Effect of Nigella sativa L. supplementation on inflammatory and oxidative stress indicators: A systematic review and meta-analysis of controlled clinical trials

Immune stimulatory effect of Nigella sativa in healthy animal models: A systematic review and meta-analysis

The immune-modulatory effects of black seeds (Nigella sativa seeds, NSS) are well documented, but the overall in vivo impact of this important natural medicinal product on immune system function has yet to be established. Here we systematically reviewed and meta-analyzed the effects of NSS on humoral [serum titers of immunoglobulins including IgG, IgM, anti-Newcastle virus disease (anti-NDV), and sheep red blood cell antigen (anti-SRBC)] and cellular immunity [total white blood cell (WBC) count and percentages of monocytes, lymphocytes, basophils, neutrophils, and eosinophils] in healthy animals. The PubMed, ScienceDirect, Web of Science, and Scopus databases were searched according to predefined eligibility criteria. Meta-analyses were performed to estimate the final effect size using RevMan software. Seventeen animal studies were eligible for analysis. For humoral immunity, the overall pooled effect size (ES) of NSS on serum titers of IgM and anti-NVD antibodies was not significantly different [mean difference (MD) 75.27, 95% CI: -44.76 to 195.30, p = 0.22 (I2 = 89%, p = 0.003), and -0.01, 95% CI: -0.27 to 0.25, p = 0.94 (I2 = 74%, p = 0.02), respectively]. However, NSS significantly increased serum titers of IgG and anti-SRBC antibodies [MD 3.30, 95% CI: 2.27 to 4.32, p = 0.00001 (I2 = 0%, p = 0.97), and 1.15, 95% CI: 0.74 to 1.56, p = 0.00001 (I2 = 0%, p = 0.43), respectively]. For cellular immunity, the ES of NSS on WBCs, monocytes, and lymphocytes were not significantly different [MD 0.29, 95% CI: -0.55 to 1.13, p = 0.50, (I2 = 14%, p = 0.32), - 0.01, 95% CI: -0.45 to 0.44, p = 0.97 (I2 = 0%, p = 0.77), and 4.73, 95% CI: -7.13 to 16.59, p = 0.43, (I2 = 99%, p = 0.00001), respectively]. In conclusion, black seeds enhance humoral immunity in healthy animals but do not affect cellular immunity.

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.

Chronic Treatment with Nigella sativa Oil Exerts Antimanic Properties and Reduces Brain Inflammation in Rats

Nigella sativa (NS) is a native herb consumed habitually in several countries worldwide, possessing manifold therapeutic properties. Among them, anti-inflammatory features have been reported, presumably relating to mechanisms involved in the nuclear factor kappa-B pathway, among others. Given the observed association between neuroimmune factors and mental illness, the primary aim of the present study was to examine the effects of chronic NS use on manic-like behavior in rats, as well as analyze levels of brain inflammatory mediators following NS intake. Using male and female rats, baseline tests were performed; thereafter, rats were fed either regular food (control) or NS-containing food (treatment) for four weeks. Following intervention, behavioral tests were induced (an open field test, sucrose consumption test, three-chamber sociality test, and amphetamine-induced hyperactivity test). Subsequently, brain samples were extracted, and inflammatory mediators were evaluated, including interleukin-6, leukotriene B4, prostaglandin E2, tumor necrosis factor-α, and nuclear phosphorylated-p65. Our findings show NS to result in a marked antimanic-like effect, in tandem with a positive modulation of select inflammatory mediators among male and female rats. The findings reinforce the proposed therapeutic advantages relating to NS ingestion.

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.

The effect of Nigella sativa (black seed) on biomarkers of inflammation and oxidative stress: an updated systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This study was conducted to assess the effect of Nigella sativa (N. sativa) supplementation on inflammatory and oxidative markers among the adult population.

METHODS

We carried out a comprehensive, systematic search of Scopus, Embase, Cochrane Library, Web of Science, PubMed, and Google Scholar till December 2022. A random-effects model was used to estimate the overall effect size.

RESULTS

In total, twenty trials consisting of 1086 participants were included in the meta-analysis. Findings from 20 RCTs included in the meta-analysis suggest that N. sativa supplementation could significantly reduce serum C-reactive protein (CRP) (SMD = - 2.28; 95% CI - 3.20, - 1.37, p < 0.001), tumour necrosis factor α (TNFα) (SMD = - 1.21; 95% CI - 2.15, - 0.26; p = 0.013), and malondialdehyde (MDA) (SMD = - 2.15; 95% CI - 3.37, - 0.93, p < 0.001) levels, and significantly improves total antioxidant capacity (TAC) (SMD = 2.28; 95% CI 1.29, 3.27, p < 0.001), glutathione peroxidase (GPx) (SMD = 1.23, 95% CI 0.25, 2.22; p = 0.014) and superoxide dismutase (SOD) (SMD = 2.05; 95% CI 1.22, 2.88, p < 0.001) levels. However, no significant reduction was found in interleukin 6 (IL-6) levels (SMD = - 1.13; 95% CI - 2.72, 0.46, p = 0.162).

CONCLUSION

N. sativa supplementation had beneficial effects on CRP, TNF-α, MDA, SOD, GPx, and TAC. Thus, Nigella sativa can be recommended as an adjuvant anti-oxidant agent and anti-inflammatory.

Nigella sativa and health outcomes: An overview of systematic reviews and meta-analyses

Background

Nigella sativa (N. sativa) consumption has been associated with various health outcomes; however, the results are not completely consistent.

Objectives

This overview of systematic reviews and meta-analyses aimed to evaluate the reporting and methodological quality, and to grade the available evidence of associations between N. sativa and health outcomes.

Methods

PubMed, Cochrane Library, Embase, and Scopus databases were searched from their inception to September 30, 2022. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2009 statement, Assessment of Multiple Systematic Reviews (AMSTAR) 2 checklist, and Grades of Recommendations, Assessment, Development and Evaluations (GRADE) systems were used to assess the reporting, methodological, and evidence quality for each meta-analysis, respectively. The results were synthesized in a narrative form.

Results

This overview included 20 eligible meta-analyses published in peer-reviewed journals between 2013 and 2021. The overall methodological quality was relatively poor, with only one moderate quality, four low quality, and 15 critically low quality studies. For reporting quality, items two, five, eight, nine, 15, and 24 need to improve. Among the 110 outcome indicators of the quality of evidence, five were graded as moderate, 17 as low, and 88 as very low. Risk of bias, inconsistency, and imprecision were the main downgrading factors.

Conclusion

This overview suggests that N. sativa is beneficial for various clinical outcomes. However, there are certain limitations to reporting and methodological quality. The clinical efficacy of N. sativa requires confirmation in high-quality, large-sample, randomized controlled trials.

Effects of almond intake on oxidative stress parameters: A systematic review and meta-analysis of clinical trials

BACKGROUND AND AIMS

Several randomized controlled trials (RCTs) have shown that almonds can improve oxidative stress indices, but the results are controversial. Therefore, the goal of this research was to carry out a systematic review and meta-analysis of all RCTs that evaluated the effect of almonds on selected oxidative stress indices.

METHODS

A systematic search was conducted up to April 2022 on PubMed, Scopus, Web of Science, and Google Scholar. We have selected the studies that investigated the effects of almonds on malondialdehyde (MDA), and oxidized low-density lipoprotein (Ox-LDL) levels in adults. Data were pooled by using the random-effects model. The risk of bias in individual studies was assessed using the Cochrane Collaboration risk of bias tool.

RESULTS

Seven RCTs involving 424 participants were analyzed. The results indicated that almond intake led to a significant decrease in MDA levels (WMD: - 6.63 nmol/ml; 95 % CI: - 8.72 to - 4.54; P < 0.001). However, no significant effect was observed on Ox-LDL (Hedges' g: - 0.12; 95 % CI: - 0.34 to 0.10; P = 0.28). Sensitivity analysis showed that overall estimates were not affected by the elimination of any study. We did not observe any evidence regarding publication bias.

CONCLUSION

The present meta-analysis suggests that almond intake can improve MDA levels and might play a beneficial role in the reinforcement of the antioxidant defense system and amelioration of oxidative stress in adults. There is a need for more studies with larger groups to better estimate this effect.

Efficacy of nigella sativa oil on endothelial function and atherogenic indices in patients with coronary artery diseases: A randomized, double-blind, placebo-control clinical trial

A therapeutic compound with antioxidant and anti-inflammatory effects might be a practical approach in endothelial dysfunction caused by oxidation and inflammation associated with atherosclerosis. Therefore, we aim to examine the efficacy of Nigella sativa (NS) oil supplementation on endothelial function and atherogenic indices in coronary artery disease (CAD) patients. Sixty individuals aged between 35 to 65 years old were recruited and divided into two groups, receiving either 2 g/daily of NS oil or sunflower oil as the placebo for 8 weeks. Serum levels of adhesion molecules, oxidative markers, and atherogenic parameters were evaluated at the starting point and the end of supplementation. Serum levels of vascular cell adhesion protein 1 (sVCAM-1) [-264.44 95% C, (156.83, 372.04)], intercellular adhesion molecule 1 (sICAM-1) [-132.38 95% C, (40.64, 224.1)], and malondialdehyde (MDA) [-0.21 95% C, (0.03, 0.40)] declined significantly following NS supplementation, while total antioxidant capacity increased [0.03 95% C, (0.03, 0.16)]. NS oil supplementation demonstrated a potential beneficial effect on endothelial function by reducing ICAM-1, VCAM-1 levels and affecting oxidative markers. However, further studies are necessary to elucidate NS oil as a therapeutic agent and complementary therapy in patients with stable CAD.

The Effect of Thymoquinone on Oxidative Stress Parameters and Apolipoprotein E in Alzheimer Model in Rats

INTRODUCTION

In this study, it was aimed to investigate the effect of thymoquinone (TQ) on oxidative stress and apolipoprotein E (ApoE) in an experimental Alzheimer's model created with AlCl3 and D-galactose in rats.

METHODS

Thirty-six Wistar Albino male rats saline group (Group 1), aluminum chloride (AlCl3) + D-galactose (D-Gal) group (Group 2), AlCl3 + D-Gal + TQ group (Group 3) were divided into 3 groups. The study was completed with 33 rats. Group 1 was given saline intraperitoneally (i.p) for 28 days. 2nd group; D-Gal at a dose of 60 mg/kg/day and AlCl3 at a dose of 40 mg/kg/day were given i.p. daily for 28 days. 3rd group; D-Gal at a dose of 60 mg/kg/day and AlCl3 at a dose of 40 mg/kg/day were given i.p. daily for 28 days. Group 3 rats were given 20 mg/kg/day TQ in corn oil by gavage for 14 days. Malonyl dialdehyde (MDA), superoxide dismutase (SOD), total antioxidant capacity (TAS), total oxidant capacity (TOS), glutathione peroxidase (GsH-Px), and ApoE levels were determined in the blood and brain tissues of rats in all three groups. One-way ANOVA test was used in the statistical analysis of the data.

RESULTS

Means of TAS, TOS, GSH-Px, SOD, MDA, and ApoE in blood and brain tissue of all three groups (excluding ApoE in brain tissue) were different from each other and this difference was statistically significant (p < 0.05).

CONCLUSION

In this study, TQ, it was determined that all oxidative stress parameters examined had positively affected and decreased blood tissue ApoE levels. TQ can be used as an antioxidant and curative in Alzheimer's disease.

Effect of Black Cumin Cake Addition on the Chemical Composition, Glycemic Index, Antioxidant Activity, and Cooking Quality of Durum Wheat Pasta

Pasta is a good carrier for plant enrichment substances due to its popularity among consumers. The purpose of the study was to investigate the functional potential and optimize the recipe of pasta made from durum semolina with the addition of black cumin cake at the level of 5, 10, 15, 20, and 25%. The use of black cumin cake resulted in a statistically significant (p ≤ 0.05) increase in the content of protein, fat, ash, and fiber, including both the insoluble and soluble fractions. A reduction in the digestible carbohydrate content, in vitro starch hydrolysis index (HI), was observed. Pasta with a reduced glycemic index (GI) compared to the semolina control was obtained. The content of polyphenols, including flavonoids, in the cake-enriched pasta increased significantly (p ≤ 0.05), which resulted in higher antioxidant activity against DPPH. The increase in the iron content was over 2.5 times higher in the sample with the 25% addition of black cumin cake than in the control sample. The functional addition significantly (p ≤ 0.05) increased the loss of dry matter and influenced the cooking time of pasta.

Efficacy of a Persian herbal medicine compound on coronavirus disease 2019 (COVID-19): a randomized clinical trial

Background

The global attention to the capacities of traditional medicine for alleviating the clinical manifestations of COVID-19 has been growing. The present trial aimed to evaluate the efficacy and safety of a Persian herbal medicine formula among patients with COVID-19.

Methods

The present trial was conducted in Afzalipour hospital, Kerman, Iran, from June to September 2020. Hospitalized COVID-19 patients were randomly divided into intervention (Persian herbal medicine formula + routine treatment) or control (only routine treatment) groups. The intervention group received both capsule number 1 and 2 every 8 hours for 7 days. Capsule number 1 contained extract of the Glycyrrhiza glabra, Punica granatum, and Rheum palmatum, and the second capsule was filled by Nigella sativa powder. Participants were followed up to 7 days. The primary outcome was the number of hospitalization days, while cough, fever, and respiratory rate, days on oxygen (O₂) therapy, and mortality rate were considered as the secondary outcomes.

Results

Eighty-two patients were enrolled to the study, while 79 cases completed the trial and their data were analyzed (mean age: 59.1 ± 17.1 years). Based on the results, the Persian medicine formula decreased the mean hospitalization days, so that the mean difference of length of hospitalization as primary outcome was 2.95 ± 0.43 days. A significant clinical improvement was observed regarding dyspnea, need for O₂) therapy, and respiratory rate in the intervention group. No adverse effects were reported.

Conclusion

The present study supported the use of the Persian medicine formula as an adjuvant therapy for hospitalized COVID-19 patients. Study registration: Iranian Registry of Clinical Trials (www.irct.ir): IRCT20200330046899N1.

Study registration

Iranian Registry of Clinical Trials (www.irct.ir): IRCT20200330046899N1.

Black Seed (Nigella sativa) Efficacy in Improving Clinical Symptoms and Interleukin-6 Levels Schizophrenic Patients

BACKGROUND: Schizophrenia with a global prevalence of 0.33–0.75% and one of the top 15 causes of disability. The etiology underlying this disease is still controversial. One of the causes is the Vulnerability Stress-Schizophrenia Inflammatory Model which shows an increase in pro-inflammatory cytokines, one of which is Interleukin-6 (IL-6). AIM: It is hoped that through the adjuvant anti-inflammatory effect of black seed or Nigella sativa can improve the clinical symptoms of schizophrenia and reduce levels of Serum IL-6 as a marker of therapeutic efficacy, as well as observing the effect of treatment on liver function. METHODS: The present study was conducted 22 schizophrenic patients hospitalized at the psychiatric hospital (Rumah Sakit Khusus Daerah) of South Sulawesi aged 20–45 years and received risperidone 4 mg/day therapy. Patients were divided into two groups, the control and treatment groups received N. sativa 1000 mg/d for 4 weeks. Each group was measured for baseline and week 4 clinical symptoms of schizophrenia with Positive and Negative Symptom of Schizophrenia (PANSS) and serum IL-6 levels. The analysis also measured serum IL-6 levels in 14 healthy people by assessing the side effects of N. sativa adjuvants by measuring liver function enzymes of Serum Glutamic Oxaloacetic Transaminase (SGOT) and Serum Glutamic Pyruvic Transaminase (SGPT). RESULTS: Serum IL-6 levels of schizophrenic patients were higher than healthy controls. Administration of adjuvant N. sativa 1000 mg for 4 weeks significantly p < 0.001 improved PANSS value, decreased serum IL-6 levels 2.5 times faster in the treatment group and did not give a significant change in SGOT and SGPT values. CONCLUSION: This study suggests that N. sativa may consider as an adjuvant therapy to improve clinical symptoms of schizophrenia and reduce levels of IL-6 was faster than control group and is safe for liver function.

The effect of Nigella sativa on TAC and MDA in obese and overweight women: secondary analysis of a crossover, double blind, randomized clinical trial

Purpose

Since obesity is a risk factor for various diseases and is associated with increased oxidative stress conditions, some herbs are considered to be effective in reducing obesity and its complications.

Methods

This secondary analysis investigates the effect of Nigella sativa (N.S) oil supplement on total antioxidant capacity (TAC) and malondialdehyde (MDA) levels in obese/overweight women. Obese and overweight healthy women were randomized to receive 2,000 mg/d of N.S supplement and placebo. The intervention periods lasted 8 weeks and were separated by a 4-week washout period. Also, each participant was given an iso-calorie diet. Baseline characteristics and TAC and MDA levels were measured. Pkcross analysis was performed for statistical analysis using Stata software. Also, Cohen's d was estimated as effect size for all results to assess the magnitude of the effects.

Results

39 women completed the study. N.S oil supplementation at a dose of 2000 mg/d significantly increased serum TAC (P effect = 0.017, Cohen's d = 1.81) and reduced serum MDA (P effect < 0/001, Cohen's d =  - 0.32).

Conclusion

Based on our findings taking N.S supplementation for 8 weeks can improve antioxidant conditions in obese and overweight adults. However, more studies with a larger population and the presence of both genders need to be done to confirm the results.Registration number: IRCT20180430039475N1.