Asian Journal of Research in Chemistry

Assia Belfar ¹, Assia Belfar ², Cheyma Bensaci ¹, Cheyma Bensaci ³, Mahdi Belguidoum ⁴, Mahdi Belguidoum ⁵, Mokhtar Saidi ¹, Zineb Ghiaba ¹

Affiliations
1 Laboratory of Valorization and Promotion of Saharan Resources, Kasdi Merbah University, 30000 Ouargla, Algeria., IN
2 Department of Exact Sciences, Higher Normal School of Ouargla, 30000 Ouargla, Algeria., IN
3 Department of Exact Sciences, Higher Normal School of Ouargla, 30000 Ouargla, Algeria, IN
4 Laboratory of Valorization and Promotion of Saharan Resources, Kasdi Merbah University, 30000 Ouargla, Algeria, IN
5 Department of Agronomy, Faculty of Nature and Life Sciences and Earth Sciences, University of Ghardaia, 47000 Ghardaia, Algeria., IN

Abstract

In this study we used spectrophotometrical techniques to estimate antioxidant efficacy by using 2,2-diphenyl-1- picrylhydrazyl free radical scavenging capacity and reducing power capacity. We have used also electrochemical techniques performed by cyclic voltammetry. The present study examined the antioxidant activities of the methanolic extract (ME) of date palm (Phoenix dactylifera. L) fruits (DPF) of four native cultivars from Algeria, namely, Ghars (Gh), Chtaya (Cht), Degla Beïda (DB) and Tinissine (Tns). Quantitative estimation of total phenol and flavonoid content by a colorimetric assay showed that methanol extracts are rich in these components. The content of total phenolics of different cultivars extracts was in the range of 26.083 - 35.850 GAE/100g DW. while it was the content of total flavonoids of the different cultivars extracts was in the range of 5.276 - 6.055 QE/100g DW. The value of IC50 for DPPH radical test ranged from 0.193 to 0.400mg/ml. All extracts showed very good activity of ferric reducing power, the higher power was in methanolic extract of Tns. The less IC50 value in cyclic voltammetry method (CV), which meet the highest effective antioxidant was 0.121 mg/ml in methanolic extract of Tns.

Keywords

Phoenix dactylifera L, Phenolic content, Flavonoids contents, antioxidant activity, cyclic voltammetry.

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Yamina Benkrima ¹, Abdelkader Souigat ², Yassine Chaouche ³, Zineb Korichi ¹, Mohammed Elbar Soudani ⁴, Assia Belfar ¹

Affiliations
1 Ecole Normale Supérieure de Ouargla, 30000 Ouargla, Algeria., IN
2 Ecole Normale Supérieure de Ouargla, 30000 Ouargla, Algeria ., IN
3 Larbi Tebessi University, Tebessa, Laboratoire de Physique Appliquée et Théorique, Route de Constantine 12002 Tebessa, Algeria., IN
4 Laboratoire de Développement des Energies Nouvelles et Renouvelables dans les Zones Arides et Sahariennes, Faculté des Mathématiques et des Sciences de la Matière, Université Kasdi Merbah Ouargla, Ouargla 30000, AlgérieTebessi University, Tebessa, Laboratoire de Physique Appliquée et Théorique,, IN

Abstract

This search paper is focus on the investigation of the most stability structures of Pt3 and Cu3 clusters adsorbed on ZnO (000 ̅1) surfaces in the Wurtzite stable structure. The results are obtained by using the Density Function Theory (DFT). All the calculations are performed using the Gradient Generalized Approximation to describe the exchange correlation term in SIESTA code. From this work we found new structures of Pt3 and Cu3 clusters with lowest energy. Also we have calculated the binding energy, relaxation interlayer for each cluster, bond lengths, vertical ionization potential PIv and the density of states DOS. Through the results we found that the Pt3 cluster is more stable than Cu3 cluster and confirmed by the DOS, in the other hand the ZnO-O surface is more stable than ZnO-Zn surface. The computed electron structure and DOS illustrate that the Pt3/ZnO and Cu3/ZnO clusters adsorbed on ZnO-O surfaces display metallic characteristics.

Keywords

Ab initio calculations, Pt3 and Cu3 clusters, ZnO surfaces, Stability structure, electronic properties, catalysis.

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