Synthesis and antioxidant activity evaluation of new compounds from hydrazinecarbothioamide and 1,2,4-triazole class containing diarylsulfone and 2,4-difluorophenyl moieties.

In the present investigation, new hydrazinecarbothioamides 4-6 were synthesized by reaction of 4-(4-X-phenylsulfonyl)benzoic acids hydrazides (X=H, Cl, Br) 1-3 with 2,4-difluorophenyl isothiocyanate and further these were treated with sodium hydroxide to obtain 1,2,4-triazole-3-thione derivatives 7-9. The reaction of 7-9 with α-halogenated ketones, in basic media, afforded new S-alkylated derivatives 10-15. The structures of the synthesized compounds have been established on the basis of 1H-NMR, 13C-NMR, IR, mass spectral studies and elemental analysis. The antioxidant activity of all compounds has been screened. Hydrazinecarbothioamides 4-6 showed excellent antioxidant activity and 1,2,4-triazole-3-thiones 7-9 showed good antioxidant activity using the DPPH method.

Original Contributions to the Chemical Composition, Microbicidal, Virulence-Arresting and Antibiotic-Enhancing Activity of Essential Oils from Four Coniferous Species.

This study aimed to establish the essential oil (EO) composition from young shoots of Picea abies, Larix decidua, Pseudotsuga menziesii, and Pinus nigra harvested from Romania and evaluate their antimicrobial and anti-virulence activity, as well as potential synergies with currently used antibiotics. The samples' EO average content varied between 0.62% and 1.02% (mL/100 g plant). The mono- and sesquiterpene hydrocarbons were dominant in the composition of the studied EOs. The antimicrobial activity revealed that the minimum inhibitory concentration (MIC) values for the tested EOs and some pure compounds known for their antimicrobial activity ranged from 6.25 to 100 µL/mL. The most intensive antimicrobial effect was obtained for the Pinus nigra EO, which exhibited the best synergistic effect with some antibiotics against Staphylococcus aureus strains (i.e., oxacillin, tetracycline, erythromycin and gentamycin). The subinhibitory concentrations (sMIC) of the coniferous EOs inhibited the expression of soluble virulence factors (DN-ase, lipase, lecithinase, hemolysins, caseinase and siderophore-like), their efficiency being similar to that of the tested pure compounds, and inhibited the rhl gene expression in Pseudomonas aeruginosa, suggesting their virulence-arresting drug potential.

The inhibitory activity of pomelo essential oil on the bacterial biofilms development on soft contact lenses.

The aim of present study was to investigate the microbial colonization of worn contact lenses (CLs) and to evaluate the inhibitory effect of pomelo (Citrus maxima) peels essential oil on the biofilm development on unworn CLs. The essential oil was isolated by steam distillation and analyzed by gas chromatography coupled with mass spectrometry, twenty compounds being isolated. The antimicrobial activity of pomelo oil was tested against S. epidermidis and P. aeruginosa strains, known for their ability to develop biofilms on prosthetic devices, by qualitative screening methods and quantitative assay of the minimal inhibitory concentrations (MIC) in order to evaluate the antibiofilm activity. Our study revealed that all worn CLs where 100% colonized by staphylococci and Enterobacteriaceae strains. The pomelo essential oil inhibited the development of bacterial biofilms formed by Gram-positive and Gram-negative microorganisms on soft CLs, its antibiofilm activity being specific and dependent on different physical parameters (contact time and temperature). The architecture of bacterial biofilms developed on soft contact lenses was analyzed using confocal scanning laser microscopy (CSLM).

Chemical and biological studies of Ribes nigrum L. buds essential oil.

Ribes nigrum buds are used in medicine for the diuretic and antiseptic properties of their volatile compounds. We present in this paper comparative data concerning the chemical composition of Ribes nigrum buds essential oils obtained from three blackcurrant varieties. Essential oils were isolated by steam distillation and were analyzed by gas chromatography coupled with mass spectrometry. The Ribes nigrum essential oils (extracted from all three varieties) exhibited similar and large antibacterial spectrum, acting against Acinetobacter (A.) baumanii, Escherichia (E.) coli, Pseudomonas (P.) aeruginoasa and Staphylococcus (S.) aureus, as proved by the very low MIC values observed for the respective strains. The subinhibitory concentrations of the essential oils induced a decrease in the bacterial ability to colonize the inert substratum for A. baumanii, E. coli and S. aureus, demonstrating that besides the bactericidal activity, the Ribes nigrum essential oils also exhibit anti-pathogenic potential.

Capillary gas chromatography-mass spectrometry of volatile and semi-volatile compounds of Salvia officinalis.

The essential oil and infusion of Salvia officinalis leaves have been widely applied in traditional medicine since ancient times and nowadays subjected to extensive research of their antibacterial, antiviral and cytotoxic properties. This paper shows chemical composition data of S. officinalis leaves essential oil isolated by steam distillation using a Clevenger-type apparatus. Also, the paper presents the chemical content of volatile and semi-volatile compounds of S. officinalis leaves infusion. The volatile and semi-volatile compounds of S. officinalis leaves infusion were isolated by solid-phase extraction (SPE) and liquid-liquid extraction with hexane and dichloromethane. SPE was carried out on 500 mg octadecylsilane (C18) cartridges and elution with dichloromethane. Liquid-liquid extraction was performed with hexane and dichloromethane. The essential oil in dichloromethane and infusion extracts in hexane and dichloromethane were analyzed by gas chromatography coupled with mass spectrometry. The quantitative results obtained by solid-phase extraction and liquid-liquid extraction showed that SPE on C18 performed the highest recovery of the volatile compounds from infusion sample.