Continuing the search for new antimicrobial agents with antibiofilm activity, bis-quaternary ammonium compounds based on natural (3,5-dibromo-4-hydroxyphenyl)acetic acid derivatives were synthesized. Antibacterial and antibiofilm activity of ammonium salts was evaluated in vitro against S. aureus, E. coli, and P. aeruginosa, including antibiotic-resistant strains. Bis-quaternary ammonium salts 1, 5, and 6 showed antibacterial activity with MIC values ranging from 25.0 to 200.0 μg/mL. Notably, these compounds demonstrated a high level of antibiofilm activity. Ammonium salts 1 and 6 reduced biofilm formation against S. aureus ATCC 25923, P. aeruginosa PA01, E. coli ATCC 25922, and antibiotic-resistant P. aeruginosa by 92 - 97% at a concentration of 100.0 μg/mL. In addition, compounds 1 and 6 inhibited the biofilm formation of antibiotic-resistant E. coli isolate by 60% and 63%, respectively.

New analogues of pulmonarin B were synthesized from (3,5-dibromo-4-hydroxyphenyl)acetic acid derivatives, and their antibacterial and antibiofilm activities against E. coli, S. aureus, and P. aeruginosa were evaluated. The antibacterial activity of synthesized ammonium salts against the methicillin-resistant strain of S. aureus 222 depends on the length of the alkyl chain. Bisquaternary ammonium salt 5 demonstrated better activity against S. aureus 222, E. coli 311, and P. aeruginosa 449 compared to mono-alkylated derivatives. Analogues of pulmonarin B 5 and 4d reduced S. aureus 222 biofilm formation by 74.5% and 89.4%, respectively. In addition,
compound 4c turned out to be the most active against the biofilm formation of P. aeruginosa 449 (biomass decreased by 39.8%).

Nanomaterials have attracted a great deal of attention from the scientific community due to their unique properties and applications. The small size metal oxides have opened up the door for intensive research to utilize their properties for biomedical applications. Silver nanoparticle (AgNPs) and metal oxide nanomaterials like MgO, ZnO, NiO and its silver doped nanocomposites (Ag-MgO, Ag-ZnO, Ag-NiO) have been prepared using solid state combustion method using polyvinyl alcohol (PVA) as a fuel. The structure of as prepared oxides and its silver doped nanocomposites were characterized using X-ray diffraction (XRD) tool and morphology by Scanning Electron Micrograph (SEM) tool as well as Transmission electron micrograph tool respectively. Presence of the metals in the oxides and its Ag composite was confirmed by the EDX pattern. Bonding nature in the composite is well studied by the Fourier transform infrared (FT-IR) tool. Antibacterial activity studies of the nanocomposites are carried out against various bacteria.

Fused pyrimidines play an imperative role in our life due to their biological importance in the struggle of microorganisms. A series of 4-aryl-3-methyl-1-phenyl-1,4,6,7-tetrahydropyrazolo[3,4-d] thiazolo[3,2-a]pyrimidine (4a-j) were synthesized by cyclization of 3-methyl-1-phenyl-4-aryl-1,4,5,7-tetrahydro-6H-pyrazolo[3,4-d]pyrimidine-6-thiones (3a-j) with 1,2-dibromoethane in presence of anhydrous potassium carbonate. Earlier, compounds (3a-j) were synthesized by the condensation of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (2), different substituted benzaldehyde and thiourea with catalytic amount of con. HCl in methanol. Compound 2 was synthesized by condensation of ethyl acetoacetate (1) and phenylhydrezine in presence of a catalytic amount of acetic acid at reflux temperature. The constitution of the synthesized products has been characterized by using elemental analysis, Infrared, ¹H-NMR spectroscopy and further supported by Mass spectroscopy. All the products have been screened for their in-vitro biological assay like antibacterial and antifungal activity at concentration of 500 μg/ml. It was exposed that most of the compounds displayed inspiring antibacterial and antifungal activity compared to the used reference standard.

In this work, we have reported a synthesis of some novel pyrazol-pyrimidine derivatives (3a-f) obtained by the reaction of substituted pyrazole aldehydes and barbituric acid derivatives in presence of L-proline as a catalyst via Knoevengal condensation reaction. The structures of the synthesized compounds were characterized by spectral methods. From antibacterial activity, compounds 3d and 3f exhibited highest zone of inhibition as compared to standard drug gentamicin. Cytotoxicity results revealed that compound 3e exhibited a promising IC50 value against both the cell lines (A549 and MCF-7) as compared to the standard drug doxorubicin. Docking study discloses that, all the newly synthesized compounds displayed promising binding energies with the protein receptor EGFR kinase domain.

The 1,3,4-Oxadiazole is an aromatic heterocyclic moiety recognized in drug research for its low lipophilicity. The multiple functionalities, heterocyclic azinane, sulfonamide, 1,3,4-oxadiazole and acetamide, are combined collectively to enhance the bioactivity potential of synthesized molecules. All the compounds were acquired by following microwave assisted and conventional techniques in a comparative way. The synthesized derivatives were screened for their antibacterial and enzyme inhibition potential. Furthermore, BSA binding analysis was executed to infer about the interaction with serum albumin. The spectral data of IR, EI-MS, ¹H-NMR and ¹³C-NMR were used to elucidate the final structures of compounds. The synthesized compounds had a modest antibacterial potential. Compound 8f bearing 2-methyl-4,5-dinitrophenyl group was the most active one against all the bacterial strains taken into account and α-glucosidase enzyme. Compound 8d bearing 4-nitrophenyl group was the best acetyl cholinesterase inhibitor and 8i bearing phenylethyl group was the best urease inhibitor.

The synthesis, anticancer and antimicrobial properties of novel N-aryl-2-(5-aryltetrazol-2-yl)acetamides were discussed. Novel N-aryl-2H-tetrazoles were synthesized and modified in order to obtain the compounds with a satisfactory pharmacological profile. The structures of target substances were confirmed by using ¹H spectroscopy, mass spectrometry and elemental analysis. Anticancer activity screening was carried out within the framework of Developmental Therapeutic Program of the National Cancer Institute's (DTP, NCI, Bethesda, Maryland, USA). The compounds with significant levels of anticancer activities have been found that can be used for further optimization. The antimicrobial activity of the synthesized substances was evaluated by the value of the MIC and minimum fungicidal and bactericidal concentration. The findings exhibited that the compounds possessed moderate antimicrobial potential.

A series of azo dyes incorporated acridine chromophore labelled as 8 (a-d), 10 (a, b), 12 and 14 were prepared in very good yields starting from 9-chloroacridine 1 followed by amination, diazotization and coupling either with rhodanine analogues 6 (a, b) or other coupling partners 9 (a, b), 11 and 13. FT-IR, ¹H NMR, and mass spectroscopic analysis were used to establish the structures of the produced azo dispersed dyes. Moreover, the synthesized azo dyes were used to prepare pastes that were used to print polyester fabric using classic silk-screen printing techniques. The dyes were tested for color strength and fastness properties, and they showed good fastness resistance to washing, rubbing, and perspiration, as well as fastness to sublimation and light. The dyes were further screened for their in vitro antibacterial activity against both Gram (+) and Gram (-) bacterial species. Most of them showed promising activities against these tested organisms.

Several Plant products have been found to be a part of phytomedicines since time immemorial. These plant products can be derived from barks, leaves, flowers, roots, fruits, and seeds. It has been found that the light radiation affects the antimicrobial activity of herbal products. The present study was aimed to investigate the phytochemical screening and antimicrobial activities of Calotropis gigantea leaf extracts. In addition to these studies we also check the effect of UV light radiation on the anti microbial activity of leaf extract. Phytochemical screening revealed the presence of various active phytochemicals in the extracts of aerial part of Calotropis gigantea. Ethanol, chloroform and hexane extract of leaves were tested against Clostridium botulinum, Proteus vulgaris, Escherichia coli and Arthrographis cuboid, Aspergillus fumigatus, Aspergillus niger by the agar disc diffusion method. The antimicrobial activity of the extracts generally reduces significantly after exposure to the UV radiations.

A group of new fluoroaniline Schiff bases (3a–3f) were synthesized and structurally characterized by various spectroscopic techniques such as ¹H-NMR, LC-MS and FT-IR spectral studies. All compounds were evaluated for in vitro antibacterial activity. Compounds exhibited good to moderate antibacterial activity. Compound 3f (Zone of Inhibition = 10.08±0.06 µM) was found to be the most active one, and comparable to the standard Streptomycin (IC50 = 15.95±0.08 µM). The compounds having chloro substituent exhibit good membrane damage property against Methicillin-resistant Staphylococcus aureus (MRSA) confirmed by SEM analysis. Structure-activity relationship (SAR) was rationalized by looking at the varying structural features of the molecules.