Therapeutic effects of thymoquinone or capsaicin on acrylamide-induced reproductive toxicity in rats mediated by their effect on oxidative stress, inflammation, and tight junction integrity

Drug Chem Toxicol. 2021 Jul 7:1-13. doi: 10.1080/01480545.2021.1942485. Online ahead of print. ABSTRACT In the field of environmental toxicology, endocrine-disrupting effects have become a major concern. The present research set out to investigate the possible reproductive toxicity of acrylamide. The research was also expanded to explore the protective effects of two nutraceuticals, thymoquinone (TQ) and […]

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The effect of Nigella sativa on oxidative stress and inflammatory biomarkers: a systematic review and meta-analysis

OBJECTIVES: The present systematic review of literature was conducted to study the effect of Nigella sativa (N.S) on oxidative stress and inflammatory biomarkers. OUTLOOK: Generally speaking, N.S probably results in the improvement of superoxide dismutase serum levels, TNF-α, and total antioxidant capacity. Thus, further studies are required to fully assess its impacts on all oxidative stress and inflammatory biomarkers.

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Inactivation Effect of Thymoquinone on Alicyclobacillus acidoterrestris Vegetative Cells, Spores, and Biofilms

Alicyclobacillus acidoterrestris (A. acidoterrestris), a spore-forming bacterium, has become a main challenge and concern for the juices and acid beverage industry across the world due to its thermo-acidophilic characteristic. Thymoquinone (TQ) is one of the active components derived from Nigella sativa seeds. The objective of this study was to investigate antibacterial activity and associated molecular mechanism of TQ against A. acidoterrestris vegetative cells, and to evaluate effects of TQ on A. acidoterrestris spores and biofilms formed on polystyrene and stainless steel surfaces. Minimum inhibitory concentrations of TQ against five tested A. acidoterrestris strains ranged from 32 to 64 μg/mL. TQ could destroy bacterial cell morphology and membrane integrity in a concentration-dependent manner. Field-emission scanning electron microscopy observation showed that TQ caused abnormal morphology of spores and thus exerted a killing effect on spores. Moreover, TQ was effective in inactivating and removing A. acidoterrestris mature biofilms. These findings indicated that TQ is promising as a new alternative to control A. acidoterrestris and thereby reduce associated contamination and deterioration in the juice and acid beverage industry.

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Effect of thymoquinone on high fat diet and STZ-induced experimental type 2 diabetes: A mechanistic insight by in vivo and in silico studies

The aim was to investigate whether thymoquinone (TQ) attenuates hyperglycemia-induced insulin resistance in experimental type 2 diabetes. Type 2 diabetes mellitus (T2DM) was induced by injection of streptozotocin (STZ, 40 mg/kg) in high fat diet (HFD) rats. The levels of glucose, insulin, area under curve (AUC) of glucose, lipid profile parameters, homeostasis model assessment of insulin resistance (HOMA-IR), peroxisome proliferator-activated receptor-γ (PPARγ), and dipeptidyl peptidase peptidase-IV (DPP-IV) were evaluated in HFD + STZ-induced type 2 diabetic rats. TQ treatment significantly reduced elevated levels of glucose, AUC of glucose, insulin, and DPP-IV in diabetic-treated groups. In addition, TQ treatment significantly reduced high levels of triglycerides (TG) and cholesterols (total, low-density and very low-density lipoprotein) accompanied by significant augmentation in high-density lipoprotein (HDL) levels in diabetic-treated groups. However, TQ treatment significantly improved insulin sensitivity in diabetic-treated groups, which was confirmed by increased level of PPARγ and decreased level of HOMA-IR. Molecular docking of TQ exhibited substantial binding affinity with PPARγ and DPP-IV target proteins, which is supported by in vivo results.

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Inactivation Effect of Thymoquinone on Alicyclobacillus acidoterrestris Vegetative Cells, Spores, and Biofilms

Alicyclobacillus acidoterrestris (A. acidoterrestris), a spore-forming bacterium, has become a main challenge and concern for the juices and acid beverage industry across the world due to its thermo-acidophilic characteristic. Thymoquinone (TQ) is one of the active components derived from Nigella sativa seeds. The objective of this study was to investigate antibacterial activity and associated molecular mechanism of TQ against A. acidoterrestris vegetative cells, and to evaluate effects of TQ on A. acidoterrestris spores and biofilms formed on polystyrene and stainless steel surfaces. Minimum inhibitory concentrations of TQ against five tested A. acidoterrestris strains ranged from 32 to 64 μg/mL. TQ could destroy bacterial cell morphology and membrane integrity in a concentration-dependent manner. Field-emission scanning electron microscopy observation showed that TQ caused abnormal morphology of spores and thus exerted a killing effect on spores. Moreover, TQ was effective in inactivating and removing A. acidoterrestris mature biofilms. These findings indicated that TQ is promising as a new alternative to control A. acidoterrestris and thereby reduce associated contamination and deterioration in the juice and acid beverage industry.

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Effect of Nigella sativa oil extract on cardiometabolic risk factors in type 2 diabetes: A randomized, double-blind, placebo-controlled clinical trial

The objective of this study was to determine the effects of Nigella sativa oil extract on cardiometabolic risk factors in people with type 2 diabetes (T2D). A randomized, controlled, clinical trial was conducted on 43 patients with T2D (23 women and 20 men; aged 53.5 ± 7.4 years). The intervention group (N = 23) received two 500-mg per day soft gel capsules containing Nigella sativa oil extract and the control group (N = 20) received two identical placebo soft gel capsules containing sunflower oil per day for the same period, 8 weeks. Pre- and post-intervention cardiometabolic risk factors were measured. Compared with the placebo, the N. sativa oil significantly decreased FBS (p = .03(, HbA1c (p = .001), total cholesterol (p = .04), TG (p = .003), LDL-c (p = .001), BMI (p < .001), waist circumference (p < .001), SBP (p = .001), and DBP (p = .002). HOMA-IR (p = .51) and HDL-c (p = .91) did not change significantly following Nigella sativa supplementation. Nigella sativa oil exerted beneficial effects on glycemic control, serum lipid profile, blood pressure, and body weight among people with T2D. Further long-term trials in the future may help confirm the current therapeutic benefits of Nigella sativa in T2D.

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Inhibition effect of thymoquinone and lycopene compounds on glutathione reductase enzyme activity purified from human erythrocytes

Glutathione reductase (GR, EC 1.8.1.7) is a specific antioxidant enzyme that catalyzes oxidized glutathione (GSSG) to reduced glutathione (GSH). GR enzyme maintains the cellular reduced GSH level and plays a central role in cell defense against reactive oxygen species. Herein, GR was purified with affinity chromatography method in one step using 2′,5′-ADP Sepharose 4B from human erythrocytes. The purification rate of glutathione reductase enzyme purified from human erythrocytes was 6224 fold and specific activity was calculated as 9.586 EU/mg protein. The molecular weight of GR was determined to be 53 kDa by SDS-PAGE. The effect of thymoquinone and lycopene compounds on the GR activity purified from human erythrocytes was researched. Both compounds showed an inhibitory effect on GR activity. IC50 values for thymoquinone and lycopene were calculated as 62.12 µM and 35.79 µM, respectively. Inhibition type and Ki values were determined from the Lineveawer-Burk graph. The type of inhibition for thymoquinone and lycopene was found to be non-competitive inhibition. Ki value was calculated as 57.71 µM for thymoquinone and 46.65 µM for lycopene. In this study, it was concluded that antioxidant compounds thymoquinone and lycopene, which have an inhibitory effect on GR activity, may have a therapeutic effect on cancer disease.Communicated by Ramaswamy H. Sarma.

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Ameliorative Effect of Thymoquinone-Loaded PLGA Nanoparticles on Chronic Lung Injury Induced by Repetitive Intratracheal Instillation of Lipopolysaccharide in Rats

Thymoquinone (TQ), the active constituent of Nigella sativa, possesses several benefits in traditional and modern medicines. This study examined the effect of a single dose of Nano-TQ on chronic lung injury induced by repetitive intratracheal installation of lipopolysaccharide (LPS). Rats received LPS twice weekly for 8 weeks via intratracheal installation and a single dose of TQ-PLGA NPs on the day after the last dose of LPS. Six rats from each group were sacrificed after 8 and 10 weeks, and samples were collected for analysis. Repetitive intratracheal installation of LPS caused histopathological alterations, including partial or complete obstruction of the alveoli, interstitial edema, mild fibroblastic proliferation, fibrous strands besides lymphocytes and plasma infiltrations, suffered fetalization, bronchiectasis, hypertrophied arterioles, and others. Investigation of the ultrastructure revealed prominent necrotic pneumocytes with destructed chromatin and remnant of necrotic debris in the narrowing alveolar lumen in LPS-induced rats. TQ-PLGA NPs effectively ameliorated LPS-induced histopathological and ultrastructural alterations in the lung of rats. In addition, TQ-PLGA NPs significantly alleviated serum levels of IL-10 and TGF-β1 in LPS-induced rats. In conclusion, TQ-PLGA NPs prevented inflammation and tissue injury in the lungs of rats challenged with repetitive intratracheal installation of LPS. Therefore, TQ-PLGA NPs represent a promising candidate for the prevention of lung injury induced by LPS, pending further studies to determine its safety and exact protective mechanism.

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Effect of Nigella sativa, atorvastatin, or L-Carnitine on high fat diet-induced obesity in adult male Albino rats

Obesity is increasing rapidly across the globe. It is widely accepted that natural products with a long safety background may modulate obesity. The current work aimed to investigate the effect of Nigella sativa, atorvastatin, or L-Carnitine on high-fat diet-induced obesity in white male albino rats. A regular basal diet was fed to 7 rats, and a high-fat diet (HFD) was fed to 24 rats throughout the study for 12 weeks. The HFD group was split equally into four subgroups, each containing six rats. The first group fed on HFD with no medication, the second group received HFD+ Nigella sativa, the third group received HFD+ atorvastatin, and the fourth group received HFD+L-carnitine. At the beginning of the seventh week (the start of the treatment regimen), Nigella sativa, atorvastatin, or L-Carnitine were administered for six weeks. Glucose, body weight, serum atherogenic index (AI), ALT, and AST activities were analyzed. The pathological alterations in the hepatic tissues were examined microscopically and scored. The results revealed that the HFD diet significantly increased the final body weight, serum AI, and serum levels of liver enzymes. Treatment with L-carnitine or Nigella sativa significantly normalized the lipid profile and decreased the final body weight, serum AI, and Serum ALT. Histopathological examination of the liver of HFD received rats showed features of steatosis, which were mitigated by the administration of Nigella sativa or L-Carnitine, while atorvastatin had no significant effect on the improvement of hepatic lesions. Collectively, study findings showed that Nigella sativa or L-Carnitine has mitigated effects on metabolic and histopathological changes in the liver tissues of rats fed with HFD.

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The positive effect of black seed (Nigella sativa L.) essential oil on thyroid hormones in rats with hypothyroidism and hyperthyroidism

In our study, the effect of essential oil obtained from Nigella sativa L. (NSE) on thyroid hormones and antioxidant balance in hypothyroidism (HT) and hyperthyroidism (HP) models induced by propylthiouracil(PTU) and L-thyroxine(LT4 ), respectively, in rats were investigated for 4 weeks. NSE was administered by gastric gavage at a dose of 200 mg/kg body weight. In this study, 48 male Wistar albino rats with an average weight of 180-290 g and age 5-6 months were divided into eight groups, as follows: groups with HT, (1) control, (2) HT, (3) NSE, and (4) HT + NSE; groups with HP, (1) control, (2) HP, (3), and NSE (4) HP + NSE. As a result, we found that NSE administration increased total triiodothyronine (TT3 ) and decreased nitric oxide in HT + NSE. Besides, it decreased TT3 in HP + NSE and increased total antioxidant capacity. Our findings suggest that NSE may have beneficial effects on thyroid gland abnormalities owing to its antioxidant properties. PRACTICAL APPLICATIONS: Essential oils derived from Nigella sativa L. seed contain many bioactive substances such as thymoquinone and cymene. This paper emphasizes the effect of NSE on thyroid hormone abnormalities and negative oxidative state that occurs in HT and HP models. The present study provides evidence of a positive effect of NSE particularly on TT3 levels in the HT and HP models. It can therefore be assumed that NSE could be used as a supportive natural alternative source to improve thyroid hormone levels and relieve increased oxidative stress.

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