Anti-inflammatuar and anti-oxidative effects of Nigella sativa L.: 18FDG-PET imaging of inflammation

Protective effect of thymoquinone nanoemulsion in reducing the cardiotoxic effect of 5-fluorouracil in rats

5-Fluorouracil (5-FU), which is one of the most widely used chemotherapy drugs, has various side effects on the heart. Thymoquinone (TMQ), the main bioactive component of Nigella sativa, has antioxidant and protective effects against toxicity. In this study, we investigated the protective effect of thymoquinone against cardiotoxicity caused by 5-FU in vitro and in vivo models. H9C2 cells were exposed to 5-FU and TMQ, and cell viability was evaluated in their presence. Also, 25 male Wistar rats were divided into five control groups, 5-FU, 2.5, and 5 mg TMQ in nanoemulsion form (NTMQ) + 5-FU and 5 mg NTMQ. Cardiotoxicity was assessed through electrocardiography, cardiac enzymes, oxidative stress markers, and histopathology. 5-FU induced cytotoxicity in H9c2 cells, which improved dose-dependently with NTMQ cotreatment. 5-FU caused body weight loss, ECG changes (increased ST segment, prolonged QRS, and QTc), increased cardiac enzymes (aspartate aminotransferase [AST], creatine kinase-myocardial band [CK-MB], and lactate dehydrogenase [LDH]), oxidative stress (increased malondialdehyde, myeloperoxidase, nitric acid; decreased glutathione peroxidase enzyme activity), and histological damage such as necrosis, hyperemia, and tissue hyalinization in rats. NTMQ ameliorated these 5-FU-induced effects. Higher NTMQ dose showed greater protective effects. Thus, the results of our study indicate that NTMQ protects against 5-FU cardiotoxicity likely through antioxidant mechanisms. TMQ warrants further research as an adjuvant to alleviate 5-FU chemotherapy side effects.

Evaluation and comparison of flexural strength, surface roughness and porosity percentage of denture base resins incorporated with Thymoquinone and silver nano-antimicrobial agents-an in vitro study

Aim

To evaluate and compare the flexural strength, surface roughness and porosity percentage of acrylic denture base material modified with two antimicrobial agents, Thymoquinone (TQ) and Silver nanoparticles (AgNP).

Materials and methods

A total of 90 specimens were fabricated and divided into groups A, B and C with 30 specimens each. Of the 30 specimens, 10 specimens measuring 65mmx 10mmx 2.5 mm were used to study the flexural strength, 10 specimens measuring 10 mm × 20 mm × 3 mm to study surface roughness and 10 specimens measuring 10 mm × 20 mm × 3 mm to study porosity percentage. Group A specimens were made of unmodified denture base resin, group B and C were modified with 2.5% AgNP and 1% TQ respectively. The specimens were processed in the conventional manner. A universal testing machine was used to measure flexural strength and a profilometer was used to measure surface roughness. Porosity percentage was evaluated with help of a desiccator. The data obtained was subjected to statistical analyses using One-way ANOVA and the Tukey-post hoc test, with statistical significance at p ≤ 0.05.

Results

Addition of 2.5% AgNP and 1% TQ to acrylic denture base resin significantly reduced flexural strength and increased the porosity percentage (p < 0.01) but within clinically acceptable limits. No significant difference was found in the surface roughness between the various groups tested.

Conclusions

Heat cured acrylic denture base resins modified with 2.5% AgNPs,1% TQ exhibited clinically acceptable flexural strength and surface properties and could be incorporated into the denture base material as an antimicrobial agent.

Nigella sativa Oil Reduces LPS-Induced Microglial Inflammation: An Evaluation on M1/M2 Balance

Objectives

The immune system plays a critical defence role against infections, injuries, and carcinogenic stimuli. As the macrophages of the brain resides in the innate immune system, microglia and their polarisation (M₁/M₂) play regulatory roles in inflammation in CNS, such as Parkinson's, Alzheimer's, dementia complex, and multiple sclerosis. Nigella sativa belongs to the Ranunculaceae family and has different anti-inflammatory and antioxidant effects. We conducted this study to evaluate the anti-inflammatory and protective properties of N. sativa oil (NSO) on the microglial cells and their polarisation (M₁/M₂) in the presence of LPS as a model of neuroinflammation.

Methods

The protective effects of NSO (10–40 µg/ml) were studied on the LPS-induced microglial cells, and the levels of tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, prostaglandin E₂ (PGE₂), and IL-10 were evaluated using both ELISA and gene expression methods. The levels of cyclooxygenase-2 (COX-2), inducible NOS (iNOS), and arginase-1 (Arg1) were also evaluated using the real-time PCR method. In addition, nitrite oxide (NO) and urea were measured using biochemical methods.

Results

NSO decreased LPS-induced toxicity at all doses (P < 0.001). NSO (10–40 μg/ml) also significantly reduced the levels of TNF-α, PGE2, IL-1β, and IL-6 in the presence of LPS (P < 0.01 to 0.001). Pretreatment with NSO attenuated the levels of iNOS but increased Arg1 (P < 0.001). The ratio of iNOS/Arg1 was also decreased in the presence of NSO (P < 0.001) than that of the LPS group (P < 0.001).

Conclusion

NSO attenuated LPS-induced inflammation and increased microglia's anti-inflammatory status. These results may prove that NSO is potentially an immunomodulator for various neurodegenerative diseases by M1 phenotype dominancy, such as Alzheimer's and Parkinson's diseases.

Suppressive effects of thymoquinone on the initiation stage of diethylnitrosamine hepatocarcinogenesis in rats

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death globally. Chemoprevention is the most effective technique for reducing HCC incidence. Thymoquinone (TQ), the main bioactive constituent of Nigella sativa, exhibits anti-inflammatory and antineoplastic activities against various cancers. Therefore, TQ was tested as an inhibitor of the initial phase of diethylnitrosamine (DEN)-induced HCC in rats. Twenty-four male Wistar albino rats were randomly placed into four equal groups. Group 1 received saline and acted as the negative control; Group 2 received TQ; Group 3 received DEN; and Group 4 received TQ for 7 days and DEN on the 8th day. After 24 h of fasting, blood samples were taken from the slaughtered rats. Additionally, each rat's liver was dissected and separated into two halves for histological and biochemical investigation. DEN-induced hepatotoxicity was detected by elevated hepatic enzymes and HCC biomarkers reduced antioxidant and proapoptotic statuses. DEN administration caused a significant increase in the levels of glutathione, superoxide dismutase, malondialdehyde, caspase-3, alpha-fetoprotein (AFP), AFPL3, glypican 3, and the expression of BAX. However, DEN significantly decreased glutathione peroxidase, catalase, and CYP2E1 and the expression of BCl-2. Furthermore, it caused histological changes and showed a strong positive GSH S-transferase P expression in the hepatic parenchyma. Pretreatment with TQ prevented the histopathological and most of the biochemical changes and improved the antioxidant status. TQ supplementation appears to suppress the development of DEN-initiated liver cancer by reducing oxidative stress, activating the intrinsic mitotic apoptosis pathway, and retaining the antioxidant enzymes.

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.

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.

CONTENT

Different online databases such as Cochrane Central Register of Controlled Trials, MEDLINE (PubMed), Scopus, Web of Sciences, EMBASE, and Clininaltrial.gov for English articles and national databases of SID, Magiran, Irandoc, and Iranmedex for Persian articles, which were published until March; 2019 were scrutinized. All Randomised Controlled Trials (RCTs) and quasi-experimental studies that aimed to compare the impact of N.S along, with placebo or without supplementation, on inflammatory factors and oxidative stress were entered in the present study.

SUMMARY

Finally, 11 RCTs covering 710 women and men, in total, were participated in the present meta-analysis. Significant differences were observed in Tumor Necrosis Factor alpha (TNF-α) (Weighted Mean Difference (WMD) =-2.15 pg/mL, 95% Confidence Interval (CI) =-3.22--1.09, I²=32%; 5 trials with 262 participants) superoxide dismutase (WMD=63.79 µ/gHb, 95% CI=6.84-120.75, I²=0%; 2 trials, with 88 participants), and total antioxidant capacity (WMD=0.34 mmol/L, 95% CI=0.04 to 0.63, I²=94%; 5 trials with 232 participants). Nevertheless, there was no significant difference in high sensitivity C-reactive protein (WMD=-0.98 mg/L, 95% CI=-1.98-0.03, I²=78%; 5 trials with 267 participants), Interleukin 6 (IL-6) (WMD=-0.25 pg/mL, 95% CI=-0.65 to 0.16, I²=0%; 2 trials with 134 participants), and malondialdehyde (WMD=-0.95 nmol/mL, 95% CI=-1.97-0.08, I²=68%; 4 trials with 179 participants).

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.

Flavonoids Activation of the Transcription Factor Nrf2 as a Hypothesis Approach for the Prevention and Modulation of SARS-CoV-2 Infection Severity

The Nrf2-Keap1-ARE pathway is the principal regulator of antioxidant and phase II detoxification genes. Its activation increases the expression of antioxidant and cytoprotective proteins, protecting cells against infections. Nrf2 modulates virus-induced oxidative stress, ROS generation, and disease pathogenesis, which are vital in the viral life cycle. During respiratory viral infections, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an inflammatory process, and oxidative stress of the epithelium lining cells activate the transcription factor Nrf2, which protects cells from oxidative stress and inflammation. Nrf2 reduces angiotensin-converting enzyme 2 (ACE2) receptors expression in respiratory epithelial cells. SARS-CoV2 has a high affinity for ACE2 that works as receptors for coronavirus surface spike glycoprotein, facilitating viral entry. Disease severity may also be modulated by pre-existing conditions, such as impaired immune response, obesity, and age, where decreased level of Nrf2 is a common feature. Consequently, Nrf2 activators may increase Nrf2 levels and enhance antiviral mediators' expression, which could initiate an "antiviral state", priming cells against viral infection. Therefore, this hypothesis paper describes the use of flavonoid supplements combined with vitamin D3 to activate Nrf2, which may be a potential target to prevent and/or decrease SARS-CoV-2 infection severity, reducing oxidative stress and inflammation, enhancing innate immunity, and downregulating ACE2 receptors.

Administration of Nigella sativa during neonatal and juvenile growth period improved liver function of propylthiouracil-induced hypothyroid rats

Aim: Propylthiouracil (PTU) is frequently used as an antithyroid medication. It is also commonly used to induce hypothyroidism in rodents. PTU administration and hypothyroidism have been shown to affect the liver function. Nigella sativa (NS) has been suggested to have antioxidant and hepatoprotective effects. The objective of this study was to investigate the effects of NS extract administration during neonatal and juvenile growth period on liver function of PTU-induced hypothyroid rats.Methods: The pregnant rats were kept in separate cages. After delivery, the mothers and their offspring were randomly divided into five groups and were treated with the following programs: (1) control; (2) PTU, 0.005% in their drinking water (3-5); PTU-plus 100, 200, or 400 mg/kg NS extract. After lactation period, the offspring continued to receive the same experimental treatment for the first 8 weeks of their life. Ten offspring of each group were randomly selected and weighted at days 10, 30, and 60 after delivery. Their blood samples were collected and the liver tissues were removed.Results: Malondialdehyde (MDA) concentration was increased while, thiol concentration and superoxide dismutase (SOD) and catalase (CAT) activity were decreased in the liver tissues of PTU-treated rats. Serum aspartate amino transferase (AST), alkaline phosphatase (ALK-P), and alanine aminotransferase (ALT) levels in the PTU group were higher than the control group. Treatment with 200 and 400 mg/kg decreased MDA while increasing thiol concentration in the liver tissues compared to the PTU group. Treatment with all doses of the extract decreased serum ALK-P concentration compared with the PTU group. Treatment with 400 mg/kg NS increased CAT and SOD concentrations in the liver tissues and decreased serum AST and ALT concentrations compared to the PTU group. PTU decreased body weight gain of offspring and while, the extract increased the body weight gain of offspring rats.Conclusion: The results of this study demonstrated that administration of NS hydroalcoholic extract in the neonatal and juvenile growth period has an improving effect on the liver function of PTU- induced hypothyroid rats.

The natural phenolic compounds as modulators of NADPH oxidases in hypertension

BACKGROUND

Hypertension is a major public health problem worldwide. It is an important risk factor for other cardiovascular diseases such as coronary artery disease, stroke, heart failure, atrial fibrillation, peripheral vascular disease, chronic kidney disease, and atherosclerosis.

PURPOSE

There is strong evidence that excess ROS-derived NADPH oxidase (NOX) is an important agent in hypertension. It augments blood pressure in the presence of other pro-hypertensive factors such as angiotensin II (Ang II), an important and potent regulator of cardiovascular NADPH oxidase, activates NOX via AT1 receptors. NADPH oxidase, a multi-subunit complex enzyme, is considered as a key source of ROS production in the vasculature. The activation of this enzyme is needed for assembling Rac-1, p^40phox, p^47phox and p^67phox subunits. Since, hypertensive patients need to control blood pressure for their entire life and because drugs and other chemicals often induce adverse effects, the use of natural phenolic compounds which are less toxic and potentially beneficial may be good avenues of addition research in our understand of the underlying mechanism involved in hypertension. This review focused on several natural phenolic compounds as berberine, thymoquinone, catechin, celastrol, apocynin, resveratrol, curcumin, hesperidine and G-hesperidine, and quercetin which are NOX inhibitors. In addition, structure activity relationship of these compounds eventually as the most inhibitors was discussed.

METHODS

This comprehensive review is based on pertinent papers by a selective search using relevant keywords that was collected using online search engines and databases such as ScienceDirect, Scopus and PubMed. The literature mainly focusing on natural products with therapeutic efficacies against hypertension via experimental models both in vitro and in vivo was identified.

RESULTS

It has been observed that these natural compounds prevent NADPH oxidase expression and ROS production while increasing NO bioavailability. It have been reported that they improve hypertension due to formation of a stable radical with ROS-derived NADPH oxidase and preventing the assembly of NOX subunites.

CONCLUSION

It is clear that natural phenolic compounds have some potential inhibitory effect on NADPH oxidase activity. In comparison to other phenolic plant compounds, the structural variability of the flavonoids should off different impacts on oxidative stress in hypertension including inhibition of nadph oxidase and direct scavenging of free radicals.

Essential Oils and Their Major Compounds in the Treatment of Chronic Inflammation: A Review of Antioxidant Potential in Preclinical Studies and Molecular Mechanisms

Inflammatory diseases result from the body's response to tissue damage, and if the resolution is not adequate or the stimulus persists, there will be progression from acute inflammation to chronic inflammation, leading to the development of cancer and neurodegenerative and autoimmune diseases. Due to the complexity of events that occur in inflammation associated with the adverse effects of drugs used in clinical practice, it is necessary to search for new biologically active compounds with anti-inflammatory activity. Among natural products, essential oils (EOs) present promising results in preclinical studies, with action in the main mechanisms involved in the pathology of inflammation. The present systematic review summarizes the pharmacological effects of EOs and their compounds in in vitro and in vivo models for inflammation. The research was conducted in the following databases: PubMed, Scopus, BIREME, Scielo, Open Grey, and Science Direct. Based on the inclusion criteria, 30 articles were selected and discussed in this review. The studies listed revealed a potential activity of EOs and their compounds for the treatment of inflammatory diseases, especially in chronic inflammatory conditions, with the main mechanism involving reduction of reactive oxygen and nitrogen species associated with an elevation of antioxidant enzymes as well as the reduction of the nuclear factor kappa B (NF-κB), reducing the expression of proinflammatory cytokines. Thus, this review suggests that EOs and their major compounds are promising tools for the treatment of chronic inflammation.

Flexural and Surface Properties of PMMA Denture Base Material Modified with Thymoquinone as an Antifungal Agent

PURPOSE

To evaluate the effect of addition of different concentrations of thymoquinone (TQ) on the flexural strength, elastic modulus, surface roughness, and hardness of PMMA denture base material.

MATERIALS AND METHODS

A total of 160 rectangular specimens were prepared from heat-polymerized acrylic resin, with dimensions of 65 × 10 × 2.5 mm³ for flexural strength testing and 10 × 20 × 3 mm³ for surface property testing. The specimens were divided into eight groups of 20 specimens: one control group without addition of TQ and seven test groups prepared by adding TQ to acrylic powder in concentrations of 0.5, 1, 1.5, 2, 2.5, 3, and 5 wt%. The polymer was added to the monomer before being mixed, packed, and processed using the conventional water bath method. A universal testing machine was used to measure flexural strength and elastic modulus. A profilometer and a Vickers hardness tester were used to measure surface roughness and hardness, respectively. One-way ANOVA and the Tukey-Kramer multiple-comparison test were used for statistical analysis, with statistical significance at p ≤ 0.05.

RESULTS

Addition of TQ to PMMA denture base material significantly decreased flexural strength and elastic modulus at high concentrations (p < 0.01), while no significant differences were observed at low concentrations (0.5%, 1% TQ) in comparison with the control group. At high TQ concentrations, surface roughness increased while hardness decreased (p < 0.0001), and no significant differences were observed at low concentrations (0.5%, 1% TQ) in comparison with the control group. The most favorable addition values were 0.5% and 1% TQ in all TQ groups.

CONCLUSIONS

Addition of TQ did not affect the flexural and surface properties of PMMA denture base material at low concentrations (0.5%, 1% TQ) and could be incorporated into PMMA denture base material as an antifungal agent.

Effect of Nigella sativa against cisplatin induced nephrotoxicity in rats

In this study, the gross composition and mineral content of Nigella sativa seed powder (NSP) and fatty acid composition of Nigella sativa oil (NSO) were investigated. The ability of NSP, extract (NSE) and NSO in reducing the effects of cisplatin-induced renal toxicity in Sprague-Dawley rats were examined. The obtained results showed that NSP contains high amounts of carbohydrates, protein, and fiber while NSO has higher amounts of linoleicacid, oleic acid, and myristic acid. Rats treated with NSP, NSO, and NSE exhibitedreducedserum levels of urea, creatinine, and potassium, and a significant increase of Na, Na/K, vitamin D, nutritional markers, and antioxidant enzymes compared to the cisplatin-induced renal toxicity group receiving no Nigella sativa seed treatment. This study determined that all powder, oil, and extracts of N. sativa contain potent bioactive components that may aid in treatment against cisplatininduced renal toxicity in rats.

Propolis Protects Endotoxin Induced Acute Lung and Liver Inflammation Through Attenuating Inflammatory Responses and Oxidative Stress

Propolis is a natural bee product, and it has many effects, including antioxidant, anti-inflammatory, antihepatotoxic, and anticancer activity. In this study, we aimed to explore the potential in vivo anti-inflammatory, antioxidant, and antiapoptotic properties of propolis extract on lipopolysaccharide (LPS)-induced inflammation in rats. Forty-two, 3- to 4-month-old male Sprague Dawley rats were used in six groups. LPS (1 mg/kg) was administered intraperitoneally to rats in inflammation, inflammation + propolis30, and inflammation+propolis90 groups. Thirty milligram/kilogram and 90 mg/kg of propolis were given orally 24 h after LPS injection. After the determination of the inflammation in lung and liver tissues by ¹⁸F-fluoro-deoxy-d-glucose-positron emission tomography (¹⁸FDG-PET), samples were collected. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), nitric oxide (NO), and DNA fragmentation were determined. The decrease of MDA levels in inflammation + propolis30 and inflammation + propolis90 groups was determined compared to the inflammation group in lung and liver tissues. The increase of SOD% inhibition in inflammation + propolis90 group was determined in liver, lung, and hemolysate compared to the inflammation group. Increased CAT activities in inflammation + propolis30 and inflammation + propolis90 groups were observed in liver tissue and hemolysate compared to inflammation group. In lung tissue, NO levels were lower in inflammation group compared to the control group, but DNA fragmentation levels were higher. ¹⁸F-FDG uptake of tissues in inflammation + propolis30 and inflammation + propolis90 groups was decreased compared to the inflammation group. In conclusion, the data of this study indicate that the propolis application may serve as a potential approach for treating inflammatory diseases through the effect of reducing inflammation and free oxygen radical production.

Thymoquinone Ameliorates Doxorubicin-Induced Cardiotoxicity in Swiss Albino Mice by Modulating Oxidative Damage and Cellular Inflammation

Thymoquinone is the active constituent of Nigella sativa, having antioxidant and anti-inflammatory actions. In present study, we have analyzed the effects of thymoquinone on doxorubicin (DOX) induced cardiotoxicity in mice. In this experiment, thirty mice (25–35 gm) were divided into five groups (Groups A, B, C, D, and E) each containing six animals. Normal saline was given to a control group (Group A) for 14 days. Cardiotoxicity was induced by DOX (15 mg/kg, i.p.) in Group B, once on the 13th day of the study, and Groups C and D also received DOX (15 mg/kg, i.p.) and were then treated with thymoquinone (10 and 20 mg/kg, b/w, p.o.), respectively, for 14 days. Group E was given only thymoquione (20 mg/kg b/w, p.o.). A blood serum marker (AST, ALT, CK-MB, and LDH) and oxidative stress marker (LPO, GSH, CAT, SOD, GPx, GR, and GST) were evaluated. Results revealed that serum enzyme marker like aspartate aminotransferase (AST), creatinine kinase-MB (CKMB), and lactate dehydrogenase (LDH) were significantly elevated in Group B as compare to Group A. Similarly, the oxidative stress marker lipid peroxidation (LPO) was also elevated in Group B while the antioxidant enzyme catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase (CAT, SOD, GPx, GR, and GST) were also decreased in Group B. The treatment with thymoquinone 10 and 20 mg/kg resulted in a significant decrease in the serum marker and increase in the antioxidant enzymes. In this study, we have found that thymoquinone prevented DOX-induced cardiotoxicity by accelerating heart antioxidant defense mechanisms and down regulating the LPO levels towards normalcy in Groups C and D. The effect of doxorubicin increases the inflammatory cytokine (IL2) in Group B as compared to Group A, and it overcomes by the thymoquinone in Groups C and D. Thus, thymoquinone may have utility as a potential drug for cardiomyopathy.

Inhibition of cytochrome P450 enzymes by thymoquinone in human liver microsomes

The aim of the present study was to investigate the potential effect of thymoquinone (TQ) on the metabolic activity of four major drug metabolizing enzymes in human liver microsomes, namely cytochrome P450 (CYP) 1A2, CYP2C9, CYP2D6 and CYP3A4. The inhibition of CYP enzymatic activities by TQ was evaluated by incubating typical substrates (phenacetin for CYP1A2, tolbutamide for CYP2C9, dextromethorphan for CYP2D6, and testosterone for CYP3A4) with human liver microsomes and NADPH in the absence or presence of TQ (1, 10 and 100 µM). The respective metabolite of the substrate that was formed was measured by HPLC. Results of the presented study presented that the metabolic activities of all the investigated CYP enzymes, viz. CYP1A2, CYP2C9, CYP2D6 and CYP3A4, were inhibited by TQ. At 1 µM TQ, CYP2C9 enzyme activity was maximally inhibited by 46.35%, followed by CYP2D6 (20.26%) > CYP1A2 (13.52%) > CYP3A4 (12.82%). However, at 10 µM TQ, CYP2C9 enzyme activity was maximally inhibited by 69.69%, followed by CYP3A4 (23.59%) > CYP1A2 (23.51%) > CYP2D6 (11.42%). At 100 µM TQ, CYP1A2 enzyme activity was maximally inhibited by 81.92%, followed by CYP3A4 (79.24%) > CYP2C9 (69.22%) > CYP2D6 (28.18%). The IC₅₀ (mean ± SE) values for CYP1A2, CYP2C9, CYP2D6 and CYP3A4 inhibition were 26.5 ± 2.9 µM, 0.5 ± 0.4 µM, >500 µM and 25.2 ± 3.1 µM, respectively. These findings suggest that there is a high probability of drug interactions resulting from the co-administration of TQ or herbs containing TQ with drugs that are metabolized by the CYP enzymes, particularly CYP2C9.

In Vitro Evaluation of the Inhibitory Activity of Thymoquinone in Combatting Candida albicans in Denture Stomatitis Prevention

Candida albicans adhesion and proliferation on denture bases may lead to denture stomatitis, which is a common and recurrent problem in denture wearers. The goal of this study was to assess the inhibitory effect of thymoquinone incorporated in the polymethyl methacrylate denture base material against Candida albicans. Eighty acrylic resin specimens were fabricated and divided into eight groups (n = 10) according to thymoquinone concentrations of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, and 5% of acrylic powder. Two methods were used to evaluate the effect of thymoquinone on Candida albicans: the slide count and the serial dilution test. A multivariate analysis of variance (MANOVA) and the post-hoc Tukey’s Honestly Significant Difference (HSD) test were performed to compare the difference of means between the observations taken at various intervals with baseline. The p value was statistically significant at ≤0.05. According to the slide count and the serial dilution test, the mean number of adhered Candida albicans in the control group was 5436.9 ± 266 and 4691.4 ± 176.8; however, this number dramatically decreased to 0 ± 0 and 32.4 ± 1.7 in group 8 (concentration 5%). These results suggest that the incorporation of thymoquinone into the acrylic resin denture base material might be effective in preventing Candida albicans adhesion.

β-Sitosterol Reduces the Expression of Chemotactic Cytokine Genes in Cystic Fibrosis Bronchial Epithelial Cells

Extracts from Nigella arvensis L. seeds, which are widely used as anti-inflammatory remedies in traditional medicine of Northern Africa, were able to inhibit the expression of the pro-inflammatory neutrophil chemokine Interleukin (IL)-8 in Cystic Fibrosis (CF) bronchial epithelial IB3-1 cells exposed to the Gram-negative bacterium Pseudomonas aeruginosa. The chemical composition of the extracts led to the identification of three major components, β-sitosterol, stigmasterol, and campesterol, which are the most abundant phytosterols, cholesterol-like molecules, usually found in plants. β-sitosterol (BSS) was the only compound that significantly reproduced the inhibition of the P. aeruginosa-dependent expression of IL-8 at nanomolar concentrations. BSS was tested in CF airway epithelial CuFi-1 cells infected with P. aeruginosa. BSS (100 nM), showed a significant and consistent inhibitory activity on expression of the P. aeruginosa-stimulated expression chemokines IL-8, GRO-α GRO-β, which play a pivotal role in the recruitment of neutrophils in CF inflamed lungs. Preliminary mechanistic analysis showed that BSS partially inhibits the P. aeruginosa-dependent activation of Protein Kinase C isoform alpha, which is known to be involved in the transmembrane signaling activating IL-8 gene expression in bronchial epithelial cells. These data indicate BSS as a promising molecule to control excessive lung inflammation in CF patients.

Mitigation of cadmium-induced lung injury by Nigella sativa oil

Induction of oxidative stress and inflammation are considered the primary mechanism of cadmium (Cd) toxicity. Nigella sativa (NS) seeds and their oil (NSO) have been reported to possess antioxidant and anti-inflammatory potential. This study was conducted to assess the protective effect of NSO on Cd-induced lung damage in rat. Forty adult male Wistar rats were divided equally into 4 groups. Animals in groups I, II, and III received 1 ml of isotonic saline intraperitoneally (IP), 2 mg/kg of cadmium chloride (CdCl₂) dissolved in isotonic saline IP, and 1 ml/kg of NSO by gastric gavage, respectively. Group IV rats received NSO an hour prior to CdCl₂ administration via the same routes and doses as previously described. All animals were treated for 28 days. At the end of the study, animals were sacrificed; lungs were harvested for histopathological studies using light and electron microscopy. Saline-treated and NSO-treated rats showed normal lung parenchyma. However, CdCl₂-treated rats showed massive degenerative changes in alveolar epithelial lining, disrupted interalveolar septa, and hemolytic debris in alveoli. Rats treated with both NSO and CdCl₂ (group IV) showed amelioration of most Cd-induced lung damage with minimal histopathological changes in lung architecture. This study elucidates the protective effects of NSO on Cd-induced lung injury in rats and highlights the possibility of using NSO as a protective agent in individuals at high risk of Cd-induced lung toxicity.

Thymoquinone inhibits growth of human medulloblastoma cells by inducing oxidative stress and caspase-dependent apoptosis while suppressing NF-κB signaling and IL-8 expression

Medulloblastoma (MB) is the most common malignant brain tumor of childhood. The transcription factor NF-κB is overexpressed in human MB and is a critical factor for MB tumor growth. NF-κB is known to regulate the expression of interleukin-8 (IL-8), the chemokine that enhances cancer cell growth and resistance to chemotherapy. We have recently shown that thymoquinone (TQ) suppresses growth of hepatocellular carcinoma cells in part by inhibiting NF-κB signaling. Here we sought to extend these studies in MB cells and show that TQ suppresses growth of MB cells in a dose- and time-dependent manner, causes G2M cell cycle arrest, and induces apoptosis. TQ significantly increased generation of reactive oxygen species (ROS), while pretreatment of MB cells with the ROS scavenger N-acetylcysteine (NAC) abrogated TQ-induced cell death and apoptosis, suggesting that TQ-induced cell death and apoptosis are oxidative stress-mediated. TQ inhibitory effects were associated with inhibition of NF-κB and altered expression of its downstream effectors IL-8 and its receptors, the anti-apoptotic Bcl-2, Bcl-xL, X-IAP, and FLIP, as well as the pro-apoptotic TRAIL-R1, caspase-8, caspase-9, Bcl-xS, and cytochrome c. TQ-triggered apoptosis was substantiated by up-regulation of the executioner caspase-3 and caspase-7, as well as cleavage of the death substrate poly(ADP-ribose)polymerase. Interestingly, pretreatment of MB cells with NAC or the pan-caspase inhibitor zVAD-fmk abrogated TQ-induced apoptosis, loss of cyclin B1 and NF-κB activity, suggesting that these TQ-mediated effects are oxidative stress- and caspase-dependent. These findings reveal that TQ induces both extrinsic and intrinsic pathways of apoptosis in MB cells, and suggest its potential usefulness in the treatment of MB.

Involvement of Immune Responses in the Efficacy of Cord Blood Cell Therapy for Cerebral Palsy

This study evaluated the efficacy of umbilical cord blood (UCB) cell for patients with cerebral palsy (CP) in a randomized, placebo-controlled, double-blind trial and also assessed factors and mechanisms related to the efficacy. Thirty-six children (ages 6 months to 20 years old) with CP were enrolled and treated with UCB or a placebo. Muscle strength and gross motor function were evaluated at baseline and 1, 3, and 6 months after treatment. Along with function measurements, each subject underwent (18)F-fluorodeoxyglucose positron emission tomography at baseline and 2 weeks after treatment. Cytokine and receptor levels were quantitated in serial blood samples. The UCB group showed greater improvements in muscle strength than the controls at 1 (0.94 vs. -0.35, respectively) and 3 months (2.71 vs. 0.65) after treatment (Ps<0.05). The UCB group also showed greater improvements in gross motor performance than the control group at 6 months (8.54 vs. 2.60) after treatment (P<0.01). Additionally, positron emission tomography scans revealed decreased periventricular inflammation in patients administered UCB, compared with those treated with a placebo. Correlating with enhanced gross motor function, elevations in plasma pentraxin 3 and interleukin-8 levels were observed for up to 12 days after treatment in the UCB group. Meanwhile, increases in blood cells expressing Toll-like receptor 4 were noted at 1 day after treatment in the UCB group, and they were correlated with increased muscle strength at 3 months post-treatment. In this trial, treatment with UCB alone improved motor outcomes and induced systemic immune reactions and anti-inflammatory changes in the brain. Generally, motor outcomes were positively correlated with the number of UCB cells administered: a higher number of cells resulted in better outcomes. Nevertheless, future trials are needed to confirm the long-term efficacy of UCB therapy, as the follow-up duration of the present trial was short.