No abstract

In the present study, chemical composition and the antibacterial mechanism of ambrette seed oil are investigated. Chemical composition of the oil was analysed by gas chromatography-mass spectrometry (GC-MS). Thirty-five compounds were identified and the major compounds were found to be farnesol acetate (51.45%) and ambrettolide (12.96%). OPEN ACCESSMolecules 2015, 20 385The antibacterial activity was performed by well diffusion assay and the mechanisms were studied by measuring the alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and protein leakage assays. The antibacterial effect of the ambrette seed oil showed inhibitory effect against Bacillus subtilis, Staphylococcus aureus and Enterococcus faecalis. The LDH activity was high in all tested bacteria compared with control, whereas the ALP and protein concentrations were also increased in E. faecalis. Molecular docking revealed the ligands farnesol acetate and ambrettolide had satisfactory binding energy towards the beta lactamase TEM-72 and dihydrofolate reductase (DHFR) protein. Due to its better antibacterial properties, the ambrette seed oil could be used as a source of antibacterial agents.

Aim of the present study is to focus on the biosynthesis of silver nanoparticles using Taraxacum officinale floral extract. The color of solution changes into dark brown indicating the formation of silver nanoparticles (AgNPs) upon addition of 1 mM silver nitrate. These nanoparticles were characterized by UV-Vis spectrophotometry which showed the absorption peak at 465 nm specific for AgNPs. Scanning electron microscopic image showed that the synthesized AgNPs were seemed to be spherical in morphology. Dynamic light Scattering (DLS)was used to determine the particles size of the nanoparticles and average diameter of AgNPs is found to be 545 nm ± 5 nm. Antibacterial activity of these green synthesized Ag-NPs was evaluated against selected pathogns such as Enterococcus faecalis and Pseudomonas aeruginosa by disc diffusion assay.These synthesized AgNPs showed a good antimicrobial activity against the selected bacterial pathogens.

Esterification of phenylacetic acid with phenol, cresols, nitrophenols and resorcinol has been carried out in the presence of montmorillonite clay exchanged with H + -ions, Al 3+ -ions and polyhydroxy oligomer cations of Al. Na + -montmorillonite (raw clay) was inactive, H + -and Al 3+ -montmorillonites, dried at 100• C, showed 52 and 67% conversions to ester, respectively, upon refluxing the phenylacetic acid (20 mmol) and p-cresol (40 mmol) for 6 h. While Al 3+ -montmorillonite dried at 200• C showed a conversion of 36% the same catalyst when dried at 400• C showed no conversion. Montmorillonite exchanged with aluminium polyhydroxy oligomers dried at 100 • C and calcined at 500• C to get pillared clay (d0 0 1=17.5Å) failed to bring about the esterification. Effect of concentration of reactants, amount of catalyst and the reaction time on the yield of p-cresyl phenylacetate has been investigated. The esterification of phenylacetic acid with phenol and substituted phenols like m-cresol, o-cresol, p-nitro phenol and o-nitro phenol showed reduced yield due to steric factors. The activity of the clay catalyst after regeneration has also been studied.