Structure-activity relationship and MM2 energy minimized conformational analysis of quercetin and its derivatives in the DPPH• radical scavenging capacity

  • Gan B Bajracharya Nepal Academy of Science and Technology (NAST)
  • Mohan Paudel Department of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu
  • Rajendra K. C. Department of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu
  • Sajan L. Shyaula Faculty of Science, Nepal Academy of Science and Technology (NAST), Khumaltar, Lalitpu
Keywords: Antioxidant, 1,1-Diphenyl-2-picrylhydrazyl, Flavonoid, Free radical, IC50, SAR

Abstract

Antioxidant activity of quercetin (1) and its derivatives (2-15) was evaluated by using DPPH assay and IC50 values were calculated. Dihedral angles α of C3-C2-C1’-C6’ chain and β of O1-C2-C-1’-C2’ chain between AC and B rings of these flavones were determined by using MM2 energy minimized structures. Structure-activity relationship study revealed that quercetin (1), quercetin-5-methyl ether (2), quercetin-3’-methyl ether (3) and quercetin-3’,5-dimethyl ether (4) displaying a high antioxidant activity (IC50 = 47.20-119.27 μM) possess similar dihedral angles (α 11.1-11.5º and β 6.3-6.6º). Mono- and/or di-methoxy substituent(s) at 3’ and 5 positions of the flavone are most suitable for the preservation of the antioxidant capacity while retaining conformational geometry.

BIBECHANA 17 (2020) 19-26

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Author Biographies

Rajendra K. C., Department of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu

Department of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu

Sajan L. Shyaula, Faculty of Science, Nepal Academy of Science and Technology (NAST), Khumaltar, Lalitpu

Faculty of Science, Nepal Academy of Science and Technology (NAST), Khumaltar, Lalitpur

Published
2020-01-01
How to Cite
Bajracharya, G., Paudel, M., K. C., R., & Shyaula, S. (2020). Structure-activity relationship and MM2 energy minimized conformational analysis of quercetin and its derivatives in the DPPH• radical scavenging capacity. BIBECHANA, 17, 20-27. https://doi.org/10.3126/bibechana.v17i0.25208
Section
Research Article