Beneficial effects of thymoquinone on hepatic key enzymes in streptozotocin–nicotinamide induced diabetic rats

The effect of Nigella sativa supplementation on glycemic status in adults: An updated systematic review and meta-analysis of randomized controlled trials

This systematic review and meta-analysis of randomized controlled trials (RCTs) sought to evaluate the effects of Nigella sativa (N. sativa) consumption on glycemic index in adults. A systematic literature search up to December 2023 was completed in PubMed, Scopus, and Web of Science, to identify eligible RCTs. Random effects models were assessed based on the heterogeneity tests, and pooled data were determined as weighted mean differences with a 95 % confidence interval. Finally, a total of 30 studies were found to be eligible for this meta-analysis. The pooled results using random effects model indicated that N. sativa supplementation significantly reduced FBS (SMD: -1.71; 95 % CI: -2.11, -1.31, p <0.001; I2= 92.7 %, p-heterogeneity <0.001) and HA1c levels (SMD: -2.16; 95 % CI: -3.04, -1.29, p <0.001; I2= 95.7 %, p-heterogeneity <0.001) but not effect on insulin (SMD = 0.48; 95 % CI: -0.53, 1.48, P = 0.353; I2= 96.1 %, p-heterogeneity <0.001), and HOMA-IR (SMD: -0.56; 95 % CI: -1.47, 0.35, p=0.229; I2= 95.0 %, p-heterogeneity <0.001).Overall, the evidence supports the consumption of N. sativa to reduce FBS and HA1c levels. Additional research, featuring extended durations and robust study designs, is necessary to determine the ideal dosage and duration of N. sativa supplementation for achieving a positive impact on glycemic markers.

Nigella sativa L. and its bioactive and nutraceutical components in the management of diabetic peripheral neuropathy

Diabetes-induced hyperglycemia leads to excessive production of oxygen free radicals, inflammatory cytokines, and oxidative stress, which initiates diabetic peripheral neuropathy (DPN). Currently, this condition affects 20% of adults with diabetes. Despite significant advances in the treatment of diabetes, the incidence of its complications, including DPN, is still high. Thus, there is a growing research interest in developing more effective and treatment approaches with less side effects for diabetes and its complications. Nigella sativa L. (NS) has received much research attention as an antioxidant, anti-yperglycemic factor, and anti-inflammatory agent. This natural compound demonstrates its antidiabetic neuropathy effect through various pathways, including the reduction of lipid peroxidation, the enhancement of catalase and superoxide dismutase enzyme activity, and the decrease in inflammatory cytokine levels. The present review focuses on the bioactive and nutraceutical components of black cumin (Nigella sativa L.) and their effects on DPN. In addition, we have also summarized the findings obtained from several experimental and clinical studies regarding the antidiabetic neuropathy effect of NS in animal models and human subjects.

Thymoquinone Nanoparticle Induces Apoptosis and Cell Migration Retardation through Modulating of SUMOylation Process Genes in Breast Cancer Cell Line

Background

Due to the heterogeneity of breast cancer, most advanced-stage patients are resistant to therapy. Disruption of SUMOylation, a post-translational modification, is linked to breast cancer.

Objective

This study aimed to assess the impact of thymoquinone nanoparticles (Liposomal-TQ), an anti-cancer drug, combined with doxorubicin (DXR), the most effective chemotherapeutic drug used to treat breast cancer, on the expression of SENP2 and SENP6, two major components involved in the SUMOylation process, in normal and cancerous breast cell lines.

Materials and Methods

The MCF7 cell line, a breast cancer cell line, and MCF10, a non-tumor epithelial cell line, were separately treated with Liposomal-TQ and DXR. Cell viability and cell migration were assessed using MTT and scratch tests. Apoptosis analysis was performed using annexin-V/PI staining. Gene expression analysis of SENP2 and SENP6 was conducted using quantitative real-time PCR (RT-qPCR). Additionally, the scratch test evaluated the anti-cell migratory effect of Liposomal-TQ.

Results

The findings obtained from RT-qPCR analysis indicated a significant increase in the expression of SENP2 and SENP6 genes in the TQ and DXR treatment groups compared to the control group in MCF7 but not in MCF10 cell lines (p-value < 0.05). Also, after 24 hours of treatment of MCF7 and MCF10 cells with liposomal-TQ, late apoptotic cells were significantly increased compared to the control and liposome groups (p-value < 0.0001) and compared to the control group, both DXR and Liposomal-TQ dramatically reduced the migratory ability of breast cancer cells (p-value = 0.001 and p-value = 0.001, respectively).

Conclusion

Our study indicated that Liposomal-TQ promotes apoptosis in breast cancer cells and inhibits cell migration ability. These findings enhance our understanding of the role of Liposomal-TQ in the carcinogenic activities of SENP2 and SENP6 in the SUMOylation pathway of breast cancer.

Therapeutic and Phytochemical Properties of Thymoquinone Derived from Nigella sativa

BACKGROUND

Nigella sativa (N. sativa), commonly known as black seed or black cumin, belongs to the family Ranunculaceae. It contains several phytoconstituents, Thymoquinone (TQ), thymol, thymohydroquinone, carvacrol, and dithymoquinone. TQ is the main phytoconstituent present in N. sativa that is used as an herbal compound, and it is widely used as an antihypertensive, liver tonic, diuretic, digestive, anti-diarrheal, appetite stimulant, analgesic, and antibacterial agent, and in skin disorders.

OBJECTIVE

The study focused on collecting data on the therapeutic or pharmacological activities of TQ present in N. sativa seed.

METHODS

Antidiabetic, anticancer, immunomodulator, analgesic, antimicrobial, anti-inflammatory, hepato-protective, renal protective, and antioxidant properties of TQ have been studied by various scientists.

CONCLUSION

TQ seems to have a variety of consequences on how infected cells behave at the cellular level.

Mechanism of the antidiabetic action of Nigella sativa and Thymoquinone: a review

Introduction

Long used in traditional medicine, Nigella sativa (NS; Ranunculaceae) has shown significant efficacy as an adjuvant therapy for diabetes mellitus (DM) management by improving glucose tolerance, decreasing hepatic gluconeogenesis, normalizing blood sugar and lipid imbalance, and stimulating insulin secretion from pancreatic cells. In this review, the pharmacological and pharmacokinetic properties of NS as a herbal diabetes medication are examined in depth, demonstrating how it counteracts oxidative stress and the onset and progression of DM.

Methods

This literature review drew on databases such as Google Scholar and PubMed and various gray literature sources using search terms like the etiology of diabetes, conventional versus herbal therapy, subclinical pharmacology, pharmacokinetics, physiology, behavior, and clinical outcomes.

Results

The efficiency and safety of NS in diabetes, notably its thymoquinone (TQ) rich volatile oil, have drawn great attention from researchers in recent years; the specific therapeutic dose has eluded determination so far. TQ has anti-diabetic, anti-inflammatory, antioxidant, and immunomodulatory properties but has not proved druggable. DM's intimate link with oxidative stress, makes NS therapy relevant since it is a potent antioxidant that energizes the cell's endogenous arsenal of antioxidant enzymes. NS attenuates insulin resistance, enhances insulin signaling, suppresses cyclooxygenase-2, upregulates insulin-like growth factor-1, and prevents endothelial dysfunction in DM.

Conclusion

The interaction of NS with mainstream drugs, gut microbiota, and probiotics opens new possibilities for innovative therapies. Despite its strong potential to treat DM, NS and TQ must be examined in more inclusive clinical studies targeting underrepresented patient populations.

Nigella sativa L. and Its Active Compound Thymoquinone in the Clinical Management of Diabetes: A Systematic Review

Despite existing conventional hypoglycemic drugs to manage diabetes, their non-availability and cost in low-income countries coupled with the associated side effects remain a major concern. Consequently, exploring for alternative treatments to manage diabetes has been a continuous priority. Nigella sativa L. (NS) (Family: Ranunculaceae) is regarded as a valuable traditional remedy in diabetes management and extensively studied for its biological properties. This systematic review provides a comprehensive and critical analysis of clinical studies on the efficacy, safety, and mechanism of action of NS and its compound thymoquinone (TQ) in diabetes management. The main scientific databases which were scrutinised were Scopus, PubMed, Google Scholar, and Web of Science. Data search was conducted from inception to January 2022. A total of 17 clinical studies were obtained; 16 studies on Nigella sativa L. and 1 study on its compound TQ. N. sativa was found to be highly potent in terms of its hypoglycemic activity when compared to placebo based on improvement in parameters including fasting blood glucose (FBG), postprandial blood glucose (PPBG), Hemoglobin A1C (HbA1c), homeostatic model assessment for insulin resistance (HOMA-IR), and homeostatic model assessment for assessment of beta-cell functionality (HOMA-β). The compound TQ in combination with a daily dose of metformin demonstrated a greater reduction in the levels of HbA1c and blood glucose compared to metformin alone. The bioavailability of TQ can be enhanced by using nanoparticulate drug delivery systems. Considering the findings of the clinical studies along with negligible adverse effects, NS has strong potential application in bioproduct development for the management of diabetes. Further investigations should explore the detailed mechanism of actions by which TQ exerts its therapeutic antidiabetic effects to provide more insights into its clinical use in the management of diabetes.

Therapeutic significance of thymoquinone-loaded chitosan nanoparticles on streptozotocin/nicotinamide-induced diabetic rats: In vitro and in vivo functional analysis

To overcome the low bioavailability of lipophilic free thymoquinone (TQ), this study aims to evaluate a novel oral formula of TQ-loaded chitosan nanoparticles (TQ-CsNPs) for the effective treatment of diabetes. The XRD, FTIR, FESEM, HRTEM, and dynamic light scattering were all conducted on the prepared formula. The release pattern of TQ, cytotoxicity against MRC-5 cell line (human lung fibroblast cells), and antidiabetic activity on streptozotocin/nicotinamide (STZ/NA) rat model of diabetes were investigated. The results confirmed the formation of TQ-CsNPs with an entrapment efficiency of 75.7 ± 6.52 %, a mean Zetasizer distribution of 84.25 nm, and an average particle size of about 50 nm. After 24 h, the percentage of free TQ-cumulative release was approximately 35.8 %, whereas TQ-CsNPs showed a sustained release pattern of 78.5 %. The investigated formula was not toxic to normal lung cells, and more efficient in ameliorating the altered glycemia, dyslipidemia, inflammation, and oxidative stress induced by STZ/NA than free TQ, blank CsNPs, and metformin-HCl (as a reference drug). Additionally, TQ-CsNPs restored the normal pancreatic islets' configuration and morphometry, suggesting a potent insulinotropic action. In conclusion, the antidiabetic efficacy of TQ was improved by engaging TQ with CsNPs as an excellent nanoplatform to enhance the oral bioavailability of TQ.

Nigella sativa supplementation improves cardiometabolic indicators in population with prediabetes and type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

Objective

Nigella sativa (N. sativa) from the family Ranunculaceae has medicinal properties. Previous studies have reported promising findings showing that N. sativa may benefit cardiometabolic health; however, current evidence on its cardiometabolic effects on those with prediabetes and type 2 diabetes mellitus (T2DM) is still unclear. Hence, we conducted a systematic review and meta-analysis to assess the efficacy of N. sativa on cardiometabolic parameters in population with prediabetes and T2DM.

Methods

PubMed/Medline, ISI Web of Science, Scopus, and Cochrane library were systematically searched up to June 20, 2022. Meta-analyses using random-effects models were used.

Results

Eleven randomized controlled trials (RCTs) were included in the meta-analysis. N. sativa intervention resulted in significant changes in fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), c-reactive protein (CRP), and malondialdehyde (MDA), without overall changes in glucose levels after oral glucose tolerance test (OGTT), fasting insulin, homeostatic model assessment of insulin resistance (HOMA-IR), triglyceride, high-density lipoprotein cholesterol (HDL-C), and body mass index (BMI) when compared with the control group. In subgroup analyses, N. sativa supplementation enhanced serum levels of HDL-C in subjects with baseline HDL-C lower than 40 mg/dL. Furthermore, HOMA-IR and BMI values decreased in the N. sativa-supplemented group compared with the control group, when the length of follow-up was more than 8 weeks and the dose was more than 1 g/day for N. sativa supplementation, respectively.

Conclusion

Our findings indicate that N. sativa supplementation may effectively improve cardiometabolic profiles in individuals with prediabetes and T2DM.

Nutrition in the management of type 2 diabetes mellitus: review

Type 2 diabetes mellitus (T2DM) is the most prevalent disease and becoming a serious public health threat worldwide. In recent years, numerous effective T2DM intervention regimens have been developed, with promising results. However, these regimens are not usually economically available, and they are not well tolerated due to treatment-related toxicities. The focus nowadays is to identify new effective therapeutic agents, with relatively low cost and low toxicity, which can be used regularly to control a progression of T2DM in the prediabetic population. Accordingly, there has been growing attention in herbal remedies that can be presented into the general population with the tiniest side effects and the maximal preventive outcome. This article reviews recent publications in experimental models of T2DM not revised before, and supporting the potential use of nutraceuticals and phytochemicals through different mechanisms with promising results in the context of T2DM.

Antidiabetic Activity of Nigella Sativa (Black Seeds) and Its Active Constituent (Thymoquinone): A Review of Human and Experimental Animal Studies

The use of herbal medicine to manage chronic conditions including diabetes has become a recent global trend. Diabetes mellitus (DM) is a group of metabolic disorders characterized by hyperglycemia. The present review is aimed to analyze the antidiabetic activity of N. sativa as many type 2 diabetic patients use it as a complementary therapy along with their modern allopathic medications or as an alternative therapy. The literature was reviewed in databases like Medline/PubMed Central/PubMed, Google Scholar, Science Direct, EBSCO, Scopus, Web of science, EMBASE, Directory of open access journals (DOAJ), and reference lists to identify relevant articles supporting the use of N. sativa in diabetes management. Numerous clinical and animal studies have demonstrated the antidiabetic efficacy of black seeds (N. sativa) and its major bioactive constituent thymoquinone. Based on these findings patients with diabetes may use N. sativa as an adjuvant therapy, which may help to reduce the dose and incidence of adverse effects of modern antidiabetic medicines.

Hepato-protective effects of thymoquinone and beta-aminoisobutyric acid in streptozocin induced diabetic rats

We investigated the hepato-protective effects of thymoquinone (TQ) and beta-aminoisobutyric acid (BAIBA). We used five groups of 8-week-old male rats: untreated control group, streptozotocin (STZ) diabetic group, STZ + TQ group, STZ + BAIBA group, and STZ + TQ + BAIBA group. After experimental diabetes mellitus (DM) was established using STZ, TQ was given to the STZ + TQ group, BAIBA to the STZ + BAIBA group, and TQ and BAIBA to the STZ + TQ + BAIBA group. In the STZ group, body weight, relative liver weight, and glutathione, blood albumin and insulin levels were decreased compared to the control. Also, water and food consumption, tumor necrosis factor-α expression, malondialdehyde, blood glucose, alanine aminotransferase, aspartate aminotransferase and gamma glutamyl transferase levels were increased the STZ group compared to the control group. In the STZ group, sinusoid congestion and dilation, monocyte and lymphocyte infiltration and microvesicular steatosis were observed in the liver tissue. Pathological changes caused by DM were reduced significantly in the STZ + TQ, STZ + BAIBA and STZ + TQ + BAIBA groups. The protective effect of BAIBA was greater than for TQ; the greatest protective effect was observed following combined use of TQ + BAIBA. We suggest that our findings for the STZ + TQ, STZ + BAIBA and STZ + TQ + BAIBA groups were due to the antioxidant effects of TQ and BAIBA. TQ and BAIBA appear to be potential therapeutic agents for ameliorating hepatic damage due to DM.

The ameliorative effects of thymoquinone and beta-aminoisobutyric acid on streptozotocin-induced diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a cardiac dysfunction observed in a patient with diabetes that may lead to heart failure. No specific treatment has yet been tested in DCM. Therefore, in this study, it was investigated that the potential of thymoquinone (TYM) and beta-aminoisobutyric acid (BAIBA) to treat DCM. Five groups (n = 7) were formed, namely control, diabetes, TYM, BAIBA and TYM + BAIBA, with a random selection from 35 adult male rats. Diabetes mellitus was induced by intraperitoneal administration of 50 mg/kg streptozotocin to all groups except the control. After establishing experimental diabetes, TYM (20 mg/kg/day) and BAIBA (100 mg/kg/day) were administered alone or in combination with other groups other than the control and diabetes groups for five weeks by gavage. Serum aspartate aminotransferase, lactate dehydrogenase, creatine kinase-MB, and tissue malondialdehyde levels increased significantly, and tissue glutathione levels decreased in the diabetes group compared to the control group. An increase in the expression of tumor necrosis factor-α in the myocardium and the rate of fibrosis and apoptosis were found in the histopathological analysis. In the TYM and BAIBA groups, all pathological changes observed in the diabetes group improved significantly. The therapeutic effects of these agents on DCM are probably due to their antihyperglycemic, antidiabetic, antioxidant, and anti-inflammatory effects. The present results suggested that TYM and BAIBA have the potential therapeutic effects on DCM that were used alone or combined.

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.

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.

Protective roles of thymoquinone and vildagliptin in manganese-induced nephrotoxicity in adult albino rats

Despite being important in the body's mechanisms, excessive accumulation of manganese (Mn) can induce severe toxicity in vital organs of the body. Thymoquinone (TQ) is extracted from Nigella sativa seeds which recently gained popularity as dietary supplements and plant-based antioxidants. Vildagliptin (VLD) is a dipeptidyl peptidase IV (DPPIV) inhibitor, approved as anti-hyperglycemic agents with cardioprotective and renoprotective effects. The present study aimed to investigate the nephrotoxicity of Mn and the potential protective effects of thymoquinone and vildagliptin. Sixty-four adult male albino rats were equally divided into 8 groups: group I (control, received no medication), group II (vehicle, received normal saline), group III (TQ, 50 mg/kg/day), group IV (VLD, 10 mg/kg/day), group V (MnCl₂, 50 mg/kg/day), group VI (Mn+TQ), group VII (Mn+VLD), and group VIII (Mn+TQ+VLD). Groups VI, VII, and VIII, received the same previously mentioned doses. All drugs were orally gavaged for 12 weeks. Manganese administration resulted in an elevation in the levels of serum and tissues Mn, blood glucose, serum urea, creatinine, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and reduction in insulin, kidney superoxide dismutase (SOD), glutathione (GSH), and interleukin-10. Histopathological structural renal damage was detected associated with strong positive immunoexpression of caspase-3. On the other hand, individual or combined TQ and VLD administration with Mn significantly decreased the serum and tissue levels of Mn, declined the blood glucose, inflammatory markers, oxidative stress markers, ameliorated the histopathological effects, and down-regulated the immunoexpression of caspase-3. In conclusion, TQ and VLD co-administration elicited protective effects against Mn-induced nephrotoxicity.

Effect of Administration of CHAGURO Made of Chayote (Sechium edule) and Tuna (Thunnus sp.) on Rats Induced with Streptozotocin-Nicotinamide and a High-Fat Diet

This study was conducted to develop Chaguro, a low-cost supplementary food made of chayote (Sechium edule (Jacq.) Swartz) and tuna fish (Thunnus sp.), for diabetes and dyslipidemia diet therapy. In order to find a formula with effective hypoglycaemic and antidyslipidemic properties, dried tuna and chayote were mixed at different ratios: F1 (75% tuna, 25% chayote), F2 (50% tuna, 50% chayote), and F3 (25% tuna, 75% chayote). Thirty male Sprague Dawley rats were assigned into healthy control group or groups induced with streptozotocin-nicotinamide and a high-fat diet. Chaguro was administered 2.7 g/ kgBW/ day using a gavage for 28 days. The administration of all Chaguro formulas improved blood markers compared to the negative control group (p < 0.001). Chaguro F2 lowered fasting blood glucose (97.07±1.18 vs 266.31±5.31), total cholesterol (113.59±2.22 vs 208.78±4.31), triglycerides (89.93±2.51 vs 142.35±2.83), LDL-c (33.87±1.87 vs 87.85±3.34) and increased HDL-c (69,08±1,85 vs 23,91±1,64) level the most compared to the negative control group (p < 0.001). Streptozotocin-induced weight loss was also prevented in all diabetic rats fed with Chaguro, with the bodyweight being similar to that of healthy controls at the end of the intervention (p < 0.001). This study found that Chaguro may be a potential food product to help lower blood glucose and improve lipid profile in diabetes and dyslipidemia.

Thymoquinone Lowers Blood Glucose and Reduces Oxidative Stress in a Rat Model of Diabetes

The aim of the present study was to assess the short-term effects of Thymoquinone (TQ) on oxidative stress, glycaemic control, and renal functions in diabetic rats. DM was induced in groups II and III with a single dose of streptozotocin (STZ), while group I received no medication (control). The rats in groups I and II were then given distilled water, while the rats in group III were given TQ at a dose of 50 mg/kg body weight/day for 4 weeks. Lipid peroxidase, nitric oxide (NO), total antioxidant capacity (TAC), glycated haemoglobin (HbA1c), lipid profiles, and renal function were assessed. Moreover, the renal tissues were used for histopathological examination. STZ increased the levels of HbA1c, lipid peroxidase, NO, and creatinine in STZ-induced diabetic rats in comparison to control rats. TAC was lower in STZ-induced diabetic rats than in the control group. Furthermore, rats treated with TQ exhibited significantly lower levels of HbA1c, lipid peroxidase, and NO than did untreated diabetic rats. TAC was higher in diabetic rats treated with TQ than in untreated diabetic rats. The histopathological results showed that treatment with TQ greatly attenuated the effect of STZ-induced diabetic nephropathy. TQ effectively adjusts glycaemic control and reduces oxidative stress in STZ-induced diabetic rats without significant damaging effects on the renal function.

Thymoquinone, the Most Prominent Constituent of Nigella Sativa, Attenuates Liver Damage in Streptozotocin-Induced Diabetic Rats via Regulation of Oxidative Stress, Inflammation and Cyclooxygenase-2 Protein Expression

Diabetes mellitus (DM) is a multifaceted metabolic disorder that results in dysfunction and failure of various organs. The present study aimed to evaluate the role of Thymoquinone (TQ), on antidiabetic, oxidative stress, and anti-inflammatory activities in streptozotocin (STZ)-induced (55 mg/kg b.w) diabetic rats. TQ was orally given for 8 consecutive weeks at dose of 150 mg/kg b.w. The blood glucose, insulin, total cholesterol, triglycerides, liver function enzymes, high density lipoprotein (HDL)-cholesterol, and low-density lipoprotein (LDL)-cholesterol levels were measured accordingly in control, diabetes control (DC), and TQ-treatment groups. These experiments confirmed that TQ conserves the insulin level (0.4 ng/mL vs. 0.23 ng/mL), fasting blood glucose (146 ± 7 mg/dL vs. 225 ± 5 mg/dL), and HbA1c (7.5% vs. 10.6%) quite considerably as compared to DC animals. Our results also confirmed that TQ treatment conserves the body weight and lipid profile significantly in STZ-treated animals as compared to the DC group. Moreover, the antioxidant enzymes (GSH, SOD, GST, and CAT) levels decreased, liver function enzymes (ALT, AST, and ALP), lipid peroxidation and inflammatory markers (TNF-α, CRP, IL-1β, IL-6) increased by STZ treatment, that is significantly restored after TQ treatment. As compared to untreated animals, TQ restored the hepatocytes architectural changes and collagen fibers and cox-2 protein expression in liver tissues as evaluated by hematoxylin and eosin, Masson’s trichrome, and immunohistochemistry staining. Taken together, all these findings indicated that TQ ameliorates glucose level and lipid metabolism. It restores liver function, antioxidant enzymes, anti-inflammatory markers, and maintains hepatocytes architecture in STZ-induced diabetes mellitus rats. Here, in this study, we have demonstrated for the first time the role of TQ in the reduction of the expression of cyclooxygenase-2 and fibrosis formation in diabetic rats. Based on the findings, the study suggests that TQ is a novel natural drug with a wide range of clinical applications including the management of diabetes mellitus.

Anti-inflammatory effects of thymoquinone and its protective effects against several diseases

Thymoquinone (TQ, 2-methyl-5-isopropyl-1, 4-benzoquinone), a monoterpene molecule present in Nigella sativa L., has an anti-inflammatory, anti-oxidant, and anti-apoptotic properties in several disorders such as asthma, hypertension, diabetes, inflammation, bronchitis, headache, eczema, fever, dizziness and influenza. TQ exerts its anti-inflammatory and anti-oxidant effects via several molecular pathways, including the release of cytokines, and activation of cyclooxygenase-2 (COX2), nuclear factor erythroid 2-related factor 2 (Nrf2), phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT), nuclear factor kappa-light-chain-enhancer of activated B (NF-Κβ). In this review, recent reports on the anti-inflammatory efficacy of TQ in heart disorders, respiratory diseases, neuroinflammation, diabetes and arthritis are summarized. We suggest that further investigation is necessary to better characterize the efficacy of TQ as a therapeutic agent.

Neuroprotective Effects of Thymoquinone by the Modulation of ER Stress and Apoptotic Pathway in In Vitro Model of Excitotoxicity

Experimental evidence indicates that the activation of ionotropic glutamate receptors plays an important role in neurological disorders’ models such as epilepsy, cerebral ischemia and trauma. The glutamate receptor agonist kainic acid (KA) induces seizures and excitotoxic cell death in the CA3 region of the hippocampus. Thymoquinone (TQ) is the most important component of the essential oil obtained from black cumin (Nigella sativa L.) seeds. It has many pharmacological actions including antioxidant, anti-inflammatory, and anti-apoptotic effects. TQ was used in an in vitro experimental model of primary cultures where excitotoxicity was induced. Briefly, rat organotypic hippocampal slices were exposed to 5 µM KA for 24 h. Cell death in the CA3 subregions of slices was quantified by measuring propidium iodide fluorescence. The cross-talk between TQ, ER stress and apoptotic pathways was investigated by Western blot. In untreated slices TQ (10 µM) induced a significant increase on the PSD95 levels and it decreased the excitotoxic injury induced by KA. Additionally, TQ was able to ameliorate the KA-induced increase in unfolded proteins GRP78 and GRP94 expression. Finally, TQ was able to partially rescue the reduction of the KA-induced apoptotic pathway activation. Our results suggest that TQ modulates the processes leading to post-kainate neuronal death in the CA3 hippocampal area.

Effects of resistance training and nigella sativa on type 2 diabetes: implications for metabolic markers, low-grade inflammation and liver enzyme production

CONTEXT

Proper nutrition and exercise are effective strategies to improve overall metabolic health in diabetic patients.

OBJECTIVE

This study evaluated the effects of Nigella sativa (NS) supplementation during resistance training (RT) on some biochemical variables in type 2 diabetes patients.

METHODS

Forty patients were assigned to groups: RT + NS (RN), NS, RT + placebo (RP), and control (CO). RT was performed and NS was consumed for 8 weeks. Blood samples were collected at rest immediately before and after the 8 week intervention.

RESULTS

RT or NS by themselves reduced HOMA-IR, insulin, glucose, TG, TC, LDL, ESR, CRP, AST, ALT and ALP, and increased HDL and HOMA-S. The combination of RT and NS, rather than each intervention alone, had significant effects on reduction of HOMA-IR, insulin, ESR and CRP as well as increases in HDL, HOMA-β/S.

CONCLUSION

RT combined with NS is sometimes a better strategy compared to single interventions for improving diabetes related biomarkers in type 2 diabetic patients.

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 protective effects of thymoquinone on lung damage caused by cigarette smoke

Chronic obstructive pulmonary disease (COPD) is characterized by systemic inflammation that usually is caused by exposure to noxious particles or gases. Thymoquinone (TQ) prevents the production of inflammatory mediators, such as thromboxane B2 and leukotriene, by altering arachidonic acid metabolism. We investigated the preventive and curative effects of TQ on lung damage in rats caused by cigarette smoke (CS). We used 50 adult male rats, 30 of which were exposed to CS every day for 3 months. TQ in dimethylsulfoxide (DMSO) was administered intraperitoneally (i.p.) every day to ten animals to investigate the protective effects of TQ, and to ten other animals during the last 21 days to investigate the curative effect. Ten rats received saline for the last 21 days. Ten subjects were untreated controls. Ten controls that were not exposed to CS received TQ for the last ten days. Serum IL-8, IL-6, IL-1β and MMP-9 levels were measured using ELISA. IL-1β and IL-8 levels were elevated in the group exposed to CS compared to controls. IL-8 levels were decreased in the group that received only TQ compared to controls, which indicated the anti-inflammatory effect of TQ. The apoptotic index (AI) was increased in all groups that were exposed to CS compared to controls. The AI index was decreased in the group that received TQ for the last 21 days compared to the other CS groups. AI was increased in the group that received TQ daily compared to the other CS groups. Our findings indicate that TQ exerts curative effects for the inflammation caused by CS and may prevent apoptosis if administered in appropriate doses; however, long term TQ or DMSO exposure may produce cumulative toxic effects.

Prostaglandin E1 attenuates high glucose-induced apoptosis in proximal renal tubular cells by inhibiting the JNK/Bim pathway

Proximal renal tubular damage is a critical process underlying diabetic kidney disease (DKD). Our previous study shows that prostaglandin E1 (PGE1) reduces the apoptosis of renal tubular cells in DKD rats. But its underlying mechanisms remain unclear. In this study we investigated the protective effects of PGE1 in DKD rats and high glucose (HG, 30 mM)-treated HK-2 proximal tubular cells. Four weeks after uninephrectomized streptozotocin-induced diabetic rats were established, the DKD rats were administered PGE1 (10 µg· kg⁻¹· d⁻¹, iv.) for 10 consecutive days. We showed that PGE1 administration did not change blood glucose levels, but alleviated diabetic kidney injury in the DKD rats, evidenced by markedly reduced proteinuria and renal tubular apoptosis. In the in vitro experiments, PGE1 (0.1–100 µM) significantly enhanced HG-reduced HK-2 cell viability. In HG-treated HK-2 cells, PGE1 (10 µM) significantly suppressed the c-Jun N-terminal kinase (JNK) and the mitochondrial apoptosis-related protein expressions such as Bim, Bax, caspase-3 and cleaved caspase-3; similar changes were also observed in the kidney of PGE1-treated DKD rats. By using two pharmacological tools-JNK activator anisomycin (AM) and JNK inhibitor SP600125, we revealed that PGE1 blocked HG-triggered activation of JNK/Bim pathway in HK-2 cells; JNK was an upstream regulator of Bim. In conclusion, our results demonstrate that the nephroprotective effects of PGE1 against apoptosis of proximal renal tubule in DKD rats via suppressing JNK-related Bim signaling pathway.

Natural Products Derived from the Mediterranean Diet with Antidiabetic Activity: from Insulin Mimetic Hypoglycemic to Nutriepigenetic Modulator Compounds

BACKGROUND

The Mediterranean diet is a healthy eating pattern that protects against the development of Type 2 diabetes mellitus (T2DM), a metabolic disease characterized by elevated blood sugar levels due to pancreatic beta-cell functional impairment and insulin resistance in various tissues. Inspired by the ancient communities, this diet emphasizes eating primarily plant-based foods, including vegetables, legumes, fruits, cereals, and nuts. Importantly, virgin olive oil is used as the principal source of fat. Red meat is consumed in low amounts while wine and fish are consumed moderately.

OBJECTIVE

Here, we review the most beneficial components of the Mediterranean Diet and tentative mechanisms of action for prevention and/or management of T2DM, based on research conducted within the last decade.

METHODS

The references over the last five years have been reviewed and they have been selected properly according to inclusion/ exclusion criteria.

RESULTS

Several bioactive diet components were evaluated to prevent inflammation and cytokine-induced oxidative damage, reduce glucose concentration, carbohydrate absorption and increase insulin sensitivity and related gene expression.

CONCLUSION

The adherence to a healthy lifestyle, including diet, exercise and habits remains the best approach for the prevention of diabetes as well as frequent check-ups and education. Though diabetes has a strong genetic component, in recent years many reports strongly point to the critical role of lifestyle specific epigenetic modifications in the development of T2DM. It remains to be established how different components of the Mediterranean Diet interact and influence the epigenetic landscape to prevent or treat the disease.

In-Vitro Anti-Proliferative, Apoptotic and Antioxidative Activities of Medicinal Herb Kalonji (Nigella sativa)

BACKGROUND

Natural product with apoptotic activity could serve as a potential new source for anti-cancer medicine. Numerous phytochemicals from plants have shown to exert antineoplastic effects via programmed cell death (apoptosis). Cancer is one of the leading causes of death in prosperous countries. The subject study was intended to evaluate the anticancer properties of Kalonji extracts against cancer cell lines HeLa and HepG2 and normal cell lines BHK and VERO were used as normal controls.

MATERIALS & METHODS

For the evaluation of anti-proliferative effects, cell viability and cell death in all groups of cells were evaluated via MTT, crystal violet and trypan blue assays. For the evaluation of angiogenesis, Immunocytochemistry and ELISA of VEGF were done. Immunocytochemistry and ELISA of Annexin-V and p53 were performed for the estimation of apoptosis in all groups of cells. Furthermore, LDH assay, antioxidant enzymes activity (GSH, APOX, CAT and SOD) and RT-PCR with proliferative and apoptotic markers along with internal control were also performed. Cancer cells of both cell lines HepG2 and HeLa cells showed reduced viability, angiogenesis and proliferation with increased apoptosis when treated with Kalonji extracts. Whereas anti-oxidative enzymes show enhanced levels in treated cancer cells as compared to untreated ones.

CONCLUSION

It was observed that Kalonji extracts have the ability to induce apoptosis and improve the antioxidant status of HeLa and HepG2 cells. They can also inhibit the proliferation and angiogenesis in both these cancer cell lines.

Connective tissue growth factor in hepatocytes is elevated by carbon tetrachloride via STAT3 activation

Carbon tetrachloride (CCl4) is widely used to induce hepatic fibrosis. Therapeutic agents alleviate hepatic fibrosis by inhibiting signal transducer and activator of transcription 3 (STAT3) activation. To understand the direct effects of CCl4 on STAT3 expression in the liver, the present study incubated cultured hepatocytes expressing connective tissue growth factor (CTGF) with CCl4. Rats exposed to CCl4 for 8 weeks exhibited hepatic fibrosis, which was confirmed through the assessment of plasma biomarkers. Isolated liver samples were used to determine the protein levels of CTGF and STAT3 using western blotting. In addition, STAT3 expression was silenced in α mouse liver 12 (AML‑12) cells using small interfering RNA transfection. In addition, a pharmacological inhibitor, stattic, was used to inhibit STAT3 expression. The incubation of AML‑12 cells with CCl4 induced a dose‑dependent increase in CTGF expression and STAT3 activation. Notably, silymarin, an extract from milk thistle, inhibited these changes in AML‑12 cells and the antioxidant tiron produced similar effects. Silencing of STAT3 reduced the CTGF expression promoted by CCl4 in the hepatocytes. Additionally, similar to tiron, stattic inhibited CTGF expression induced by CCl4. In conclusion, CCl4 may activate STAT3 through oxidative stress to promote CTGF expression, which is one of the main factors contributing to the risk of hepatic fibrosis.

Animal Models of Diabetes-Associated Renal Injury

Diabetic nephropathy (DN) is the main factor leading to end-stage renal disease (ESRD) and subsequent morbidity and mortality. Importantly, the prevalence of DN is continuously increasing in developed countries. Many rodent models of type 1 and type 2 diabetes have been established to elucidate the pathogenesis of diabetes and examine novel therapies against DN. These models are developed by chemical, surgical, genetic, drug, and diet/nutrition interventions or combination of two or more methods. The main characteristics of DN including a decrease in renal function, albuminuria and mesangiolysis, mesangial expansion, and nodular glomerulosclerosis should be exhibited by an animal model of DN. However, a rodent model possessing all of the abovementioned features of human DN has not yet been developed. Furthermore, mice of different genetic backgrounds and strains show different levels of susceptibility to DN with respect to albuminuria and development of glomerular and tubulointerstitial lesions. Therefore, the type of diabetes, development of nephropathy, duration of the study, cost of maintaining and breeding, and animals' mortality rate are important factors that might be affected by the type of DN model. In this review, we discuss the pros and cons of different rodent models of diabetes that are being used to study DN.

Antidiabetic activity enhancement in streptozotocin + nicotinamide-induced diabetic rats through combinational polymeric nanoformulation

Background: The bioactive compounds glycyrrhizin (GL) and thymoquinone (TQ) have been reported for antidiabetic activity in pure and nanoformulation (NF) form. However, the antidiabetic effect of a combined nanoformulation of these two has not been reported in the literature. Here, a combinational nanomedicine approach was investigated to enhance the antidiabetic effects of the two bioactive compounds of GL and TQ (GT), in type 2 diabetic rats in reference to metformin. Methods: Two separately prepared NFs of GL (using polymeric nanoparticles) and TQ (using polymeric nanocapsules) were mixed to obtain a therapeutic cargo of nanomedicine and then characterized with respect to particle size, stability, morphology, chemical interaction, and in vivo behavior. Additionally, NFs were evaluated for their cytotoxic effect on Vero cell lines compared to the pure form. This nanomedicine was administered orally, both independently and in combination (pure form or NF) for 21 successive days to type 2 diabetic rats and the effect assessed in term of body weight, fasting blood-glucose level, and various biochemical parameters (such as lipid-profile parameters and HbA_1c). Results: When these nanomedicines were applied in combined rather than individual forms, significant decreases in blood glucose and HbA_1c and significant improvements in body weight and lipid profile were observed, despite them containing lower amounts than the pure forms. The treatment of diabetic rats with GL and TQ, when administered independently in either pure or NF forms, did not lead to favorable trends in any studied parameters. Conclusion: The administration of combined GT NFs exhibited significant improvement in studied parameters. Improvements in antidiabetic activity could have been due to a synergistic effect of combined NFs, leading to enhanced absorption of NFs and lesser cytotoxic effects compared to pure bioactive compounds. Therefore, GT NFs demonstrated potential as a new medicinal agent for the management of diabetes.

Thymoquinone and fluoxetine alleviate depression via attenuating oxidative damage and inflammatory markers in type-2 diabetic rats

The study was designed to find out the effect of thymoquinone (TQ) alone and combination of TQ + fluoxetine in depression of type-2 diabetic rats. Glucose level was significantly decreased in TQ alone treated group, whereas no significant change was recorded when TQ was combined with fluoxetine. Administration of TQ alone and combination of TQ and fluoxetine significantly decreased immobility time, increased latency to immobility and increased locomotor activity. Treatment with TQ alone significantly decreased level of TBARS, increased GSH and restored the activities of antioxidant enzymes (GPx, GR & CAT). However, TQ and fluoxetine combination reduced TBARS level, increased GSH content but no change in the antioxidant enzymes activities. Inflammatory markers (IL-1β, IL-6 & TNF-α) levels were significantly reduced after the administration of TQ alone and TQ + fluoxetine. The study suggests that combination of TQ and fluoxetine can be used to control depression in type-2 diabetes mellitus.

GLP-1 mediates the modulating effect of thymoquinone on feeding behaviors in diabetic rats

Background: Thymoquinone (TQ) is a safe nutrient isolated from the seeds or volatile oil extract of Nigella sativa. In addition to its benefits in glucose regulation, TQ improves feeding disorders in diabetic animals. Glucagon-like peptide-1 (GLP-1) analogs improve glycemic control and ameliorate obesity or hyperphagia. Therefore, the present study aimed to investigate the role of GLP-1 in TQ-induced anorexia. Method: Type 2 diabetes was induced in rats by nicotinamide and streptozotocin injection. TQ was orally administered to diabetic rats at different doses for 45 days. Following TQ treatment, changes in serum glucose levels, GLP-1 concentration, body weight, food intake, and water intake were determined. To further explore the interaction between GLP-1 and TQ, the inhibitor of dipeptidyl peptidase 4, sitagliptin and the GLP-1 receptor antagonist exendin 9-39 (Ex 9-39) were separately administered to TQ- or vehicle-treated diabetic rats. Results: TQ treatment attenuated hyperglycemia and reduced hyperphagy and water intake in streptozotocin-induced diabetic rats in a dose-dependent manner. Moreover, TQ treatment elevated plasma GLP-1 levels compared to those in control rats. The effects of TQ were enhanced by treatment with sitagliptin and reduced by the injection of Ex 9-39 into the brain. In contrast, similar treatment with another antioxidant (either ascorbic acid or N-acetylcysteine) produced the same anorexic effect as TQ without changing the plasma GLP-1 levels in diabetic rats. Therefore, TQ attenuated hyperphagy while increasing plasma GLP-1 levels and had antioxidant-like effects. Conclusion: TQ increased endogenous GLP-1 levels to reduce hyperphagy in diabetic rats.

Spice-Derived Bioactive Ingredients: Potential Agents or Food Adjuvant in the Management of Diabetes Mellitus

Spices possess tremendous therapeutic potential including hypoglycemic action, attributed to their bioactive ingredients. However, there is no study that critically reviewed the hypoglycemic potency, safety and the bioavailability of the spice-derived bioactive ingredients (SDBI). Therefore, the aim of the study was to comprehensively review all published studies regarding the hypoglycemic action of SDBI with the purpose to assess whether the ingredients are potential hypoglycemic agents or adjuvant. Factors considered were concentration/dosages used, the extent of blood glucose reduction, the IC50 values, and the safety concern of the SDBI. From the results, cinnamaldehyde, curcumin, diosgenin, thymoquinone (TQ), and trigonelline were showed the most promising effects and hold future potential as hypoglycemic agents. Conclusively, future studies should focus on improving the tissue and cellular bioavailability of the promising SDBI to achieve greater potency. Additionally, clinical trials and toxicity studies are with these SDBI are warranted.

Thymoquinone inhibits cell proliferation, migration, and invasion by regulating the elongation factor 2 kinase (eEF-2K) signaling axis in triple-negative breast cancer

BACKGROUND/PURPOSE

Triple-negative breast cancer (TNBC) is the most aggressive and chemoresistant subtype of breast cancer. Therefore, new molecular targets and treatments need to be developed to improve poor patient prognosis and survival. We have previously shown that eukaryotic elongation factor 2 kinase (eEF-2K) is highly expressed in TNBC cells, is associated with poor patient survival and prognosis, and promotes cell proliferation, migration, and invasion. In vivo targeting of eEF-2K significantly reduces the tumor growth of orthotopic TNBC xenograft mouse models, suggesting that eEF-2K may serve as a potential novel therapeutic target.

METHODS/RESULTS

In the current study, we identified thymoquinone (TQ), an active ingredient of Nigella sativa, as a potential safe and effective eEF-2K inhibitor in TNBC. We demonstrated for the first time that TQ inhibits the protein and mRNA expression of eEF-2K, as well as the clinically relevant downstream targets, including Src/FAK and Akt, and induces the tumor suppressor miR-603, in response to NF-kB inhibition. This effect was associated with a significant decrease in the proliferation, colony formation, migration, and invasion of TNBC cells. Furthermore, systemic in vivo injection of TQ (20 and 100 mg/kg) significantly reduced the growth of MDA-MB-231 tumors and inhibited the eEF-2K expression in an orthotopic tumor model in mice.

CONCLUSION

Our study provides first evidence that TQ treatment inhibits cell proliferation, migration/invasion, and tumor growth, in part through the inhibition of eEF-2K signaling in TNBC. Thus, our findings suggest that systemic TQ treatment may be used as a targeted therapeutic strategy for the inhibition of eEF-2K in TNBC tumor growth and progression.

The Neuroprotective Effects of Thymoquinone: A Review

Thymoquinone (TQ), one of the main components active of Nigella sativa, exhibited very useful biomedical effects such as anti-inflammatory, antioxidant, antimicrobial, antiparasitic, anticancer, hypoglycemic, antihypertensive, and antiasthmatic effects. There are several studies about pharmacological activities of TQ but its neuroprotection effects are not fully described. The literature search has indicated many studies pertaining to the effects of TQ in neurological problems such as epilepsy, parkinsonism, anxiety, and improvement of learning and memory, and so on. In addition, TQ protected brain cells from various injuries due to its antioxidant, anti-inflammatory, and apoptotic effects in cell line and experimental animal models. The present study has been designed to review the scientific literature about the pharmacological activities of TQ to the neurological diseases. This study purposed that although experimental studies indicated the beneficial effects of TQ against nervous system problems, better designed clinical trials in humans are needed to confirm these effects.

Improvement of antihyperglycemic activity of nano-thymoquinone in rat model of type-2 diabetes

Thymoquinone is a bioactive constituent of Nigella sativa seeds. It has been reported to possess antihyperglycemic effect in rats. However, the effect of nanoformulation (NF) of thymoquinone has not been reported in literature. So, the present study was designed with the aim to investigate the effect of nanoformulation of thymoquinone in streptozotocin-nicotinamide induced type-2 diabetic rats and compare its effect with pure bioactive compound as well as metformin, a standard antidiabetic drug. It is the first study reporting the use of thymoquinone NF against diabetes. Polymeric nanocapsules (NCs) of thymoquinone and metformin were prepared by nanoprecipitation method using gum rosin, a biocompatible polymer. Box-Behnken statistical analysis tool was used for the optimization of polymer and other excipients. The NCs were then characterized with respect to particle size, stability, morphology, and in vitro drug dissolution profiles. Furthermore, thymoquinone (20, 40 & 80 mg/kg), metformin (150 mg/kg) and their nanoformulations (20, 40 & 80 mg/kg for thymoquinone and 80 mg/kg for metformin) per se were administered for 21 successive days to type-2 diabetic rats. Body weight and blood glucose levels were measured every week for 3 weeks. Serum lipid profile and glycosylated hemoglobin were estimated on 22^nd day. The nanocapsules were stable, spherical in shape and size was less than 100 nm. Thymoquinone-and metformin-loaded NCs showed sustained release profile as compared to their pure forms. Oral administration of thymoquinone, metformin and their nanoformulations significantly decreased blood glucose level and glycated haemoglobin; and improved the lipid profile of diabetic rats as compared to diabetic control rats. Thymoquinone-loaded NCs (containing 10, 20 and 40 mg of thymoquinone) produced dose-dependent antihyperglycemic effect and this effect was comparable to thymoquinone and metformin. In conclusion, thymoquinone nanocapsules (actually containing half of the doses of thymoquinone) produced better antihyperglycemic effect in type-2 diabetic rats as compared to thymoquinone alone.

The Effect of Thymoquinone on Nuclear Factor Kappa B Levels and Oxidative DNA Damage on Experimental Diabetic Rats

Background:

Thymoquinone (TQ), the basic bioactive phytochemical constituent of seed oil of Nigella sativa, is one of these herbal drugs known for antidiabetic effects. This study was carried out to assess the effects of the possible role of TQ on nuclear factor kappa B (NF-κB) and oxidative DNA damage levels in experimental diabetic rats.

Materials and Methods:

Twenty-eight male Wistar Albino rats (200–250 g) were used as experimental subjects. The rats were divided into four groups, including the control, control supplemented with TQ (CT), diabetic (D), and diabetic supplemented with TQ (DT), each containing seven rats. The D and the DT groups were treated with 45 mg/kg streptozotocin (STZ) (intraperitoneal). TQ was administered 30 mg/kg/day for 21 days by oral gavage in the DT and the T groups.

Results:

It was determined that glucose, glycosylated hemoglobin (HbA1c) levels and alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transpeptidase activities were decreased significantly and approached the control group in the DT group after TQ supplement (P < 0.05). Urea levels were the lowest in CT (P < 0.05). Oxidative DNA damage (8 hydroxy-2-deoxyguanosine) was increased in both of the diabetic groups (D and DT). The NF-κB levels were the highest in Group D (P < 0.05).

Conclusion:

It was observed that increased glucose and HbA1c levels and the indicators of liver and kidney damages were decreased significantly after TQ supplementation. Oxidative DNA damage and NF-κB levels were increased in the diabetic group, and TQ administration caused a statistically insignificant reduction.

SUMMARY

In this study, the effects of thymoquinone (TQ), the basic bioactive phytochemical constituent of seed oil of Nigella sativa, on nuclear factor kappa B (NF-κB), oxidative DNA damage levels, and, some biochemical parameters was invesigated. It was observed that some biochemical parameters (glucose, glycosylated hemoglobin (HbA1c), ALT, AST, GGT) were close to the control group after TQ treatment in diabetic group. Oxidative DNA damage (8 hydroxy 2 deoxyguanosine) and NF-κB were highest levels and TQ implementation caused statistically insignificant decrease, in the diabetic group.

Abbreviations used: 8-OHdG: 8 hydroxi-2-deoxiguanosin; ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; GGT: Gamma-glutamyl transpeptidase; HbA1c: Glycosylated hemoglobin; NF-κB: Nuclear factor kappa protein; STZ: Streptozotocin; TQ: Thymoquinone.

Thymoquinone ameliorates diabetic phenotype in Diet-Induced Obesity mice via activation of SIRT-1-dependent pathways

Thymoquinone, a natural occurring quinone and the main bioactive component of plant Nigella sativa, undergoes intracellular redox cycling and re-oxidizes NADH to NAD⁺. TQ administration (20 mg/kg/bw/day) to the Diet-Induced Obesity (DIO) mice reduced their diabetic phenotype by decreasing fasting blood glucose and fasting insulin levels, and improved glucose tolerance and insulin sensitivity as evaluated by oral glucose and insulin tolerance tests (OGTT and ITT). Furthermore, TQ decreased serum cholesterol levels and liver triglycerides, increased protein expression of phosphorylated Akt, decreased serum levels of inflammatory markers resistin and MCP-1, and decreased NADH/NAD⁺ ratio. These changes were paralleled by an increase in phosphorylated SIRT-1 and AMPKα in liver and phosphorylated SIRT-1 in skeletal muscle. TQ also increased insulin sensitivity in insulin-resistant HepG2 cells via a SIRT-1-dependent mechanism. These findings are consistent with the TQ-dependent re-oxidation of NADH to NAD⁺, which stimulates glucose and fatty acid oxidation and activation of SIRT-1-dependent pathways. Taken together, these results demonstrate that TQ ameliorates the diabetic phenotype in the DIO mouse model of type 2 diabetes.

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.

Reversal of endothelial dysfunction in aorta of streptozotocin-nicotinamide-induced type-2 diabetic rats by S-Allylcysteine

Dietary measures and plant-based therapies as prescribed by native systems of medicine have gained attraction among diabetics with claims of efficacy. The present study investigated the effects of S-Allylcysteine (SAC) on body weight gain, glucose, insulin, insulin resistance, and nitric oxide synthase in plasma and argininosuccinate synthase (AS) and argininosuccinate lyase (ASL), lipid peroxides and antioxidant enzymes in aorta of control and streptozotocin-nicotinamide (STZ-NA)-induced diabetic rats. Changes in body weight, glucose, insulin, insulin resistance, and antioxidant profiles of aorta and mRNA expressions of nitric oxide synthase, AS, and ASL were observed in experimental rats. SAC (150 mg/kg b.w) showed its therapeutic effects similar to gliclazide in decreasing glucose, insulin resistance, lipid peroxidation, and increasing body weight; insulin, antioxidant enzymes, and mRNA levels of nitric oxide synthase, argininosuccinate synthase, and argininosuccinate lyase genes in STZ-NA rats. Histopathologic studies also revealed the protective nature of SAC on aorta. In conclusion, garlic and its constituents mediate the anti-diabetic potential through mitigating hyperglycemic status, changing insulin resistance by alleviating endothelial dysregulation in both plasma and tissues.