Antioxidant properties of methanolic extract of ‘Veronica multifida’ and DFT and HF analyses of its the major flavonoid component

Abstract

The experimental part of this study, investigated the effects of a methanolic extract of Veronica multifida on total phenolic and flavonoid content, antioxidant capacities; and DPPH scavenging activity. The methanol extract of V. multifida showed an equivalent of phenolic content of 196.67 mg gallic acid per gram dry weight, flavonoid content of 206.17 mg quercetin per gram dry weight and total antioxidant capacities of 134.41 mM α-tocopherol acetate per gram dry weight. Additionally, the amount of extract supplying 50% inhibition of DPPH was assayed as 66.65 mg L−1. The V. multifida plant extract to be used in the study was reported to contain luteolin as its main flavonoid component. The luteolin content of 0.2–0.5 μg g−1 was reported to be within the normal concentration range. Additionally, the antioxidant properties of luteolin were theoretically examined and compared to butylated hydroxytoluene and curcumin, which are respectively synthetic and natural antioxidants. The density functional theory (DFT) and Hartree-Fock methods were used in all calculations. The most stable structures of molecules were determined by using the B3LYP functional with the 6-311G(d,p) basis set. The theoretical methods showed that the antioxidant properties of pure luteolin are similar to those of butylated hydroxytoluene.