Radiation-modifying abilities of Nigella sativa and thymoquinone on radiation-induced nitrosative stress in the brain tissue

Will Nigella sativa oil protect parotid glands of rats against cranium gamma irradiation? Histological and immunohistochemical evaluation

BACKGROUND

Radiation plays an essential role in treating malignancies. Radiation exposure of salivary glands often results in permanent loss of their functions; therefore, their protection against radiation is crucial. Nigella sativa oil (NSO) is a useful antioxidant against free radicals. The purpose of this study was to investigate the radio-protective effect of NSO on oxidative injury of parotid glands of gamma-irradiated rats.

METHODS

Twenty-eight male albino rats were divided into four groups (n = 7): Group 1: Neither NSO nor radiation, Group 2: Rats received NSO 400 mg/kg, Group 3: Rats received 15 Gy cranium gamma irradiation & Group 4: Rats received gamma irradiation and NSO. Rats were sacrificed two weeks after the last NSO dose. Histological sections of parotid glands were stained with H&E, Masson's trichrome and anti-TGF-β antibodies. Area percentage of Masson's trichrome and TGF-β expression was morphometrically examined.

RESULTS

Parotid glands of control and NSO groups revealed normal morphology. Gamma-irradiated glands showed loss of normal acinar architecture and slight acinar shrinkage. NSO treatment of gamma-irradiated glands preserved acinar outline and architecture. Masson's trichrome stained samples revealed trace amounts of collagen fibers in control and NSO groups, and excessive amounts of collagen fibers in gamma-irradiated group, in addition to few collagen fibers for gamma-irradiated glands treated with NSO. Additionally, control and NSO groups showed negative TGF-β expression. Gamma-irradiated group showed high TGF-β expression, while NSO treated gamma-irradiated group showed moderate TGF-β expression.

CONCLUSIONS

Gamma-irradiation adversely affected parotid glands, and in contrast, NSO seemed to positively counteract this adverse effect.

Inhibitory effect of thymoquinone from Nigella sativa against SARS-CoV-2 main protease. An in-silico study

Abstract Nigella sativa is known for the safety profile, containing a wealth of useful antiviral compounds. The main protease (Mpro, 3CLpro) of severe acute respiratory syndrome 2 (SARS-CoV-2) is being considered as one of the most attractive viral target, processing the polyproteins during viral pathogenesis and replication. In the current investigation we analyzed the potency of active component, thymoquinone (TQ) of Nigella sativa against SARS-CoV-2 Mpro. The structures of TQ and Mpro was retrieved from PubChem (CID10281) and Protein Data Bank (PDB ID 6MO3) respectively. The Mpro and TQ were docked and the complex was subjected to molecular dynamic (MD) simulations for a period 50ns. Protein folding effect was analyzed using radius of gyration (Rg) while stability and flexibility was measured, using root means square deviations (RMSD) and root means square fluctuation (RMSF) respectively. The simulation results shows that TQ is exhibiting good binding activity against SARS-CoV-2 Mpro, interacting many residues, present in the active site (His41, Cys145) and also the Glu166, facilitating the pocket shape. Further, experimental approaches are needed to validate the role of TQ against virus infection. The TQ is interfering with pocket maintaining residues as well as active site of virus Mpro which may be used as a potential inhibitor against SARS-CoV-2 for better management of COVID-19.

Radioprotective effect of Ginkgolide B on brain: the mediating role of DCC/MST1 signaling

PURPOSE

The risk of brain exposure to ionizing radiation increases gradually due to the extensive application of nuclear technology in medical, industrial, and aerospace fields. Radiation-induced brain injury (RBI) is highly likely to cause a wide range of neurological complications, including schizophrenia, Alzheimer's disease (AD), depression. Ginkgolide B (GB) is one of the effective active components extracted from ginkgo biloba leaves, exerts protective effects on CNS, which is involved in the regulation of the Hippo signaling pathway. MST1, as one of the core kinases of the Hippo pathway, participated in regulating cell proliferation, differentiation, and apoptosis. However, it remains unclear whether GB attenuates radiation brain injury (RBI) and whether the radioprotective effect of GB refers to MST1 signaling. Hence, our study aimed to explore the radiation protection effect and the potential mechanism of GB.

MATERIALS AND METHODS

C57BL/6 mice were stimulated with an X-ray (20 Gy) to establish an RBI model. Then, morris water maze test (MWM) and step-down passive avoidance test (SDPAT) were used to assess the learning and memory function of mice. The open field test (OFT), tail suspension test (TST), and forced swimming test (FST) were used to assess changes in locomotor activity and hopelessness. Besides, X-ray-stimulated SH-SY5Y cells were used to verify the radioprotective effect of GB. Immunofluorescence double staining, Dihydroethidium (DHE), western blot, and flow cytometry were used to explore the role of DCC/MST1 signaling in RBI.

RESULTS

In this study, X-ray-treated mice exhibited cognitive impairment and depression-like behavior, which was ameliorated by GB treatment. GB also reduced the ROS production and the number of TUNEL-positive cells in the hippocampus. Moreover, GB increased the protein levels of p-AKT and Bcl2, while decreased the protein levels of MST1, p-p38, p-JNK, cleaved-caspase-3 and Bax both in vivo and in vitro. Additionally, exogenous Netrin-1 alleviated X-ray-induced ROS production and apoptosis, whereas knockout of Netrin-1 receptor DCC abolished the protective effect of GB.

CONCLUSION

Oxidative stress and MST1-mediated neuronal apoptosis participated in radiation-induced cognitive impairment and depression-like behaviors, and modulation of DCC by GB was an effective intervention against RBI.

Nigella sativa oil reduces oxidative/nitrosative stress in the salivary gland of rats exposed to total cranial irradiation

Patients with head and neck cancer who receive radiotherapy experience serious side-effects during and after their treatment. Radiotherapy affects the salivary glands, causing a change in the composition of the saliva and a decrease in its flow. In this study, we aimed to investigate whether Nigella sativa oil (NSO) has a possible protective effect in preventing the harmful effects of free radicals formed by radiotherapy in rats. Thirty-six male Wistar-Albino rats weighing 200 ± 20 g were used. The rats were randomly divided into four groups: control, sham, irradiation (IR), and IR plus NSO groups. Xanthine oxidase (XO), nitric oxide synthase (NOS) activities, nitric oxide (NO•), peroxynitrite (ONOO-), malondialdehyde (MDA) levels were determined in salivary tissue of rats. NOS, XO activities, NO•, ONOO-, and MDA values were found to be significantly higher in the irradiated rats only compared to all other groups. As a results, NSO reduces oxidative/nitrosative stress markers and has antioxidant effects, which also augments the antioxidant capacity in the salivary tissue of rats.

Effects of Nigella sativa Oil Fractions on Reactive Oxygen Species and Chemokine Expression in Airway Smooth Muscle Cells

BACKGROUND

many previous studies have demonstrated the therapeutic potential of N. sativa total oil fractions, neutral lipids (NLs), glycolipids (GLs), phospholipids (PLs), and unsaponifiable (IS) in asthma patients. We therefore tested its effect on airway smooth muscle (ASM) cells by observing its ability to regulate the production of glucocorticoid (GC)-insensitive chemokines in cells treated with TNF-α/IFN-γ, and its antioxidative and reactive oxygen species (ROS) scavenging properties.

MATERIALS AND METHODS

the cytotoxicity of N. sativa oil fractions was assessed using an MTT assay. ASM cells were treated with TNF-α/IFN-γ for 24 h in the presence of different concentrations of N. sativa oil fractions. An ELISA assay was used to determine the effect of N. sativa oil fractions on chemokine production (CCL5, CXCL-10, and CXCL-8). The scavenging effect of N. sativa oil fractions was evaluated on three reactive oxygen species (ROS), O₂•^-, OH•, and H₂O₂.

RESULTS

our results show that different N. sativa oil fractions used at 25 and 50 µg/mL did not affect cell viability. All fractions of N. sativa oil inhibited chemokines in a concentration-dependent manner. Interestingly, the total oil fraction showed the most significant effect of chemokine inhibition, and had the highest percentage of ROS scavenging effect.

CONCLUSION

these results suggest that N. sativa oil modulates the proinflammatory actions of human ASM cells by inhibiting the production of GC-insensitive chemokines.

Review of compounds that exhibit radioprotective and/or mitigatory effects after application of diagnostic or therapeutic ionizing radiation

PURPOSE

Exposure to ionizing radiation can be accidental or for medical purposes. Analyzes of the frequency of radiation damage in the general population, it has been determined that by far the most common are those that occur as a result of diagnostic or therapeutic procedures. Damage caused by radiation, either accidentally or for therapeutic purposes, can be reduced by the use of radioprotectors, mitigators or other therapeutic agents. A detailed research of the available literature shows that there is little systematized data of potentially radioprotective and/or mitigating effects of drugs from the personal therapy of patients during the application of therapeutic ionizing radiation. The aim of this paper is to present review of compounds, especially personal therapy drugs, that exhibit radioprotective and/or mitigating effects after the application of diagnostic or therapeutic ionizing radiation.

CONCLUSIONS

Given the widespread use of ionizing radiation for diagnostic and therapeutic purposes, there is a clear need to create a strategy and recommendations of relevant institutions for the use of radioprotectors and mitigators in everyday clinical practice, with individual evaluation of the patient's condition and selection of the compounds that will show the greatest benefit in terms of radioprotection.

The influence of Nigella sativa essential oil on proliferation, activation, and apoptosis of human T lymphocytes in vitro

In previous work, we tested the immunomodulatory effect of Nigella sativa (NS) fatty oil. Our results demonstrated that unrefined, obtained by cold pressing black cumin seed oil inhibited lymphocytes' proliferation and induced their apoptosis in a dose-dependent manner. In this study, we examined the immunomodulatory properties of essential oil (EO) obtained from the NS seeds by hydrodistillation and its two main constituents: thymoquinone (TQ) and p-cymene. We analyzed the proliferation, activation phenotype, and apoptosis rates of human T lymphocytes stimulated with an immobilized monoclonal anti-CD3 antibody in the presence of serial ethanol dilutions of tested oil or serial distilled water dilutions of tested compounds with flow cytometry. Our results showed that NSEO significantly inhibited the proliferation of CD4⁺ and CD8⁺ T lymphocytes, induced cell death in a dose-dependent manner, and reduced the expression of CD28 and CD25 antigens essential for lymphocyte activation. TQ inhibited the proliferation of T lymphocytes and induced cell death, particularly in high concentrations. Meanwhile, p-cymene did not influence lymphocyte proliferation. However, its high concentration induced cell necrosis. These results show that the essential oil from Nigella sativa has powerful immunomodulatory properties, which, at least partially, are related to the TQ component.

Thymoquinone Radiosensitizes Human Colorectal Cancer Cells in 2D and 3D Culture Models

Resistance of cancer cells and normal tissue toxicity of ionizing radiation (IR) are known to limit the success of radiotherapy. There is growing interest in using IR with natural compounds to sensitize cancer cells and spare healthy tissues. Thymoquinone (TQ) was shown to radiosensitize several cancers, yet no studies have investigated its radiosensitizing effects on colorectal cancer (CRC). Here, we combined TQ with IR and determined its effects in two-dimensional (2D) and three-dimensional (3D) culture models derived from HCT116 and HT29 CRC cells, and in patient-derived organoids (PDOs). TQ sensitized CRC cells to IR and reduced cell viability and clonogenic survival and was non-toxic to non-tumorigenic intestinal cells. TQ sensitizing effects were associated with G2/M arrest and DNA damage as well as changes in key signaling molecules involved in this process. Combining a low dose of TQ (3 µM) with IR (2 Gy) inhibited sphere formation by 100% at generation 5 and this was associated with inhibition of stemness and DNA repair. These doses also led to ~1.4- to ~3.4-fold decrease in organoid forming ability of PDOs. Our findings show that combining TQ and IR could be a promising therapeutic strategy for eradicating CRC cells.

Thymoquinone: A Review of Pharmacological Importance, Oxidative Stress, COVID-19, and Radiotherapy

Widely consumed worldwide, Nigella sativa (NS) is a medicinal herb commonly used in various alternative medicine systems such as Unani and Tibb, Ayurveda, and Siddha. Recommended for regular use in Tibb-e-Nabwi (Prophetic Medicine), NS is considered one of the most notable forms of healing medicine in Islamic literature. Thymoquinone (TQ), the main component of the essential oil of NS, has been reported to have many properties such as antioxidant, anti-inflammatory, antiviral, and antineoplastic. Its chemical structure indicates antiviral potential against many viruses, including the hepatitis C virus, human immunodeficiency virus, and other coronavirus diseases. Interestingly, molecular docking studies have demonstrated that TQ can potentially inhibit the development of the coronavirus disease 2019 (COVID-19) by binding to the receptor site on the transmembrane serine proteinase 2 (the activator enzyme that attaches the virus to the cell). In addition, TQ has been shown to be effective against cancer cells due to its inhibitory effect by binding to the different regions of MDM2, according to the proposed molecular docking study. Detailed in this review is the origin of TQ, its significance in alternative medicine, pharmacological value, potential as a cancer anti-proliferative agent, use against the coronavirus disease 2019 (COVID-19), and treatment of other diseases.

Effects of Nigella sativa oil and thymoquinone on radiation-induced oxidative stress in kidney tissue of rats

Ionizing radiation leads to release of free radicals into the systemic circulation from irradiated tissues. These free radicals cause oxidative stress in distant organs. Oxidative status may be reversed by naturally occurring antioxidant agents. The aim of this study was to investigate protective and antioxidant effects of Nigella sativa oil (NSO) and thymoquinone (TQ) in kidney tissue of rats exposed to cranial irradiation. Forty-eight Sprague-Dawley rats were divided into six groups: IR group received irradiation (IR) to total cranium plus saline; IR plus NSO group received IR and NSO; IR plus TQ group received IR and TQ; sham group did not receive NSO, TQ or IR; control group of TQ received dimethyl sulfoxide; control group of NSO received saline. Total oxidant status (TOS), oxidative stress index (OSI) and lipid hydroperoxide (LOOH) levels were studied as oxidative parameters, and total antioxidant status (TAS), total sulfhydryl levels, paraoxonase (PON), ceruloplasmin (Cp) and arylesterase activities were determined as antioxidative parameters in the kidney tissue of rats. Kidney TOS, OSI and LOOH levels were significantly lower in IR plus TQ, IR plus NSO and sham groups compared to IR group (p < 0.001). TAS, PON and Cp activities in IR group were significantly lower compared to the control group (p < 0.001). PON and Cp activities were significantly higher in IR plus NSO and IR plus TQ groups compared to IR group (p < 0.001). In conclusion, free radicals generated by cranial ionizing radiation exposure cause oxidative stress in kidney. NSO and TQ exhibit protective and antioxidant effects against oxidative damage in rats.

Protective effects of thymoquinone against acrylamide-induced liver, kidney and brain oxidative damage in rats

Acrylamide (AA), an industrial monomer, may cause multi-organ toxicity through induction of oxidative stress and inflammation. The antioxidant properties of thymoquinone (TQ), an active constituent of Nigella sativa, have been established before. The aim of the current study was to assess the protective effects of TQ against AA-induced toxicity in rats. Forty-eight male Wistar rats were divided into six groups each of eight rats. The first group acted as a negative control and received normal saline. Groups II and III were administered TQ orally at doses of 10 and 20 mg/kg b.wt., respectively, for 21 days. The four group received AA (20 mg/kg b.wt.) for 14 days. The five and six groups were given TQ at either dose for 21 days, starting seven days before AA supplementation (for 14 days). Acrylamide intoxication was associated with significant (p < 0.05) increases in serum levels of liver injury biomarkers (alanine transferase, aspartate transferase, and alkaline phosphatase), renal function products (urea, creatinine), DNA oxidative damage biomarker (8-oxo-2'-deoxyguanosine), and pro-inflammatory biomarkers (interleukin-1β, interleukin-6, and tumor necrosis factor-α). Moreover, AA intoxication was associated with increased lipid peroxidation and nitric oxide levels, while reduced glutathione concentration and activities of glutathione peroxidase, superoxide dismutase, and catalase in the liver, kidney, and brain. TQ administration normalized AA-induced changes in most serum parameters and enhanced the antioxidant capacity in the liver, kidney, and brain tissues in a dose-dependent manner. In conclusion, the current experiment showed that TQ exerted protective and antioxidant activities against AA-induced toxicity in mice.

Neuroprotective effect of resveratrol against radiation after surgically induced brain injury by reducing oxidative stress, inflammation, and apoptosis through NRf2/HO-1/NF-κB signaling pathway

The impact of resveratrol (RSV) on radiation (RAD)-induced brain injury in rats' brains was investigated. A total of 40 male Wistar Albino rats were randomly divided into four groups (control, RAD, RAD + RSV, and RSV groups, with 10 rats in each group). The results revealed a significant decrease in catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase activities, as well as glutathione (GSH) content. Further, a significant elevation in malondialdehyde, nitric oxide, interleukin-1-beta (IL-1β), IL-6, and transforming growth factor-β1 levels were observed. Furthermore, decreased B-cell lymphoma 2 (Bcl-2), increased Bcl-2-associated X, and tumor necrosis factor-α genes expression, decreased nuclear factor erythroid-related factor 2, heme oxygenase-1, and increased nuclear factor-κB protein levels were noticed. Also, an apoptosis marker, caspase-3-positive cells, was seen in the hippocampus. Those effects were observed in the RAD group of rats. The treatment of RSV displayed a significant amendment of the studied parameters in the brain tissues of the RAD group of animals. This effect is interrelated to the ability of RSV to scavenge the free radicals, enhance the activity of the antioxidant enzymes, increase GSH contents, and downregulate the inflammatory responses and apoptosis markers in the brain tissues of RAD animals. In conclusion, this study demonstrated that the potent antioxidant, anti-inflammatory, and antiapoptotic activities of RSV can improve the antioxidant status and suppress the inflammatory responses and apoptosis in the brain tissues of RAD animals.

Neuroprotective effect of melatonin on radiation-induced oxidative stress and apoptosis in the brainstem of rats

This study aimed to determine the effects of melatonin on irradiation-induced apoptosis and oxidative stress in the brainstem region of Wistar rats. Therefore, the animals underwent whole-brain X-radiation with a single dose of 25 Gy in the presence or absence of melatonin pretreatment at a concentration of 100 mg/kg BW. The rats were allocated into four groups (10 rats in each group): namely, vehicle control (VC), 100 mg/kg of melatonin alone (MLT), irradiation-only (RAD), and irradiation plus 100 mg/kg of melatonin (RAM). An hour before irradiation, the animals received intraperitoneal (IP) melatonin and then were killed after 6 hr, followed by measurement of nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and total antioxidant capacity (TAC) in the brainstem region. Furthermore, the western blot analysis technique was performed to assess the caspase-3 expression level. Results showed significantly higher MDA and NO levels in the brainstem tissues for the RAD group when compared with the VC group (p < .001). Moreover, the irradiated rats exhibited a significant decrease in the levels of CAT, SOD, GPx, and TAC (p < .01, p < .001, p < .001, and p < .001, respectively) in comparison to the VC group. The results of apoptosis assessment revealed that the expression level of caspase-3 significantly rose in the RAD group in comparison with the VC group (p < .001). Pretreatment with melatonin ameliorated the radiation-induced adverse effects by decreasing the MDA and NO levels (p < .001) and increasing the antioxidant enzyme activities (p < .001). Consequently, the caspase-3 protein expression level in the RAM group showed a significant reduction in comparison with the RAD group (p < .001). In conclusion, melatonin approximately showed a capacity for neuroprotective activity in managing irradiation-induced oxidative stress and apoptosis in the brainstem of rats; however, the use of melatonin as a neuroprotective agent in humans requires further study, particularly clinical trials.

Protective effects of thymoquinone and diallyl sulphide against malathion-induced toxicity in rats

Malathion is a potent organophosphate insecticide that inhibits acetylcholinesterase (AChE) enzyme. Our experimental objective was to investigate the beneficial effects of diallyl sulphide (DAS) and thymoquinone (TQ) against malathion-induced oxidative stress in rat cerebral, hepatic, and renal tissues. For 30 days, rats received corn oil alone (negative control) or malathion by intragastric gavage (200 mg/kg daily), either alone (positive control) or combined with oral DAS (200 mg/kg daily) or TQ (10 mg/kg daily) (treatment groups). Later, blood samples were collected via direct cardiac puncture and tissue samples were obtained for biochemical analysis. Malathion administration was associated with significant increases (p < 0.05) in the serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, γ-glutamyl transferase, cholesterol, urea, creatinine, and 8-OHdG (DNA damage biomarker), as well as significant (p < 0.05) decreases in the serum levels of total proteins, albumin, triglycerides, and AChE. Moreover, it significantly increased the tissue concentrations of malondialdehyde and nitric oxide and reduced tissue glutathione concentration and activities of antioxidant enzymes (glutathione peroxidase, superoxide dismutase, and catalase). Treatment of malathion-intoxicated rats with DAS or TQ significantly minimized these biochemical and oxidative effects with more frequent reversal to normal ranges of serum biomarkers, tissue oxidative markers, and antioxidant enzymes in the TQ group. In conclusion, treatment with DAS or TQ ameliorated the biochemical and oxidative effects of malathion, probably through reducing the generation of reactive oxygen and nitrogen radicals, as well as enhancing the antioxidant defense mechanisms.

Nigella sativa oil and thymoquinone reduce oxidative stress in the brain tissue of rats exposed to total head irradiation

Purpose: To evaluate the antioxidant and radio-protective effects of Nigella sativa oil (NSO) and thymoquinone (TQ) on radiation-induced oxidative stress in brain tissue.Materials and methods: Fifty-four Sprague-Dawley rats were divided into six groups to test the radio-protective effectiveness of Nigella sativa oil and thymoquine administered by either orogastric tube or intraperitoneal injection. Appropriate control groups were also studied.Results: Brain antioxidant capacity, as measured by the levels of total superoxide scavenger activity (TSSA), non-enzymatic superoxide scavenger activity (NSSA), superoxide dismutase, paraoxonase (PON) activities, total antioxidant status and total sulfhydryl (-SH) group, were lower in the irradiation (IR) only group while xanthine oxidase (XO) activity, total oxidant status (TOS), oxidative stress index (OSI) and lipid hydroperoxide (LOOH) levels were higher in the group compared with all other groups. Brain glutathione-S-transferase (GST) activity significantly decreased in the IR only group when compared with the control groups. Glutathione peroxidase (GSH-Px) activity was lower in the IR only, NSO plus IR, TQ plus IR groups when compared with the control group of TQ. Arylesterase (ARYL) activity was not statistically significant in the IR only group compared with all other groups.Conclusions: The results suggest that Nigella sativa oil (NSO) and its active component, TQ, clearly protect brain tissue from radiation-induced oxidative stress.

Nigella sativa L. for prevention of acute radiation dermatitis in breast cancer: A randomized, double-blind, placebo-controlled, clinical trial

OBJECTIVE

The present study aimed to evaluate the effectiveness of Nigella sativa L. (N. sativa) extract on preventing the incidence of acute radiation dermatitis (ARD) in breast cancer patients.

METHODS

Sixty-two breast cancer patients undergoing radiotherapy (RT) were randomly assigned to receiveN. sativa 5% gel or placebo. Patients were instructed to apply the medications twice daily during RT period. The severity of ARD, the incidence of moist desquamation, worst experienced pain, and skin-related quality of life (SRQOL) scores were assessed weekly during RT.

RESULTS

Patients who were treated with the N. sativa gel developed ARD significantly less frequently compared to those who used the placebo (p < 0.05 for all weeks except week 2, p = 0.36). The incidence time of grade 2 and 3 of Radiation Therapy Oncology Group and the European Organization for Research and Treatment of Cancer (RTOG/EORTC) toxicity was prolonged significantly with N. sativa gel as compared to placebo (35 vs. 29 days, p = 0.00 and 42 vs. 40 days, p = 0.01, respectively). Furthermore, the occurrence of moist desquamation was delayed in the N. sativa gel group compared with the placebo group (37 vs. 33 days, p = 0.01). The mean score of the worst pain that patients experienced in the placebo group was significantly higher than that of the N. sativa gel group at week 3 (2.5 ± 0.5 vs. 1.2 ± 0.3, p < 0.05). Nonetheless, the application of N. sativa gel had no significant effect on the SRQOL of patients at any week.

CONCLUSION

N. sativa extract significantly decreases the severity of ARD and delays the onset of moist desquamation in breast cancer patients.

Thymoquinone and geraniol alleviate cisplatin-induced neurotoxicity in rats through downregulating the p38 MAPK/STAT-1 pathway and oxidative stress

AIMS

Cisplatin (CP) is a widely used broad-spectrum antineoplastic agent used to treat a variety of human malignancies. Neurotoxicity is clinically evident in patients who have undergone a full course of chemotherapy. The aim of this study was to investigate the possible protective effects of thymoquinone (TQ) and geraniol (Ger) against CP-induced neurotoxicity in rats.

MAIN METHODS

Forty male Wistar albino rats were allocated into four groups as follows: normal control, CP-induced neurotoxicity, CP + TQ and CP + Ger.

KEY FINDINGS

Our results demonstrated that simultaneous treatment with either TQ or Ger and CP significantly abrogated oxidative stress and downregulated the apoptotic markers p38 mitogen-activated protein kinase (MAPK), STAT-1, p53, p21 and MMP9; FMO3, however, was insignificantly decreased. In addition to the biochemical results, we assessed the histopathological findings, which confirmed the protective effect of TQ and Ger against the brain damage induced by CP.

SIGNIFICANCE

The results of the present study indicate that simultaneous treatment with either TQ or Ger as natural antioxidants can provide protection against cisplatin-induced neurotoxicity in rats by attenuating oxidative stress and cell apoptosis.

Effects of thymoquinone, the major constituent of Nigella sativa seeds, on penicillin-induced epileptiform activity in rats

Objective:

To investigate the effects of thymoquinone (TQ) in a penicillin-induced epilepsy model in rats.

Methods:

This experimental study included 56 adult male Wistar rats. Experiments were performed in the Research Laboratory of the Department of Physiology, Medical School, Duzce University, Duzce, Turkey, between October 2013 and December 2014. Animals were divided into the following 7 groups: sham, control, only thymoquinone, vehicle (Dimethylsulfoxide), and doses of 10, 50, and 100 mg/kg of TQ. After rats were anesthetized, the left part of the skull was removed. A pair of silver/silver chloride electrodes was placed on the somatomotor area, and electrocorticographic recording was started. After 5 minutes basal activity was recorded, and TQ was applied intraperitoneally. At the thirtieth minute after TQ, epileptiform activity was induced by intracortical penicillin. The first spike latency, spike frequency, and the amplitude of epileptiform activity were analyzed statistically.

Results:

The different doses of TQ significantly increased the latency time to onset of first spike wave, and decreased the frequency, and amplitude of epileptiform activity in the first 20 minutes compared with the control group.

Conclusion:

Thymoquinone shows potential as an antiepileptic drug resulting from its effects of prolonged latency time, and reduced spike wave frequency and amplitude of epileptiform activity.

Thymoquinone and diallyl sulfide protect against fipronil-induced oxidative injury in rats

Fipronil (FPN) is a phenylpyrazole insecticide, widely used for agricultural and veterinary activities. Early reports indicated that FIP organ toxicity is primarily mediated by the induction of oxidative stress. Both thymoquinone (TQ) and diallyl sulfide (DAS) are natural antioxidants with established health benefits. This study investigated the potential ameliorative effects of DAS and TQ against FPN-induced toxicity in rats. Thirty-two male Wistar rats (150-180 g) were randomized into four treatment groups, receiving (I) saline, (II) FPN (10 mg/kg bw), (III) FPN with DAS (200 mg/kg bw), and (IV) FPN with TQ (10 mg/kg bw). All treatments were administered once daily for 28 days. The results showed that compared to the control rats, FPN-treated rats had significantly increased (p < 0.05) serum levels of uric acid, urea, creatinine, cholesterol, aspartate transferase, alanine transferase, alkaline phosphatase, lactate dehydrogenase, and γ-glutamyl transferase. Moreover, FPN significantly reduced (p < 0.05) the serum levels of total proteins, albumin, and triglycerides. In addition, compared with the control group, FPN-treated rats had significantly elevated (p < 0.05) malondialdehyde and nitric oxide levels, as well as significantly reduced glutathione concentration and activities of glutathione peroxidase, superoxide dismutase, and catalase enzymes in the hepatic, renal, and brain tissues. Cotreatment with DAS or TQ significantly ameliorated (p < 0.05) the FPN-induced alterations in all the previously mentioned parameters with more frequent restoration of normal control ranges in the TQ group. In conclusion, both DAS and TQ alleviated the oxidative injury of FPN, probably by enhancing tissue antioxidant defenses.

Thymoquinone: A novel strategy to combat cancer: A review

The higher consumption of fruit, herbs, spices, and vegetables is well known and practical strategy to cure human cancers owing to their presence of bioactive compounds. Among these, Nigella sativa is a promising source of bioactive compounds including thymoquinone, monoterpenes, p-cymene and α-piene etc. Thymoquinone has been found effective to inhibit the different cancer stages such as proliferation, migration and invasion. It also acts as anticancer agent against different human cancers such as breast, pancreatic, prostate, blood, oral, bone, head and neck, cervical, liver and lung. It significantly mediated miR-34a up-regulation, enhanced the levels of miR-34a through p53, and down controlled Rac1 expression. Thymoquinone induces apoptosis, regulates the levels of pro- and anti- apoptotic genes. It also has been known to lower the phosphorylation of NF-κB and IKKα/β and reduces the metastasis as well as also lowered the ERK1/2 and PI3K activities. Thymoquinone inhibits the metastasis through activation of JNK and p38. The present review article highlights the anticancer perspectives of thymoquinone in human by various pathways and use of this compound as diet based therapy has proven new pharmacological agent against several types of cancers.

Neuropharmacological Potential and Delivery Prospects of Thymoquinone for Neurological Disorders

Thymoquinone (TQ) is an active ingredient isolated from Nigella sativa and has various pharmacological activities, such as protection against oxidative stress, inflammation, and infections. In addition, it might be a potential neuropharmacological agent because it exhibits versatile potential for attenuating neurological impairments. It features greater beneficial effects in toxin-induced neuroinflammation and neurotoxicity. In various models of neurological disorders, it demonstrates emergent functions, including safeguarding various neurodegenerative diseases and other neurological diseases, such as stroke, schizophrenia, and epilepsy. TQ also has potential effects in trauma mediating and chemical-, radiation-, and drug-induced central nervous system injuries. Considering the pharmacokinetic limitations, research has concentrated on different TQ novel formulations and delivery systems. Here, we visualize the neuropharmacological potential, challenges, and delivery prospects of TQ, specifically focusing on neurological disorders along with its chemistry, pharmacokinetics, and toxicity.

Neuroprotective effects of Nigella sativa extract upon the hippocampus in PTU-induced hypothyroidism juvenile rats: A stereological study

This study aimed to examine the neuroprotective effects of Nigella sativa (N. sativa) in the hippocampus of propylthiouracil (PTU)-induced hypothyroid rats during neonatal and juvenile growth. Twenty- five pregnant rats from early gestation (GD 0) were divided into five groups: (1) control (received drinking water), (2) PTU (received 0.005% PTU in drinking water), (3-5) PTU + NS 0.05%, PTU + NS 0.1%, PTU + NS 0.2% (along with PTU, received 0.05%, 0.1% and 0.2% W/V of N. sativa respectively) and treatment continued until postnatal day 60 (PN 60). The brains of male pups were removed for histological and stereological assessments. N. sativa extract significantly reduced the production of dark neurons and apoptotic cells in different areas of the hippocampus compared to the PTU group. Moreover, it significantly attenuated the effect of hypothyroidism on the volume reduction of the hippocampus. The results of the present study suggested that N. sativa extract has a potential ability to prevent the hippocampal neural damage after inducing hypothyroidism during neonatal and juvenile growth in rats.

Protective Mechanisms of Thymoquinone on Methotrexate-induced Intestinal Toxicity in Rats

Background:

Intestinal toxicity is a serious side effect in methotrexate (MTX) chemotherapy.

Objective:

To investigate the mechanisms by which the anticancer drug MTX-induced intestinal damage could be prevented by thymoquinone (TQ), an active ingredient of Nigella sativa.

Materials and Methods:

TQ was given orally for 10 days, and MTX toxicity was induced at the end of day 3 of the experiment, with or without TQ pretreatment.

Results:

MTX caused intestinal damage, represented by distortion in normal intestinal histological structure, with significant oxidative stress, exhibited as decrease in reduced glutathione concentration and catalase activity, along with significant increase in malondialdehyde level compared to control group. MTX also caused nitrosative stress evident by increased intestinal nitric oxide (NO) level, with up-regulation of inducible NO synthase expression shown in immunohistochemical staining. Furthermore, MTX caused inflammatory effects as evident by up-regulation of intestinal necrosis factor-kappa beta and cyclooxygenase-2 expressions, which were confirmed by increased intestinal tumor necrosis factor-alpha level via enzyme-linked immunosorbent assay. Moreover, MTX caused apoptotic effect, as it up-regulated intestinal caspase 3 expression. Concomitant TQ significantly reversed the MTX-induced intestinal toxic effects by reversing intestinal microscopic damage, as well as significantly improving oxidative/nitrosative stress, inflammatory and apoptotic markers tested compared to MTX alone.

Conclusion:

TQ may possess beneficial intestinal protective effects as an adjuvant co-drug against MTX intestinal toxicity during cancer chemotherapy. TQ protection is conferred via antioxidant, anti-nitrosative, anti-inflammatory, and anti-apoptotic mechanisms.

SUMMARY

Methotrexate induces oxidative and nitrosative stress in intestinal tissues

Methotrexate also initiates inflammatory and apoptotic intestinal injury

Thymoquinone co-administration ameliorates methotrexate-induced intestinal toxicity

Thymoquinone has antioxidative, anti-nitrosative, anti-inflammatory, and anti-apoptotic mechanisms.

Abbreviations used: COX-2: Cyclooxygenase-2, ELISA: Enzyme-linked immunosorbent assay, H and E: Hematoxylin and eosin, iNOS: Inducible nitric oxide synthase, MDA: Malondialdehyde, MTX: Methotrexate, NO: Nitric oxide, NF-κB: Nuclear factor-κB, GSH: Reduced glutathione, TQ: Thymoquinone, TNF-α: Tumor necrosis factor-alpha