The beneficial health effects of Nigella sativa on Helicobacter pylori eradication, dyspepsia symptoms, and quality of life in infected patients: A pilot study

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.

Nocebo response intensity and influencing factors in the randomized clinical trials of functional dyspepsia: A systematic review and meta-analysis

OBJECTIVES

In this study we aimed to evaluate the nocebo response rate in patients with functional dyspepsia (FD) and to explore its influencing factors.

METHODS

A literature search of the EMBASE, PubMed, and Cochrane Library databases was conducted for all articles published up to March 2021. Randomized, parallel-designed, placebo-controlled trials on pharmacological interventions for patients with FD were included. A meta-analysis that utilized random effects to analyze the incidence of adverse events (AEs) among participants who were given placebo was conducted, and the correlation between trial characteristics and the magnitude of the nocebo response rate was analyzed.

RESULTS

Altogether, 27 studies including 1866 paitents were deemed eligible and included in the analysis. The total nocebo response rate was 26% (95% confidence interval [CI] 18%-33%). The most frequently reported AEs included nasopharyngitis (9%), constipation (6%), headache (5%), and diarrhea (3%). There were significant differences in nocebo response rates among studies conducted in different country or region, treatment duration, types of medication, sponsorship and different versions of the Rome criteria used for FD diagnosis. While number of centers engaged in the study, types of FD diagnosis and dosing frequency were not significantly associated with the nocebo response rate.

CONCLUSIONS

Patients with FD exhibit notable nocebo response strength in clinical trials. The researchers should adopt a more careful approach when analyzing the relationships between AEs and interventions in such trials.

Non-Chinese herbal medicines for functional dyspepsia

BACKGROUND

One-third of people with gastrointestinal disorders, including functional dyspepsia, use some form of complementary and alternative medicine, including herbal medicines.

OBJECTIVES

The primary objective is to assess the effects of non-Chinese herbal medicines for the treatment of people with functional dyspepsia.

SEARCH METHODS

We searched the following electronic databases on 22 December 2022: Cochrane Central Register of Controlled Trials, MEDLINE, Embase, Allied and Complementary Medicine Database, Latin American and Caribbean Health Sciences Literature, among other sources, without placing language restrictions.

SELECTION CRITERIA

We included RCTs comparing non-Chinese herbal medicines versus placebo or other treatments in people with functional dyspepsia.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references, extracted data and assessed the risk of bias from trial reports. We used a random-effects model to calculate risk ratios (RRs) and mean differences (MDs). We created effect direction plots when meta-analysis was not possible, following the reporting guideline for Synthesis without Meta-analysis (SWiM). We used GRADE to assess the certainty of the evidence (CoE) for all outcomes.

MAIN RESULTS

We included 41 trials with 4477 participants that assessed 27 herbal medicines. This review evaluated global symptoms of functional dyspepsia, adverse events and quality of life; however, some studies did not report these outcomes. STW5 (Iberogast) may moderately improve global symptoms of dyspepsia compared with placebo at 28 to 56 days; however, the evidence is very uncertain (MD -2.64, 95% CI -4.39 to -0.90; I2 = 87%; 5 studies, 814 participants; very low CoE). STW5 may also increase the improvement rate compared to placebo at four to eight weeks' follow-up (RR 1.55, 95% CI 0.98 to 2.47; 2 studies, 324 participants; low CoE). There was little to no difference in adverse events for STW5 compared to placebo (RR 0.92, 95% CI 0.52 to 1.64; I2 = 0%; 4 studies, 786 participants; low CoE). STW5 may cause little to no difference in quality of life compared to placebo (no numerical data available, low CoE). Peppermint and caraway oil probably result in a large improvement in global symptoms of dyspepsia compared to placebo at four weeks (SMD -0.87, 95% CI -1.15 to -0.58; I2 = 0%; 2 studies, 210 participants; moderate CoE) and increase the improvement rate of global symptoms of dyspepsia (RR 1.53, 95% CI 1.30 to 1.81; I2 = 0%; 3 studies, 305 participants; moderate CoE). There may be little to no difference in the rate of adverse events between this intervention and placebo (RR 1.56, 95% CI 0.69 to 3.53; I2 = 47%; 3 studies, 305 participants; low CoE). The intervention probably improves the quality of life (measured on the Nepean Dyspepsia Index) (MD -131.40, 95% CI -193.76 to -69.04; 1 study, 99 participants; moderate CoE). Curcuma longa probably results in a moderate improvement global symptoms of dyspepsia compared to placebo at four weeks (MD -3.33, 95% CI -5.84 to -0.81; I2 = 50%; 2 studies, 110 participants; moderate CoE) and may increase the improvement rate (RR 1.50, 95% CI 1.06 to 2.11; 1 study, 76 participants; low CoE). There is probably little to no difference in the rate of adverse events between this intervention and placebo (RR 1.26, 95% CI 0.51 to 3.08; 1 study, 89 participants; moderate CoE). The intervention probably improves the quality of life, measured on the EQ-5D (MD 0.05, 95% CI 0.01 to 0.09; 1 study, 89 participants; moderate CoE). We found evidence that the following herbal medicines may improve symptoms of dyspepsia compared to placebo: Lafonesia pacari (RR 1.52, 95% CI 1.08 to 2.14; 1 study, 97 participants; moderate CoE), Nigella sativa (SMD -1.59, 95% CI -2.13 to -1.05; 1 study, 70 participants; high CoE), artichoke (SMD -0.34, 95% CI -0.59 to -0.09; 1 study, 244 participants; low CoE), Boensenbergia rotunda (SMD -2.22, 95% CI -2.62 to -1.83; 1 study, 160 participants; low CoE), Pistacia lenticus (SMD -0.33, 95% CI -0.66 to -0.01; 1 study, 148 participants; low CoE), Enteroplant (SMD -1.09, 95% CI -1.40 to -0.77; 1 study, 198 participants; low CoE), Ferula asafoetida (SMD -1.51, 95% CI -2.20 to -0.83; 1 study, 43 participants; low CoE), ginger and artichoke (RR 1.64, 95% CI 1.27 to 2.13; 1 study, 126 participants; low CoE), Glycyrrhiza glaba (SMD -1.86, 95% CI -2.54 to -1.19; 1 study, 50 participants; moderate CoE), OLNP-06 (RR 3.80, 95% CI 1.70 to 8.51; 1 study, 48 participants; low CoE), red pepper (SMD -1.07, 95% CI -1.89 to -0.26; 1 study, 27 participants; low CoE), Cuadrania tricuspidata (SMD -1.19, 95% CI -1.66 to -0.72; 1 study, 83 participants; low CoE), jollab (SMD -1.22, 95% CI -1.59 to -0.85; 1 study, 133 participants; low CoE), Pimpinella anisum (SMD -2.30, 95% CI -2.79 to -1.80; 1 study, 107 participants; low CoE). The following may provide little to no difference compared to placebo: Mentha pulegium (SMD -0.38, 95% CI -0.78 to 0.02; 1 study, 100 participants; moderate CoE) and cinnamon oil (SMD 0.38, 95% CI -0.17 to 0.94; 1 study, 51 participants; low CoE); moreover, Mentha longifolia may increase dyspeptic symptoms (SMD 0.46, 95% CI 0.04 to 0.88; 1 study, 88 participants; low CoE). Almost all the studies reported little to no difference in the rate of adverse events compared to placebo except for red pepper, which may result in a higher risk of adverse events compared to placebo (RR 4.31, 95% CI 1.56 to 11.89; 1 study, 27 participants; low CoE). With respect to the quality of life, most studies did not report this outcome. When compared to other interventions, essential oils may improve global symptoms of dyspepsia compared to omeprazole. Peppermint oil/caraway oil, STW5, Nigella sativa and Curcuma longa may provide little to no benefit compared to other treatments.

AUTHORS' CONCLUSIONS

Based on moderate to very low-certainty evidence, we identified some herbal medicines that may be effective in improving symptoms of dyspepsia. Moreover, these interventions may not be associated with important adverse events. More high-quality trials are needed on herbal medicines, especially including participants with common gastrointestinal comorbidities.

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.

Effect of Nigella sativa on Selected Gastrointestinal Diseases

Nigella sativa L. (family Ranunculaceae), also known as black cumin, has been used in cuisine around the world for many years. Due to its health-promoting properties, it can be used not only in the food industry but also in medicine. The main bioactive compound contained in the black cumin extract is thymoquinone (TQ), which has a special therapeutic role. The results of research in recent years confirmed its hypoglycemic, hypolipemic, and hepatoprotective effects, among others. In addition, the results of laboratory tests also indicate its immunomodulatory and anticancer effects, although there is still a lack of data on the mechanisms of how they are involved in the fight against cancer. Including this plant material in one’s diet can be both an element of prophylaxis and therapy supporting the treatment process, including pharmacological treatment. However, attention should be paid to its potential interactions with drugs used in the treatment of chronic diseases.

A Comprehensive Review of the Role of Complementary and Dietary Medicines in Eradicating Helicobacter pylori

Antibiotic-resistant Helicobacter pylori isolates have become a global concern. The standard triple or quadruple therapies have recently become the most effective protocol for eradicating H. pylori in the gastrointestinal tract. There is evidence regarding the impact of different complementary or dietary supplements on H. pylori eradication. This review article intended to search electronic bibliographic databases for any clinical studies that evaluated the use of any herbal or dietary supplements to eradicate H. pylori up to June 2021. A total of 20 human studies met our criteria and were reviewed. Although some herbal medicines have shown their efficacy and safety in eradicating H. pylori in different clinical trials, more randomized blind, placebo-controlled human trials with a large sample size must be performed to extend our knowledge.

Nigella sativa L. Phytochemistry and Pharmacological Activities: A Review (2019-2021)

Medicinal and aromatic plants are mainly characterized by the presence of different bioactive compounds which exhibit various therapeutic activities. In order to investigate the different pharmacological properties of different Nigella sativa extracts, a multitude of research articles published in the period between 2019 and 2021 were obtained from different databases (Scopus, Science Direct, PubMed, and Web of Science), and then explored and analyzed. The analysis of the collected articles allows us to classify the phytochemicals and the pharmacological activities through their underlying molecular mechanisms, as well as to explore the pharmacological activities exhibited by several identified compounds in Nigella sativa which allow a better understanding, and better elucidation, of the bioactive compounds responsible for the pharmacological effects. Also shown are the existence of other bioactive compounds that are still unexplored and could be of great interest. This review could be taken as a guide for future studies in the field.

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

AIMS

The objective of the present study was to perform a systematic review and meta-analysis on randomized controlled trials (RCTs) assessing the effects of Nigella sativa L. supplementation on the circulating inflammatory and oxidative stress markers, including C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), total antioxidant capacity (TAC) and malondialdehyde (MDA).

METHODS

Systematic search was performed up to March 2020 using PubMed, Scopus, and ISI web of science databases. Two reviewers independently assessed study eligibility, extracted data, and evaluated methodological quality of included primary studies. Statistical heterogeneity was assessed using I-square (I²) statistic. Data were pooled by using the random-effect model and standardized mean difference (SMD) was considered as the summary effect size.

RESULTS

Twelve trials were identified to be suitable for our meta-analysis. The pooled results using random effects model indicated that Nigella sativa supplementation significantly reduced CRP (SMD: -0.35; 95% CI: -0.59, -0.12, P < 0.001, I² = 10.5%) and MDA concentrations (SMD: -0.56; 95% CI: -0.98, -0.15, P < 0.001, I² = 64.7%). Moreover, Nigella sativa supplementation increased TAC (SMD: 0.48; 95% CI: 0.09, 0.87, P = 0.01, I² = 65.6%) levels; however, it did not affect TNF-α (SMD: -0.35; 95% CI: -0.70, 0.01, P = 0.05, I² = 58.2%).

CONCLUSION

Nigella sativa supplementation is associated with improved inflammation and oxidative status. Additional prospective studies are recommended using higher supplementation doses and longer intervention period.

Recent Progress on Chemical Constituents and Pharmacological Effects of the Genus Nigella

Seeds of the genus Nigella plants as folk medicine are often used to prevent and treat asthma, diarrhea, dyslipidemia, and other diseases around the world. Pharmacological researches showed that seed extract and seed oil have antibacterial, antioxidant, hypoglycemic, and hepatoprotective effects which attributed to their bioactive constituents such as alkaloids, saponins, flavones, and phenols. This paper has covered recent progresses on chemical and pharmacological researches on these plants, including their compounds and pharmacological effects. It was found that the chemical component researches were focused on the seed oil. Therefore, more attention should be paid to the profile of the whole constituents in the seeds.