Antibacterial Potential of Chlorella vulgaris and Dunaliella salina Extracts Against Streptococcus mutans

[Background and Objectives]Chlorella vulgaris and Dunaliella salina has been utilized as a part of nourishment and medicine to enhance the human way of life. This work was directed to assess the impacts of chloroform, methanol, and acetone (in ratio of 2/1/1 respectively) extract from C. vulgaris and D. salina on in-vitro biofilms formed by Streptococcus mutans along with their antibacterial activity.[Methods]The standardized combinatorial extract was primarily examined for their antimicrobial properties using disc diffusion, well diffusion, minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) methods. The crystal violet assay was used for assessing anti-biofilm activity of S. mutans. Moreover, toxicity properties of these extracts were evaluated on Brine shrimp Artemia urmiana.[Results]The best observed clear zones were 13.5 ± 0.92 mm for C. vulgaris and 18.5 ± 0.97 for D. salina in disc diffusion assay as well as 19 ± 0.87 mm for C. vulgaris and 25.4 ± 0.97 mm for D. salina in well diffusion assay. In addition, significant antibiofilm activity was recorded in the concentration of 4 mg/ml for C. vulgaris and 2 mg/ml for D. salina. Findings indicated appropriate antimicrobial activity for D. salina and C. vulgaris extract.[Conclusions] In addition, the biofilms of S. mutans were more effectively prohibited by D. salina extract than C. vulgaris extract. Moreover, D. salina extract showed less mortality in comparison with C. vulgaris extract in brine shrimp mortality test. The anti-adherent and antibacterial potential of both microalgae on in vitro biofilms formed by S. mutans were verified, which provides the importance of studies regarding these microalgae extracts for controlling dental plaque formation and consequent dental cavities formation.