Composition, Antioxidant and Antimicrobial Activities of Algerian Rosmarinus officinalis L. Extracts

Abstract

This study was designed to examine the in vitro antioxidant and antimicrobial activities of ethanol extracts and essential oils of three samples of Rosmarinus officinalis L. from different origins of Algeria. The compositions of the essential oils obtained by hydrodistillation were investigated by GC and GC-MS. A total of eighty components were identified in the oils and the main components of two samples were α-pinene (24.7-51.0 %), limonene (4.5-14.3 %) and camphor (7.8-13.8 %), while the third one was characterized by camphor (32.0 %), camphene (22.0 %) and α-pinene (20.9 %) as the main components. The antioxidant capacity of the oils and ethanol extracts was examined using an in vitro radical scavenging test and reducing power. In the 2,2-diphenylpicrylhydrazyl (DPPH) test system, ethanol extracts exhibited more efficiency (IC50=10.4-20.7 mg/l) than butylated hydroxytoluene (BHT) (IC50=28±0.7 mg/l). In contrast, essential oils were less effective than BHT and failed to scavenge 50 % DPPH radical. The reductive potential of the ethanol extracts was also found to be higher than those of the oils. The antimicrobial activity was evaluated by determining the minimum inhibitory concentration (MIC) against eight bacteria, six filamentous fungi and one yeast. In comparison with oils, the ethanol extracts were the most active, especially towards gram positive bacteria.