| Considering the different untoward effects of the drugs prescribed
for the treatment of rheumatoid arthritis (RA), there
has been an increasing interest in adjuvant therapies devoid
of such unfavorable reactions. Although the beneficial effects
of Nigella sativa (N. sativa) on RA have been established, it
seems that its mechanisms of action have not still been reviewed.
The present review is designed to evaluate the effects
of N. sativa on RA systematically. We searched these electronic
databases until April 2019: PubMed, Scopus, ISI Web
of Science, Cochrane Library, Embase, Ovid, ProQuest, and
Google scholar. No restriction was conducted based on language
or publication date. We selected all of the related clinical,
animal, and in vitro studies. Review papers, abstracts in
conferences, book chapters, and papers regarding the effects
of N. sativa combined with other herbs, as well as articles regarding
the effects of N. sativa on other diseases, were excluded.
Each article was assessed critically for the possible risk
of bias. Nineteen articles were reviewed. Animal and in vitro
investigations supported the favorable effects of N. sativa on
clinical, inflammatory, oxidative, and immunologic parameters
on RA, whereas results of limited clinical studies did not
illustrate any change or improvement of inflammatory and
oxidative biomarkers in RA. N. sativa could control RA via multiple
ways such as decreasing inflammation, inhibiting oxidative
stress, and modulating the immune system. This paper
provides persuasive clues to defend the efficacy of N. sativa
in RA and justifies the significance of subsequent clinical trials. |