Alleviating effects of Nigella sativa supplements on biomarkers of inflammation and oxidative stress: Results from an umbrella meta-analysis

Abstract

Several meta-analyses have examined the effect of Nigella sativa (N. Sativa) supplementation on inflammatory and oxidative markers, with conflicting results. So, the current study evaluated the effect of N. Sativa on some oxidative and inflammatory parameters. The Embase, Web of Science, Scopus, PubMed databases, and Google Scholar were systemically searched to identify papers indexed before February 2023. The pooled results were calculated with the use of a random-effects model to evaluate the effects of N. Sativa on inflammatory and oxidative markers. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to assess the certainty of evidence. Overall, seven meta-analyses were included in the study. N. Sativa supplementation significantly decreased serum C-reactive protein (CRP) (ES = −0.42; 95 % CI: −0.58, −0.25, p < 0.001), tumor necrosis factor-alpha (TNF-α) (ES= −1.27; 95 % CI: −2.29, −0.25; p = 0.015), and malondialdehyde (MDA) (ES = −0.67; 95 % CI: −0.97, −0.36, p < 0.001) levels, and significantly improved total antioxidant capacity (TAC) (ES = 0.34; 95 % CI: 0.20, 0.47, p < 0.001) and superoxide dismutase (SOD) (ES = 50.66; 95 % CI: 34.15, 67.18, p < 0.001) levels. N. Sativa supplementation had beneficial effects on CRP, TNF-α, MDA, SOD, and TAC. Thus, N. Sativa can be recommended as an adjuvant anti-inflammatory and anti-oxidant agent.