An improved HPLC-DAD method for simultaneously measuring phenolics in the leaves of Tilia platyphyllos and Ailanthus altissima

Phenolic compounds are one of the most important groups of secondary metabolites in plants, with various physiological functions. Their diverse chemical structure and susceptibility to auto-oxidation, and their ability to act as both antioxidants and prooxidants in the presence of metal ions, are some of the main reasons why it is difficult to measure phenolic groups in plant tissues accurately. We present an optimized extraction and hydrolysis procedure which preserves the original chemical structure of phenolics. The presented HPLC method was improved to enable the simultaneous separation and quantification of 39 compounds from different phenolic subclasses (benzoic acids, hydroxycinnamic acids, flavones, flavonols, flavanones, flavanols, isoflavones, anthocyanidins; aglycones and glycosides). Recovery after extraction and complete hydrolysis of glycosides was more than 95% and 84%, respectively. The method was applied to the analysis and comparison of phenolic profiles in the leaves of two species, Ailanthus altissima (Mill.) Swingle and Tilia platyphyllos Scop. from an urban forest park and busy traffic area. The presence of cyanidin glycosides in A. altissima leaves was reported for the first time. Results indicated higher accumulation of phenolics, with two hydroxyl groups in the ortho- position, than flavonoids, with a monohydroxy substitution in the leaves of both species from a busy traffic area

An improved HPLC-DAD method for simultaneously measuring phenolics in the leaves of Tilia platyphyllos and Ailanthus altissima

Phenolic compounds are one of the most important groups of secondary metabolites in plants, with various physiological functions. Their diverse chemical structure and susceptibility to auto-oxidation, and their ability to act as both antioxidants and prooxidants in the presence of metal ions, are some of the main reasons why it is difficult to measure phenolic groups in plant tissues accurately. We present an optimized extraction and hydrolysis procedure which preserves the original chemical structure of phenolics. The presented HPLC method was improved to enable the simultaneous separation and quantification of 39 compounds from different phenolic subclasses (benzoic acids, hydroxycinnamic acids, flavones, flavonols, flavanones, flavanols, isoflavones, anthocyanidins; aglycones and glycosides). Recovery after extraction and complete hydrolysis of glycosides was more than 95% and 84%, respectively. The method was applied to the analysis and comparison of phenolic profiles in the leaves of two species, Ailanthus altissima (Mill.) Swingle and Tilia platyphyllos Scop. from an urban forest park and busy traffic area. The presence of cyanidin glycosides in A. altissima leaves was reported for the first time. Results indicated higher accumulation of phenolics, with two hydroxyl groups in the ortho- position, than flavonoids, with a monohydroxy substitution in the leaves of both species from a busy traffic area

Antioxidative status and acclimatization capacity of bamboo - potential use for air quality improvement in urban areas

Phyllostachis bissetti was introduced to urban areas in Belgrade with the aim to improve the quality of air polluted by heavy traffic. Dust released from fuel combustion adsorbed on the leaves reaching up to 10% of leaf dry weight. Adsorbed dust was analyzed for its morphological structure, chemical content and prooxidant activity. SEM analysis of dust indicated the presence of particulate matter fractions PM10 and PM2.5. Determination of peroxidase levels (POD, EC 1.11.1.7), ascorbate concentration and total antioxidant capacity in the leaves showed that, overall, P. bissetii had high antioxidative potential to cope with oxidative stress under urban environmental conditions. Leaf protein and chlorophyll content accompanied by high growth rate of seedlings planted at different locations indicated excellent acclimatization capacity of P. bissetti to the heavily polluted urban areas

ALICE: Physics performance report, volume I

ALICE is a general-purpose heavy-ion experiment designed to study the physics of strongly interacting matter and the quark-gluon plasma in nucleus-nucleus collisions at the LHC. It currently includes more than 900 physicists and senior engineers, from both nuclear and high-energy physics, from about 80 institutions in 28 countries. The experimentwas approved in February 1997. The detailed design of the different detector systems has been laid down in a number of Technical Design Reports issued between mid-1998 and the end of 2001 and construction has started for most detectors. Since the last comprehensive information on detector and physics performance was published in the ALICE Technical Proposal in 1996, the detector as well as simulation, reconstruction and analysis software have undergone significant development. The Physics Performance Report (PPR) will give an updated and comprehensive summary of the current status and performance of the various ALICE subsystems, including updates to the Technical Design Reports, where appropriate, as well as a description of systems which have not been published in a Technical Design Report. The PPR will be published in two volumes. The currentVolume I contains: 1. a short theoretical overview and an extensive reference list concerning the physics topics of interest to ALICE, 2. relevant experimental conditions at the LHC, 3. a short summary and update of the subsystem designs, and 4. a description of the offline framework and Monte Carlo generators. Volume II, which will be published separately, will contain detailed simulations of combined detector performance, event reconstruction, and analysis of a representative sample of relevant physics observables from global event characteristics to hard processes. © 2004 IOP Publishing Ltd