ايمن القدسى
20-08-2008, 10:24 AM
INTRODUCTION
Infectious diseases are one of leading cause of premature death. In recent years, drug resistance to human pathogenic bacteria has been commonly reported from all over the world due to indiscriminate use of antibiotics.1 New therapeutic agents are of great demand. Many infectious diseases are known to be treated with herbal medicines throughout the human civilization. Even today, plant materials continue to play major role in primary health care and higher plants have been shown to be potential sources for the new anti-microbial agents.2 Different species of the genus Zizyphus like vulgaris, sativa, jujuba, etc. belong to the family Rhamnaceae showed hypoglycemic activity.3,4 In continuation of our work on screening of biologically active plant materials Zizyphus rugosa and Z. oenoplia have been chosen for studies of their antibacterial, antifungal, and b-glucuronidase inhibitory activities for discovery of new therapeutic agent(s) from natural sources. No previous report on biological activity of these two species is available.
Antibacterial Assay. The agar well diffusion protocol was used to test antibacterial activity5 against six bacterial strain, Bacillis subtilis, Streptococcus pyogens, Stapylococcus aureus (Gram-positive) and Escherichia coli, Pseudomonas aerogenes, Salmonella typhi (Gram-negative). Tetracycline (0.5 mg/mL) was used as reference or positive control while DMSO without sample was used as negative control. Antibacterial activity is given in Table 1 and 2.
Test for Antifungal Activity. The agar tube dilution method was applied for determination of the antifungal activity6 against six pathogenic fungi, Trichophyton longiformis, Candida albicans, Aspergillus flavis, Microsporum canis, Fusarium solani and Fusarium moniliformis. Miconazole was used as positive control. Antifungal activity of the extracts is presented in the Table 3.
RESULTS AND DISCUSSION
The methanol extract of Z. rugosa bark showed significant antibacterial activity against Streptococcus pyogens, Staphylococcus aureus and Pseudomonas aerogenes by showing zone of inhibition 18, 18 and 20 mm, respectively, whereas the methanol extract of the leaves was significantly active against only one bacteria, Salmonella typhi (18 mm) (Table 1). Chloroform extract of bark showed significant inhibition against Staphylococcus aureus (25 mm) but good inhibition against Streptococcus pyogens (15 mm), Pseudomonas aerogenes (15 mm) and Salmonella typhi (15 mm). On the other hand the chloroform extract of leaves of Z. rugosa showed good inhibition of growth of few bacteria. Methanol and chloroform extracts of Z. oenoplia also showed good activity against a few bacteria but none of them was significant.
The chloroform extract of bark gave significant (88%) antifungal activity against Microsporum canis and that of leaves against Fusarium solani (88%). The ethyl acatate extract of leaves showed significant antifungal activity against Fusarium solani (83%). Methanol extracts of both leaves and bark were found to be inactive (Table 3).
b-glucuronidase has been discovered in animals, plants and bacteria8 which catalyzes the hydrolysis of b-glucuronides produced in the body such as benzo[a]pyreneglucuronides. Pineda et. al. demonstrated that liver damage caused an increase in the enzyme in blood and liver cancer could be related to the enzyme9. Methanol and ethyl acetate extracts of the bark of Z. rugosa showed significant b-glucuronidase inhibition activity (100%) while they were tested using saccharic acid 1,4-lactone as a standard inhibition for positive control (Table 4). It can be expected that these extracts can reduce the risk factor of liver cancer by inhibiting the hydrolysis to glucuronides of proximate metabolites and active b-glucuronides enzyme inhibitors can be isolated from them. Chloroform and methanol extract of leaves of Z. oenoplia showed good activity (60% and 74%, respectively) whereas bark extract was found to be inactive. Lupeol, betuline, betulinaldehyde and betulinic acid isolated10 earlier from Z. rugosa also showed good activity against a few bacteria (Table 2).
The biological activities exhibited by different extracts of Z. rugosa and Z. oenoplia might be due to the presence of different types of chemical components in the extracts.
Infectious diseases are one of leading cause of premature death. In recent years, drug resistance to human pathogenic bacteria has been commonly reported from all over the world due to indiscriminate use of antibiotics.1 New therapeutic agents are of great demand. Many infectious diseases are known to be treated with herbal medicines throughout the human civilization. Even today, plant materials continue to play major role in primary health care and higher plants have been shown to be potential sources for the new anti-microbial agents.2 Different species of the genus Zizyphus like vulgaris, sativa, jujuba, etc. belong to the family Rhamnaceae showed hypoglycemic activity.3,4 In continuation of our work on screening of biologically active plant materials Zizyphus rugosa and Z. oenoplia have been chosen for studies of their antibacterial, antifungal, and b-glucuronidase inhibitory activities for discovery of new therapeutic agent(s) from natural sources. No previous report on biological activity of these two species is available.
Antibacterial Assay. The agar well diffusion protocol was used to test antibacterial activity5 against six bacterial strain, Bacillis subtilis, Streptococcus pyogens, Stapylococcus aureus (Gram-positive) and Escherichia coli, Pseudomonas aerogenes, Salmonella typhi (Gram-negative). Tetracycline (0.5 mg/mL) was used as reference or positive control while DMSO without sample was used as negative control. Antibacterial activity is given in Table 1 and 2.
Test for Antifungal Activity. The agar tube dilution method was applied for determination of the antifungal activity6 against six pathogenic fungi, Trichophyton longiformis, Candida albicans, Aspergillus flavis, Microsporum canis, Fusarium solani and Fusarium moniliformis. Miconazole was used as positive control. Antifungal activity of the extracts is presented in the Table 3.
RESULTS AND DISCUSSION
The methanol extract of Z. rugosa bark showed significant antibacterial activity against Streptococcus pyogens, Staphylococcus aureus and Pseudomonas aerogenes by showing zone of inhibition 18, 18 and 20 mm, respectively, whereas the methanol extract of the leaves was significantly active against only one bacteria, Salmonella typhi (18 mm) (Table 1). Chloroform extract of bark showed significant inhibition against Staphylococcus aureus (25 mm) but good inhibition against Streptococcus pyogens (15 mm), Pseudomonas aerogenes (15 mm) and Salmonella typhi (15 mm). On the other hand the chloroform extract of leaves of Z. rugosa showed good inhibition of growth of few bacteria. Methanol and chloroform extracts of Z. oenoplia also showed good activity against a few bacteria but none of them was significant.
The chloroform extract of bark gave significant (88%) antifungal activity against Microsporum canis and that of leaves against Fusarium solani (88%). The ethyl acatate extract of leaves showed significant antifungal activity against Fusarium solani (83%). Methanol extracts of both leaves and bark were found to be inactive (Table 3).
b-glucuronidase has been discovered in animals, plants and bacteria8 which catalyzes the hydrolysis of b-glucuronides produced in the body such as benzo[a]pyreneglucuronides. Pineda et. al. demonstrated that liver damage caused an increase in the enzyme in blood and liver cancer could be related to the enzyme9. Methanol and ethyl acetate extracts of the bark of Z. rugosa showed significant b-glucuronidase inhibition activity (100%) while they were tested using saccharic acid 1,4-lactone as a standard inhibition for positive control (Table 4). It can be expected that these extracts can reduce the risk factor of liver cancer by inhibiting the hydrolysis to glucuronides of proximate metabolites and active b-glucuronides enzyme inhibitors can be isolated from them. Chloroform and methanol extract of leaves of Z. oenoplia showed good activity (60% and 74%, respectively) whereas bark extract was found to be inactive. Lupeol, betuline, betulinaldehyde and betulinic acid isolated10 earlier from Z. rugosa also showed good activity against a few bacteria (Table 2).
The biological activities exhibited by different extracts of Z. rugosa and Z. oenoplia might be due to the presence of different types of chemical components in the extracts.