Phytochemical Characterization, Antioxidant, and Antimicrobial Activity of the Vegetative Buds from Romanian Spruce, Picea abies (L.) H. Karst.

This study aims to investigate the vegetative buds from Picea abies (spruce), naturally found in a central region of Romania, through a comprehensive analysis of the chemical composition to identify bioactive compounds responsible for pharmacological properties. Using HPLC/derivatization technique of GC-MS and quantitative spectrophotometric assays, the phenolic profile, and main components of an ethanolic extract from the buds were investigated. The essential oil was characterized by GC-MS. Moreover, the antioxidant activity with the DPPH method, and the antimicrobial activity were tested. Heavy metal detection was performed by graphite furnace atomic absorption spectrometry. The main components of the alcoholic extract were astragalin, quercetin, kaempferol, shikimic acid, and quinic acid. A total content of 25.32 ± 2.65 mg gallic acid equivalent per gram of dry plant (mg GAE/g DW) and of 10.54 ± 0.083 mg rutin equivalents/g of dry plant (mg RE/g DW) were found. The essential oil had D-limonene, α-cadinol, δ-cadinene, 13-epimanool, and δ-3-carene as predominant components. The spruce vegetative buds exhibited significant antioxidant activity (IC50 of 53 µg/mL) and antimicrobial effects against Staphylococcus aureus. Furthermore, concentrations of heavy metals Pb and Cd were below detection limits, suggesting that the material was free from potentially harmful contaminants. The results confirmed the potential of this indigenous species to be used as a source of compounds with pharmacological utilities.

Novel antipathogenic strategies against adherent enterobacterial strains isolated from the hospital environment.

The emergence of the bacterial antibiotic multi-resistance made more and more stringent the developing of new anti-microbial strategies. The purpose of the present study was to investigate the antimicrobial potential of six (6) newly synthesized chemical compounds (derivating from phenantroline and dimethylguanin-copper complex combinations) versus 97 enterobacterial strains isolated from the hospital environment. The qualitative screening of the antimicrobial activity of the chemical compounds was performed by an adapted diffusion method. The minimal inhibitory concentrations (MIC) of the active chemical compounds were established by Mueller Hinton broth microdillution method. The tested chemical compounds were also tested for their ability to inhibit microbial adherence and biofilm development on inert substrata by a simple microtiter method. All six chemical compounds proved to have antimicrobial activity versus the most of the tested strains, the phenantroline derivatives exhibiting higher antimicrobial activity than the dimethylguanidine-copper complex combinations. The subinhibitory concentrations of the tested chemical products slightly inhibited the adherence ability of the bacterial strains to the inert substratum. Our results demonstrated that phenantroline derivatives may represent a new strategy of antimicrobial treatment, simultaneously with the bactericidal effect, the subinhibitory concentrations of these newly synthesized chemical compounds decreasing the adherence ability of bacteria to the inert substratum.