This work examines the chemical composition, antimicrobial and antioxidant activities of four phenolic extracts and essential oil of Juniperus phoenicea L. (cuprecaceae) aerial parts growing spontaneously in el Bayedh region of southwestern Algeria. The hydro-distillated essential oil from this plant was characterized by gas chromatography-mass spectrometry (GC-MS). This oil is mainly composed of monoterpene and Sesquiterpenes at 59.885 and 21.814%, respectively. A total of 45 compounds were identified which makes up 100% composition of the oil and α-pinene (46.437%), Linalool (5.972%), δ-3-carene (5.82%), were the dominant components. In vitro antibacterial activity of organic fractions extracted from Juniperus phoenicea L. was evaluated against nine food-borne bacterial pathogens and one yeast Candida albicans using the method of disc diffusion, then minimum inhibitory concentration (MIC) values were examined using the micro-dilution method. Obtained results suggest that essential oil as non-polar organic fraction is the main active in this plant against C. albicans with (MIC=63 µg/ml) and for bacteria the most sensitive were Bacillus subtilis, Micrococcus luteus , Bacillus cereus as gram positive bacteria with (MIC= 80, 80 and 40 µg/ml). However, the four phenolic extracts have proved to have a moderate to good activity on most of the microbial strains tested, especially against the gram positive strains Bacillus cereus, Staphylococcus aureus Bacillus subtilis, Listeria monocytogenes and Micrococcus luteus with minimum inhibitory concentration MIC between 40 to 187 µg /ml, and vis Kleibseilla pneumonie as gram negative strain with minimum inhibitory concentration MIC between (23 to 93 µg/ml). On the other hand, the antioxidant activity evaluated by the DPPH test has enabled us to infer that most of phenolic extracts have a relatively strong antioxidant potential compared with the standards butylated hydroxyl anisole (BHA) and ascorbic acid. The contemporary presence of bioactivities suggests that J. phoenicea L. aerial parts may be a source for such new preservatives and natural antioxidant and antimicrobial molecules.
Keywords: Juniperus phoenicea L., chemical compositions, essential oil, phenolic compounds, antibacterial activity, antioxidant activity.