Antioxidant activity, NMR, X-ray, ECD and UV/vis spectra of (+)-terrein: Experimental and theoretical approaches

作者：Al Trabolsy Zuhra Bashir Khalifa; Anouar El Hassane^*; Zakaria Nur Shahidatul Shida; Zulkeflee Manar; Hasan Mizaton Hazizul; Zin Maisarah Mohd; Ahmad Rohaya; Sultan Sadia; Weber Jean Frederic F

来源：Journal of Molecular Structure, 2014, 1060: 102-110.

DOI：10.1016/j.molstruc.2013.12.034

• Terrein
• Aspergillus terreus
• DET
• ECD spectra
• Antioxidant activity

Fungal metabolite terrein isolated from Aspergillus terreus is endowed with diverse biological and antioxidant activities. To determine the stereochemistry of the isolated terrein, we combined spectroscopic methods (CD and NMR spectra) and theoretical calculations (DFT and TD-DFT methods). Stereochemistry effects on the antioxidant activity of isolated terrein were evaluated by calculating bond dissociation enthalpies (BDEs), ionization potentials (IPs) and spin density delocalization of terrein and isoterrein stereoisomers with B3P86/6-31+G (d,p) method in gas and polarizable continuum model. The results showed a good agreement between experimental data and theoretical calculations which confirmed the (+)-terrein stereochemistry of isolated metabolite. Theoretical calculations showed that the antioxidant activity is relatively influenced by isomeric geometry of the terrein (a variation of 2 kcal/mol between BDEs of terrein and isoterrein isomers), while chirality has no influence on the antioxidant activity 10.2 kcal/ mol difference between BDEs of (+)- and (-)-terrein]. The low antioxidant activity of (+)-terrein with respect to trolox and ascorbic acid was explained by the positive free Gibbs energy of the hydrogen atom transfer (HAT) mechanism and high BDE values of the 2-OH active site.

• 出版日期2014-2-24