The antimicrobial effect of aqueous & alcoholic extracts of eucalyptus leaves on oral mutans streptococci, lactobacilli & candida albicans : an in vitro study

الملخص EN

Background: The antimicrobial properties of the plants constituents have been known for many years and have been used against a wide variety of bacteria and fungi including oral pathogens.

The purpose of this research is to find out and to compare between the antimicrobial properties of eucalyptus leaves aqueous and alcoholic extracts on the most cariogenic bacteria in mouth (Mutans streptococci and Lactobacilli) and against Candida albicans.

Materials and methods : Mutans streptococci, Lactobacilli and Candida albicans were isolated from 25 saliva samples from dental students.

These isolates were purified and diagnosed according to morphological characteristics and biochemical tests.

Aqueous and alcoholic extracts were prepared from eucalyptus leaves in different concentrations and estimated in mg / ml.

Chlorhexidine 2mg / ml (0.2 %) was used in the in vitro experiments while absolute ethanol used as control.

Susceptibility of Mutans streptococci, Lactobacilli and Candida albicans were tested by agar diffusion technique.

Results : there was statistically highly significant difference (p < 0.001) between different concentrations of the aqueous and alcoholic extracts on the sensitivity of the isolates, whilst the alcoholic extract was more effective than aqueous extract just at low concentrations.

At 100mg/ml and 150mg / ml the alcoholic and the aqueous extracts were better than the 2mg / ml Chlorhexidine in relation to Mutans streptococci and Candida albicans.

Minimum bactericidal concentration for the aqueous extract was 5-8mg/ml, 6-10mg/ml and 3-7mg / ml for Mutans streptococci, Lactobacilli and Candida albicans respectively while that of the alcoholic extract was 4-8mg/ml, 6-10mg/ml and 2-6mg / ml in relation to Mutans streptococci, Lactobacilli and Candida albicans respectively.

Conclusion : leaves extracts (aqueous and alcoholic) showed antimicrobial action against Mutans streptococci, Lactobacilli and Candida albicans.