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Abstract In the present work two key regulator proteins, monomeric MipZ of Caulobacter vibrioides (similar to Pseudomonas aeruginosa) and Pyruvate kinase of Staphylococcus aureus were docked with curcumin, the wonder molecule from the spice turmeric and structures of its twelve analogues were designed, synthesized and tested in-vitro for antibacterial activity. Based on the test results a comparative account of the probable mechanism has been given Two major alternative targets are possible for antibacterial activity of drug molecules. These may be bacterial cell wall lipids or the proteins responsible for smooth functioning of bacterial cells. In the former case, due to significant difference in the structural components of the cell walls of Gram positive and Gram negative bacteria, it is improbable that same ligand will affect both equally. Majority of commercial drugs are anti-Gram negative bacteria while in the present work we have found most effective drugs against Gram positive bacteria. Based on the test results a comparative account of the probable mechanism has been given. Evidently along with the cell wall damaging mechanism other parallel mechanisms are also operative. Highlights Highlights of the paper, "In-silico designing, chemical synthesis, characterization and in-vitro assessment of antibacterial properties of some analogues of curcumin"n • In this paper twelve different derivatives of curcumin besides curcumin and nano curcumin were synthesized and characterized. •The derivatives were designed by in silico methods by docking against two key regulator proteins, monomeric MipZ of Caulobacter vibrioides (similar to Pseudomonas aeruginosa) and Pyruvate kinase of Staphylococcus aureus (Gram negative and Gram positive respectively) and tested i n-vitro for antibacterial activity. •Based on the test results a comparative account of the probable mechanism has been given. •Evidently along with the cell wall damaging mechanism other parallel mechanisms are also operative. •Majority of commercial drugs are anti-Gram negative bacteria while in the present work we have found most effective drugs against Gram positive bacteria. [ABSTRACT FROM AUTHOR]

In this paper, we have reported the synthesis, characterization, and evaluation of antimicrobial and antioxidant potential of monodispersed Zinc Oxide (ZnO) nanoparticles synthesized by the room temperature precipitation (aqueous phase) and polyol method (organic phase). ZnO nanoparticle synthesized by both the methods had shown excellent DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging, metal chelating (MC), ABTS (2,2′-azino-bis; 3-ethylbenzothiazoline-6-sulphonic acid), hydroxyl radical and superoxide radical scavenging activity (SAS). Scavenging activities were assayed within a concentration range of 25–75 ng ml −1 . The antibacterial activities with MIC were investigated against two Gram-positive bacteria Streptococcus mutans (MTCC 497) and S. pyogens (MTCC 1926); three Gram negative bacteria Vibrio cholerae (MTCC 3906), Shigella flexneri (MTCC 1457) and Salmonella typhii (MTCC 1252). ZnO nanoparticles synthesized by the polyol method showed better MIC values against both Gram-positive and Gram-negative bacteria as compared to particles synthesized by aqueous precipitation method. Present study demonstrates the successful synthesis of ZnO nanoparticles with antioxidant property and significant broad spectrum antibacterial activity against several clinical bacterial pathogens. [ABSTRACT FROM AUTHOR]

The main objective of the current study was to investigate the chemical composition of the essential oil of Artemisia asiatica together with investigating the antibacterial effects it exerts on several common respiratory infection causing bacteria including Haemophilus influenzae . Its mechanism of action was studied using various state-of-the-art assays like scanning electron microscopy, DNA, RNA and protein leakage assays, growth curve assays etc. The essential oil was extracted from the leaves of A. asiatica by supercritical CO 2 fluid extraction technology. Chemical composition of essential oils was analyzed by gas chromatography-mass-spectrometry (GC-MS). The antibacterial activity was evaluated against 6 bacteria by the paper disc diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericide concentration (MBC) values of the essential oil were estimated by agar dilution method. The antibacterial mechanism was evaluated by growth curve, the integrity of cell membrane and scanning electronmicroscope (SEM). Gas chromatographic analysis of the A. asiatica essential oil led to the identification of 16 chemical constituents accounting for 97.2% of the total oil composition. The major components were found to be Piperitone, (z)-davanone, p-cymene and 1, 8-cineole. The essential oil showed maximum growth inhibition against Haemophilus influenzae with a zone of inhibition of 24.5 mm and MIC/MBC values of 1.9/4.5 mg/mL respectively. Bacteria treated with the essential oil led to a rapid decrease in the number of viable cells. On adding the essential oil of A. asiatica to the bacterial culture, the constituents of the bacterial cell got released into the medium and this cell constituent release increased with increasing doses of the essential oil. SEM showed that the bacterial cells treated with the essential oil showed damaged cell wall, deformed cell morphology and shrunken cells. [ABSTRACT FROM AUTHOR]

Multidrug-resistant (MDR) bacteria have increased at an alarming rate over recent decades and cause serious problems. The emergence of resistant infections caused by these bacteria has led to mortality and morbidity; consequently there is an urgent need to find solution for combating bacterial resistance. In the present paper, first, some mechanisms of antibiotic resistance such as changing the antibacterial agent's uptake and biofilm formation are discussed. Following, for removing the antibacterial resistance, a wide range of approaches like developing new generations of antibiotics, combination therapy, natural antibacterial substances and applying nanoparticulate systems have been explained. Among them, antibiotic delivery via nanoparticles, has been attracted more attention recently, so discussed in present review, separately. [ABSTRACT FROM AUTHOR]