I Al-Saimary, S Bakr, B Khudaier, Y Abass
antibacterial agents, antibiotics, plant extracts
I Al-Saimary, S Bakr, B Khudaier, Y Abass. Efficiency of antibacterial agents extracted from Thymus vulgaris l. (lamiaceae). The Internet Journal of Nutrition and Wellness. 2006 Volume 4 Number 1.
Antibacterial activity of various concentrations of leaves, flowers and mixtures of
Alcoholic extracts are more efficient on various pathogenic bacteria and mixed extracts have a highly antibacterial activity. In general, all extracts in various concentrations with few exceptions are more efficacious on Gram positive bacteria than on Gram negative bacteria. The biggest inhibition zone recorded for 1000 µg/ml of mixed alcoholic extracts was (35 mm) against
The limits of minimal inhibitory concentrations (MICs) of all extracts are between (400-1300) µg/ml.
The efficiency of antibacterial activity of
All cultures from ancient times to the present day have used plants as a source of medicine. Today, as many as 80 % of the world's people depend on traditional medicine for their primary health care needs. The greater part of traditional therapy involves the use of plant extracts on their active principle. (1)
The Iraqi flora are rich in plants unsubmitted to any previous study. The possibility of finding new antimicrobial agents is still widely ahead.
The studied plant is one of these Iraqi flora
It is grown native in Iraq, in the area between Al-Mousl and Dhoook districts. The uses of
This investigation is the first study designed to study the
Materials & Methods
The plant and Extraction:
Studied plant parts: leaves, flowers and mixed (all plant).
1 gm of each dried plant parts was mixed with 100 ml of distilled water and 90 % Ethyl alcohol (Ethanol). The mixture was mixed by hot plate magnetic stirrer for 48 hours at 50-55 Oc. The mixture was put in centrifuge (5000 xg) for 30 minutes, then made various concentrations from crude extracts (50, 100, 250, 500, 750, 1000) mcg/ml (mcg = µg), in order to study the influence of these concentrations on different bacteria. (6,7)
The antibacterial activity of plant extracts was compared with (12) standard commercial antibiotics (as a single pharmacological dose of concentration for each one). Penicillin, Ampicillin, Carbencillin, Chloramphenicol, Nitrofurantoin, Nalidixic acid, Cephalexin, Tetracycline, Kanamycin, Erythromycin, Gentamicin and Neomycin.
Various types of pathogenic bacteria isolated from clinical specimens and identified by roatine methods were used. These bacteria are:
Blood agar (BA) and Nutrient agar (NA) (Difco) prepared for isolation of bacteria. The antibacterial activity was carried out by two techniques. (8)
1- Agar diffusion technique: To determine the diameters of inhibition zone by using Mueller Hinton agar (MHA) (Oxoid).
2- Tube technique: To determine the minimal inhibitory concentrations (MICs) by using Brain Heart Infusion (BHI) (Difco).
0.1 ml (103 cell/ml) from each bacterial isolates were inoculated on to MHA and BHI.
In general, the present study showed that the alcoholic extracts are more effective on various pathogenic bacteria than aqueous extracts.
The result summarized in Table 1.
Table (1) illustrates efficacious of various concentrations of alcoholic and aqueous extracts from
The limits of minimal inhibitory concentrations of all (mixed, leaves and flowers) extracts are between (400-1300 µg/ml).
Also we can see that all extracts in concentrations 50 and 100 µg/ml are not effected on all isolated bacteria, while some of concentrations (250 and 500) also are not effected on some bacterial types.
Depending on statistical analysis (ANOVA: Analysis of Variance and/or f-test carried by Havard computer program), we can showed that the mixed extracts in each alcoholic and aqueous extracts have a highly efficacious (P<0.01), followed by leaves and flowers (P<0.05).
We illustrated the antibacterial activity of twelve standard antibacterial measured by also two methods (I.Z. and MICs) and taken from previous study of the same authors. (9)
The inhibition zone diameters of antibiotics were as follow: 23 mm for
The minimal inhibitory concentrations (MICs) for all antibiotics ranged from 30-350 mcg/ml.
The result of the present study showed that
Our results revealed that all extracts in general are more effective on Gram positive bacteria than on Gram negative bacteria, these results may be due to the nature of bacterial cell membrane. The cell membrane of Gram positive bacteria contain mucopolysaccharides, proteins, and less amounts of phospholipids, while Gram negative bacteria have a huge amounts of phospholipids, and more pores in cell envelope. So, the permeability, entrance and reaction of the most antibiotics and/or antimicrobial agents through cell envelope (the outer and cytoplasmic membrane) are highly efficient for Gram positive bacteria depending on reaction with the protein layer (mucopolysaccharides or peptidoglycans). (8,11)
The antibacterial activity of
Our results supported the results of advanced studies that used
Other experimental evidence suggests that the in vitro activity of thyme preparations are due to the presence of polymethoxy flavones that have antibacterial activity. (3)
Conclusion & Recommendation
We concluded that both alcoholic and aqueous extracts of