ANTIMICROBIAL EFFECT OF DODONAEA VISCOSA JACQ.EXTRACTS AGAINST SOME PATHOGENIC MICROORGANISMS

Abstract

The present study has been conducted to evaluate the inhibitory effects of the
aerial plant part (leaves and bark) extracts of D. viscosa before and during flowering
against some pathogenic bacteria for human, plants, and against yeast (Candida
albicans) by using different polarity organic solvents: Ethanol and Diethyl ether.
The agar well diffusion method was used to evaluate the inhibitory actions of these
extracts with eight concentrations: 0, 2.5, 5, 10, 20, 30, 40 or 50 mg/ml. The
Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration
(MBC) values were also determined, in addition to compare the results of the plant
extracts with the results of the susceptibility of pathogenic microorganisms for
antibiotics, The completely randomized design (CRD) was used with three
replications. Better effect was observed in the liquid dilution assay with all extracts
showing a degree of effect. The results showed that ethanolic extracts of the bark
and leaves, and diethyl ether extracts of the leaves demonstrated clear inhibitory
effect against the tested microorganisms. ethanolic extracts of the bark was superior
over leaf extracts in the inhibitory effects on the growth of C. albicans. In general,
the results showed no significant differences between the concentrations of 30, 40 or
50 mg/ml. The microbial screening showed that the MIC of ethanolic extracts of the
bark before and during flowering was at a concentration of 2.5 mg/ml, and for leaf
extracts ranged between 2.5-10 mg/ml. As for MBC effects was ranged between 5-
50 mg/ml, depending on the type of solvents, microorganism and the period of
collection (before or during flowering). In comparison with antibiotics, the results
showed high similitude between D. viscosa extracts at concentrations of 30, 40 or 50
mg/ml and antibiotics against the tested microorganisms. When our results compares
with other studies that conducted in other parts of the world, we concluded that the
type of solvent, method of extraction, period of collection (before or during
flowering) and the geographical distribution of D. viscosa significantly affect the
rate of the chemical components and its effect against microorganisms.