Direct Determination of Selenium in Serum Matrix by Electrothermal Atomic Absorption Spectrometry: Application on Healthy Individuals from Algeria  - Pages 13-19

Abderrezak Khelfi, Mohammed Azzouz, Rania Abtroun, Mohammed Reggabi and Berkahoum Alamir

DOI: https://doi.org/10.6000/1927-5951.2018.08.01.3

Published: 08 February 2018

Abstract: Selenium is a trace element implicated significantly in oxidative stress in biological systems. In this work, a direct method for selenium determination in serum samples by electrothermal atomic absorption spectrometry with Zeeman background correction is proposed.

Serum samples were five-fold diluted in a 0.14% HNO₃ and 0.2% Triton X-100 solution. Aliquots of 20 µL of the diluted serum samples were directly introduced into transversely heated graphite tubes. A total of 5 µg Pd and 3 µg Mg(NO₃)₂ was used as chemical modifier. Optimization of heating program was conducted by varying pyrolysis and atomization characteristic values. The optimal conditions were found to be 1400 and 2000 °C for pyrolysis and atomization temperatures respectively and 11 seconds for pyrolysis hold time.

The standard additions method was employed for calibration. Intra-day and inter-day validation using quality control samples at each point of the addition calibration curve were performed. Good accuracy, precision and recovery were achieved with the proposed method (less than 5% for accuracy and precision). A characteristic mass of 92.550 pg, a limit of detection of 4.010 ppb and a limit of quantification of 13.375 ppb in undiluted serum samples were obtained.

Several reference values of serum selenium concentrations were reported. As an application of the present method, selenium levels were determined in serum samples collected from 20 healthy individuals from Northern-Center of Algeria. Selenium concentrations ranged from 86.883 to 133.955 ppb with a mean value of 110.824±11.898 ppb.

Keywords: Selenium, serum, optimization, electhrothermal atomic absorption spectrometry, healthy individuals

Phytochemical Investigation and Antimicrobial Evaluation of Foeniculum vulgare Leaves Extract Ingredient of Ethiopian Local Liquor - Pages 20-28

Mohammed Seid, Aman Dekebo and Neelaiah Babu

DOI: https://doi.org/10.6000/1927-5951.2018.08.01.4

Published: 08 February 2018

Abstract: Medicinal plants are of great interest to the researcher in the field of biotechnology, as natural products, including medicinal plants, accounts 25% of prescribed drugs. Plants are sources for fragrances, drink colors and flavors in several countries including Ethiopia. All parts of Foeniculum vulgare were traditionally used as antispasmodic, aromatic, carminative, digestive, galactagogues, stomach and kidney ailment. Foeniculum vulgare leaves extract was investigated for its phytochemicals as well as antimicrobial effects. The petroleum ether, CHCl₃, CHCl₃/CH₃OH (1:1) and CH₃OH crude extract were subjected to phytochemicals screening test which revealed that it is rich in any primary and secondary metabolites such as steroids, tannins, flavonoids, cholesterol, terpenoids, saponins, phenols, cardiac glycosides, carbohydrates, and proteins. The essential oil of the plant leaves was investigated by GC‑MS and was found to have (64.92%) anethole, as a major constituent followed by (30.88%) estragole and (3.21%)fenchyl acetate. The crude extracts, oil, and the isolated compound were tested against four bacterial species (Gram negative bacteria, Escherichia coli and Shigella flexneri; Gram positive bacteria: Staphylococcus aureus and Streptococcus pyrogenes) and two fungal species (Fusarium oxysporum and Aspergillus niger) using paper disc diffusion method. Tests of antimicrobial activity showed that all crude extracts and isolated pure compound were active against all the tested bacterial and fungal species. However, the hydrodistillation extract was found to have no antibacterial activity towards the tested bacterial species but active against the two fungal species and thus the present study supported the traditional claims of the plant.

Keywords: Antimicrobial activities, Disc diffusion method, Phytochemical screening, anethole, estragole, GC‑MS, Essential oil, Apiaceae.