Antibacterial Assay of the Whole Plant Ethanolic Extract of Amaranthus viridis, Aerva sanguinolenta and Cynodon dactylon against Streptococcus mutans and Lactobacillus acidophillus – An in vitro Microbiological Study

Background: Dental caries, a multifactorial, microbial disease of calcified portion of tooth, can be controlled by controlling the microbial factor either by synthetically derived or naturally derived antibacterial components. Aim: Antibacterial assay of three whole plant ethanolic extracts against two cariogenic bacteria to find out a plant extract which could be used as therapeutically effective method of controlling dental caries by controlling its microbial factor. Materials and Methods: Antimicrobial activity of 1000 μg/ml, 750 μg/ml, 500 μg/ml and 250 μg /ml concentration of Amaranthus viridis (A1), Aerva sanguinolanta (A2), Cynodon dactylon (A3) ethanolic whole plant extracts were measured by agar disc diffusion and broth microdilution method against Streptococcus mutans, and Lactobacillus acidophilus, 5% DMSO (negative control) and 30% Vancomycin (positive control). Result: The 1000 μg/ml (100%), ethanolic extracts of (A2) showed greatest inhibition zone (mean-11.860 mm) against Streptococcus mutans and (mean= 9.730 mm) against Lactobacillus acidophillus which were more than negative control but less than positive control. (A2) exhibited the lowest MIC of 0.02050 μg/ml and 0.02050 μg/ml against Streptococcus mutans and Lactobacillus acidophillus respectively. Conclusion: Aerva sanguinolenta whole plant ethanolic extract can be used to inhibit growth of cariogenic bacteria, thereby can be used for controlling microbial factor of dental caries in human being.