Author(s): Nadia Djermane, Noureddine Gherraf, Rabah Arhab and Khellaf Rebbas

Abstract: Evaluation of in vitro antibacterial and antioxidant activities of essential oil and organic extracts (methanolic, chloroformic and hexanic) of the aerial part of an aromatic and medicinal plant harvested in southern Algeria, belonging to the Asteraceae (Rhanterium adpressum Cosson & Durieu). The agar diffusion method was used to assess the antimicrobial activity of different extracts. These extracts were tested against eleven (11) microbial strains, ten (10) of them are bacterial species (gram positive and gram negative) and one (01) is yeast species. To evaluate the antioxidant activity, the DPPH free radical catching method was used. For the antimicrobial activity, all extracts showed inhibitory ability against at least one of the tested microbial strains, the essential oil showed the best antibacterial and antifungal activity followed by the hexanic (In-Hex), the chloroformic (EDCM) and the methanolic (EMeOH) extracts respectively. In fact, nonpolar extracts are the most active. The results of the antioxidant activity showed that the methanolic extract (EMeOH) presented the best antiradical capacity, followed by the chloroformic (EDCM) and the hexanic (In-Hex) extracts and ultimately the essential oil. Indeed, methanol is the best solvent for the concentration of the plant active substances. Extracts of Rhanterium adpressum have antioxidant and antimicrobial activities.