Rhamnus Prinoides (gesho) Stem Extract Prevents Co-Culture Biofilm Formation by Streptococcus Mutans and Candida Albicans.

Streptococcus mutansandCandida albicansexhibit a symbiotic relationship to form polymicrobial biofilms that exacerbate oral infections including early-childhood caries, periodontitis and candidiasis.Rhamnus prinoides(gesho) has traditionally been used for the treatment of a variety of illnesses and was recently found to inhibit Gram-positive bacterial biofilm formation. We hypothesized thatRhamnus prinoidesextracts have anti-biofilm activity againstS. mutansandC. albicansmono- and dual-species biofilms. Ethanol extracts were prepared from gesho stems and leaves; then anti-biofilm activity was assessed using crystal violet, resazurin and XTT staining. Ethanol extracts significantly inhibitedStreptococcus mutansandCandida albicansmono-species biofilm formation up to 97 and 75%, respectively. The stem ethanol extract disruptedS. mutansandC. albicansco-culture synergism, with 98% less polymicrobial biofilm formation than the untreated control. Additionally, this extract inhibited planktonicS. mutanscell growth and decreased biofilm polysaccharide production up to 99%. The reduction in polysaccharide production is likely a contributing factor in the anti-biofilm activity of GSE. These findings indicate that gesho or gesho-derived compounds may have potential as additives to oral hygiene products.