Identification of oral cavity biofilm forming bacteria and determination of their growth inhibition by Acacia arabica, Tamarix aphylla L. and Melia azedarach L. medicinal plants

Abstract

Objective: Biofilms are complex, multi-species bacterial communities that colonize the oral cavity in the form of plaque and are known to cause dental caries and periodontal disease. Present study demonstrated the potential of three selected medicinal plants against isolated and identified dental biofilm forming strains.

Methods: Pathogenic bacteria from dental biofilms were isolated, cultured, identified by phylogenetic analysis using PCR-based 16S ribosomal RNA (or 16S rRNA) nucleotide sequences and were analyzed for their biofilm forming capability. The antimicrobial activity of the three important medicinal plant extracts (Acacia arabica, Tamarix aphylla L. and Melia azadirachta L.) was determined against the highest biofilm forming bacteria.

Results: Phylogenetic analysis revealed that the 19 strains belonged to Proteobacteria, Firmicutes and Actinobacteria. Among the 19 isolates, eleven strains were found to possess high biofilm formation capability comparatively and antimicrobial activity assay showed that the selected plants considerably inhibited their growth. Extract from A. arabica stem had strong effect on the ability of bacteria isolated from dental carries as evident by up to 73% reduction in biofilm formation on surface pre-treated with extract from this plant. The same extract also showed tremendous biofilm cleaning potential up to 87% of the biofilm.

Conclusion: The results suggested that the extracts of selected medicinal plants could be used for protection against pathogenic dental biofilm causing bacteria and attempts should be taken by pharmaceutical industries to utilize it in dental caring products.

Keywords: 16S rRNA sequencing; Antimicrobial activity; Dental biofilm; Plant extracts.