer cells apoptosis and tumor growth inhibition both in vitro and in vivo. The novel combinational regimen also contributes to alterations of multiple molecular signaling targets, such as the suppression of Notch1, NICD accompanying with up-regulation of PTEN, the inactivation of Akt/mTOR/S6 signaling pathways, and the suppression of phosphorylation and nuclear translocation of p65 induced by TNF-α. Thymoquinone pretreatment and gemcitabine also induced down-regulation of anti-apoptotic Bcl-2, Bcl-xL, XIAP and up-regulation and activation of pro-apoptotic molecules including Caspase-3, Caspase-9, Bax and increased release of cytochrome c. This novel modality of thymoquinone pretreatment can enhance the anti-cancer activity of gemcitabine and may be a promising option in the treatment of pancreatic cancer.

Antidepressant Effect of Thymoquinone in Animal Models of Depression.

The present study was carried out to determine the role of thymoquinone (TQ) in modulating the levels of neurotransmitter and reducing the oxidative stress in animal models of depression. Mice were divided into 5 groups, each group had 6 animals. TQ (20 mg/kg) in corn oil and fluoxetine (10 mg/kg) in normal saline were administered intraperitoneally (i.p.) half an hour before performing behavioural tests. Modified forced swim test (MFST) and tail suspension test (TST) were used to assess the antidepressant effect in mice. Animals were sacrificed and their brains were removed for biochemical estimation after performing behavioural tests. TQ treatment showed increased swimming, climbing and decreased immobility times in MFST and TST. Combination of TQ with fluoxetine in MFST and TST showed potentiating effect in the present study. A significant elevation of 5-hydroxytryptamine (5-HT) levels was observed following TQ administration in the behavioural models studied. MFST and TST reduced glutathione and elevated TBARS levels in mice. Pre-treatment of TQ restored glutathione and decreased TBARS levels. TQ combination with fluoxetine also showed reduction of TBARS and increased glutathione levels. TQ demonstrated antidepressant effects in MFST and TST respectively in the present study. It further demonstrated antioxidant effects by reducing thiobarbituric acid reactive substance (TBARS) and increasing reduced glutathione (GSH) levels. Although our results are preliminary, further investigations may be required however, based on afore mentioned results, it may be suggested that TQ could be a potential candidate for the management of depression.