Abstract

The present work evaluates the antioxidant and antibacterial activities of four Libyan plants (Arbutus pavarii, Pegnanum harmal, Pistachia atlantica, and Fagonia bruguieri) using various assays including reducing power, Phosphomolybdenum, 1,1-diphenyl-2-picrylhydrazyl (DPPH)  and nitric oxide free-radical scavenging activity. In vitro, the antibacterial activity of crude and flavonoids extracts were determined against five strains, Staphylococcus aureus, Bacillus subtilis, Streptococcus faecalis, Escherichia coli, Salmonella typhi. In the extracts of all plants under investigation, the total flavonoids and polyphenols were quantitatively estimated. Leaves of A. pavarii possess the highest antioxidant potential with significant free-radical-scavenging effects; the highest flavonoids content (1504.28±80.89 mg Rutin g^-1) and a relatively high content of phenolics (1217.14±50.52 mg GAE g^-1) compared to the other tested plants. Regression analysis of the antioxidant assays showed a strong correlation between phenolics or flavonoids content and nitric oxide scavenging activity as well as total antioxidant activity. Also the crude extracts especially A. pavarii showed greater growth inhibition capacity towards tested bacterial strains. Results of the antioxidant assays and antimicrobial screening showed that, all tested plants can act as radical scavengers and antimicrobial agents to a certain extent. Future study is recommended to further purify and examine individual bioactive compounds from these extracts and evaluate their in vivo antioxidant and bacterial activities.

Key words: Arbutus pavarii, Pegnanum harmal, Pistachia atlantica, Fagonia bruguieri, polyphenols, antioxidant activity, antibacterial activity.