Hassan Y. Aboul-Enein

Chiral Analyses of Pollutants by Capillary Electrophoresis

In this study some heavy metal uptake in mushroom species, their metal content in soil substrate and the relation in between metal concentration in mushroom and soil were investigated. Mushroom species and soil in which mushroom species were grown were collected from Tokat region of Turkey. Six different mushroom species and their underlying soil (0–10 cm layer) samples were analyzed for some heavy metals (Cu, Pb, Fe, Zn, Cd, Mn, Ni, Cr and Co). The analysis was performed with an atomic absorption spectrometer. The results indicate that in general, heavy metal contents in all mushroom species were lower than the underlying soil substrates except for some mushroom species. The results obtained from the analyses of mushroom and underlying soil samples were evaluated using linear correlation analysis and concentration factors to identify the metal accumulation of mushrooms.

U.S. Food and Drug Administration issues certain guidelines for marketing of optically active drugs as some enantiomers racemize into human body, leading to the generation of other antipodes, which may be toxic or ballast to the human beings. Moreover, racemization reduces the administrated dosage concentration as optically active enantiomer converted into its inactive counter part. Therefore, the study of racemization of such type of drugs is an important and urgent need of today. This article describes in vitro and in vivo racemization of optically active drugs. The racemization process of various optically active drugs has been discussed considering the effect of different variables i.e. pH, temperature, concentration of the drug, ionic concentration, etc. Attempts have also been made to discuss the mechanisms of racemization. Besides, efforts have been made to suggest the safe dosages of such type of drugs too. Chirality, 2007.

Phenolic compounds are widely present in plants and they have received considerable attention due to their antioxidant property. In this article we report the results of a study of the reactivity of 10 selected phenolics (sesamol, three phenolic acids, three flavonols, one flavone, and two flavanones) with superoxide anion radical (O), hydroxyl radical (HO^•) and singlet oxygen (¹O₂). The following generators of reactive oxygen species were used: 18‐crown‐6/KO₂/dimethylsulfoxide (DMSO) or hypoxanthine/xanthine oxidase as sources of O, the Fenton reaction carried out in a sodium trifluoroacetate (pH 6.15) for HO^•, and a mixture of alkaline aqueous H₂O₂ and cobalt ions for ¹O₂. We have employed chemiluminescence, electron spin resonance spin trapping, and spectrophotometry techniques to examine an antioxidative property. All tested compounds acted as scavengers of various reactive oxygen species. The reactivity indexes (β) for the reaction of the phenolic compounds with HO^• were calculated. © 2007 Wiley Periodicals, Inc. Biopolymers 86: 222–230, 2007.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com

A rapid, simple, and sensitive method is described for the determination of the food preservative sodium benzoate in soft drinks, various jams, and ketchup. The method utilizes high performance liquid chromatography followed by diode array detection. Chromatographic separation was achieved using a C₁₈ reversed phase column and methanol: water (70∶30, v/v) adjusted to pH 3.45 with glacial acetic acid as mobile phase, 0.45 mL . min⁻¹ flow rate, and UV detection at 245 nm. Amoxicillin was used as the internal standard. The retention time observed for sodium benzoate and amoxicillin were 5.01 and 12.07 min, respectively. The method is selective, reliable, and reproducible with a relative standard deviation of 0.66 and linear in the range of 50–450 ng/mL sodium benzoate concentration. The limit of detection and limit of quantification concentrations were 61 pg/mL and 203 pg/mL, respectively. The proposed method can be used for the routine analysis of sodium benzoate in soft drinks and jams.

A simple, fast, and reproducible capillary electrophoretic method is developed and validated for analysis of melatonin in pharmaceutical preparations. The CE method was developed by using a fused silica capillary (60 cm×50 µm I.D.), phosphate buffer (50 mM, 3.0 pH) as the background electrolyte (BGE), 20 kV applied voltage with UV detection at 214 nm, and at a working temperature of 23±1°C. Linearity was observed in the concentration range from 10 to 100 µg/L with a correlation coefficient (R²) of 0.9996. The limits of detection and quantification achieved were 10 and 15 µg/mL, respectively. The percentage recovery of melatonin from pharmaceutical preparations was 95.0. Validation parameters prove the precision of the method and its applicability for the determination of melatonin in pharmaceutical tablet formulations.

A Fourier transform infrared (FT‐IR) spectrometric method was developed for the rapid, direct measurement of coenzyme Q₁₀ (CoQ₁₀) in different pharmaceutical products. Conventional KBr spectra were compared for the best determination of active substance in drug preparations. Lambert‐Beer's law and two chemometric approaches, partial least squares (PLS) and principal component regression (PCR+) methods, were used in data processing.

The antioxidant properties of plants have been investigated, in the light of recent scientific developments, throughout the world due to their potent pharmacological activities and food viability. Basil (Ocimum basilicum L. Family Lamiaceae) is used as a kitchen herb and as an ornamental plant in house gardens. In the present study, the possible radical scavenging and antioxidant activity of the water (WEB) and ethanol extracts (EEB) of basil was investigated using different antioxidant methodologies: 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) free radical scavenging, scavenging of superoxide anion radical‐generated non‐enzymatic system, ferric thiocyanate method, reducing power, hydrogen peroxide scavenging and metal chelating activities. Experiments revealed that WEB and EEB have an antioxidant effects which are concentration‐dependent. The total antioxidant activity was performed according to the ferric thiocyanate method. At the 50 µg/mL concentration, the inhibition effects of WEB and EEB on peroxidation of linoleic acid emulsion were found to be 94.8% and 97.5%, respectively. On the other hand, the percentage inhibition of a 50 µg/mL concentration of BHA, BHT and α‐tocopherol was found to be 97.1%, 98.5% and 70.4% inhibition of peroxidation of linoleic acid emulsion, respectively. In addition, WEB and EEB had effective DPPH radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, reducing power and metal chelating activities. Additionally, these various antioxidant activities were compared with BHA, BHT and α‐tocopherol as reference antioxidants. The additional total phenolic content of these basil extracts was determined as the gallic acid equivalent and were found to be equivalent. Copyright © 2007 John Wiley & Sons, Ltd.