The effect of Nigella sativa on oxidative stress and inflammatory biomarkers: a systematic review and meta-analysis.

Abstract

The present systematic review of literature was conducted to study the effect of Nigella sativa (N.S) on oxidative stress and inflammatory biomarkers. Different online databases such as Cochrane Central Register of Controlled Trials, MEDLINE (PubMed), Scopus, Web of Sciences, EMBASE, and Clininaltrial.gov for English articles and national databases of SID, Magiran,Irandoc, and Iranmedex for Persian articles, which were published until March; 2019 were scrutinized. AllRandomised Controlled Trials (RCTs) and quasi-experimental studies that aimed to compare the impact of N.S along, with placebo or without supplementation, on inflammatory factors and oxidative stress were entered in the present study. Finally, 11 RCTs covering 710 women and men, intotal, were participated in the present meta-analysis. Significant differences were observed in TumorNecrosis Factor alpha (TNF-α) (Weighted Mean Difference (WMD)=-2.15pg/mL, 95% Confidence Interval (CI)=-3.22--1.09, I2=32%; 5 trials with 262 participants) superoxide dismutase (WMD=63.79µ/gHb, 95% CI=6.84-120.75, I2=0%; 2 trials, with 88 participants), and total antioxidant capacity (WMD=0.34mmol/L, 95% CI=0.04 to 0.63, I2=94%; 5 trials with 232 participants). Nevertheless, there was no significant difference in high sensitivity C-reactive protein (WMD=-0.98mg/L, 95% CI=-1.98-0.03, I2=78%; 5 trials with 267 participants), Interleukin 6 (IL-6) (WMD=-0.25pg/mL, 95% CI=-0.65 to 0.16, I2=0%; 2 trials with 134 participants), and malondialdehyde (WMD=-0.95nmol/mL, 95% CI=-1.97-0.08, I2=68%; 4 trials with 179 participants). Generally speaking, N.S probably results in theimprovement of superoxide dismutase serum levels, TNF-α, and total antioxidant capacity. Thus, further studies are required to fully assess its impacts on all oxidative stress and inflammatory biomarkers.