Blood pressure lowering effect of Nigella sativa L. seed oil in healthy volunteers: a randomized, double-blind, placebo-controlled clinical trial

Deciphering the anticancer potential of thymoquinone: in-depth exploration of the potent flavonoid from Nigella sativa

Since its first written description around 3000 BC until the present day, cancer has stood as a leading global cause of death, claiming the lives of 1 in 6 individuals. Due to its widespread impact and lethality, it remains one of the most explored yet most challenging disease for the global scientific community. Throughout history, various plant extracts have been used in treating numerous diseases, including cancer. These natural extracts are regaining attention due to their therapeutic benefits and lesser side effects. Thymoquinone, chemically 2-isopropyl-5-methylbenzo-1,4-quinone, constitutes the primary bioactive component of the plant Nigella sativa. Extensive research across in vivo, in vitro models, and clinical trials has revealed Thymoquinone's noteworthy therapeutic potential against cancer. Thymoquinone has shown promising anti-cancer activity in various cancers including breast cancer, lung cancer, prostate cancer, colorectal cancer, cervical cancer, pancreatic cancer, gastric cancer and blood cancers. However, there are challenges such as limited clinical trials, low bioavailability, and the need for more research to understand its long-term safety and effectiveness. This article provides a comprehensive and thorough review of thymoquinone, covering its effectiveness across various malignancies, the molecular signalling pathways it influences, and its role in triggering apoptosis and inhibiting inflammation, angiogenesis, and metastasis. Additionally, the review includes a thorough examination of thymoquinone's pharmacokinetics and safety, making it the first of its kind in its comprehensiveness.

Nigella sativa: A Comprehensive Review of Its Therapeutic Potential, Pharmacological Properties, and Clinical Applications

Nigella sativa (NS) is an annual herb belonging to the Ranunculaceae family, also known as black cumin or black seed. This plant has been used since ancient times due to its therapeutic properties and has proven effective in gastrointestinal, respiratory, cardiovascular, infectious, and inflammatory conditions. In this review, the aim is to highlight the therapeutic effects of the plant known in Arab countries as "the plant that cures any disease", which are provided by the phytochemical compounds in its composition, such as thymoquinone, p-cymene, α-thujene, longifolene, β-pinene, α-pinene, and carvacrol. These compounds confer an antioxidant effect to the seeds, leading to a significant decrease in ROS and a potent anti-inflammatory effect. Also, in this review, the aim is to highlight that NS seeds may have a synergistic effect with other drugs, such as chemotherapeutic agents or antibiotics, which may lead to a reduction in the therapeutic dose, may have an improved effect, and could lead to overcoming obstacles such as drug resistance. The studies provided in this review showed that NS has the potential to be a therapeutic agent both as a monotherapy and as an adjuvant. Although there are studies demonstrating the therapeutic properties of NS, there is a need for much more extensive research and more clinical trials with clearly established objectives so that the mechanism of action of the active substances in NS is much better understood. With the data provided so far, NS can be used in food and drug production in small quantities and can be administered for short periods. Further investigations may lead to an understanding of the therapeutic profile and the most effective mode of administration, as well as a clearer perspective on the toxicological profile of NS.

The Use of Nigella sativa in Cardiometabolic Diseases

Nigella sativa L. is an herb that is commonly used in cooking and in traditional medicine, particularly in Arab countries, the Indian subcontinent, and some areas of eastern Europe. Nigella sativa is also called "black cumin" or "black seeds", as the seeds are the most-used part of the plant. They contain the main bioactive component thymoquinone (TQ), which is responsible for the pleiotropic pharmacological properties of the seeds, including anti-oxidant, anti-inflammatory, anti-hypertensive, anti-hepatotoxic, hypoglycemic, and lipid-lowering properties. In this narrative review, both the potential mechanisms of action of Nigella sativa and the fundamental role played by pharmaceutical technology in optimizing preparations based on this herb in terms of yield, quality, and effectiveness have been outlined. Moreover, an analysis of the market of products containing Nigella sativa was carried out based on the current literature with an international perspective, along with a specific focus on Italy.

The efficacy of Nigella sativa L. oil on serum biomarkers of inflammation and oxidative stress and quality of life in patients with knee osteoarthritis: A parallel triple-arm double-blind randomized controlled trial

The aim of this double-blind clinical trial was to investigate the effects of Nigella sativa oil on serum inflammatory and oxidative stress biomarkers and quality of life in patients with knee osteoarthritis (OA). Forty-five patients who met the eligibility criteria were randomly divided into three groups with a ratio of 1:1:1. The first group received 2.5 mL oral N. sativa oil twice/day plus placebo topical oil, the second group received 2.5 mL topical N. sativa oil three times/day plus placebo oral oil, and the third group received oral and topical oil placebos. There were no intergroup differences in baseline characteristics. After 6 weeks of supplementation, oral N. sativa caused a significant improvement in the serum levels of hs-CRP (p = .003), MDA (p = .003), and TAC (p = .001). Oral N. sativa oil compared to placebo (aMD (95% CI): -0.81 (-1.45 to -0.19); p = .012) and topical N. sativa oil [aMD (95% CI): -0.76 (-1.38 to -0.15); p = .016] significantly reduced hs-CRP serum levels. Significant improvements were observed in the general, physical, and mental health subscales in the oral and topical N. sativa oil compared to the placebo group (p < .05). The six-week oral N. sativa oil supplementation was effective in improving inflammatory biomarkers in knee OA. Both oral and topical N. sativa oil increased the quality of life.

Potential Pharmacological Applications of Nigella Seeds with a Focus on Nigella sativa and Its Constituents against Chronic Inflammatory Diseases: Progress and Future Opportunities

The leading cause of death worldwide has been identified as chronic illnesses, according to the World Health Organization (WHO). Chronic inflammatory conditions such as asthma, cancer, diabetes, heart disease, and obesity account for three out of every five deaths. Although many people benefit from using nonsteroidal anti-inflammatory medicines (NSAIDs) for pain and inflammation relief, there are significant adverse effects to using these medications. Medicinal plants possess anti-inflammatory properties with minimal or no side effects. Nigella sativa (NS), also known as black cumin, is one of the plants used in traditional medicine the most. Many studies on the NS have shown that their therapeutic properties are attributed to the seed, oil, and secondary metabolites. This plant has been studied extensively and has many medical uses, such as anti-inflammatory. NS or its phytochemical compounds, such as thymoquinone, can cause cell apoptosis via oxidative stress, block efflux pumps, enhance membrane permeability, and exert potent biocidal effects. Notwithstanding the extensively documented anti-inflammatory effectiveness observed in the experimental model, the precise mechanisms underlying its anti-inflammatory effects in diverse chronic inflammatory diseases and its multi-targeting characteristics remain largely unexplored. This review examines NS or its secondary metabolites, a valuable source for the therapeutic development of chronic inflammatory diseases. Most clinical studies were done for diabetes and cardiovascular disease; therefore, more studies are required to examine the NS extracts and phytoconstituents to treat cancer, obesity, diabetes, asthma, neurological disorders, and COVID-19. This study will be a significant resource for clinicians and biologists seeking a pharmaceutical solution for inflammatory diseases.

Bioactive molecules from terrestrial and seafood resources in hypertension treatment: focus on molecular mechanisms and targeted therapies

Hypertension (HTN), a complex cardiovascular disease (CVD), significantly impacts global health, prompting a growing interest in complementary and alternative therapeutic approaches. This review article seeks to provide an up-to-date and thorough summary of modern therapeutic techniques for treating HTN, with an emphasis on the molecular mechanisms of action found in substances found in plants, herbs, and seafood. Bioactive molecules have been a significant source of novel therapeutics and are crucial in developing and testing new HTN remedies. Recent advances in science have made it possible to understand the complex molecular mechanisms underlying blood pressure (BP)-regulating effects of these natural substances better. Polyphenols, flavonoids, alkaloids, and peptides are examples of bioactive compounds that have demonstrated promise in influencing several pathways involved in regulating vascular tone, reducing oxidative stress (OS), reducing inflammation, and improving endothelial function. The article explains the vasodilatory, diuretic, and renin-angiotensin-aldosterone system (RAAS) modifying properties of vital plants such as garlic and olive leaf. Phytochemicals from plants are the primary in traditional drug development as models for novel antihypertensive drugs, providing diverse strategies to combat HTN due to their biological actions. The review also discusses the functions of calcium channel blockers originating from natural sources, angiotensin-converting enzyme (ACE) inhibitors, and nitric oxide (NO) donors. Including seafood components in this study demonstrates the increased interest in using bioactive chemicals originating from marine sources to treat HTN. Omega-3 fatty acids, peptides, and minerals obtained from seafood sources have anti-inflammatory, vasodilatory, and antioxidant properties that improve vascular health and control BP. Overall, we discussed the multiple functions of bioactive molecules and seafood components in the treatment of HTN.

Effect of Nigella sativa on general health and immune system in young healthy volunteers; a randomized, placebo-controlled, double-blinded clinical trial

Nigella sativa ( N. sativa) is traditionally used as an immune enhancer in different communities. The aim of this study was to evaluate the effect of N. sativa on immunity related parameters in young healthy subjects. This study was a double blind, randomized, placebo controlled clinical trial. Fifty-two healthy subjects (48 male and 4 female) 18-25 years old were enrolled in the study. They were randomly divided into four groups; the first received charcoal capsules and served as controls and the other three received 0.5, 1 g, and 2 g of powdered N. sativa capsules, respectively. Two blood samples were obtained from all participant, before initiation of the trial and at the end of the four weeks intervention. One sample was used for routine health screening by evaluating liver and renal functions as well as complete blood count and differential. The second sample was used to measure certain cytokines including; IL-1, IL-4, IL-6, IL-10, and TNF. A third and fourth samples were obtained from the last cohort of subjects before and after treatment; the third was used for measuring immunoglobulins and CD profile and the fourth for evaluating certain gene expressions (INF-γ, NF-κ-B, TNF-α, IL-1β, IL-13, IL-8, and IL-6). Only 1 g dose of N. sativa produced a significant elevation in total lymphocyte count, CD3+ and CD4+ counts. One gram N. sativa increased the absolute lymphocyte count from 1850±0.24 to 2170±0.26 (p=0.008), CD3+ from 1184.4±75.60 to 1424±114.51 (p=0.009), and CD4+ from 665.6±141.66 to 841±143.36 (p=0.002).  This elevation in T cells was lost by increasing the dose of N. sativa to 2g. The rest of the parameters were not changed significantly in all doses. The results show a promising immunopotentiation effect of N. sativa by elevating helper T cells and the optimum dose for young age group seems to be 1 g.

A Review of the Potential Health Benefits of Nigella sativa on Obesity and Its Associated Complications

Obesity has become a worldwide epidemic and its prevalence continues to increase at an alarming rate. It is considered a major risk factor for the development of several comorbidities, including type 2 diabetes, stroke, other cardiovascular diseases and even cancer. Conventional treatments for obesity, such as dietary interventions, exercise and pharmacotherapy, have proven to have limited effectiveness and are often associated with undesirable side effects. Therefore, there is a growing interest in exploring alternative therapeutic approaches. Nigella sativa (NS), a medicinal plant with multiple pharmacological properties, has gained attention due to its potential role in the treatment of obesity and its associated complications. The aim of this review is therefore to assess the effects of NS on obesity and its complications and to provide insights into the underlying mechanisms. From this review, NS appears to play a complementary or supportive role in the treatment of obesity and its complications. However, future studies are needed to verify the efficacy of NS in the treatment of obesity and its complications and to prove its safety so that it can be introduced in patients with obesity.

John M, Alhiyari Y. Nigella sativa oil mitigates xerostomia and preserves salivary function in radiotherapy-treated mice

Objective

This study aimed to assess if Nigella sativa oil (NSO), a health supplement containing thymoquinone as a major component, can act as a protective agent in salivary gland stem cells following radiotherapy (RT) damage.

Methods

Forty, 10-week-old, male C3H/HeJ mice were randomized to four experimental groups: sham RT + H2O gavage (control) (N = 4); 15 Gy RT + H2O gavage (N = 12); sham RT + NSO gavage (N = 12); and 15 Gy RT + NSO gavage (N = 12). Weight changes, saliva production, and salivary gland histopathologic staining were recorded for each group over the course of the experiment.

Results

All mice in the sham RT + H2O gavage and sham RT + NSO gavage groups demonstrated 100% 60-day survival. RT + H2O compared to RT + NSO gavaged mice were significantly underweight by an average of 6.4 g (p < .001). Salivary output showed significant decline in RT + H2O gavaged mice at days 3 and 16, whereas salivary output in RT + NSO during these same time periods was comparable to the control. At day 60, all mice that survived recovered salivary function regardless of their treatment arm. Salivary specimens from the RT + NSO gavage group demonstrated early signs of recovery of Kr 5+ salivary gland stem cells in both submandibular and sublingual glands at day 16 with complete recovery by day 60, marked by strong histopathologic staining, whereas the RT + H2O gavage group did not recover as effectively.

Conclusion

NSO may help preserve salivary function in mice treated with RT and may mitigate xerostomia by accelerating the recovery of salivary gland stem cells.

Level of evidence

Not applicable.

Antihypertensive effects of Nigella sativa supplementation: An updated systematic review and meta-analysis of randomized controlled trials

Clinical studies have suggested that Nigella Sativa (N. sativa) supplementation may effectively reduce blood pressure, but the findings are controversial. Therefore, this study aimed to examine the effects of N. sativa on blood pressure in adults. PubMed, Cochrane Library, Web of Science, Scopus, Embase databases, and Google Scholar were searched till August 2022. To analyze weighted mean differences (WMDs), a random-effects model was utilized. Nonlinear dose-response analysis and a meta-regression were conducted. N. sativa supplementation was effective in reducing both systolic (WMD: -3.06 mmHg; 95% CI: -3.89 to -2.22, p < 0.001; I2  = 84.7%, p < 0.001) and diastolic blood pressure (WMD = -2.69 mmHg; 95% CI: -3.72, -1.66, p < 0.001; I2  = 97.3%, p < 0.001). The current meta-analysis suggests that N. sativa supplementation can improve blood pressure and claims that N. sativa could be used as an effective approach to blood pressure management.

Effects of Thymoquinone Alone or in Combination with Losartan on the Cardiotoxicity Caused by Oxidative Stress and Inflammation in Hypercholesterolemia

Dietary cholesterol accelerates oxidative and pro-inflammatory processes, causing hypercholesterolemia and cardiovascular diseases. Thus, the purpose of the current study is to compare the protective effects of thymoquinone (TQ) alone or in combination with losartan (LT) against the heart damage caused by a high-cholesterol diet (HCD). HCD-fed rat groups revealed an elevated activity of indicators of cardiac enzymes in the serum. Serum and cardiac lipids were also found to be significantly higher in HCD-fed rat groups. Cardiac pro-inflammatory and oxidative markers were also increased in HCD-fed rat groups, whereas antioxidant indicators were decreased. However, all of these biochemical, inflammatory, antioxidant, and oxidative change indicators returned to levels similar to those of normal rats after treatment with TQ alone or in combination with LT administered to HCD-fed rat groups. Hypercholesterolemia considerably induced the lipid peroxidation product, thiobarbituric acid reaction substances (TBARs), and oxidative radicals in cardiac cells, which were attenuated by QT and LT treatments, particularly when combined. Finally, QT, LT, and their combination were able to reduce the histological changes changes brought on by cholesterol excess in cardiac tissues. In conclusion, administration of TQ in a combination with LT which has a better protective effect, significantly reduced the hypercholesterolemic-induced oxidative and inflammatory changes that occurred in cardiac tissue.

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.

Screening of Thymoquinone Content in Commercial Nigella sativa Products to Identify a Promising and Safe Study Medication

(1) Background: Thymoquinone (TQ) is the leading compound accounting for the pharmacological effects of Nigella sativa seed oil, also known as black seed oil. This study aimed to analyze the TQ content of commercial black seed oils and black seed oil-containing capsules to obtain information on the quality of the products and to find a promising and safe study medication for a putative clinical study. (2) Methods: Six black seed oils and five black seed oil-containing capsules were analyzed. TQ was quantified using a validated method consisting of a simple methanolic extraction and a fast HPLC-UV analysis. (3) Results: The TQ content varied from 3.08 to 809.4 mg/100 g (mean). The highest TQ content was found in a bottled oil, which might be considered for a clinical study. A dose of 4 mL of this oil per day contains 30 mg TQ, which is unlikely to be harmful. Based on the literature, a safe daily TQ dosage appears to be <48.6 mg per adult. (4) Conclusions: These findings suggest that black seed products should be regulated regarding TQ content to enable consumers to buy black seed food supplements of known content for the maintenance and improvement of health.

The effect of nigella supplementation on blood pressure: A systematic review and dose-response meta-analysis

This study was performed to assess the effect of nigella supplementation on blood pressure levels among the adult population. A comprehensive search was carried out through PubMed, Scopus, Web of Science, and Cochrane Library by using relevant keywords to find out the randomized clinical trials evaluating the effect of nigella administration on systolic blood pressure (SBP) and diastolic blood pressure (DBP). A random-effect model was applied to achieve the overall effect size. Subgroup analysis and meta-regression were used to explore the source of heterogeneity and the effects of the possible moderators. Of the twenty-two trials that were eligible for the present study, seventeen studies consisting of 1048 participants were included in the meta-analysis. The results indicated that nigella administration could significantly reduce both SBP (-4.58 mmHg; 95%CI: -6.22, -2.94) and DBP (-3.08 mmHg; 95%CI: -4.62, -1.55). Subgroup analysis did not show any superiority between subgroups of variables. Dose-response analysis detected a nonlinear association between dose and duration of administration and change in blood pressure outcomes, highlighting that maximum SBP and DBP reduction was experienced at 2000 mg/day and 8 weeks of nigella administration, respectively. The present study suggests that nigella supplementation can be beneficial for managing blood pressure.

The effect of Nigella sativa oil on vascular dysfunction assessed by flow-mediated dilation and vascular-related biomarkers in subject with cardiovascular disease risk factors: A randomized controlled trial

Cardiovascular diseases (CVD) are the leading causes of mortality worldwide. Flow-mediated dilation (FMD) is a marker of vascular function. Beneficial cardiometabolic effects of Nigella sativa (N. sativa) have been observed. We evaluated the effect of N. sativa oil on FMD, plasma nitrite, and nitrate (NOx) as nitric oxide (NO) metabolites, and inflammatory markers in subjects with CVD risk factors. Fifty participants were randomly assigned to either the N. sativa (two capsules of 500 mg N. sativa oil) or the placebo group (two capsules of 500 mg mineral oil), for 2 months. The brachial FMD, plasma NOx, vascular cellular adhesion molecule-1 (VCAM-1), and intracellular adhesion molecule-1 (ICAM-1) were measured. FMD and plasma NOx levels was significantly increased in the N. sativa group compared to the placebo group (changes: 2.97 ± 2.11% vs. 0.71 ± 3.19%, p < 0.001 for FMD and 4.73 ± 7.25 μmol/L vs. 0.99 ± 5.37 μmol/L, p = 0.036 for plasma NOx). However, there was no significant difference in ICAM-1 and VCAM-1 levels between groups. Therefore, N. sativa oil improves vascular NO and FMD in subjects with cardiovascular risk factors. However, more studies are warranted to confirm the beneficial impacts of the N. sativa oil on vascular inflammation.

Thymoquinone ameliorates pressure overload-induced cardiac hypertrophy by activating the AMPK signalling pathway

Prolonged pathological myocardial hypertrophy leads to end‐stage heart failure. Thymoquinone (TQ), a bioactive component extracted from Nigella sativa seeds, is extensively used in ethnomedicine to treat a broad spectrum of disorders. However, it remains unclear whether TQ protects the heart from pathological hypertrophy. This study was conducted to examine the potential utility of TQ for treatment of pathological cardiac hypertrophy and if so, to elucidate the underlying mechanisms. Male C57BL/6J mice underwent either transverse aortic constriction (TAC) or sham operation, followed by TQ treatment for six consecutive weeks. In vitro experiments consisted of neonatal rat cardiomyocytes (NRCMs) that were exposed to phenylephrine (PE) stimulation to induce cardiomyocyte hypertrophy. In this study, we observed that systemic administration of TQ preserved cardiac contractile function, and alleviated cardiac hypertrophy, fibrosis and oxidative stress in TAC‐challenged mice. The in vitro experiments showed that TQ treatment attenuated the PE‐induced hypertrophic response in NRCMs. Mechanistical experiments showed that supplementation of TQ induced reactivation of the AMP‐activated protein kinase (AMPK) with concomitant inhibition of ERK 1/2, p38 and JNK1/2 MAPK cascades. Furthermore, we demonstrated that compound C, an AMPK inhibitor, abolished the protective effects of TQ in in vivo and in vitro experiments. Altogether, our study disclosed that TQ provides protection against myocardial hypertrophy in an AMPK‐dependent manner and identified it as a promising agent for the treatment of myocardial hypertrophy.

Effect of Nigella sativa on general health and immune system in young healthy volunteers; a randomized, placebo-controlled, double-blinded clinical trial

Nigella sativa (N. sativa) is traditionally used as an immune enhancer in different communities. The aim of this study was to evaluate the effect of N. sativa on immunity related parameters in young healthy subjects. This study was a double blind, randomized, placebo controlled clinical trial. Fifty-two healthy subjects (48 male and 4 female) 18-25 years old were enrolled in the study. They were randomly divided into four groups; the first received charcoal capsules and served as controls and the other three received 0.5, 1 g, and 2 g of powdered N. sativa capsules, respectively. Two blood samples were obtained from all participant, before initiation of the trial and at the end of the four weeks intervention. One sample was used for routine health screening by evaluating liver and renal functions as well as complete blood count and differential. The second sample was used to measure certain cytokines including; IL-1, IL-4, IL-6, IL-10, and TNF. A third and fourth samples were obtained from the last cohort of subjects before and after treatment; the third was used for measuring immunoglobulins and CD profile and the fourth for evaluating certain gene expressions (INF-γ, NF-κ-B, TNF-α, IL-1β, IL-13, IL-8, and IL-6). Only 1 g dose of N. sativa produced a significant elevation in total lymphocyte count, CD3+ and CD4+ counts. One gram N. sativa increased the absolute lymphocyte count from 1850±0.24 to 2170±0.26 (p=0.008), CD3+ from 1184.4±75.60 to 1424±114.51 (p=0.009), and CD4+ from 665.6±141.66 to 841±143.36 (p=0.002).  This elevation in T cells was lost by increasing the dose of N. sativa to 2g. The rest of the parameters were not changed significantly in all doses. The results show a promising immunopotentiation effect of N. sativa by elevating helper T cells and the optimum dose for young age group seems to be 1 g.

Herbs and their bioactive ingredients in cardio-protection: Underlying molecular mechanisms and evidences from clinical studies

BACKGROUND

Medicinal plants or herbs produce a bounty of bioactive phytochemicals. These phytochemicals can influence a variety of physiological events related to cardiovascular health through multiple underlying mechanisms, such as their role as antioxidative, anti-ischemic, anti-proliferative, hypotensive, anti-thrombotic, and anti-hypercholesterolemic agents.

PURPOSE

The purpose of this review is to summarize and connect evidences supporting the use of phytotherapy in the management of some of the most common cardiovascular impairments, molecular mechanisms underlying cardio-protection mediated by herbs, and clinical studies which are positively linked with the use of herbs in cardiovascular biology. Additionally, we also describe several adverse effects associated with some of the herbal plants and their products to provide a balanced set of studies in favor or against phytotherapy in cardiovascular health that may help global discourses on this matter.

METHODS

Studies relating to the use of medicinal plants were mined by strategically searching scientific databases including Google Scholar, PubMed and Science Direct. Investigations involving approximately 175 articles including reviews, research articles, meta-analyses, and cross-sectional and observational studies were retrieved and analyzed in line with the stated purpose of this study.

RESULTS

A positive correlation between the use of medicinal plants and cardiovascular health was observed. While maintaining cardiovascular physiology, medicinal plants and their derivatives seem to govern a variety of cellular mechanisms involved in vasoconstriction and vasorelaxation, which in turn, are important aspects of cardiovascular homeostasis. Furthermore, a variety of studies including clinical trials, cross-sectional studies, and meta-analyses have also supported the anti-hypertensive and thus, cardio-protective effects, of medicinal plants. Apart from this, evidence is also available for the potential drawbacks of several herbs and their products indicating that the unsupervised use of many herbs may lead to severe health issues.

CONCLUSIONS

The cardio-protective outcomes of medicinal plants and their derivatives are supported by ever-increasing studies, while evidences exist for the potential drawbacks of some of the herbs. A balanced view about the use of medicinal plants and their derivative in cardiovascular biology thus needs to be outlined by researchers and the medical community. The novelty and exhaustiveness of the present manuscript is reflected by the detailed outline of the molecular basis of "herbal cardio-protection", active involvement of several herbs in ameliorating the cardiovascular status, adverse effects of medicinal plants, and the clinical studies considering the use of phytotherapy, all on a single platform.

The Role of Bioactive Compounds of Nigella sativa in Rheumatoid Arthritis Therapy-Current Reports

Black cumin (Nigella sativa, NS) is included in the Ranunculaceae family and is classified as a medicinal plant due to very high levels of various bioactive compounds. They determine its therapeutic effects, including anti-inflammatory, anti-allergic, anti-cancer, hypoglycemic, antioxidant, hypotensive, hypolipidemic, and immunomodulating properties. The results of scientific studies indicate a supporting role of black cumin in the treatment of autoimmune diseases, including rheumatoid arthritis, due to the health-promoting properties of its bioactive ingredients. The aim of the current article is to analyze the results of scientific publications on the role of bioactive ingredients contained in black cumin in the treatment of rheumatoid arthritis.

A randomized, double-blind, placebo-controlled, clinical trial to evaluate the benefits of Nigella sativa seeds oil in reducing cardiovascular risks in hypertensive patients

The efficacy, safety, and utility of Nigella sativa seeds oil as a complementary treatment for hypertension, glucose control, and lipid metabolism were evaluated. Hypertensive patients in the intervention (n = 26) and placebo (n = 29) groups received 2.5 ml of N. sativa seeds oil and sunflower oil twice daily for 8 weeks, respectively. The levels of systolic and diastolic blood pressure (SBP, DBP), blood lipid profile, and fasting blood sugar (FBS), at different stages of the treatment period (0, 3, 6, 8 weeks), and malondialdehyde (MDA) and glutathione reductase (GR), at the baseline and end of the study, were assessed. SBP level in the intervention group was significantly reduced, compared with the baseline values (p < .001) and the placebo group (p < .05). A significant decline was observed in the levels of DBP, total cholesterols, and low density lipoprotein (LDL) (p < .000), MDA, and FBS (p < .001); also, a significant increase was observed in the levels of high density lipoprotein (HDL) and GR (p < .001). The use of N. sativa seeds oil as an adjunct to common medications exhibited additional antihypertensive effects as well as beneficial effects on glucose control and lipid metabolism in hypertensive patients with no renal, hepatic, and patient-reported adverse events.

Potential influence of Nagella sativa (Black cumin) in reinforcing immune system: A hope to decelerate the COVID-19 pandemic

The world is witnessing a difficult time. The race of developing a new coronavirus (COVID-19) vaccine is becoming more urgent. Many preliminary studies on the pathophysiology of COVID-19 patients have provided some clues to treat this pandemic. However, no suitable treatment has found yet. Various symptoms of patients infected with COVID-19 indicated the importance of immune regulation in the human body. Severe cases admitted to the intensive care unit showed high level of pro-inflammatory cytokines which enhanced the disease severity. Acute Respiratory Distress Syndrome (ARDS) in COVID-19 patients is another critical factor of disease severity and mortality. So, Immune modulation is the only way of regulating immune system. Nigella sativa has been used for medicinal purposes for centuries. The components of this plant are known for its intense immune-regulatory, anti-inflammatory, and antioxidant benefits in obstructive respiratory disorders. A molecular docking study also gave evidences that N. sativa decelerates COVID-19 and might give the same or better results than the FDA approved drugs. The aim of this review was to investigate the possible immune-regulatory effects of N. sativa on COVID-19 pandemic. Our review found N. sativa's Thymoquinone, Nigellidine, and α-hederin can be a potential influencer in reinforcing the immune response on molecular grounds.

Nigella Plants - Traditional Uses, Bioactive Phytoconstituents, Preclinical and Clinical Studies

Nigella is a small genus of the family Ranunculaceae, which includes some popular species due to their culinary and medicinal properties, especially in Eastern Europe, Middle East, Western, and Central Asia. Therefore, this review covers the traditional uses and phytochemical composition of Nigella and, in particular, Nigella sativa. The pharmacological studies reported in vitro, in vivo, and in humans have also been reviewed. One of the main strength of the use of Nigella is that the seeds are rich in the omega-6 fatty acid linoleic acid and provide an extra-source of dietary phytochemicals, including the bioactive thymoquinone, and characteristics saponins, alkaloids, and flavonoids. Among Nigella species, N. sativa L. is the most studied plant from the genus. Due to the phytochemical composition and pharmacological properties, the seed and seed oil from this plant can be considered as good candidates to formulate functional ingredients on the basis of folklore and scientific knowledge. Nonetheless, the main limations are that more studies, especially, clinical trials are required to standardize the results, e.g. to establish active molecules, dosage, chemical profile, long-term effects and impact of cooking/incorporation into foods.

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.

Review of Natural Resources With Vasodilation: Traditional Medicinal Plants, Natural Products, and Their Mechanism and Clinical Efficacy

For decades, chronic diseases including cardiovascular and cerebrovascular diseases (CCVDs) have plagued the world. Meanwhile, we have noticed a close association between CCVDs and vascular lesions, such as hypertension. More focus has been placed on TMPs and natural products with vasodilation and hypotension. TMPs with vasodilatory and hypotensive activities are mainly from Compositae, Lamiaceae, and Orchidaceae (such as V. amygdalina Del., T. procuinbens L., M. glomerata Spreng., K. galanga L., etc.) whereas natural products eliciting vasorelaxant potentials were primarily from flavonoids, phenolic acids and alkaloids (such as apigenin, puerarin, curcumin, sinomenine, etc.). Furthermore, the data analysis showed that the vasodilatory function of TMPs was mainly concerned with the activation of eNOS, while the natural products were primarily correlated with the blockage of calcium channel. Thus, TMPs will be used as alternative drugs and nutritional supplements, while natural products will be considered as potential therapies for CCVDs in the future. This study provides comprehensive and valuable references for the prevention and treatment of hypertension and CCVDs and sheds light on the further studies in this regard. However, since most studies are in vitro and preclinical, there is a need for more in-depth researches and clinical trials to understand the potential of these substances.

Plants Used as Antihypertensive

Hypertension is a critical health problem and worse other cardiovascular diseases. It is mainly of two types: Primary or essential hypertension and Secondary hypertension. Hypertension is the primary possibility feature for coronary heart disease, stroke and renal vascular disease. Herbal medicines have been used for millions of years for the management and treatment of hypertension with minimum side effects. Over aim to write this review is to collect information on the anti-hypertensive effects of natural herbs in animal studies and human involvement as well as to recapitulate the underlying mechanisms, from the bottom of cell culture and ex-vivo tissue data. According to WHO, natural herbs/shrubs are widely used in increasing order to treat almost all the ailments of the human body. Plants are the regular industrial units for the invention of chemical constituents, they used as immunity booster to enhance the natural capacity of the body to fight against different health problems as well as herbal medicines and food products also. Eighty percent population of the world (around 5.6 billion people) consume medicines from natural plants for major health concerns. This review provides a bird's eye analysis primarily on the traditional utilization, phytochemical constituents and pharmacological values of medicinal herbs used to normalize hypertension i.e. Hibiscus sabdariffa, Allium sativum, Andrographis paniculata, Apium graveolens, Bidenspilosa, Camellia sinensis, Coptis chinensis, Coriandrum sativum, Crataegus spp., Crocus sativus, Cymbopogon citrates, Nigella sativa, Panax ginseng,Salviaemiltiorrhizae, Zingiber officinale, Tribulus terrestris, Rauwolfiaserpentina, Terminalia arjuna etc.

Nigella sativa in controlling Type 2 diabetes, cardiovascular, and rheumatoid arthritis diseases: Molecular aspects

Oxidative stress is an important factor in the etiology of several chronic diseases that include cardiovascular disease (CVD), Type 2 diabetes (T2D), and rheumatoid arthritis (RA). Oxidative stress can lead to inflammation, and this can contribute to these chronic diseases. Reducing inflammation and oxidative stress may, therefore, be useful in the prevention and treatment of these conditions. One of the treatment options for chronic diseases is the use of traditional medicine and herbs, such as Nigella sativa. This is one of the herbs that have recently been assessed for its ability to reduce inflammation and oxidative stress. We have reviewed the reported effects of N. sativa on risk factors of chronic diseases (CVD, DM, and RA) with emphasis on molecular and cellular mechanisms in controlling inflammation and oxidative stress. Various mechanisms have been proposed to contribute to the beneficial properties of N. sativa, including a reduction of lipid peroxidation via its antioxidant properties; agonist of peroxisome proliferator-activated receptor gamma in adipose tissue; activation of AMP-activated protein kinase, increased antioxidants, inhibition of nuclear factor-kappa B pathway; increased in interleukin-10 expression, CD4+ T-cell percentage, T regulatory cell percentage (CD4+ CD25+ T-cell) in peripheral blood, and CD4+/CD8+ ratio, but to prove this claim, it is necessary to conduct experimental and well-designed clinical trial studies with a larger sample size on the effects of N. sativa on these chronic diseases.

Phytotherapy for Cardiovascular Disease: A Bench-to-Bedside Approach

At present, cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide, and global trends suggest that this panorama will persist or worsen in the near future. Thus, optimization of treatment strategies and the introduction of novel therapeutic alternatives for CVD represent key objectives in contemporary biomedical research. In recent years, phytotherapy-defined as the therapeutic use of whole or minimally modified plant components-has ignited large scientific interest, with a resurgence of abundant investigation on a wide array of medicinal herbs (MH) for CVD and other conditions. Numerous MH have been observed to intervene in the pathophysiology of CVD via a myriad of molecular mechanisms, including antiinflammatory, anti-oxidant, and other beneficial properties, which translate into the amelioration of three essential aspects of the pathogenesis of CVD: Dyslipidemia, atherosclerosis, and hypertension. Although the preclinical data in this scenario is very rich, the true clinical impact of MH and their purported mechanisms of action is less clear, as large-scale robust research in this regard is in relatively early stages and faces important methodological challenges. This review offers a comprehensive look at the most prominent preclinical and clinical evidence currently available concerning the use of MH in the treatment of CVD from a bench-to-bedside approach.

An updated knowledge of Black seed (Nigella sativa Linn.): Review of phytochemical constituents and pharmacological properties

N. sativa (N. sativa) has been used since ancient times, when a scientific concept about the use of medicinal plants for the treatment of human illnesses and alleviation of their sufferings was yet to be developed. It has a strong religious significance as it is mentioned in the religious books of Islam and Christianity. In addition to its historical and religious significance, it is also mentioned in ancient medicine. It is widely used in traditional systems of medicine for a number of diseases including asthma, fever, bronchitis, cough, chest congestion, dizziness, paralysis, chronic headache, back pain and inflammation. The importance of this plant led the scientific community to carry out extensive phytochemical and biological investigations on N. sativa. Pharmacological studies on N. sativa have confirmed its antidiabetic, antitussive, anticancer, antioxidant, hepatoprotective, neuro-protective, gastroprotective, immunomodulator, analgesic, antimicrobial, anti-inflammatory, spasmolytic, and bronchodilator activity. The present review is an effort to explore the reported chemical composition and pharmacological activity of this plant. It will help as a reference for scientists, researchers, and other health professionals who are working with this plant and who need up to date knowledge about it.

The Effects of Nigella sativa Supplementation on Liver Enzymes Levels: a Systematic Review and Meta-analysis of Randomized Controlled Trials

The present systematic review and meta-analysis aimed to investigate the effects of Nigella sativa (N. sativa) supplementation on liver enzymes levels including aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Relevant studies, published from inception up to January 2020, were searched through PubMed, Scopus and Google Scholar conducted on randomized controlled trials (RCTs) investigating the effect of N. sativa on serum AST and ALT levels. Meta-analysis was applied using a random-effects model. Eight studies met inclusion criteria (n=281 in the N. sativa and n = 279 in placebo group). This meta-analysis showed that N. sativa supplementation significantly reduced AST level (weighted mean difference [WMD], -8.11 IU/L; 95% confidence interval [CI], -13.6, -2.53; p = 0.004) with significant heterogeneity (I-squared, 95.9%; p < 0.001) while the decrease in ALT level was not statistically significant (WMD, -7.26 IU/L; 95% CI, -15.4, 0.04; p = 0.051) with significant heterogeneity (I-squared, 97.8%; p < 0.001). This meta-analysis suggests that N. sativa supplementation may improve AST levels and ALT levels, however more RCTs with larger sample size are needed to found effects of N. sativa on liver enzymes in patients with non-alcoholic fatty liver disease.

The effect of Nigella sativa on appetite, anthropometric and body composition indices among overweight and obese women: A crossover, double-blind, placebo-controlled, randomized clinical trial

OBJECTIVES

Obesity is a global concern which is associated with several complications and disease.

DESIGN

Present study is the first crossover, double-blind, placebo-controlled, randomized clinical trial aimed to evaluate the effect of Nigella Sativa (N. sativa) intervention on anthropometric and body composition parameters as well as dietary intake and appetite in a crossover design.

METHOD

Forty-five healthy women with obesity or overweight were randomized into two groups of intervention and placebo, and the study conducted in two 8-week periods of intervention separated by a 4-week washout period. Anthropometric and body composition indices and dietary intake were measured. Also, appetite sensation was evaluated via a standard visual analog scale (VAS) questionnaire. Pkcross procedure was performed for statistical analysis using STATA. Cohen's d effect size was estimated for all outcomes to determine the magnitude of the effects.

RESULTS

Supplementation with 2000 mg of N. sativa oil found to have a considerable increment in the measures of body mass index (P < 0.001, Cohen's d = 0.5), body weight (P < 0.001, Cohen's d = 0.6) and waist circumference (P = 0.020, Cohen's d = 0.4) with a medium effect size measure, and a significant decrease in body fat mass (P = 0.019, Cohen's d = 0.2), body fat percent (P < 0.001, Cohen's d = 0.2) and visceral fat area (P = 0.011, Cohen's d = 0.2) with a small effect size measure.

CONCLUSION

The overall improvements in anthropometric and body composition parameters and a significant decrease in appetite represents the beneficial effects of N. sativa supplements in the treatment of obesity. More studies with different dosages, a larger number of participants, and longer intervention duration are recommended to illustrate the exact effects of N. sativa as a complementary therapy for obesity.

The effect of Nigella sativa supplementation on cardiovascular risk factors in obese and overweight women: a crossover, double-blind, placebo-controlled randomized clinical trial

PURPOSE

To assess the effect of Nigella sativa (N.S) oil supplements on CVD risk factors in a crossover design for the first time.

METHODS

Obese and overweight healthy women were randomized to receive N.S oil (2000 mg/day) and placebo. This intervention period lasted for 8 weeks and separated by a 4-week washout period. An iso-caloric diet was given to every individual throughout the study. Blood pressure, lipid profile, atherogenic indices and liver enzymes were measured. Pkcross procedure was performed for statistical analyses using Stata software. Cohen's d was estimated as effect size for all outcomes to measure the magnitude of the effects.

RESULTS

Thirty-nine participants completed the study. Capsules of N.S increased serum high-density lipoprotein cholesterol (Cohen's d = 0.47, P = 0.009), reduced low-density lipoprotein cholesterol (Cohen's d = - 0.33, P = 0.031), reduced TC/HDL-C ratio (as an atherogenic index, Cohen's d = - 0.9, P < 0.001), reduced serum glutamic-oxaloacetic transaminase (Cohen's d = 0- 0.5, P = 0.038) and reduced systolic blood pressure (Cohen's d = - 0.4, P < 0.001). There was no effect on diastolic blood pressure measures (P = 0.96).

CONCLUSION

The overall improvements in cardiovascular disease (CVD) risk factors showed beneficial effects of N.S supplements among adults with obesity to prevent possible cardiovascular diseases. More studies with different designs and in other populations are suggested to clarify the exact effects of N.S as a complementary therapy for modulating CVD risk factors in individuals with overweight and obesity.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials, IRCT20180528039884N1, Registered on February 15th, 2019.

Nigella sativa (black seed) safety: an overview

Nigella sativa (commonly known as black seed or black cumin), from the family Ranunculaceae, is a plant that grows in countries bordering the Mediterranean Sea. This narrative review discusses the toxicological profile reported by short- to long-term studies that examined different extracts and oils of N. sativa seeds. Scientific databases including Web of Science, PubMed, Scopus, and Google Scholar were searched using appropriate keywords. LD50 for administered N. sativa seed fixed oil varied from 28.8 mL/kg to 3,371 mg/kg in mice, while 21 g/kg of aqueous, methanol, and chloroform extracts of N. sativa did not lead to any mortality. Subacute toxicity evaluations indicated that aqueous, methanol, and chloroform extracts of N. sativa at doses as high as 6 g/kg do not produce toxicity. Investigation of chronic toxicity found that 2 mL/kg of N. sativa fixed oil is slightly toxic. Cytotoxicity studies indicated that N. sativa chloroform and petroleum ether extracts are more cytotoxic than its other extracts. Although studies that assessed N. sativa toxicity generally introduced it as a safe medicinal herb, to draw a more definitive conclusion on its safety, more detailed studies must be conducted.

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

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

Effect of Nigella sativa and Fenugreek on the Pharmacokinetics and Pharmacodynamics of Amlodipine in Hypertensive Rats

BACKGROUND

The present article is related to in-vitro and in-vivo herb-drug interaction studies.

OBJECTIVES

This study aimed to investigate the effect of Nigella sativa and fenugreek on the pharmacodynamics and pharmacokinetics of amlodipine.

METHOD

Hypertensive rats of group-I were treated with amlodipine and rats of group-II and III were treated with N. sativa, and N. sativa + amlodipine and fenugreek, and fenugreek + amlodipine, respectively. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP) of group-I, II and III rats were measured by the "tail-cuff system".

RESULTS

N. sativa, as well as fenugreek, reduced the SBP, DBP and MBP. Simultaneously, administration of fenugreek + amlodipine or N. sativa + amlodipine showed better control of BP. Individually, fenugreek, as well as N. sativa, showed a surprising reduction in the heart rate. There was no remarkable effect of any of these two herbs on Cmax, AUC0-t, Kel, and terminal elimination half-life of amlodipine, but fenugreek altered the Tmax of amlodipine significantly, from 2 ± 1.2h in control to 7.2 ± 1.7h in fenugreek treated group, probably by delaying the absorption.

CONCLUSION

Results of pharmacodynamics and pharmacokinetics studies suggested that simultaneous administration of fenugreek or N. sativa with amlodipine improved the pharmacological response of amlodipine in hypertensive rats, though there was no remarkable change in pharmacokinetic parameters (Cmax, Kel, elimination t1/2, and AUC0-t).

Potential pharmacodynamic and pharmacokinetic interactions of Nigella Sativa and Trigonella Foenum-graecum with losartan in L-NAME induced hypertensive rats

The objective of this investigation was to study whether Nigella Sativa and Trigonella Foenum-graecum, could modulate the losartan pharmacodynamic (PD) and pharmacokinetic (PK) in experimental L-NAME induced hypertensive rats. For in vivo study, the systolic blood pressure (SBP) of rats was measured by the “tail-cuff system” after the treatment of rats with herb alone and herb + losartan in hypertensive rats. The SBP of rats treated with L-NAME + losartan also recorded. For the PK study, blood samples were obtained for up to 12 h to determine the concentrations of the drug, and various PK parameters were calculated. The data displayed that the SBP was significantly (p < 0.05) decreased in the rats when administered with L-NAME + N. Sativa or L-NAME + T. Foenum-graecum in contrast to the rats administered with L-NAME alone. A more prominent decline (p < 0.05) in SBP was detected in rats administered with L-NAME + N. Sativa + losartan and L-NAME + T. Foenum-graecum + losartan. In a PK study, higher losartan C_max and AUC_0-t were noted in rats treated with N. Sativa + losartan and T. Foenum-graecum + losartan, although the difference was not significant in contrast to the control group. This study proposed that the interaction between N. Sativa & losartan and T. Foenum-graecum & losartan could take place on concurrent administration; consequently, the dose of losartan may need to be accustomed when they are utilized simultaneously.

Effects of Bread with Nigella Sativa on Blood Glucose, Blood Pressure and Anthropometric Indices in Patients with Metabolic Syndrome

Nigella sativa (N. sativa) is one of important herbal foods in traditional medicine and many studies have conducted to show the effects of this plant on several diseases. The goal of this study was the evaluation of effects of bread with N. Sativa on clinical parameters such as blood glucose, blood pressure (BP) and anthropometry indices in subjects with metabolic syndrome (MetS). A study as double-blind, cross-over, randomized clinical trial was performed in 51 MetS patients in Chalus, north region of Iran. After dividing of patients randomly in 2 groups, in phase 1, intervention group (A, n = 27) used daily a bread with N. sativa and control group (B, n = 24) used the same bread but without N. sativa for 2 months. After considering of 15 day wash out period, phase 2 was began with changing of position of 2 groups. Measuring of parameters including fasting blood glucose (FBG), systolic blood pressure (SBP), diastolic blood pressure (DBP), weight, body mass index (BMI), and waist circumference (WC) was done before and after of 2 phases. After evaluation of treatment, sequence and time effects of intervention on parameters, it is shown that consumption of this bread has not significant treatment effect (as main effect) on FBG, SBP, DBP, WC, weight, and BMI (p > 0.05). Sequence effect on FBG, weight, WC, and BMI was significant (p < 0.05), but was not on BP. Time effect was only significant for DBP. Consumption of bread with N. sativa in MetS patients has not significant effect on FBG, BP, weight, WC, and BMI.

Trial Registration

Iranian Registry of Clinical Trials Identifier: IRCT2015041821815N1.

Efficacy of black seed (Nigella sativa L.) on kidney stone dissolution: A randomized, double-blind, placebo-controlled, clinical trial

Preclinical studies have shown beneficial effects of black seed (Nigella sativa L.) in the prevention and treatment of renal stones. Hence, we designed a study to evaluate the renal-stone-dissolving efficacy of black seed. Sixty patients with renal stones were randomly enrolled in two arms of a randomized, triple-blind, placebo-controlled, clinical trial. The patients were treated by black seed capsules (500 mg) or placebo two times per day for 10 weeks. Patients were assessed in terms of size of renal stones by using sonography before and after intervention. In the black seed group, 44.4% of patients excreted their stones completely, and the size of the stones remained unchanged and decreased in 3.7% and 51.8% of patients, respectively. In contrast, in the placebo group, 15.3% of the patients excreted their stones completely, 11.5% had reduction in stone size, 15.3% had increase in stone size, and 57.6% had no change in their stone size. The difference in the mean size of renal stones after the study was significant between the two groups (p < 0.05). N. sativa L., as compared with placebo, is demonstrated to have significant positive effects on disappearance or reduction of size of kidney stones.

The natural phenolic compounds as modulators of NADPH oxidases in hypertension

BACKGROUND

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The standardized extract of Nigella sativa and its major ingredient, thymoquinone, ameliorates angiotensin II-induced hypertension in rats

Background This study investigated the effect of hydroalcoholic extract of Nigella sativa (N. sativa) and its active component, thymoquinone (TQ) on hypertension induced by angiotensin II (AngII), the main product of renin-angiotensin system (RAS). Methods Seven animal groups (n=7 for each group) were used as follows: (1) control, (2) AngII (300 ng/kg), (3) AngII+losartan (Los; 10 mg/kg), (4) TQ (40 mg/kg)+AngII, and (5-7) three doses of N. sativa (200, 400, and 600 mg/kg)+AngII. Los and AngII were injected intravenously; TQ and extracts were injected intraperitoneally. In TQ and N. sativa-treated groups, 30 min after injection of the extract and TQ, AngII was injected. Cardiovascular parameters were recorded by power lab system after cannulation of femoral artery. The maximum changes (∆) of systolic blood pressure (SBP), mean arterial pressure (MAP), and heart rate (HR) were calculated and used for statistical analysis. Results AngII significantly increased maximal ∆SBP, ∆MAP, and ∆HR compared with the control (p<0.001), and these effects significantly were blunted by Los. TQ and two higher doses (400 and 600 mg/kg) of N. sativa significantly could antagonize effect of AngII on ∆SBP, ∆MAP (p<0.05 to p<0.001). AngII-induced changes of HR are also significantly decreased by TQ and dose 600 mg/kg of extract (p<0.01 and p<0.05, respectively). Conclusions The N. sativa and its component TQ have the beneficial effect on hypertension probably due to attenuation cardiovascular effects of AngII.

Effect of Nigella sativa supplementation on obesity indices: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & OBJECTIVE(S)

No meta-analysis is available on the effect of Nigella sativa (NS) on obesity indices. This systematic review and meta-analysis was conducted to systematically review the available Randomized Clinical Trials (RCTs) that examined the effects of NS on Body Weight (BW), Body Mass index (BMI), and Waist Circumference (WC) in adults.

METHODS

Relevant articles published up to January 2018 were searched through PubMed/Medline, SCOPUS, Cochrane Library, and Google Scholar databases, using relevant keywords. All RCTs that examined the effect of NS supplementation on BW, BMI, or WC were included.

RESULTS

Overall, thirteen RCTs, including 875 subjects (64% males) were included in this study. Combining effect sizes from ten studies, NS supplementation significantly reduced BW (Weighted Mean Differences (WMD): -1.76 kg, 95% CI: -3.34 to -0.17, I² = 87.4%), as compared to placebo. Subgroup analysis by the intervention type (I² = 0.0%), participants' gender (I² = 0.0%), and age (I² = 5.5%) removed between-study heterogeneity. A significant reduction was seen in BMI (WMD: -0.85 kg/m², 95% CI: -1.23, -0.46, I² = 70.6%) after NS supplementation than placebo among eleven trials. Subgroup analysis based on study duration (I² = 0.0%), participants' gender (females: I² = 0.0% & both genders: I² = 20.9%), an age (I² = 35.9%) disappeared the heterogeneity. However, no significant reduction was found in WC comparing NS supplementation to placebo (WMD: -4.04 cm, 95% CI: 11.37, 3.27, I² = 97.8%) in five studies.

CONCLUSIONS

We find a significant effect of NS supplementation on BW and BMI in adults. However, the effect of NS supplementation on WC was not significant in this meta-analysis.