Analytical procedure for the in-vial derivatization-extraction of phenolic acids and flavonoids in methanolic and aqueous plant extracts followed by gas chromatography with mass selective detection.

An in-vial simple method for the combined derivatization and extraction of phenolic acids and flavonoids from plant extracts and their direct determination with GC-MS, is described. The method is taking advantage of the beneficial potentials of phase transfer catalysis (PTC). Catalysts in soluble and polymer-bound form were tested with the latter being the format of choice due to its high reaction yield and facile separation from the rest of the reaction system. Optimization of experimental conditions was established. Chromatographic separation of eight phenolic acids and four flavonoids methylated via the PTC derivatization step was achieved in 45 min. The detection limits for the described GC-MS(SIM) method of analysis ranged between 2 and 40ng/ml whereas limits of quantitation fall in the range 5-118 ng/ml, with flavonoids accounting for the lowest sensitivity due to their multiple reaction behavior. Four methanolic extracts from Tilia europea, Urtica dioica, Mentha spicata and Hypericumperforatum grown wild in north-westem Greece and four aquatic infusions from commercially available Mentha spicata, Origanum dictamnus, Rosemarinus officinalis and Sideritis cretica were analyzed. Good trueness of the method was demonstrated as no matrix effects were found for the analytes concerned. (C) 2004 Elsevier B.V. All rights reserved

An Efficient Disinfectant, Composite Material {SLS@[Zn3(CitH)2]} as Ingredient for Development of Sterilized and Non Infectious Contact Lens

The [Zn3(CitH)2] (1) (CitH4= citric acid), was dispersed in sodium lauryl sulphate (SLS) to form the micelle of SLS@[Zn3(CitH)2] (2). This material 2 was incorporated in hydrogel made by hydroxyethyl-methacrylate (HEMA), an ingredient of contact lenses, toward the formation of pHEMA@(SLS@[Zn3(CitH)2]) (3). Samples of 1 and 2 were characterized by UV-Vis, 1H-NMR, FT-IR, FT-Raman, single crystal X-ray crystallography, X-ray fluorescence analysis, atomic absorption and TG/DTA/DSC. The antibacterial activity of 1–3 as well as of SLS against Gram-positive (Staphylococcus epidermidis (St. epidermidis) and Staphylococcus aureus (St. aureus)) and Gram-negative (Pseudomonas aeruginosa (PAO1), and Escherichia coli (E. coli)) bacteria was evaluated by the means of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and inhibitory zone (IZ). 2 showed 10 to 20-fold higher activity than 1 against the bacteria tested. Moreover the 3 decreases the abundance of Gram-positive microbes up to 30% (St. aureus) and up to 20% (PAO1) the Gram-negative ones. The noteworthy antimicrobial activity of the obtained composite 3 suggests an effective antimicrobial additive for infection-free contact lense

Enhancing polyphenol extraction from unripe apples by carbohydrate-hydrolyzing enzymes*

The effects of process variables such as enzyme types, enzyme ratio, reaction temperature, pH, time, and ethanol concentration on the extraction of unripe apple polyphenol were investigated. The results indicated that Viscozyme L had the strongest effect on polyphenols extraction and was selected to study the polyphenol composition. The ratio of enzyme (Viscozyme L) to substrate (2 fungal beta-glucanase units (FBG)) at 0.02, reaction at pH 3.7, 50 °C for 12 h, and ethanol concentration of 70% were chosen as the most favorable extraction condition. Total phenolic content (TPC), reducing sugar content (RSC), and extraction yield increased by about 3, 1.5, and 2 times, respectively, compared with control. The contents of p-coumaric acid, ferulic acid, and caffeic acid increased to 8, 4, and 32 times, respectively. The enzyme-aided polyphenol extraction process from unripe apples might be applied to food industry for enhancing bioactive compound production