Naslov
Reliability of bond dissociation enthalpy calculated by the PM6 method and experimental TEAC values in antiradical QSAR of flavonoids

Autori
Amić, Dragan ; Lučić, Bono

Izvornik
Bioorganic & medicinal chemistry (0968-0896) 18 (2010), 1; 28-35

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
flavonoids ; free radical scavenging ; QSAR modeling ; PM6 method ; RM1 method ; bond dissociation enthalpy ; ABTS assay ; TEAC ; VCEAC

Sažetak
The applicability of the newly developed RM1 and PM6 methods implemented in the semiempirical quantum chemistry MOPAC2009TM software package in modeling free radical scavenging activity of flavonoids was examined. Bond dissociation enthalpy (BDE) of OH groups could be calculated much faster than with DFT method but with similar quality. Despite the known shortcomings of the Trolox equivalent antioxidant capacity (TEAC) assay, we show that taking into account the hydrogen atom transfer (HAT) mechanism of free radical scavenging of flavonoids encoded by minimal BDE values (BDEmin) and the number of OH groups (nOH), as well as experimental data, reasonable QSAR models could be developed. For TEAC values of 38 flavonoids measured by the ABTS free radical, a model based on BDEmin and nOH was developed, having very good statistical parameters (r = 0.983, rcv = 0.976). The applicability of this model to three different data sets of flavonoids and reliability of TEAC values measured in distinct laboratories were discussed. Finally, a reasonably good model of experimental vitamin C equivalent antioxidant capacity (VCEAC) of 36 flavonoids was obtained (r = 0.954, rcv = 0.947), involving BDEmin and nOH as descriptors. Additionally, all presented models have comparable fit and cross-validated statistical parameters, as well as significant regression coefficients.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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