الفهرس 
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Abstract
Phytotherapy have a long-standing history in Egypt. Many efforts have been made to discover new antimicrobial compounds from various kinds of sources. One of such resources is folk medicine, traditional medicine is an important source of products in treating common infectious bacteria.
Extracts from twenty nine Egyptian medicinal plants were screened for their in vitro antimicrobial activity. The plant materials were extracted using aqueous and organic solvents (ethanol, methanol, acetone, chloroform, benzene, petroleum ether and diethyl ether). Extracts from these plants were studied against eleven ATCC human pathogens (G +ve, G –ve bacteria, yeasts and fungi). Results can be summarized as follow
The general screening assay of plant extracts against the antibiotic sensitive strains showed varied levels of activity with different type of solvents. The highest zones of inhibition were obtained by water extract of Azadirechta indica and diethyl ether extract of Syzygium aromaticum against Staphylococcus aureus. By methanol, chloroform and acetone extract of Salvia officinalis against Micrococcus luteus. Salvia officinalis was the most active against Bacillus cereus by the majority of solvents. Chloroform extract of Thymus vulgaris was the most active against Klebsiella pneumoniae. Of the bacterial strains tested E. coli proved to be the most difficult to inhibit with moderate susceptibility to all investigated plants. The maximum activity against Pseudomonas aeruginosa was recorded from the methanolic extract of Salvia officinalis. Diethyl ether of Syzygium aromaticum was found to be the most effective against Salmonella typhi. The marked activities against Candida albicans was obtained from diethyl ether extract of Syzygium aromaticum and against Saccharomyces cerevisiae from benzene extract .While the widest zones of
inhibition were from diethyl ether extract of Syzygium aromaticum against Aspergillus niger and Aspergillus flavus.
Concerning the effect of the plant extracts on the tested organisms, it is worthy to note that most plant extracts prepared have more potent inhibitory effect on bacterial strains (either G +ve or G –ve ) in comparison to yeasts and fungi.
from the results obtained, it was found that the best antimicrobial activity was observed for five of the twenty nine plants namely, Lawsonia inermis, Azadirechta indica, Salvia officinalis, Thymus vulgaris and Syzygium aromaticum against almost all studied strains.
Among the five chosen plants Salvia officinalis (methanol and ethanol) and Syzygium aromaticum (methanol, benzene, diethyl ether and chloroform) extracts were considered to be the most active as they presented good activity against the sensitive tested strains. It was interesting that their extracts showed response on G +ve and G -ve bacteria, yeasts and fungi. Activity of these two plants was also detected against the four tested MDR isolates (Staphylococcus aureus, Escherichia coli, Salmonella typhi and Klebsiella pneumoniae).
A broad spectrum of antimicrobial activity was detected for diethyl ether extract of clove flower buds as demonstrated by its activity in controlling all the tested microorganisms as well as the MDR isolates, suggesting that Syzygium aromaticum could be considered potentially, rich source of anti-bacterial, anti-yeast and anti-fungal agents.
The minimum inhibitory concentrations (MICs) of diethyl ether extract of the active plant (clove) against the sensitive strains tested, they ranged between 0.05 and 500µg/ml.
Increasing of antibacterial resistance is a global growing problem, consequently, isolation of microbial agents safe, effective and less susceptible to regular antibiotics is of an urgent need to substitute with no effective ones. Since S. aureus is an example of inhibition were from diethyl ether extract of Syzygium aromaticum against Aspergillus niger and Aspergillus flavus.
Concerning the effect of the plant extracts on the tested organisms, it is worthy to note that most plant extracts prepared have more potent inhibitory effect on bacterial strains (either G +ve or G –ve ) in comparison to yeasts and fungi.
from the results obtained, it was found that the best antimicrobial activity was observed for five of the twenty nine plants namely, Lawsonia inermis, Azadirechta indica, Salvia officinalis, Thymus vulgaris and Syzygium aromaticum against almost all studied strains.
Among the five chosen plants Salvia officinalis (methanol and ethanol) and Syzygium aromaticum (methanol, benzene, diethyl ether and chloroform) extracts were considered to be the most active as they presented good activity against the sensitive tested strains. It was interesting that their extracts showed response on G +ve and G -ve bacteria, yeasts and fungi. Activity of these two plants was also detected against the four tested MDR isolates (Staphylococcus aureus, Escherichia coli, Salmonella typhi and Klebsiella pneumoniae).
A broad spectrum of antimicrobial activity was detected for diethyl ether extract of clove flower buds as demonstrated by its activity in controlling all the tested microorganisms as well as the MDR isolates, suggesting that Syzygium aromaticum could be considered potentially, rich source of anti-bacterial, anti-yeast and anti-fungal agents.
The minimum inhibitory concentrations (MICs) of diethyl ether extract of the active plant (clove) against the sensitive strains tested, they ranged between 0.05 and 500µg/ml.
Increasing of antibacterial resistance is a global growing problem, consequently, isolation of microbial agents safe, effective and less susceptible to regular antibiotics is of an urgent need to substitute with no effective ones. Since S. aureus is an example of inhibition were from diethyl ether extract of Syzygium aromaticum against Aspergillus niger and Aspergillus flavus.
Concerning the effect of the plant extracts on the tested organisms, it is worthy to note that most plant extracts prepared have more potent inhibitory effect on bacterial strains (either G +ve or G –ve ) in comparison to yeasts and fungi.
from the results obtained, it was found that the best antimicrobial activity was observed for five of the twenty nine plants namely, Lawsonia inermis, Azadirechta indica, Salvia officinalis, Thymus vulgaris and Syzygium aromaticum against almost all studied strains.
Among the five chosen plants Salvia officinalis (methanol and ethanol) and Syzygium aromaticum (methanol, benzene, diethyl ether and chloroform) extracts were considered to be the most active as they presented good activity against the sensitive tested strains. It was interesting that their extracts showed response on G +ve and G -ve bacteria, yeasts and fungi. Activity of these two plants was also detected against the four tested MDR isolates (Staphylococcus aureus, Escherichia coli, Salmonella typhi and Klebsiella pneumoniae).
A broad spectrum of antimicrobial activity was detected for diethyl ether extract of clove flower buds as demonstrated by its activity in controlling all the tested microorganisms as well as the MDR isolates, suggesting that Syzygium aromaticum could be considered potentially, rich source of anti-bacterial, anti-yeast and anti-fungal agents.
The minimum inhibitory concentrations (MICs) of diethyl ether extract of the active plant (clove) against the sensitive strains tested, they ranged between 0.05 and 500µg/ml.
Increasing of antibacterial resistance is a global growing problem, consequently, isolation of microbial agents safe, effective and less susceptible to regular antibiotics is of an urgent need to substitute with no effective ones. Since S. aureus is an example of microorganisms that gained resistance against the antibiotic ciprofloxacin, so the MIC values of clove and ciprofloxacin against the resistant S. aureus were evaluated. They recorded 1024 and 256 µg/ml respectively.
The possible existence of synergy between the phytoextract and antibiotic against MRSA was tested. The combinations of the diethyl ether extract of clove with antibiotic ciprofloxacin induced significant reduction of greater than or equal 2 - 5 folds in the MIC of both microbial agents, which were considered to be synergistic based on the evaluated FIC
. The bioactive components of diethyl ether clove extract
index
were separated using TLC analysis and the relative mobilities of the bioactive components were determined by measuring their R
values. TLC analysis showed the presence of three separated components. Results of their antimicrobial assay demonstrated that the diethyl ether crude extract gave better inhibitory activity against S. aureus (ATCC 25923) compared with the activities of the separated fractions.
f
Gas Chromatography Mass Spectrometer (GC/MS) of diethyl ether extract of Syzygium aromaticum showed the presence of eugenol (59.7%) and eugenol acetate (34.5%) as two main phytochemical compounds as well as six minor compounds.
More than one mechanism may be involved in the activity of antimicrobial agents, there is a need to understand these mechanisms. The modes of action of the crude clove diethyl ether extract against S. aureus (ATCC 25923) were investigated by estimating protein profile, DNA contents and by using scanning electron microscop opy (SEM). Total protein profiling using SDS-PAGE at different time of exposure to clove extract showed high degree of protein degradation. The DNA content was significantly reduced after different time intervals of exposure to clove extract. Cells grown in the presence of clove diethyl ether extract (24 h.) were examined using SEM. The morphology of the examined cells appears deformed and exhibited moderate destruction, many cells were enlarged and elongated.
The SRB assay was used to test in vitro cytotoxicity of crude clove diethyl ether extract against two human cancer cell lines namely, breast cancer (MCF-7) and colon cancer (HCT116). Results showed that the extract exhibited a very high degree of cytotoxic activity against the two tested cancer cell lines. The concentrations required for 50 % inhibition (IC
) were 26.5 μg/ml for breast cancer and 27μg/ml for colon cancer.