Mokhtar Saidi

Experimental and Theoretical Studies of Radical Intermediate Reactivity During the Electroreduction of Dithiolethiones and the Corresponding Dithiolium Cations

Abstract

Electrochemical, spectroscopic and molecular docking studies of 4-methyl-5-((phenylimino)methyl)-3H- and 5-(4-fluorophenyl)-3H-1,2-dithiole-3-thione interacting with DNA

ABSTRACT Cyclic voltammetry (CV) and UV–Visible spectroscopy (UV–Vis) techniques were used to calculate binding parameters of 4-methyl-5-((phenylimino)methyl)-3H-1,2-dithiole-3-thione (MPDT) and 5-(4-fluorophenyl)-3H-1,2-dithiole-3-thione (FPDT) with DNA. The results obtained from both techniques were confirmed by computational molecular docking using AutoDock molecular docking software. The anodic peak potential shift in CV indicated an intercalative mode of binding. The binding constants (M−1) of the adducts MPDT-DNA and FPDT-DNA obtained from voltammetric measurements were found to be 8.0 × 104 and 2.4 × 104, respectively, with binding free energy being −27.99 and −25.01 KJ mol−1, respectively. These results are in good agreement with those obtained from UV–Visible spectroscopic studies. The diffusion coefficients of MPDT and FPDT (2.06 × 10−10 and 2.42 × 10−9, respectively) were found to be higher than those of DNA-bound compounds (1.27 × 10−10 and 1.65 × 10−9 cm2/s, respectively). The binding free energy of MPDT and FPDT to DNA was also calculated by molecular docking study. The docking study gave excellent approximation with experimental results, shedding light on the sites of binding. GRAPHICAL ABSTRACT

Lipid Classes, Fatty Acids, Tocopherols Compositions and Antioxidant Activity of Lawsonia alba Seed Oils Growing in Algeria

Background: Lawsonia alba seed oils are not widely used commercially even though they have characteristics that well suit for industrial applications and can contribute to healthy human diets. The most important aim of the present work is the evaluation of the tocopherols composition of these oils. Moreover, lipid classes, fatty acids compositions and antioxidant activity of the seed oils were also investigated. Methods: Lawsonia alba seed oils were extracted with Soxhlet device using n-hexane and chloroform/methanol. Tocopherols were analyzed by HPLC, and then their antioxidant activities were determined using two different assays: DPPH (1,1-diphenyl-2-picrylhydrazyl), and Phosphomolybdenum. Results: The content of the oils ranged from 7.52 to 10.45%. Polyunsaturated fatty acids dominated all the studied samples. Linoleic, followed by palmitic and oleic, were the major fatty acids found in the crude seed oils and their lipid classes. Results of tocopherols identification showed that the seed oils were rich in tocopherols, especially γ- and δ- tocopherols. For DPPH assay, the antioxidant powers varied from medium to low values (IC50 = 0.11 to >31.96 mg/mL). The results of the Phosphomolybdenum assay showed very important activities of the oils that were decreasing in the following order: polar lipids > neutral lipids (Chloroform/Methanol) > total lipids > neutral lipids (n-hexane). Conclusion: this current report reveals the richness of the Lawsonia alba seeds in tocopherols, which in fact is studied for the first time. Moreover, cluster analysis revealed that fatty acid composition of the seed oils of Lawsonia alba were very close to those of Walnut.