Green Antioxidants: Synthesis and Scavenging Activity of Coumarin-Thiadiazoles as Potential Antioxidants Complemented by Molecular Modeling Studies

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Abstract
Free Radicals and Antioxidants,2016,6,2,173-177.
Published:January 2016
Type:Original Article
Authors:
Author(s) affiliations:

Ahmed Al-Amiery1,2, Yasameen Al-Majedy1,2, Dunya Al-Duhaidahawi3, Abdul Amir Kadhum1, Abu Bakar Mohamad2,4

1Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Bangi, Selangor 43600, MALAYSIA.

2Department of Applied Science, Branch of Chemistry, University of Technology (UOT), Baghdad 10001, IRAQ.

3Department of Pharmaceutical Chemistry, College of Pharmacy, Kufa University, Najaf 31001, IRAQ.

4Fuel Cell Institute, University Kebangsaan Malaysia (UKM), Bangi, Selangor 43000, MALAYSIA.

Abstract:

Introduction: Coumarin is a natural product compound known for its medicinal properties. Methods: The rational design of 4-hydroxycoumarin functionalized thiadiazoles (3 and 4) was synthesized with tailor-made antioxidant properties. The strategy involves intra-molecular cyclization of 2-(coumarin-4-yloxy) acetic acid under reflux conditions. Antioxidant activity of synthesized compounds were performed using various in vitro assays against 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydrogen peroxide (H2O2) scavenging. Results: The results revealed that tested compounds 3 and 4 are much higher than well-known antioxidant compound naming ascorbic acid. They showed good scavenging capacity against DPPH and hydroxyl radicals. Ab initio HF (Hartree–Fock) with 3-21G basis set for the title compounds demonstrated the correlation of scavenging activities and theoretical parameters (such as, dipole-moment, ionization-potential, electron-affinity and highest occupied molecular orbital). Conclusion: In conclusion Coumarins were successfully synthesized and were evaluated as antioxidants by DPPH and hydrogen peroxide assays and they were indicated that they had good scavenging activities. The synthesized antioxidants were investigated theoretically and also some quantum chemical parameters were calculated.