Essential (volatile) oil from leaves of Artemisia monosperma L. belonging to family Asteraceae, and aerial parts of Tamarix aphylla L. (Athel) belonging to family Tamaricaceae were collected from the desert of Ha'il region, northern region of Saudi Arabia, hydro distilled by Clevenger apparatus and analysed by means of GC-MS techniques. Antioxidant activities of essential oils of A. monosperma and T. aphylla compared with ascorbic acid and butylated hydroxytoluene (BHT) as reference antioxidant compound were determined by method of DPPH radical scavenging assay and ABTS assay. In vitro screening of potential cytotoxicity of essential oils was also evaluated against human promyelocytic leukaemia cell lines (HL60 and NB4). The GC/MS analysis of A. monosperma essential oil resulted in identification of 61 components predominated mainly by β-Pinene as principal component (29.87%) and T. aphylla resulted in identification of 37 components of essential oil predominated mainly by 6,10,14- trimethyl-2-pentadecanone (21.43%) as principal component. Antioxidant activity as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and 2,2 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) increased with increasing essential oil concentrations of A. monosperma and T. aphylla (25, 50, 75, 100 and 200 μg mL-1). The most pronounced increases detected in the high concentrations of the two essential oils. Biologically, essential oil extracts exhibited cytotoxicity effects in dose dependent manner against human promyelocytic leukaemia cell lines (HL60 and NB4). In conclusion, A. monosperma and T. aphylla essential oils could be valuable source for cytotoxic agents with high safety and selective cytotoxicity profiles.

A simple and sensitive bioanalytical high-performance liquid chromatographic method with ultraviolet detection was developed and validated for the quantification of febuxostat (FEB) in human plasma. Ketoprofen was used as an internal standard. The analytes were extracted from human plasma samples by precipitation with acetonitrile. The reconstituted samples were chromatographed on C18 Bondapack 10 µm, 250 × 4.6 mm, Waters Column (Ireland) by using a mixture of acetonitrile and 0.5% aqueous phosphoric acid (pH 3) (52 : 48, v/v) as the mobile phase. The chromatographic separation was isocratically performed at room temperature at a flow rate of 1.0 mL/min with UV detection at 315 nm. The method exhibited a linear dynamic range over 0.05-5.00 µg/mL FEB in human plasma. The lower limit of quantification was 0.05 µg/mL. The results of the intra- and interday precision and accuracy studies were within the acceptable limits. The validated method was successfully applied for the determination of FEB in human plasma samples for application in bioequivalence studies.

KEYWORDSThree different spectrophotometric methods are developed for the determination of naftidrofuryl oxalate (NAF) in pure form and its pharmaceutical preparation. The methods are based on charge transfer complexation reactions of NAF as n-electron donor with either p-chloranilic acid (PCA) or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or tetracyano ethylene (TCNE) as π-receptors to give highly colored anion radicals species. The colored products were quantified spectrophotometrically at 515, 588 and 396 nm in PCA, DDQ and TCNE methods, respectively. Under the optimized experimental conditions, Beer's law is obeyed over the concentration ranges of 75.0-300.0, 25.0-150.0 and 15.0-50.0 μg/mL NAF for PCA, DDQ and TCNE methods, respectively. The proposed methods were applied successfully to the determination of NAF in pure form and its commercial tablets with good accuracy and precision. Statistical comparison of the results was performed using Student's t-test and Fratio at 95% confidence level, showing that there is no significant difference between the reference and the proposed methods with regard to accuracy and precision. Further, the validity of the proposed methods was confirmed by standard addition technique.Chloranilic acid Tetracyanoethylene Naftidrofuryl oxalate Pharmaceutical preparation Charge transfer complexation 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone