Synthesis of new Schiff bases bearing 1,2,4-triazole, thiazolidine and chloroazetidine moieties and their pharmacological evaluation.

New compounds based on oxindole moiety were synthesized via the reaction of 5-substitued isatins 1a-e with different nucleophiles such as benzidine, 3,3'-dimethoxybenzidine 2a,b and 2,6-diaminopyridine 3 to afford three different classes of bis-Schiff bases 4a-e, 5a-e and 6a-e, respectively. The structures of the new compounds were elucidated on the basis of their FTIR, 1H NMR, 13C NMR, GC/MS spectral data and elemental analysis. The in vitro antimicrobial activity of the new compounds was evaluated using a broth dilution technique in terms of minimal inhibitory concentration (MIC) against four bacterial and two fungal pathogens and anticancer activities against HELA cervix. The revealed data showed that compound 9d has excellent activity against Gram + ve and Gram -ve bacteria, and compounds 11b presented promising anticancer activity against HELA cervix. [Formula: see text].

New pyrano[2,3-c]pyridazine derivatives with antimicrobial activity synthesized using piperidine as the organocatalyst.

A simple and efficient method for the synthesis of highly diverse pyrano[2,3-c]pyridazines was achieved by a one pot multicomponent reaction using piperidine as the organocatalyst. The synthesis of a series of heterocyclic derivatives with varying functionality (e.g. thiazine, tetrazole and pyrimidine) incorporating the pyrano[2,3-c]pyridazine moiety were achieved via reaction of 2a-e with different reagents. The structures of the synthesized derivatives were elucidated by FTIR, MS, (1)H and (13)C NMR spectroscopy. A number of the newly synthesized targeted compounds 2b-e, 3a-c and 4a-c were evaluated for their in vitro antibacterial activity and were compared with chloramphenicol and nystatin as broad spectrum reference standard antibiotics. Tests were carried out against Staphylococcus aureus (MTCC3160) and Enterococcusi fecalis as Gram-positive bacteria, and Escherichia coli (MTCC1652) and Klebsiella pneumonia as Gram-negative bacteria. Antifungal potential against Candida albicans, and Aspergillus albicans strains were also evaluated. The results revealed that compounds 3a and 3c showed strong significant activity relative to the reference against these bacterial and fungal strains.

Synthesis and in vitro biological evaluation of new heterocycles based on the indole moiety.

New compounds based on the indole moiety were synthesized via the reaction of indole-3-carbinal 1 with different nucleophiles such as 6-aryl-[4-(2-methoxybenzyl)pyridazin-3-yl] hydrazones 2a-c, benzidine, 3,3'-dimethoxybenzidine 4a,b and 2,6-diaminopyridine 6 to afford hydrazine derivatives 3a-c and three different classes of bis-Schiff bases. The structures of the new compounds were elucidated on the basis of their FTIR, (1)H NMR, (13)C NMR spectral data, GC/MS and elemental analysis. The antimicrobial activity of the new compounds was evaluated using a broth dilution technique in terms of minimal inhibitory concentration (MIC) against four pathogenic bacteria and two pathogenic fungi strains. Compound 14b showed excellent activity against Escherichia coli and Klebsiella pneumoniae. Some of the prepared compounds were tested for anti-cancer activity against human cell lines HCT116 (colon), MCF7 (breast) and HELA (cervix). From the results of the in vitro assays, compounds 3a,b, and 18a,c presented promising anti-cancer activity.

Therapeutic applications of sustainable new chitosan derivatives and its nanocomposites: Fabrication and characterization.

Chitosan (CS) is a biologically active biopolymer used in different medical applications due to its biodegradability, biocompatibility, and nontoxicity. Nanotechnology is an exciting and quick developing field in medical applications. Nanoparticles have shown great potential in the treatment of cancer and inflammation. In the present work modification of chitosan and its (Ag, Au, or ZnO) nanocomposites by N-aminophthalimide (NAP) occurred through the reaction with epichlorohydrin (ECH) as a crosslinker in the presence or absence of glutaraldehyde (GA) under different reaction conditions using microwave irradiation to give modified chitosan derivatives CS-2, CS-6, and their nanocomposites. Modified chitosan derivatives were characterized using different tools. CS-2 and CS-6 derivatives displayed enhancement of thermal stability and crystallinity compared to chitosan. Additionally, CS-2, CS-6, and their nanocomposites exhibited improvements in antitumor activity against HeLa cancer cells and enzymatic inhibitory against trypsin and α-chymotrypsin enzymes compared to chitosan. However, CS-2 revealed the highest cell growth inhibition% toward HeLa cells (89.02 ± 1.46 %) and the enzymatic inhibitory toward α-chymotrypsin enzyme (17.13 ± 1.59 %). Furthermore, CS-Au-2 showed the highest enzymatic inhibitory against trypsin enzyme (28.14 ± 1.76 %). These results suggested that the new chitosan derivatives CS-2, CS-6, and their nanocomposites could be a platform for medical applications against HeLa cells, trypsin, and α-chymotrypsin enzymes.

Fabrication and characterization of unique sustain modified chitosan nanoparticles for biomedical applications.

Chitosan (CS) is a biopolymer that offers a wide range in biomedical applications due to its biocompatibility, biodegradability, low toxicity and antimicrobial activity. Syringaldehyde (1) is a naturally occurring organic compound characterized by its use in multiple fields such as pharmaceuticals, food, cosmetics, textiles and biological applications. Herein, development of chitosan derivative with physicochemical and anticancer properties via Schiff base formation from the reaction of chitosan with sustainable eco-friendly syringaldehyde yielded the (CS-1) derivative. Moreover, in the presence of polyethylene glycol diglycidyl ether (PEGDGE) or sodium tripolyphosphate (TPP) as crosslinkers gave chitosan derivatives (CS-2) and (CS-3NPs) respectively. The chemical structures of the new chitosan derivatives were confirmed using different tools. (CS-3NPs) nanoparticle showed improvement in crystallinity, and (CS-2) derivative revealed the highest thermal stability compared to virgin chitosan. The cytotoxicity activity of chitosan and its derivatives were evaluated against HeLa (human cervical carcinoma) and HEp-2 (Human Larynx carcinoma) cell lines. The highest cytotoxicity activity was exhibited by (CS-3NPs) compared to virgin chitosan against HeLa cell growth inhibition and apoptosis of 90.38 ± 1.46% and 30.3% respectively and IC50 of 108.01 ± 3.94 µg/ml. From the above results, it can be concluded that chitosan nanoparticle (CS-3NPs) has good therapeutic value as a potential antitumor agent against the HeLa cancer cell line.

Superior remedy colon cancer Hct-116 cells via new chitosan Schiff base nanocomposites: Synthesis and characterization.

Cancer is a serious worldwide health problem and colon cancer is the major cancer public prevailing form. The innovative pharmaceuticals with great cancer efficacy are metal nanoparticles. Therefore, the present study relies on developing chitosan Schiff base nanocomposites and investigating their antitumor ability against human colon carcinoma (HCT-116 cell line) using the MTT method. Thus, chitosan (CS) is modified with 9-ethyl-3-carbazolecarboxaldehyde (ECCA) in the absence or presence of the biomedical crosslinker poly(ethylene glycol) diglycidyl ether (PEGDGE) under microwave irradiation to afford CS-Schiff bases CS-SB-I and CS-SB-II, respectively. The assembly method is applied to formulate CS-Schiff base (Ag, Au and ZnO) nanocomposites. These new CS-Schiff bases and their nanocomposites are characterized by utilizing elemental analysis, FTIR, TGA, XRD, SEM, TEM and EDX. Cytotoxicity test showed that CS-SB-I (IC50 112.10 ±â€¯4.23 µg/mL) and CS-SB-II (IC50 98.54 ±â€¯4.09 µg/mL) inhibit the growth of HCT-116 more effectively than chitosan (IC50 181.38 ±â€¯6.54 µg/mL). Additionally, CS-Schiff base nanocomposites revealed superior anticancer efficiency which displayed the lowest IC50 values CS-SB-I-Ag (IC50 10.99 ±â€¯0.37 µg/mL), CS-SB-II-Ag (IC50 12.79 ±â€¯0.49 µg/mL), CS-SB-I-Au (IC50 14.96 ±â€¯0.51 µg/mL), CS-SB-II-Au (IC50 26.72 ±â€¯1.57 µg/mL), CS-SB-I-ZnO (IC50 22.79 ±â€¯1.28 µg/mL) and CS-SB-II-ZnO (IC50 22.24 ±â€¯1.34 µg/mL). The findings demonstrated that CS-Schiff base nanocomposites are promising agents for the HCT-116 cell therapeutic.

Microwave-assisted synthesis of antimicrobial agents based on pyridazine moiety.

An efficient and simple microwave assisted synthesis of sulfonamide derivatives incorporating the pyridazine moiety has been developed. These sulfonamides were used for the preparation of new heterocyclic compounds via reaction with different reagents using a microwave irradiation technique. The structures of the newly synthesized compounds were confirmed on the basis of FTIR, (1)H and (13)C-NMR, mass spectral techniques and elemental analyses. Some of the new synthesized compounds were assayed for their in vitro antibacterial activity against Gram-positive bacteria, Staphylococcus aureus and Staphylococcus epidermidis, Gram-negative bacteria, Escherichia coli and Klebsiella pneumonia and antifungal activity against Aspergillus fumigatus and Candida albicans. Most of the new compounds showed significant antibacterial and antifungal activity.

Synthesis of a new class of antimicrobial agents incorporating the indolin-2-one moiety.

New furanone derivatives incorporating the indolin-2-one moiety 3 were prepared via the Perkin reaction of isatins 1 with aroylpropionic acids 2 under conventional conditions or microwave irradiation. A series of functionally heterocyclic derivatives (e.g., pyridazines, pyrroles, and sulfonamides) incorporating the indolin-2-one moiety was achieved via reaction of 3 with different reagents under microwave irradiation conditions. The newly synthesized compounds were characterized on the basis of FTIR, (1)H, (13)C NMR and mass spectral studies. Some of the new synthesized compounds were screened for antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus), Gram-negative bacteria (Escherichia coli and Shigilla flexneri) and antifungal activity against Aspergillus flavus and Candida albicans. Compound 8 j was equipotent to chloramphenicol in inhibiting the growth of E. coli minimum inhibitory concentration (MIC 2.5 µg/mL). Compound 8j may possibly be used as a lead compound for developing a new antibacterial agents. The antibacterial activity is expressed as the corresponding MIC (µg/mL) values.

New potential anti-SARS-CoV-2 and anti-cancer therapies of chitosan derivatives and its nanoparticles: Preparation and characterization.

Chitosan (CS) is a biopolymer and has reactive amine/hydroxyl groups facilitated its modifications. The purpose of this study is improvement of (CS) physicochemical properties and its capabilities as antiviral and antitumor through modification with 1-(2-oxoindolin-3-ylidene)thiosemicarbazide (3A) or 1-(5-fluoro-2-oxoindolin-3-ylidene)thiosemicarbazide (3B) via crosslinking of poly(ethylene glycol)diglycidylether (PEGDGE) using microwave-assisted as green technique gives (CS-I) and (CS-II) derivatives. However, (CS) derivatives nanoparticles (CS-I NPs) and (CS-II NPs) are synthesized via ionic gelation technique using sodium tripolyphosphate (TPP). Structures of new (CS) derivatives are characterized using different tools. The anticancer, antiviral efficiencies and molecular docking of (CS) and its derivatives are assayed. (CS) derivatives and its nanoparticles show enhancement in cell inhibition toward (HepG-2 and MCF-7) cancer cells in comparison with (CS). (CS-II NPs) reveals the lowest IC50 values are 92.70 ± 2.64 µg/mL and 12.64 µ g/mL against (HepG-2) cell and SARS-CoV-2 (COVID-19) respectively and the best binding affinity toward corona virus protease receptor (PDB ID 6LU7) -5.71 kcal / mol. Furthermore, (CS-I NPs) shows the lowest cell viability% 14.31 ± 1.48 % and the best binding affinity -9.98 kcal/moL against (MCF-7) cell and receptor (PDB ID 1Z11) respectively. Results of this study demonstrated that (CS) derivatives and its nanoparticles could be potentially employed for biomedical applications.

New sustainable antimicrobial chitosan hydrogels based on sulfonamides and its nanocomposites: Fabrication and characterization.

Chitosan (Ch), a linear cationic biopolymer, has broad medical applications. In this paper, new sustainable hydrogels (Ch-3, Ch-5a, Ch-5b) based on chitosan/sulfonamide derivatives 2-chloro-N-(4-sulfamoylphenethyl) acetamide (3) and/or 5-[(4-sulfamoylphenethyl) carbamoyl] isobenzofuran-1,3-dione (5) were prepared. Hydrogels (Ch-3, Ch-5a, Ch-5b) were loaded (Au, Ag, ZnO) NPs to form its nanocomposites to improve the antimicrobial efficacy of chitosan. The structures of hydrogels and its nanocomposites were characterized using different tools. All hydrogels displayed irregular surface morphology in SEM, however hydrogel (Ch-5a) revealed the highest crystallinity. The highest thermal stability was shown by hydrogel (Ch-5b) compared to chitosan. The nanocomposites represented nanoparticle sizes <100 nm. Antimicrobial activity was assayed for hydrogels using disc diffusion method exhibited great inhibition growth of bacteria compared to chitosan against S. aureus, B. subtilis and S. epidermidis as Gram-positive, E. coli, Proteus, and K. pneumonia as Gram-negative and antifungal activity against Aspergillus Niger and Candida. Hydrogel (Ch-5b) and nanocomposite hydrogel (Ch-3/Ag NPs) showed higher colony forming unit (CFU) and reduction% against S. aureus and E. coli reaching 97.96 % and 89.50 % respectively in comparison with 74.56 % and 40.30 % for chitosan respectively. Overall, fabricated hydrogels and its nanocomposites enhanced the biological activity of chitosan and it can be potential candidates as antimicrobial drugs.