ANTIBACTERIAL ACTIVITY OF ANNONA SQUAMOSA L. AND ANNONA RETICULATA L. AGAINST CLINICAL ISOLATES OF MUTANS STREPTOCOCCI THE CAUSATIVE AGENTS OF DENTAL CARIES

ABSTRACTObjective: Evaluation of antibacterial activity of Annona squamosa L and Annona reticulata L against Streptococcus mutans and Streptococcus sobrinus(mutans streptococci MS) the causative agent of dental caries.Methods: Leaves and bark of A. squamosa and A. reticulata were collected and extracted by methanol solvent using soxhlet apparatus. Clinical sampleswere isolated from dental caries subjects, and identified by 16S rDNA sequencing. The isolates were tested to study the antibacterial activity ofA. squamosa and A. reticulata leaves and bark by disc diffusion method. 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, and100 mg concentration of the extract were used to study the antibacteial activity of S. mutans and S. sobrinus. Ampicillin (AMP) 10 μg was used as apositive control in all the species.Results: The isolates were identified based on 16S rDNA sequencing as two Streptococcus mutans and two Streptococcus sobrinus. A. squamosa barkshowed antibacterial activity against MS species, while, at 100 mg concentration leaves extract of A. squamosa did not show any inhibition againstMS species. However, no inhibitory activity being shown in A. reticulata (leaves and bark) against MS species. The result indicates that S. sobrinus ismore susceptible to the A. squamosa bark extract than S. mutans. Not much difference showed between the species in regards of different concentration.Conclusion: A. squamosa bark showed antibacterial activity against MS species, further investigation of the A. squamosa bark should be studied todetermine the anti-caries properties.Keywords: Annona squamosa, Annona reticulata, Plant extract, Dental caries, Mutans Streptococci, Antibacterial susceptibility testing,16S rDNA sequencing