Antibiofilm potential of Zanthoxylum zanthoxyloides bark-extract against biofilm-producing Streptococcus mutans in dental caries

Abstract

Streptococcus mutans is the major cause of dental caries, which is costly to treat. The burden is worse in low- and middle-income countries, due to poor access to oral health services and diets high in free sugars. Conventional antibiofilm agents in oral health often have side effects, prompting the search for safer and affordable alternatives. This study investigates the antibiofilm activity of Zanthoxylum zanthoxyloides bark extract against biofilm-forming S. mutans. Dental plaque and tooth samples were collected from hospitals after ethical approval. S. mutans was identified using standard microbiological methods on Mitis Salivarius agar supplemented with Bacitracin and potassium tellurite. Biofilm formation was assessed with Congo Red agar, biofilm-related genes gtfB and gtfC were detected using polymerase chain reaction (PCR) and biofilm production quantified using a spectrophotometric assay_. The chewing stick was authenticated and its ethanolic bark extract was obtained. The Minimum Biofilm Inhibitory Concentrations (MBIC) of the extract was determined at 0.2-100 mg/mL. Extract bioactive compounds were subsequently identified using Gas Chromatography-Mass Spectrometry (GC-MS) analysis. From 254 samples, 63 isolates were identified, with 61% being biofilm producers. gtfB and gtfC were detected in 56% and 50% of the isolates respectively. Biofilm production varied. The lowest concentration of the Z. zanthoxyloides that inhibited ≥ 80% of S.mutans biofilm was 0.20 mg/mL. The study confirms Z. zanthoxyloides, has significant biofilm inhibitory activity against S. mutans, supporting its potential as an alternative or complementary therapy.