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Microorganisms such as bacteria and fungi are developing resistance to the current therapies easily and the presently available antibacterial, antifungal agents and pesticides are certainly very pricey and harmful. So, the necessary shift to use natural antimicrobial extract (Periplaneta americana chitosan) seems to be more effective, economic and safe to the public health. The American cockroach chitosan was dissolved in 1 % acetic acid and diluted to different concentrations then, seeded in 96 well tissue culture plates to evaluate the antibacterial activity by using MTT assay and the microbial growth was calculated by ELISA microplate reader. The American cockroach chitosan showed an equal minimum inhibitory concentration (MIC) antibacterial action against two (Gram-positive) bacterial strains Staphylococcus aureus, and Bacillus subtilis, recording MIC = 2000 µg/ml. Also, chitosan showed MIC antibacterial activity against Escherichia coli and Salmonella typhimurim (Gram-negative) bacteria recording MIC = 1000 µg/ml, and MIC = 2000 µg/ml respectively. While chitosan showed non-antifungal activity against Candida albicans. Natural chitosan could be considered as a determined factor affecting on the biological activities mentioned in this study.

The exoskeleton of a cockroach plays a major role in protecting it from pathogenic microbes. It is well known that the main component of the exoskeleton is the chitin which is considered the source of chitosan. This study aimed at investigating the anticancer activity of chitosan prepared from the American cockroach. Chitosan was prepared and characterized with solubility in 1% acetic acid and Fourier transform infrared spectroscopy (FT-IR) analysis. The cytotoxicity of chitosan was investigated against Hepatoblastoma (HepG2) and Breast cancer (MCF7) cell lines by the MTT assay. The cytotoxicity has a positive relationship with the chitosan concentration. The half-maximal growth inhibitory concentrations (IC50) were 329 and 195 µg/ml with HepG2 and MCF7, respectively. Therefore, Chitosan may be a potential natural compound for the treatment of human hepatoblastoma (HepG2) and breast cancer (MCF7).

Chitosan is a sugar obtained from the shellfish exoskeleton, such as oysters, shrimp, and crab. Chitosan nanoparticles (CNPs) are used in many industrial preparations, especially pharmaceuticals, as it represents its important role in delivering drugs to treat many diseases. To examine the effect of chitosan nanoparticles against Hydroxyapatite nanoparticles, 60 male rats of albino were distributed to six equal groups. For thirty days, rats were given Nano chitosan for a dose of 140 mg per kilogram of body weight per day. For month, Nano Hydroxyapatite was administered daily at doses of 200 and 400 mg/kg body weight. Via oral gavage tube along the period of the experiment. The results showed that there was a substantial rise in the TBRAS levels, as well as a major drop in SOD, GSH and catalase activates in testicular tissues was detected in treated rats with low dose of hydroxyapatite nanoparticles (Ld HAP-NPs) as compared to high dose of hydroxyapatite. Conclusion: results revealed that; administration of rats with CNPs insignificant in total motility and progressive motilitycompared to the control group. Total motility and progressive motility were a significantly decrease in low or high dose of hydroxyapatite nanoparticles. After hydroxyapatite nanoparticles treatments, in rats given CNPs, there was a substantial reduction in sperm head abnormalities.

The present study evaluated the activity of ethanol 70%, acetone, chloroform and petroleum ether extracts of Musa acuminata leaves against the 3rd instar larvae of the mosquito vector, Culex pipiens (Diptera: Culicidae) which act as a vector of many diseases in Egypt. In addition, the repellent activity of the tested extracts against C. pipiens adults was examined. The obtained results revealed that, all tested plant extracts showed a larvicidal activity against the 3rd instar larvae of C. pipiens; however, the petroleum ether extract was more effective with LC50 571.8ppm than chloroform, acetone and ethanolic extracts, where the LC50 values recorded 1567.3, 1158.3 and 1034.1ppm; respectively. On the other hand, all tested extracts evoked a variable degree of repellent activity against C. pipiens starved females. Also, petroleum ether extract was the most effective extract that exhibited high repellent action as compared with the chloroform, acetone and ethanolic extracts. These results demonstrated that ethanolic, acetone, chloroform and petroleum ether extracts of M. acuminata leaves serve as pest control agents, even in their crude form. These results provide an opportunity to develop alternatives to costly organic pesticides with some available cheap plants which are usually safe to the environment and to non-target organisms.

Pesticides play a critical role in maintaining agricultural productivity, but intensive practice, repeated use and run off into the surface and ground water can pose a threat to the human and his domesticated animals. The study was carried out to identify the level of organochlorine pesticides and polychlorinated biphenyl residues in water wells using Limnatis nilotica leeches as bioindicators during summer and spring of the year 2013 at some localities of Al-Jabel Al-Akhdar, Libya. The chlorinated organic pesticide residues were ranged from 0.001 to 11.449 ng/g extracted from the whole homogenate body of leeches collected from five investigated wells. The obtained results showed that 100% of the analyzed samples contained detectable level of the monitored insecticides (HCH, aldrin, dieldrin, endrin, o،p-DDE, p،p-DDE, o،p-DDD, p،p-DDD and o،p-DDT). It is foundthat 100% of the samples gave results with levels below the MRL for HCH, aldrin, dieldrin, endrin concentration residues. Among all samples, 60% of the samples gave results with levels of total DDT concentration residues below the MRL, while 40% of the samples contained levels of insecticide residues above the MRL. On the other hand, there were occurrence of several polychlorinated biphenyl derivatives and 100% of the samples gave results above the level of the maximum contamination level for total PCB. The existence of total PCB at the highest levels were detected in Michael and El-Wasita wells at the summer season reaching 29 and 27 ng/g, respectively. However, the lowest detected level of total PCB reached (1.00) ng/g in leach tissues collected from Tiba well during summer season. The high levels of PCB derivatives detection in all leech samples is a health hazard reflected the continue uses of this materials source until this date and may be cause various diseases in Al-Jabel Al-Akhdar areas. Generally, the attained results emphasized that leeches are useful tools in biomonitoring of both organochlorine pesticides and polychlorinated biphenyl residues.