The antimicrobial effect of aqueous & alcoholic extracts ofeucalyptus leaves on oral Mutans streptococci, Lactobacilli& Candida albicans (an in vitro study).

Abstract

ABSTRACT
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 & 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.
Key words: eucalyptus leaves, extracts, oral mutans streptococci, lactobacilli, Candida albicans. (J Bagh Coll
Dentistry 2009; 21(4): 109-112).