Antioxidant capacity of Ocimum basilicum L. and Origanum vulgare L. extracts

The antioxidant properties of five different extracts (Et₂O, CHCl₃, EtOAc, n-BuOH, and H₂O) of Ocimum basilicum L. and Origanum vulgare L. were studied. Antioxidant activity was assessed in six different model systems. Free radical scavenging capacity (RSC) was evaluated by measuring the scavenging capacity of extracts on DPPH, NO, O₂•⁻ and OH radical, as well as on hydrogen peroxide (H₂O₂). In addition, the protective effects on lipid peroxidation in liposomes (LPx) were evaluated by TBA-assay using the Fe²⁺/ascorbate induction system. The amount of total phenolic compounds and content of total flavonoids was also determined. EtOAc, n-BuOH and H₂O extracts of O. basilicum and O. vulgare expressed very strong scavenger activity. Furthermore, the mentioned extracts showed notable inhibition of LPx. On the other hand, Et₂O and CHCl₃ extracts showed much weaker effect in the neutralization of DPPH, NO and O₂•⁻ radicals and the neutralization of H₂O₂. When examining the production of OH radicals and inhibition of LPx, the Et₂O and CHCl₃ extracts showed weak prooxidative properties. The observed differences in antioxidant activity could be partially explained by the levels of phenolics and flavonoids in the investigated O. basilicum and O. vulgare extracts.