Abhimanyu Dev

Synthesis, antibacterial and potential anti-HIV activity of some novel imidazole analogs.

Synthesis, antibacterial and potential anti-HIV activity of some novel imidazole analogs A series of 1-(2-methyl-4-nitro-imidazol-1-yl)-3-arylaminopropan-2-ones (2a-e), 2-methyl-5-nitro-1-{2-[arylmethoxy] ethyl}-1H-imidazoles (5a-d), and N-(3-hydroxyphenyl)-2-(substituted imidazol-1-yl)alkanamides (8a-e) were synthesized with the aim to develop novel imidazole analogs with broad-spectrum chemotherapeutic properties. Title compounds were evaluated for their anti-HIV and antibacterial activities. Sinteza, antibakterijsko i potencijalno anti-HIV djelovanje nekoliko novih analoga imidazola Sintetizirana je serija 1-(2-metil-4-nitro-imidazol-1-il)-3-arilamino-propan-2-ona (2a-e), 2-metil-5-nitro-1-{2-[arilmetoksi]etil}-1H-imidazola (5a-d) i N-(3-hidroksifenil)-2-(supstituiranih imidazol-1-il)alkanamida (8a-e) s ciljem dobivanja novih derivata imidazola sa širokim kemoterapijskim svojstvima. Navedeni spojevi ispitani su na anti-HIV i antibakterijsko djelovanje.

Extracellular facile biosynthesis, characterization and stability of gold nanoparticles by Bacillus licheniformis

Abstract Context: The development of a reliable, eco-friendly process for synthesis of gold nanoparticles (AuNPs) has gained impetus in recent years to counter the drawbacks of chemical and physical methods. Objective: This study illustrates simple, green synthesis of AuNPs in vitro using cell lysate supernatant (CLS) of non-pathogenic bacteria and to investigate its potential antimicrobial activity. Materials and methods: Gold nanoparticles were synthesized by the reduction of precursor AuCl4− ions using the CLS of Bacillus licheniformis at 37°C upon 24 h of incubation. The nanoparticles were characterized for their morphology, particle size, optical absorption, zeta potential, and stability. Further the antimicrobial activity was assayed using cup-plate method. Results: The process of biosynthesis was extracellular and the gold ions were reduced to stable nanogold of average size 38 nm. However, upon storage of AuNPs for longer duration at room temperature stability was influenced in terms of increase in particle size and decrease in zeta potential with respect to as synthesized nanoparticles. SEM micrographs revealed the spherical shape of AuNPs and EDX analysis confirmed the presence of gold in the sample. Also clear zone of inhibition was observed against Bacilllus subtilis MTCC 8364, Pseudomonas aeruginosa MTCC 7925, and Escherichia coli MTCC 1698 confirming the antimicrobial activity of AuNPs. Discussion: The bioprocess under study was simple and less time consuming as compared to other methods as the need for harvesting AuNPs from within the microbial cells via downstream process will be eliminated. Nanoparticles exhibited good stability even in absence of external stabilizing agents. AuNPs showed good antimicrobial activity against several Gram-negative and Gram-positive pathogenic bacteria. Conclusion: The extracellular biosynthesis from CLS may serve as a suitable alternative for large scale synthesis of gold nanoparticles in vitro. The synthesis from lysed bacterial cell strongly suggests that exposure of microbial whole cells to the gold solution for nanoparticle formation is not necessary and that microorganism even in lysed state retained its bioreduction potential. Further the potential of biologically synthesized AuNPs as antimicrobial agents will be of great commercial importance.

Anticonvulsant activity of Benkara malabarica (Linn.) root extract: In vitro and in vivo investigation

AIM OF THE STUDY To systematically investigate the anticonvulsant activity of methanol extract of Benkara malabarica roots and to provide a biochemical basis elucidating its mode of action. METHODS The median lethal dose (LD(50)) of Benkara malabarica extract was determined. The anticonvulsant activity of the extract was assessed in strychnine-induced and isoniazide-induced convulsion models; phenytoin (20mg/kg) and diazepam (1mg/kg) were used as standards, respectively. Percentage protection provided by the drug was accounted as decrease in the number of convulsions within 8h of observation. Mechanism of action was studied by performing GABA transaminase (GABA-T) assay, isolated from rat brain. Active constituent was isolated and characterized from the plant extract. RESULTS The median lethal dose (LD50) of Benkara malabarica was found to be more than 500 mg/kg. It demonstrated 30% and 35% protection against strychnine-induced convulsions and 60% and 80% protection against isoniazide-induced convulsions, at doses of 25mg/kg and 50mg/kg, respectively. Enzyme assay results revealed that Benkara malabarica extract possesses GABA-T inhibitory activity (IC50=0.721 mg/ml). Scopoletin which was identified as the major constituent of the extract was found to be an inhibitor of GABA-T (IC50=10.57 microM). CONCLUSIONS The anticonvulsant activity of the plant extract is predominantly GABA mediated and may be due to the action of scopoletin alone or is a result of synergy of different compounds in the extract in which scopoletin is the major constituent.

Oral Vaccine Antigen Induced Immune Response Signalling Pathways: Current and Future Perspectives

Vaccination is the most promising approach to control and prevent the infectious diseases. As most of pathogenic microrganisms gain entry through the mucosal surfaces of host which provide great deal of interest in developing oral vaccines. Despite the success of many vaccines, only little information is available regarding the oral vaccine antigen induced immunogenic signalling pathways. Such information will be helpful to design future vaccines against old and new infectious diseases to reduce the side effects of existing vaccines and increase their efficacy. In this review, the oral vaccine antigen inducing complex signaling pathways of immune system has been discussed. Various stra

Immune-stimulating potential of cell envelope proteins from Vibrio cholerae associated to chitosan microparticles: an in vitro study.

Abstract Context: Cholera is a severe diarrheal disease that remains an important cause of illness and death in many parts of the world. Objective: This study has been designed to check the immune-stimulating potential of antigens in their native and associated form as chitosan microparticles in vitro. Material and methods: Chitosan microparticles were prepared by the ionic gelation technique. The cell envelope proteins (CEPs) isolated from Vibrio cholerae were loaded as antigenic material. The prepared microparticles were characterized for their morphology, loading efficiency, particle size, and zeta potential. Results: The average particle size of CEPs-loaded chitosan microparticles was 2.24 µm and the zeta potential of loaded microparticles was less than blank microparticles. The in vitro release studies of CEPs from CEPs-loaded chitosan microparticles exhibited slow and extended release over a period of time. The higher release of cytokine profile, including interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), and interlukin-6 (IL-6), was observed for CEPs-loaded chitosan microparticles in comparison to CEPs as native antigen. Discussion: The particle size of microparticles was within the range for phagocytosis by macropahges, which affects the immunogenicity. The decrease in zeta potential from blank to loaded microparticles further confirms the loading of antigen. The slow and extended release of CEPs provides continuous stimulus of antigen for a longer period of time. The cytokine profiling has shown the advantage of loaded microparticles over native antigen. Conclusion: The in vitro release studies and cytokine profiling strongly suggested that CEPs-associated chitosan microparticles could be a potential candidate for oral vaccination against Vibrio cholerae.

Growth Phase-Dependent Synthesis of Gold Nanoparticles Using Bacillus Licheniformis

Biological agents play an important role in biosynthesis of nanoparticles and regarded as green technology and environmental-friendly approach, which is an important step in the field of application of nanotechnology. The present study reports biosynthesis of gold nanoparticles from gold precursor using Bacillus licheniformis at 37 °C depending upon its growth phase. Growth phase study of bacteria was performed and biosynthesis of gold nanoparticles was carried out at early log phase, mid log phase, stationary phase, and decline phase. The synthesis of gold nanoparticles was confirmed by UV–visible spectrum that showed peak between 545 and 559 nm which was later reconfirmed by SEM studies. Size of gold nanoparticles as measured by dynamic light scattering was found to be in the range of 16–95 nm. Zeta potential measurement showed that gold nanoparticles were negatively charged with zeta potential value between −20.8 and −25.8 mV. The stationary phase culture, out of early and late log phase showed best results, synthesizing small-sized gold nanoparticles.