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Research Articles

Comparative in vitro and DFT antioxidant studies of phenolic group substituted pyridine-based azo derivatives

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Pages 4921-4932 | Received 07 Nov 2020, Accepted 08 Dec 2020, Published online: 24 Dec 2020
 

Abstract

Two azo compounds 2-(3-pyridylazo)-3,5-dihydroxybenzoic acid (PAB) and 4-(3-pyridylazo)resorcinol (PAR) thought to have the potential to be used as antioxidants were designed, synthesized and antioxidant activities were investigated both in vitro and in silico. The synthesized compounds were characterized by 1H-NMR, 13C-NMR, FT-IR, UV-Vis and mass spectra. The molecular geometry and vibrational frequency calculations of the synthesized compounds in ground state were performed by the density functional theory (DFT) employing B3LYP level with the 6-311 G(d,p) basis set. The gauge independent atomic orbital (GIAO) method was used to determine the chemical shift values of 1H-NMR and 13C-NMR. HOMO–LUMO calculations were carried out by time-dependent DFT (TD-DFT) approach. Computational spectroscopic data of the synthesized compounds are fully compatible with experimental ones. The antioxidant activities of the PAB and PAR were investigated by using DPPH assay. It was determined that the PAB molecule showed better antioxidant activity than PAR and, butylated hydroxytoluene (BHT) which is the standard antioxidant. In addition, the thermodynamic stability parameters obtained with the help of DFT calculations were found to be quite compatible with the antioxidant capacity sequence derived from the DPPH assay.

    Highlights

  • Two pyridine derivative azo compounds were synthesized and evaluated for its antioxidant activity

  • Molecular geometry and spectroscopic properties of the molecules were calculated

  • in vitro and in silico antioxidant activities were investigated by DPPH free radical scavenging assay

  • The PAB molecule showed better antioxidant activity than BHT

Communicated by Ramaswamy H. Sarma

Graphical Abstract

Disclosure statement

No potential conflict of interest was reported by the authors.

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