The Role of Hydroalcoholic Extract of Nigella sativa in Biofilm Inhibition and Antimicrobial Resistance-Associated Factors in Oral Streptococcus spp.: A Review

Oral biofilms are among the most important etiological factors involved in the development of dental caries and periodontal diseases. Various species of oral Streptococcus contribute to biofilm formation through adhesion to tooth surfaces, production of extracellular polysaccharides, and interspecies communication. The increasing prevalence of antimicrobial resistance among oral bacteria has reduced the effectiveness of conventional antibiotic therapies and highlighted the need for alternative antimicrobial agents. Nigella sativa (black seed), a medicinal plant widely used in traditional medicine, possesses antimicrobial, anti-inflammatory, antioxidant, and antibiofilm activities that have attracted considerable scientific interest. The hydroalcoholic extract of Nigella sativa contains several bioactive compounds, including thymoquinone, thymohydroquinone, thymol, and carvacrol, which interfere with bacterial growth, biofilm maturation, and virulence-related mechanisms. Recent in vitro studies have demonstrated that this extract significantly inhibits the growth of oral Streptococcus species, decreases biofilm biomass, and enhances bacterial susceptibility to antimicrobial agents. Furthermore, evidence suggests that Nigella sativa may influence the expression of genes associated with biofilm formation and antimicrobial resistance. This review summarizes current findings regarding the antimicrobial mechanisms of hydroalcoholic Nigella sativa extract against oral Streptococcus spp. and discusses its potential application as a natural adjunctive agent in the prevention and management of oral biofilm-associated diseases

کلیدواژه ها:

Nigella sativa ، Oral Streptococcus ، Biofilm ، Antimicrobial resistance ، Hydroalcoholic extract