الفهرس 
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Abstract
There are two major types of Ca2+ channels; ligand-gated Ca2+ channels and voltage-gated Ca2+ channels. Based on the chemical structure, Ca2+ channel blockers (CCBs) are classified into three main subgroups; 1,4-dihydropyridines, phenylalkylamines, and benzothiazepines. 1,4-DHPs not only have cardiovascular (CV) activities due to blocking L-type calcium channels, but they also have other pharmacological activities, such as antimicrobial, antitumor, and many other activities. 1,4-DHPs are clinically used in treating CVS disorders, mainly hypertension, because they act on the channels of the myocyte membranes of the resistance vessels, CaV1.2b more than on the heart ones, CaV1.2a. In this research work, two novel series of 1,4-DHP derivatives were designed, synthesized, and evaluated as Ca2+ channel blockers. The new series are analogues of nifedipine in which the ortho-nitro group at the phenyl ring has been replaced by a meta-cyano group. The first series of eight symmetric achiral 1,4-DHPs, 4a-h, were synthesized by the classical Hantsch reaction, which involved a three-component cyclocondensation of 3-cyanobenzaldehyde 1, acetoacetic esters 2a-h, and ammonium acetate 3, whereas the second series of twelve asymmetric chiral 1,4-DHPs, 6a-l, were synthesized by the modified Hantsch reaction using a procedure reported by Iwanami, which involved a threecomponent cyclocondensation of 3-cyanobenzaldehyde 1, acetoacetic esters 2ah, and alkyl 3-aminocrotonates 5a-b. The chemical structures of target compounds were confirmed by elemental analysis, 1H, 13C NMR, and mass spectroscopy. The Ca2+ channel blocking activities of target compounds were evaluated by using rat aortic smooth muscle cells, A7r5 cells, which contain only L-type Ca2+ channels, via their impact on the intracellular calcium concentration in A7r5 cells. Compounds 6i and 6k, exhibiting an IC50 = 3.007 and 3.737 μg/mL, respectively, were more active than the reference drug, nifedipine, with an IC50 = 4.145 μg/mL. Target compounds 4a-h and 6a-l were screened at 10 μM Abstrac t Mohamed H. Saad, M. Sc. Thesis, Pharm. Chem., Faculty of Pharmacy, Tanta Univ., 2022 -XIVconcentration against NCI sixty cancer cell lines. Compounds 4g, 6e, and 6l revealed the best anti-proliferative activity, mean GI% = 41, 28, and 64, respectively. Accordingly, compounds 4g, 6e, and 6l were selected to study the reversal doxorubicin (DOX) effect of them and assess the IC50 of DOX. Compound 4g with two phenyl rings at positions C3 and C5 of the 1,4-DHP ring was generally more potential and had more reversal activity (IC50 (DOX) = 1.12 μM) than derivatives with one phenyl ring (6e, IC50 (DOX) = 3.64 μM) and (6l, IC50 (DOX) = 3.57 μM). EGFR, HER-2, and BTK inhibitory activity of the analogues 4g, 6e, and 6l were studied to investigate their potential mechanism of action. Compound 4g demonstrated the highest EGFR, HER-2, and BTK inhibitory activity with an IC50 = 62.19, 70.55, and 60.27 nM, respectively, while the reference drug, lapatinib, reported an IC50 = 54.38, 72.81, and 61.47 nM, respectively. Annexin V–FITC apoptosis assay for 4g, 6e, and 6l demonstrated that an apoptotic mechanism rather than a necrotic pathway was the mechanism of compounds 4g, 6e, and 6l-induced programmed cell death. DNA flow cytometric analysis of 4g, 6e, and 6l exposed that a significant rise in the proportion of apoptotic cells was found at the pre-G1 phase (15.57–19.36% on exposure to 4g, 6e, and 6l, respectively) compared to control (1.65%) and a noteworthy increase in cells at the G2/M phase was observed, with 26.03–31.84% for 4g, 6e, and 6l compared to control (12.52%), showing marked cell arrest at the G2/M phase. MTT assay was performed for all compounds to evaluate their cytotoxicity. Only seven compounds, 4a, 4d, 4e, 4h, 6a, 6b, and 6j, had lower cytotoxicity towards A7r5 cells, IC50 = 1212, 1633, 1214, 1323, 1362, 1632, and 3316 μg/mL, respectively, compared to nifedipine, IC50 = 1055 μg/mL. Also, the antimicrobial activity of target compounds 4a-h and 6a-l was evaluated against six different pathogens using the agar well diffusion method. The most active analogues were selected for further determination of their MIC values using the microbroth dilution method. Compound 6g was two-fold more potent antibacterial candidate against gram-positive bacteria than ciprofloxacin, MIC = Abstrac t Mohamed H. Saad, M. Sc. Thesis, Pharm. Chem., Faculty of Pharmacy, Tanta Univ., 2022 -XV- 0.5 and 1.0 μg/mL against S. aureus and B. subtilis, respectively. Compound 6g was two-fold more potent than clotrimazole against C. albicans, MIC = 1.0 μg/mL. Docking studies for selected compounds were performed at the active sites of crystal structures of five proteins to understand biological differences.