Abstract:

In this present study, various concentrations (0.5, 1, and 2%) of chitosan extracted through the chemical methods from the shells of crayfish (Astacus leptodactylus), pink shrimp (Parapenaeus longirostris), blue crab (Callinectes sapidus) shells, methanolic extracts of black cumin (Nigella sativaL), flaxseed (Linum usitatissimum), Chaste Tree (Vitex agnus-castusL.) and black cumin and flaxseed oil were tested in vitro for their antibacterial activities against two pathogenic bacteria Escherichia coli and Staphylococcus aureus, using the disk diffusion method. On the other hand, were Erythromycin and florfenicol were used as a positive control. The negative control was Acetic Acid and cotton oil. Antimicrobial activity of chitosan is affected by different intrinsic and extrinsic factors. Chitosan source, molecular weight, deacetylation degree, viscosity, and solvent material, pH, ionic strength, metal ions, and bacteria cultures. In the present study, all four extracted chitosans were showed different antimicrobial effects on two different types of bacteria, while there are not any antibacterial effect of aqueous extracts and oils of the three plants seeds that used in this study.This is the first report concerning the antimicrobial activity of chitosan compared to some plant seed extracts and oils against Escherichia coliand Staphylococcus aureus. Furthermore, results showed the chitosan of this species might be an alternative as an antimicrobial agent for the pharmaceutical industry.

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