الفهرس 
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Abstract
The present study deals with the design, synthesis, and biological evaluation of novel ciprofloxacin derivatives including ciprofloxacin-bishydrazone derivatives (IVa-j), ciprofloxacin-uracil hybrids (IXa-t), ciprofloxacin-pyrazolopyrimidine hybrids (XIIIa-k), and ciprofloxacin-cinnamoyl derivatives (XVa-f) using the known antibacterial drug, ciprofloxacin as a starting material for the synthesis of these analogs. The target compounds were investigated for different biological activities including anticancer, and antibacterial activities. Additionally, the molecular mechanisms of anticancer and antibacterial activities were studied for the most active compounds as representative examples.
This thesis includes main five parts: introduction, scope of investigation, results, and discussion, experimental, and references.
1-Introduction: represents an outline of the history, generations, chemistry, and synthetic methods of quinolones. Besides, the mechanism of action and structure-activity relationships (SAR) of fluoroquinolones. Also, it gives several literature reports about the different strategies of fluoroquinolone modifications as anticancer agents, in addition to the antitumor and antimicrobial activities of different fluoroquinolones derivatives.
2-Scope of investigation: describes the main goals and the rationale of this study, including the design, synthesis of new ciprofloxacin analogs, and evaluation of their biological activities such as anticancer and antimicrobial activities.
3-Results and discussion: explains the various data obtained from different stages of synthesis, structural elucidation, and biological evaluation of the target compounds IVa-j, IXa-t, XIIIa-k, and XVa-f. This section is subdivided into two main subsections:
A- Chemistry: explains the different methods, used for the synthesis of intermediate as well as final compounds and structural elucidations of these derivatives by different spectral analysis including 1H-NMR, 13C-NMR, 2D-NMR, MS spectroscopy and elemental analyses. In the present research study, we reported the synthesis of 50 reported intermediates, 17 new intermediates and 47 final target compounds.
B- Biology: illustrates different methods and results obtained from various biological evaluations of the synthesized compounds. It is subdivided into two main parts:
a-Evaluation of anticancer activity
1-Evaluation of in vitro cytotoxic activity for compounds IVa-j
Anticancer activity was evaluated at the National Cancer Institute, Bethesda, MD, USA. The target compounds IVa-j were selected according to the protocol of the drug evaluation branch of the National Cancer Institute. The selected compounds were screened against sixty different cancer cell lines (NCI-60 cell line panel) including leukemia, melanoma, lung, colon, CNS, ovarian, renal, prostate, and breast cancers. The results revealed that the majority of the selected compounds possess week anticancer activity against most of the tested cell lines. The ciprofloxacin-bishydrazone derivatives, IVe, IVg, IVh, and IVi exhibited promising antiproliferative activities against a majority of the tested cancer cell lines with the mean of growth percentage values, 21%, 55.7%, 12.4%, and 0.81% respectively, according to NCI protocol.
2- Five dose testing for compounds IVe, IVh and IVi
Compounds IVe, IVh and IVi were selected for five dose testing by NCI, where the in vitro antiproliferative activities of the selected compounds were tested against 60 different human cancer cell lines. The results indicated that these compounds exhibited strong antiproliferative activity against all tested cancer cell lines with MID of log10 GI50 values are -6.26, -5.39, -6.18, respectively, also, it showed broad-spectrum activities toward all the tested cancer cell lines with selectivity ratios are less than 3, at GI50 level
3-MTT assay method for anticancer activity and determination of IC50.
The compounds IVg, IVe, IVh and IVi were evaluated for their anticancer activity against leukemia cancer cell line HL-60 (TB), colon cancer cell line HCT-116, and breast cancer cell line MCF7 by MTT assay method compared to ciprofloxacin doxorubicin as a reference. The results revealed that these compounds exhibited good to excellent anticancer activities against the tested cancer cell lines with IC50 ranges, (2.23±0.08 - 77.3±2.13 µM), (0.87±0.04 - 1.21±0.02 µM), (0.85±0.02 - 5.27±0.16 µM), and (0.41±0.02 - 1.31±0.04 µM) respectively, compared to ciprofloxacin (IC50 range, 1.45±0.03 - 9.01±0.25 µM) and doxorubicin (IC50 range, 0.63±0.01 - 1.79±0.04 µM).
4-Topoisomerase I and topo IIB inhibitory activities
The inhibitory activity of the tested compounds, IVe, IVh, and IVi against Topo I and Topo IIB enzymes were investigated in the presence of Camptothecin and etoposide as positive controls. The tested compounds exhibited good inhibitory activities against Topo I enzyme with IC50 of 16.66±0.34, 12.19±0.25, and 15.14±0.31 µM respectively, comparable to camptothecin (IC50, 10.52±0.22 µM). Also, they showed inhibitory activities against Topo IIB with IC50, 120.9±2.9, 97.32±2.3, and 86.56±2.09 µM compared to etoposide (IC50, 90.64±2.2 µM) at the same concentration.
5-Cell cycle analysis and detection of apoptosis
Cell cycle analysis and induction of apoptosis were investigated for the most active compound IVi against the HL60 (TB) cell line. The results revealed a significant accumulation of cells at pre-G1 and G2/M phases indicating that the percentage of late apoptosis is more than that of early apoptosis and irreversible apoptosis activity, as well as cell cycle arrest at the G2/M phase.
6- Docking studies for Topo I and II enzymes’ targets
Enzyme-ligand docking study was carried out for the compounds IVe, IVh, and IVi to predict the binding interactions with the active site of Topo I and II enzymes using Molecular Operating Environment (MOE®) version 2014. The tested derivatives displayed good fitting scores into the active sites of Topo I and II protein compared to Camptothein and Etoposide as references, respectively.
b-Evaluation of antibacterial activities
1-Screening of the antibacterial activities
The target compounds ciprofloxacin-uracil hybrids, IXa-t, ciprofloxacin-pyrazolopyrimidine hybrids, XIIIa-j, and ciprofloxacin-cinnamoyl derivatives, XVa-f were investigated against standard strains of Gram-negative bacteria including, Escherichia coli ATCC6538, Klebsiella pneumonia ATCC10031, Pseudomonas aeruginosa ATCC27853 and Gram-positive bacteria, Staphylococcus aureus ATCC6538 in comparison with ciprofloxacin as reference drug, using standard agar cup diffusion method. The results revealed that the compound, IXb, and XVc exhibited good activities against E. coli, K. pneumonia, and S. aureus species with MIC, 0.39, 0.78, and 6.25 µg ̸ ml, and MIC, 3.12, 3.12, and 3.12 µg/ml, respectively. Also, the compounds IXa, IXm exhibited the best activities against P. aeruginosa species with MIC, 1.56, 1.56 µg ̸ ml. On the other hand, compound, XIIIg displayed the significant antibacterial activities against E. coli, K. pneumonia, P. aeruginosa, and S. aureus species with MIC, 0.78, 0.78, 1.56, and 6.25 µg ̸ ml, respectively compared to ciprofloxacin, (MIC is 0.02. 0.04, 0.02, and 25 µg ̸ ml) against the tested organisms, respectively.
2-DNA gyrase and Topo IV inhibitory activities
The inhibitory activity of the tested compounds IXb, IXg, XIIIa, XIIIg, XVa, and XVc against DNA gyrase and topo IV enzymes was investigated in the presence of ciprofloxacin as a positive control. The results revealed that all the tested compounds exhibited comparable DNA gyrase and topo IV Inhibitory activities when compared to ciprofloxacin. Compound XIIIa exhibited the highest activity among these derivatives against DNA gyrase and topo IV enzymes with IC50, 0.404 ± 0.02 and 3.647 ± 0.21µM, respectively, higher than ciprofloxacin, (IC50, 0.661 ± 0.04 and 8.159 ± 0.46 µMn respectively) at the same concentration.
3- Docking studies into DNA gyrase and Topo IV enzymes
Enzyme-ligand docking study was carried out for the compounds IXb, IXg, XIIIa, XIIIg, XVa, and XVc to predict the binding interactions with the active site of gyrase and Topo IV enzymes using Molecular Operating Environment (MOE®) version 2014.09. The tested derivatives displayed good fitting scores into the active sites of gyrase and Topo IV protein compared to ciprofloxacin as references.