Assessment of free-radical scavenging activity of Gypsophila pilulifera: assay-guided isolation of verbascoside as the main active component

Gypsophila pilulifera, Boiss & Heldr, Caryophyllaceae, is a perennial medicinal herb that grows in the southwestern region of Turkey. Except for only one report on the isolation of cytotoxic saponins from the underground parts of G. pilulifera, there are no published thorough phytochemical or bioactivity studies on this species. In the present study, the free-radical scavenging activity of extracts and fractions of the stems of G. pilulifera was evaluated, using a slightly modified and more precise version of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, reported here for the first time. The DPPH assay-guided HPLC-PDA-purification of the active solid-phase extraction fraction (50% methanol in water) of the methanolic extract exhibited verbascoside as the main free-radical scavenger present in this species. The structure of this active compound was resolved by spectroscopy, and the free-radical scavenging potential of verbascoside was determined.

Carolina poplar (Populus × canadensis Moench) as a biomonitor of trace elements in Black sea region of Turkey.

In this study, the leaves, bark and the soil supporting Populus x canadensis Moench were tested as a possible biomonitor of trace element pollution in the Middle Black Sea region of Turkey. The investigations were carried out at 23 sites. The leaves, bark and soil were analyzed for Pb++, Cd++, Fe++, Cu++ and Zn++ contents. The values of Pb++, Cd++, Fe++, Cu++ and Zn++ in the leaves varied between 14.5-40.0, 0.5-1.5, 135-486, 5.0-14.0 and 43-246 ppm, respectively. In the bark the values were between 15.5-36.5 (Pb++), 1.5-2.0 (Cd++), 39-575 (Fe++), 5.0-14.0 (Cu++) and 40.0 –1468 ppm (Zn++), whereas in the soil values for Pb++ were 1.0-4.1 ppm, for Cd++ 0.2 ppm, for Fe++ 0.6-1.8 ppm, for Cu++ 0.1-0.9 ppm and for Zn++ 0.1-1.9 ppm. A positive correlation was found between traffic density and the amount of Pb++, Fe++ and Cu++ in leaves, while a negative correlation was documented for Cd++ and Zn++. In the bark samples there was a positive correlation between traffic density and Pb++, and a negative one with Cd++, Fe++, Cu++ and Zn++. A positive correlation was determined between traffic density and the amount of Pb++, Fe++, Cu++ and Zn++ in soil. However, the amount of Cd++ was 0.2 ppm and no relationship between Cd++ and traffic density was observed.

Bioactivity of two Turkish endemic Centaurea species, and their major constituents

The antioxidant activity, general toxicity and cytotoxicity of the methanol extracts of Centaurea urvillei subs. armata and C. mucronifera have been assessed, respectively, by the DPPH assay, the brine shrimp lethality and the MTT cytotoxicity assays. The reversed-phase HPLC analysis of the methanol extracts afforded two bioactive dibenzylbutyrolactone-type lignans, matairesinoside (1) and arctiin (2). The structures of these lignans were elucidated by comprehensive spectroscopic analyses as well as by the direct comparison of experimental data with respective literature data.

A atividade antioxidante, a toxicidade geral e a citotoxidade dos extratos metanólicos de Centaurea urvillei subs. armata e C. mucronifera foram analisados, respectivamente, pelo ensaio DPPH e pelos ensaios de letalidade de Artemia salina e de citotoxidade MTT. A análise dos extratos metanólicos em CLAE de fase reversa apresentou duas lignanas biotivas do tipo dibenzilbutirolactona, matairesinosídeo (1) e arctiina (2). As estruturas destas lignanas foram elucidadas através de análises espectroscópicas completas bem como por comparação direta dos dados experimentais com os respectivos dados da literatura.