Effects of thymoquinone rich fraction and thymoquinone on plasma lipoprotein levels and hepatic low density lipoprotein receptor and 3-hydroxy-3-methylglutaryl coenzyme A reductase genes expression

Immunomodulatory Protective Effects of Nigella sativa and Lactuca sativa Oils on Liver Intoxication in Experimental Animals

<b>Background and Objective:</b> The liver plays an important role in transforming and clearing chemicals in human body. Hepatic injury is usually caused by numerous toxic chemicals such as carbon tetrachloride, thioacetamide, galactosamine and drugs including paracetamol as overdoses consumption. This investigation aimed to study the immunomodulatory protective effects of black seed (<i>Nigella sativa</i> L.) oil and lettuce (<i>Lactuca sativa</i> L.) oil against paracetamol liver intoxication in rats. <b>Materials and Methods:</b> Twenty-four male albino rats weighing 150±10 g each, were randomly divided into 4 equal groups (6 rats each) as follows: Control negative; control positive as paracetamol hepatotoxicity; <i>Nigella sativa</i> oil and <i>Lactuca sativa</i> oil at a dose of 1 mL kg¹ b.wt., as protective from hepatotoxicity, then serum analysis for all rats were conducted and the obtained data were analyzed using SPSS version-22. <b>Results:</b> All rats orally preventable injected with <i>Nigella sativa</i> and <i>Lactuca sativa</i> oils caused significant decrease in Unsaturated Iron Binding Capacity (UIBC), creatine kinase (CK), Creatine Kinase-MB (CKMB), magnesium (Mg), phosphor (Phos.), iron (Fe), sodium (Na), potassium (K), amylase (Amyl), tri-glycerides (TG), total cholesterol (TC), Low Density Lipoprotein (LDL), creatinine (Creat), Lactate Dehydrogenase (LDH) as compared to liver intoxicated rats. <b>Conclusion:</b> Black seed oils and <i>Lactuca sativa</i> oils could be used as natural immunomodulatory agents against paracetamol liver intoxication and enhance the body's immune functions with improving the health status of the liver.

Natural Monoterpenes as Potential Therapeutic Agents against Atherosclerosis

Traditional herbal medicines based on natural products play a pivotal role in preventing and managing atherosclerotic diseases, which are among the leading causes of death globally. Monoterpenes are a large class of naturally occurring compounds commonly found in many aromatic and medicinal plants. Emerging evidence has shown that monoterpenes have many biological properties, including cardioprotective effects. Remarkably, an increasing number of studies have demonstrated the therapeutic potential of natural monoterpenes to protect against the pathogenesis of atherosclerosis. These findings shed light on developing novel effective antiatherogenic drugs from these compounds. Herein, we provide an overview of natural monoterpenes' effects on atherogenesis and the underlying mechanisms. Monoterpenes have pleiotropic and multitargeted pharmacological properties by interacting with various cell types and intracellular molecular pathways involved in atherogenesis. These properties confer remarkable advantages in managing atherosclerosis, which has been recognized as a multifaceted vascular disease. We also discuss limitations in the potential clinical application of monoterpenes as therapeutic agents against atherosclerosis. We propose perspectives to give new insights into future preclinical research and clinical practice regarding natural monoterpenes.

The protective effect of Nigella sativa seeds against monosodium glutamate-induced hepatic dysfunction in rats

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MSG-challenged rats were characterized by hepatic dysfunction and redox imbalance along with increased programmed cell death.

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The negative consequences of MSG consumption have been partially overcome by the nutritional inclusion of NSS.

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NSS restores the redox potential and ameliorates the histopathological deteriorations and apoptosis in the liver.

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These outcomes are of major importance in paving the road towards the incorporation of NSS as a candidate strategy against MSG-related abnormalities.

Monosodium glutamate (MSG) is one of the most commonly used feed additives which poses a threat to public health. Nigella sativa is a promising natural approach in this issue due to its antioxidant, hypolipidemic, and cytoprotective characters. Here, we investigated the potential protective effect of Nigella sativa seed (NSS) against MSG-induced hepatotoxicity in rats. To accomplish this objective, fifteen adult Wistar albino rats were randomly and equally divided into three groups for 21 days: the control group received no treatment, MSG group supplemented with MSG at a dose of 30 g/kg feed, and MSG + NSS group supplemented with MSG at the same previous dose together with NSS at a dose of 30 g/kg feed. NSS succeeded in boosting serum alkaline phosphatase activity and total cholesterol, triglycerides, and glucose levels. It reduced lipid peroxides in the serum and down-regulated glutathione reductase and superoxide dismutase 2 immuno-expression in the hepatic cells. NSS intervention provided cytoprotection by improving the histo-architecture of the liver and reducing the number of apoptotic cells. NSS was effective in protecting against the hepatotoxicity of MSG through its antioxidant and anti-apoptotic effects. These findings are of utmost significance in directing the attention towards the incorporation of NSS in our food industry as well as a health remedy in traditional medicine to fight MSG-related hepatic abnormalities.

Thymoquinone, a major constituent in Nigella sativa seeds, is a potential preventative and treatment option for atherosclerosis

Atherosclerosis is a widespread and progressive chronic arterial disease that remains the leading cause of mortality and morbidity worldwide. It is generally accepted that atherosclerosis is a multifactorial disease characterized by dyslipidemia and inflammation in the vessel walls. Nonpharmacological interventions to treat chronic diseases like atherosclerosis have gained considerable attention in recent years. Thymoquinone (TQ), the major bioactive constituent of Nigella sativa seeds, presents one such example of a natural therapeutic agent that has captured the attention of many researchers due to its wide array of medicinal properties, including its potent anti-atherosclerotic effects. Various in vitro and in vivo studies support the potential of TQ in ameliorating hyperlipidemia, hypercholesterolemia, oxidative stress, and inflammation, all of which are key hallmarks of atherosclerosis. However, to date, no review has been conducted to substantiate the role of TQ in preventing and/or treating atherosclerosis. This comprehensive review aims to examine recent in vitro and in vivo experimental findings reported on the potential anti-atherosclerotic effects of TQ. The roles of TQ in combatting hyperlipidemia, oxidative stress, and inflammation in atherosclerosis are highlighted. We also shed light on the role of TQ in preventing foam cell formation by decreasing low-density lipoprotein (LDL) availability and oxidation. Moreover, recent findings on the protective role of TQ on early markers of atherosclerosis, including homocysteinemia and endothelial dysfunction, are also underscored. Experimental evidence suggests that TQ can potentially be employed as a natural therapeutic agent with minimal side effects against the development and/or progression of atherosclerosis and its associated complications.

Nigella sativa as a promising intervention for metabolic and inflammatory disorders in obese prediabetic subjects: A comparative study of Nigella sativa versus both lifestyle modification and metformin

AIM

This study aimed at evaluating the effect of Nigella sativa (NS) on anthropometric, metabolic and inflammatory parameters and examining its related molecular mechanisms in obese prediabetic individuals as compared to both lifestyle modification (LM) and Metformin (Met).

METHODS

This study included 117 obese prediabetic subjects who were randomized into LM group which followed controlled diet and exercise regimen, metformin group received metformin 500 mg tablets twice daily and NS group received NS oil soft gelatin capsules 450 mg twice daily. Anthropometric (weight, BMI), glycemic, lipid, inflammatory parameters and genetic expressions of Sirtuin-1 (SIRT1) and p53 genes were assessed before and six months after interventions.

RESULTS

Post-intervention pairwise comparison revealed that, NS was statistically similar to metformin in improving anthropometric, glycemic parameters and SIRT1 gene expression. There was non-significant difference between LM and NS regarding their effects on anthropometric and most of glycemic parameters. Lifestyle modification group showed significantly higher HOMA-B and SIRT1 expression than NS and metformin. Nigella sativa improved lipid panel and significantly reduced TNF-α level and Castelli risk index-I as compared to other interventions.

CONCLUSION

Nigella sativa uniquely improved lipid panel and significantly suppressed inflammation. Therefore, Nigella sativa may represent a promising intervention for obese prediabetic subjects. Clinicaltrial.gov ID: NCT03925714.

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.

Effects of Nigella sativa oil supplementation on selected metabolic parameters and anthropometric indices in patients with coronary artery disease: A randomized, double-blind, placebo-controlled clinical trial

Various metabolic parameters are risk factors related to the amplified risk of atherosclerotic cardiovascular disease. A wide variety of data exist on Nigella sativa (NS) and metabolic parameters. The current study is designed to examine NS supplementation on lipid profile, blood pressure, glycemic control, anthropometric indices, and insulin resistance in individuals with coronary artery disease (CAD). In a randomized, double-blind, placebo-controlled clinical trial, 60 patients with CAD received either 2 g of NS oil or sunflower oil as a placebo for 8 weeks. Biochemical and anthropometric measurements were assessed. NS significantly reduced weight (-1.82 Kg; 95% C, [2.72, 4.13]), body mass index (-0.67 kg/m² ; 95% C, [0.33, 1.01]), waist circumference (-2.15 cm; 95% C, [1.06, 3.23]), hip circumference (-1.26 cm; 95% C, [0.61, 1.910]), waist-to-hip ratio (0.008; 95%C, [0.001, 0.01]), systolic (-9.52 mmHg; 95% C, [7.14, 11.9]), diastolic blood pressure (-8.26 mmHg; 95% C, [4.89, 11.62]), and fasting blood glucose (FBS) (-4.32 mg/dl; 95% C, [-0.51, 9.15]) as compared with the placebo group. The results indicate a potential beneficiary effect of NS on the metabolic parameters in CAD patients including improvements in anthropometric indices, blood pressure, and FBS.

Effects of Nigella sativa on glycemic control, lipid profiles, and biomarkers of inflammatory and oxidative stress: A systematic review and meta-analysis of randomized controlled clinical trials

The aim of this systematic review and meta-analysis was to evaluate the effects of Nigella sativa (N. sativa) on glycemic control, lipid profiles, and biomarkers of inflammatory and oxidative stress. Two independent authors systematically examined online databases consisting of, EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science from inception until October 30, 2019. Cochrane Collaboration risk of bias tool was applied to assess the methodological quality of the studied trials. The heterogeneity among the included studies were assessed using the Cochrane's Q test and I-square (I² ) statistic. Data were pooled using a random-effects model and weighted mean difference (WMD) was considered as the overall effect size. A total of 50 trials were included in this meta-analysis. We found a significant reduction in total cholesterol (WMD: -16.80; 95% CI: -21.04, -12.55), triglycerides (WMD: -15.73; 95% CI: -20.77, -10.69), LDL-cholesterol (WMD: -18.45; 95% CI: -22.44, -14.94) and VLDL-cholesterol (WMD: -3.72; 95% CI: -7.27, -0.18) following supplementation with N. sativa. In addition, there was significant reductive effect observed with N. sativa on fasting glucose (WMD: -15.18; 95% CI: -19.82, -10.55) and HbA1C levels (WMD: -0.45; 95% CI: -0.66, -0.23). Effects of N. sativa on CRP (WMD: -3.61; 95% CI: -9.23, 2.01), TNF-α (WMD: -1.18; 95% CI: -3.23, 0.86), TAC (WMD: 0.31; 95% CI: 0.00, 0.63), and MDA levels (WMD: -0.95; 95% CI: -2.18, 0.27) were insignificant. This meta-analysis demonstrated the beneficial effects of N. sativa on fasting glucose, HbA1c, triglycerides, total-, VLDL-, LDL-cholesterol levels.

The impact of particulate matter (PM2.5) on skin barrier revealed by transcriptome analysis: Focusing on cholesterol metabolism

Accumulating evidence suggests that particulate matter (PM2.5), as a major air pollutant, imposes a certain degree of destruction and toxicity to the skin. It particularly impairs the structure and function of the epidermis. To study the impact of PM2.5 on the skin, transcriptome analysis was performed on PM2.5-exposed human primary keratinocytes. Functional annotation analysis demonstrates that PM2.5 significantly up-regulates cholesterol-metabolism-related genes. Via lipid extraction from PM2.5 treated three-dimensional epidermis tissue model (3D-ETM) and subsequent characterization via mass spectrometry, it was confirmed that PM2.5 significantly increases epidermal cholesterol levels in vitro. Conversely, the amount of squalene in 3D-ETM was significantly reduced by PM2.5. Interestingly, neither cholesterol nor squalene showed significant fluctuations in the green tea extract (GTE) treated epidermis tissue model under PM2.5 exposure. This study shows that PM2.5 may cause barrier disorders by increasing cholesterol synthesis, leading to transient accumulation of epidermal cholesterol and decrease of squalene. It was suggested that cholesterol and squalene, which are the key substances affecting skin barrier function, can be used as new biomarkers of skin damage induced by PM2.5. Moreover, it was demonstrated that GTE can reduce damage caused by PM2.5 exposure by not only anti-inflammatory and antioxidant mechanisms, but also by off-setting the disturbance to epidermal lipid homeostasis. This study demonstrates the strong potential of GTE as an active ingredient to be utilized in cosmetic products to effectively reduce the damage PM2.5 induces in skin.

Therapeutic Potential and Pharmaceutical Development of Thymoquinone: A Multitargeted Molecule of Natural Origin

Thymoquinone, a monoterpene molecule is chemically known as 2-methyl-5-isopropyl-1, 4-benzoquinone. It is abundantly present in seeds of Nigella sativa L. that is popularly known as black cumin or black seed and belongs to the family Ranunculaceae. A large number of studies have revealed that thymoquinone is the major active constituent in N. sativa oil this constituent is responsible for the majority of the pharmacological properties. The beneficial organoprotective activities of thymoquinone in experimental animal models of different human diseases are attributed to the potent anti-oxidant and anti-inflammatory properties. Thymoquinone has also been shown to alter numerous molecular and signaling pathways in many inflammatory and degenerative diseases including cancer. Thymoquinone has been reported to possess potent lipophilicity and limited bioavailability and exhibits light and heat sensitivity. Altogether, these physiochemical properties encumber the successful formulation for the delivery of drug in oral dosages form and restrict the pharmaceutical development. In recent past, many efforts were undertaken to improve the bioavailability for clinical usage by manipulating the physiochemical parameters. The present review aimed to provide insights regarding the physicochemical characteristics, pharmacokinetics and the methods to promote pharmaceutical development and endorse the clinical usage of TQ in future by overcoming the associated physiochemical obstacles. It also enumerates briefly the pharmacological and molecular targets of thymoquinone as well as the pharmacological properties in various diseases and the underlying molecular mechanism. Though, a convincing number of experimental studies are available but human studies are not available with thymoquinone despite of the long history of use of black cumin in different diseases. Thus, the clinical studies including pharmacokinetic studies and regulatory toxicity studies are required to encourage the clinical development of thymoquinone.

Semi-synthetic thymoquinone analogs: new prototypes as potential antihyperlipidemics in irradiated rats

AIM

Thymoquinone (TQ), has been reported to possess strong antihyperlipidemic properties. However, a variety of serious side effects has been reported for TQ. The present study aimed to evaluate the potential antihyperlipidemic activity of newly synthesized TQ analogs.

METHODS & RESULTS

first, novel TQ derivatives were studied against radiation-induced dyslipidemia in male rats. Second, the most promising sulfur derivatives (4-7), were further tested to elucidate their possible mechanism(s) of actions. Results showed that they possess Hydroxymethyl Glutaryl-Co A reductase inhibitory activity, as well as stimulatory effects on the activities of each of plasma Lecithin-Cholesterol Acyltransferase and lipoprotein lipase enzymes.

CONCLUSION

TQ derivatives (4-7), could be considered as promising agents in pathologies implicating impaired lipid metabolism, preclinical evaluation is warranted. [Formula: see text].

Mitigating role of thymoquinone rich fractions from Nigella sativa oil and its constituents, thymoquinone and limonene on lipidemic-oxidative injury in rats

Therapeutic role of Nigella sativa (NS) seed oil fractions, methanolic extract (ME) and volatile oil (VO) and their constituents, thymoquinone (TQ) and limonene (LMN) in relation to lipidemic-oxidative stress in Wistar rats was determined. The total phenolic contents of NS seed oil and their ME and VO extracts were 320.00 ± 3.00, 300.12 ± 0.04 and 288.41 ± 0.01 mg gallic acid equivalents per 100 g of NS oil, respectively. Their Fe(+2) chelating activities were 870.00 ± 2.00, 222.31 ± 5.80 and 38.59 ± 1.43 mg EDTA equivalents per 100 g of NS oil, respectively. These fractions and compounds exhibited strong antioxidant activities against 2,2-diphenyl-1-picryl hydrazyl, 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid, nitric oxide and hydroxyl radicals. Potential antiperoxidative effects of these fractions and compounds were also observed in liposome, and lipidemic-induced lipid peroxidation in atherogenic suspension fed rats, pretreated with 100 mg ME, 20 mg VO, 10 mg pure TQ or 200 mg LMN for 30 days. ME containing ω-6 linoleic acid and palmitic acid natural compounds was highly effective against lipidemic oxidative stress than VO extract possessing thymol and isothymol phenolic natural antioxidant compounds. TQ, principal compound shared to both the extracts. The test fractions and compounds effectively reduced the erythrocyte and liver lipid peroxidation markers, conjugated diene, lipid hydroperoxide and malondialdehyde to near normal levels in the order ME > TQ > VO > LMN, by directly counteracting free radicals as well as suppressing hepatic HMG-CoA reductase activity. Our findings demonstrated that these natural products, preferably ME possess significant antioxidant activities, and may be recommended as new potential sources of natural antioxidants.

A randomised controlled trial on hypolipidemic effects of Nigella Sativa seeds powder in menopausal women

BACKGROUND

The risk of cardiovascular diseases (CVD) is increased tremendously among menopausal women, and there is an increasing demand for alternative therapies for managing factors like dyslipidemia that contribute to CVD development.

METHODS

In this study, Nigella sativa was evaluated for its hypolipidemic effects among menopausal women. In a randomised trial, hyperlipidemic menopausal women were assigned to treatment (n=19) or placebo groups (n=18), and given N. sativa or placebo for two months after their informed consents were sought. At baseline, blood samples were taken and at one month intervals thereafter until one month after the end of the study.

RESULTS

The results showed that N. sativa significantly improved lipid profiles of menopausal women (decreased total cholesterol, low density lipoprotein cholesterol and triglyceride, and increased high density lipoprotein cholesterol) more than the placebo treatment over 2 months of intervention. One month after cessation of treatment, the lipid profiles in the N. sativa-treated group tended to change towards the pretreatment levels.

CONCLUSIONS

N. sativa is thought to have multiple mechanisms of action and is cost-effective. Therefore, it could be used by menopausal women to remedy hypercholesterolemia, with likely more benefits than with single pharmacological agents that may cause side effects. The use of N. sativa as an alternative therapy for hypercholesterolemia could have profound impact on the management of CVD among menopausal women especially in countries where it is readily available.

Study on the potential toxicity of a thymoquinone-rich fraction nanoemulsion in Sprague Dawley rats

Toxicological studies constitute an essential part of the effort in developing an herbal medicine into a drug product. A newly developed thymoquinone-rich fraction nanoemulsion (TQRFNE) has been prepared using a high pressure homogenizer. The purpose of this study was to investigate the potential acute toxicity of this nanoemulsion in Sprague Dawley rats. The acute toxicity studies were conducted as per the OECD guidelines 425, allowing for the use of test dose limit of 20 mL TQRFNE (containing 44.5 mg TQ)/kg. TQRFNE and distilled water (DW) as a control were administered orally to both sexes of rats on Day 0 and observed for 14 days. All the animals appeared normal, and healthy throughout the study. There was no observed mortality or any signs of toxicity during the experimental period. The effects of the TQRFNE and DW groups on general behavior, body weight, food and water consumption, relative organ weight, hematology, histopathology, and clinical biochemistry were measured. All the parameters measured were unaffected as compared to the control (DW) group. The administration of 20 mL TQRFNE /kg was not toxic after an acute exposure.

Elucidation of mechanisms of actions of thymoquinone-enriched methanolic and volatile oil extracts from Nigella sativa against cardiovascular risk parameters in experimental hyperlipidemia

BACKGROUND

Nigella sativa belonging to the Ranunculaceae family has been reported to use for thousands of years as protective and curative traditional medicine against a number of diseases. GC-MS analysis of methanolic extract (ME) and volatile oil (VO) extracted from Nigella sativa seed oil was performed by two different mass spectrometry libraries, WIlEY8 and NIST05s. The cholesterol lowering and antioxidant actions of VO and ME fractions were investigated in atherogenic suspension fed rats.

METHODS

In this study, four groups of male Wistar rats were used: normolipidemic control (NLP-C), hyperlipidemic control (HLP-C), methanolic extract (HLP-ME) and volatile oil treated (HLP-VO) groups for 30 days of duration. P value < 0.05 was assumed as significant data in groups.

RESULTS

Administration of atherogenic suspension to male Wistar rats for 30 days resulted in a marked increase of plasma triglycerides and total cholesterol, and significant change in plasma lipoprotein levels along with a decrease in antioxidant arylesterase activity in hyperlipidemic control (HLP-C) group. The oral feeding of 100 mg ME or 20 mg VO per rat/day effectively reduced the plasma triglycerides to near normal level, while high density lipoprotein cholesterol and its subfraction along with arylesterase activity levels were significantly increased. The test fractions elicited a significant decrease in hepatic HMG-CoA reductase activity. The fractions significantly blocked the ex vivo basal and in vitro maximal formation of conjugated diene and malondialdehyde, and lengthened the lag times of low density lipoprotein, small dense low density lipoprotein and large buoyant low density lipoprotein. ME possessing ω-6 linoleic acid along with palmitic acid active compounds was more effective than VO extract containing thymol and isothymol phenolic antioxidant compounds, thymoquinone phenolic compound common to the both extracts, via reduction in hepatic HMG-CoA reductase activity as well as antioxidant mechanisms.

CONCLUSION

The both extracts especially, ME significantly improve cardiovascular risk parameters in treated rats, and can be used in reactive oxygen species disorders such as cardiovascular diseases.

Nigella sativa thymoquinone-rich fraction greatly improves plasma antioxidant capacity and expression of antioxidant genes in hypercholesterolemic rats

The antioxidant activities of the thymoquinone-rich fraction (TQRF) extracted from Nigella sativa and its bioactive compound, thymoquinone (TQ), in rats with induced hypercholesterolemia were investigated. Rats were fed a semipurified diet supplemented with 1% (w/w) cholesterol and were treated with TQRF and TQ at dosages ranging from 0.5 to 1.5 g/kg and 20 to 100 mg/kg body wt, respectively, for 8 weeks. The hydroxyl radical (OH(.))-scavenging activity of plasma samples collected from experimental rats was measured by electron spin resonance. The GenomeLab Genetic Analysis System was used to study the molecular mechanism that mediates the antioxidative properties of TQRF and TQ. Plasma total cholesterol and low-density-lipoprotein cholesterol levels were significantly decreased in the TQRF- and TQ-treated rats compared to untreated rats. Feeding rats a 1% cholesterol diet for 8 weeks resulted in a significant decrease in plasma antioxidant capacity, as measured by the capacity to scavenge hydroxyl radicals. However, rats treated with TQRF and TQ at various doses showed significant inhibitory activity toward the formation of OH(.) compared to untreated rats. Upon examination of liver RNA expression levels, treatment with TQRF and TQ caused the up-regulation of the superoxide dismutase 1 (SOD1), catalase, and glutathione peroxidase 2 (GPX) genes compared to untreated rats (P<0.05). In support of this, liver antioxidant enzyme levels, including SOD1 and GPX, were also apparently increased in the TQRF- and TQ-treated rats compared to untreated rats (P<0.05). In conclusion, TQRF and TQ effectively improved the plasma and liver antioxidant capacity and enhanced the expression of liver antioxidant genes of hypercholesterolemic rats.

Thymoquinone enhances the activities of enzymes related to energy metabolism in peripheral leukocytes of diabetic rats

The aim of this study was to examine the effect of glycemic control using thymoquinone (TQ) on energy metabolism related enzymes in leukocytes of streptozotocin (STZ)-induced diabetic rats. The treatment of both TQ and insulin commenced 4weeks after induction of diabetes. Plasma glucose, cholesterol and triglycerides levels were significantly reduced after TQ treatment, whereas immunoreactive insulin (IRI) showed significant increase. The activities of malate dehydrogenase (MDH) in cytosolic and mitochondrial fractions of peripheral blood leukocytes were significantly higher in rats treated with TQ and insulin as compared to that in diabetic controls. On the other hand the activities of lactic dehydrogenase (LDH) showed no significant changes between groups. ML ratio (cytosolic MDH/LDH specific activity ratio) was restored to those in the control rats. The results of this study demonstrate that TQ significantly increased insulin level and the activities of cytosolic and mitochondrial MDH in leukocytes of STZ-diabetic rats.