Propriété antioxydante des extraits des feuilles d’Origanum vulgare (Origan) d’Ain Temouchent

Abstract

Algeria is a country rich in aromatic plants, several of which are endemic, including the species Origanum vulgare (Lamiaceae family). Essential oils and oregano extracts are widely used in the pharmaceutical and cosmetic industries and participate in the preservation of several food products. The present study is part of the valuation of the leaves of this medicinal plant present in the region of Ain Témouchent, in order to identify its bioactive molecules with antioxidant properties. In this context, this investigation is based on a set of experiments carried out on three aqueous extracts obtained after maceration, infusion and decoction of leaf powders, such as phytochemical tests and then the evaluation of the antioxidant power of the different raw aqueous extracts by two methods namely the reducing power of iron FRAP and the trapping of the radical DPPH. The results obtained showed a significant extraction yield estimated at 39.5% for the aqueous extract obtained by decoction. Regarding the phytochemical tests, a considerable content of the three aqueous extracts in flavonoids, terpenoids, tannins, quinones and reducing compounds was recorded. The results showed that the extract obtained by decoction has a very significant capacity to reduce iron and which remains higher than that of ascorbic acid with an OD equal to 2.793 at a concentration of 25mg/ml. According to the DPPH free radical scavenging method, the extract obtained by the infusion method showed excellent antioxidant activity compared to the other two extracts tested with an IC50 equal to 2.83 mg/mL. In conclusion, the present study reveals biological evidence that supports the efficacy of using leaves of O. vulgare as a traditional remedy for several pathologies.