الفهرس 
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Abstract
6. SUMMARY
Malathion is a broad spectrum organophosphate insecticide and miticide first registered in 1956. Malathion is an organophosphorus pesticide in agricultural and household products that is widely used to control pests in Egypt. It is extensively used over the whole world, especially by developing countries, to control or eradicate disease-inducing arthropods targeted by public health programs; it is also used to eliminate animal ectoparasites, human head and body lice, and household insects, and to protect grain in storage. Malathion is known to inhibit acetylcholinesterase activity in target tissues and has been linked to the dysfunction of several organ systems, including the liver, kidneys, pancreas and the reproductive system.
The present study was carried out to:
1. Study the protective effects of Melissa officinalis extract against malathion toxicities in liver, kidneys and reproductive system as well as feed intake and body weight using experimental animal (mature male albino rats) through:
a. Determination of feed intake and body weight.
b. Determination of serum biological parameters regarding liver and kidney function.
c. Evaluation of enzymatic antioxidants in liver and kidneys
d. Histopathological examination for liver, kidney and testes tissues.
2. Study the adsorbent capacity of activated carbon derived from agriculture by-product (date stone) and developed Nano-particales activated carbon to bind the malathion in aqueous solution.
3. Study the effect of agitation time, pH and temperature medium on the stability of sorbent-ML complex.
The obtained results could be summarized in the following:
Part I: The protective effects of Melissa officinalis L. extract against toxicities and oxidative stress induced by malathion.
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Protection against ML toxicity was achieved using ethanolic extract of Melissa officinalis. Thirty two male Sprague–Dawley rats were divided into four groups including control group, fed based diet, group fed basal diet and treated orally with Melissa officinalis extract, group fed basal diet and treated orally with malathion at dose 27mg/kg bw and last group fed basal diet and treated orally with malathion (27 mg/kg bw) plus Melissa officinalis extract. At the end of the experimental period, blood samples were collected for serum biochemical analyses. After collected the blood samples all animals were scarified and dissected samples of liver, kidney and testes were collected for histopathology and determination of antioxidant enzyme activities.
The results indicated that rats treated orally with malathion (27 mg/kg bw) showed a significant (p≤0.05) increase in serum alanine transaminase, aspartate aminotransferase, alkaline phosphatase triglycerides and levels of uric acid, creatinine and urea. In the same way animals treated with malathion showed significant (p≤0.05) decrease in superoxide dismutase, catalase and glutathione peroxidase accompanied a significant (p≤0.05) increase in malondialdehyde in liver and kidney homogenates. While, animals in second group, which treated with Melissa officinalis alone and fourth group which treated with Melissa officinalis plus malathion (27 mg/kg bw) showed a significant (p≤0.05) improvements in all tested parameters.
In context, the present results showed that melissa officinalis extract successed in induces an improvement in superoxide dismutase, catalase and glutathione peroxidase and malondialdehyde in homogenate of testis of rat treated with melissa officinalis plus malathion (27 mg/kg bw) compared to results of malathion treated group. Animals treated with malathion alone showed a significant increase in superoxide dismutase, catalase and glutathione peroxidase when compared to control group and melissa officinalis treated group.
On the other hand, animals treated with malathion alone at dose of (27 mg/kg bw) induce adverse effects on testicular sperm count, sperm motility analysis and epididymal sperm morphology. It induces a significant (p≤0.05) decrease in testicular sperm count, sperm motility analysis and epididymal sperm morphology compared to untreated control group and Melissa officinalis treated group. On the contrary, the animals in forth group, which treated with Melissa officinalis plus malathion showed a significant (p≤0.05) improvement in testicular tested parameter.
Moreover, the present study showed animals treated with malathion alone had a significant (p≤0.05) decrease in serum LH, FSH and testosterone when compared to control group, while animals treated with Melissa officinalis alone showed a similar results with control group.
Histological examination of the liver, kidney and testes tissues showed severe histopathological and histochemical changes in section of animals treated with malathion. But Melissa officinalis extract caused restored all histological pictures to normal structure. Melissa officinalis extract induced a significant elimination of the harmful effects of malathion in all biochemical, antioxidant parameters and the histological picture of liver kidney and testes.
Part II: Study the adsorbent capacity of activated carbon and its nano-particales to bind malathion in aqueous solution:
In this study, activated carbon and its nano-particales were prepared from date stone and characterized to tested for removal malathion from aqueous solution. The specific surface area and porosity were determined for activated carbon and nano-particales activated carbon as well particle size was determined using Scanning Electron Microscope.
An amount of 0.05, 0.1 and 0.2 g of activated carbon was incubated with a 100 ml of malathion (100µg/100 ml) using water-bath shaker at 25º C and agitated at 100 rpm for 30, 60, 120, 180, 240, and 300 min. After the agitation period, the samples were filtrated using filter paper Whitman No. 40.
The results revealed that the adsorption reached to equilibrium stage when the amount of the investigated pesticide (ML) is being adsorbed on adsorbent agents (activated carbon and its nano-particales) was equal to the amount of malathion desorbing from the adsorbent agents. Regarding activated carbon, the equilibrium stage occurred at 120 min, the removal percentages of malathion from aqueous solution were 31, 95.6 and 78 % at 0.05, 0.1 and 0.2 g activated carbon respectively at 120 min. while for nano-particales, the equilibrium stage occurred at 60 min, the removal percentage of malathion from aqueous solution were 98.6, 98.1 and 96.3%. The results indicated that nano-particales activated carbon was more effective in the removing of malathion from aqueous solution than activated.
The results revealed that the removal percentage of ML from aqueous solutions at pH 3 was found to be 88.4% for AC however; this percentage reached 95.8% when solution pH reached 7.0. Similarly, the percentage of reduction for nano-particales activated carbon reached 93.43% at pH 3, while this percentage was increased at pH7 and recorded 96.8% at the same concentration level.
In the same concern, the results indicated that when the temperature increased from 25 °C to 37 °C, the adsorption of malathion onto activated carbon and its nano-particales was slightly increased. The removal percentage of malathion from aqueous solution using activated carbon at initial level of 78µg/100ml increased from 95.6 % to 98.8 % when the temperature increased from 25 to 37 °C, since the maximum adsorption capacity was increased only from 7.46 to 7.85mg ML/g AC. In the same respect, at higher temperature (37 °C) the maximum adsorption capacity was increased and recorded 17.62 mg ML/g NPAC. Whereas, the maximum adsorption capacity (max qt) was found to be 15.41 mg ML/g nano-particales activated carbon at temperature 25 °C. The percentage removal of malathion was increased from 96.8 to 98.9 % as the temperature increased from 25 to 37 °C. from the results can be concluded that activated carbon and its nano-particales success in removal malathion from aqueous solution. Using nano-particales activated carbon lead to minimize time and dose as well as increasing the adsorptive capacity. Nano-particales activated carbon was more effective than activated carbon in removal malathion pesticide from aqueous solution.