Antimicrobial efficacy of neem and liquorice with chlorhexidine on Streptococcus sanguis, Streptococcus mutans, Lactobacillus and Actinomyces naeslundii - An In Vitro Study

The study was to formulate 2% neem and 2% liquorice mouthwashes and to compare the antimicrobial efficacy of these mouthwashes with the standard 0.2% chlorhexidine mouthwash. Alcoholic solution was prepared and added to neem mixture and liquorice mixture separately and made up to a volume of 16000 ml with purified water. Nine dilutions of each drug were done with Brain heart infusion broth (BHI) for MIC. Culture suspension was added in each serially diluted tube of 200 l. The tubes were incubated for 24 hours and observed for turbidity. Minimum inhibitory concentration (MIC) of 2% neem, 2% liquorice and 0.2% chlorhexidine against Lactobacillus, Actinomyces naeslundii, Streptococcus sanguis, Streptococcus mutans is determined by serial dilution analysis. Streptococcus mutans shows sensitivity to all three mouthwashes at a concentration starting from 0.2 g/ml. Lactobacillus shows sensitivity to neem and chlorhexidine mouthwashes at a concentration starting from 1.6 g/ml, whereas liquorice is effective at a concentration starting from 3.125 g/ml. Streptococcus sanguis shows sensitivity to chlorhexidine and liquorice mouthwashes at a concentration starting from 25 g/ml, whereas it shows sensitivity to neem at a concentration starting from 50 g/ml. Actinomyces naeslundii shows sensitivity to chlorhexidine and neem mouthwashes at a concentration starting from 1.6 g/ml, whereas it shows sensitivity to liquorice at a concentration starting from 3.125g/ml. Analysis showed an inhibition of all the four strains by the mouthwashes. The MIC for the studied mouthwashes was found to be similar to that of 0.2% chlorhexidine.