Antimicrobial properties of aqueous extracts from three medicinal plants growing wild in arid regions of Tunisia

Abstract

Seed extracts of three plant species that grow wild in the arid regions of Tunisia, Juniperus phoenicea L. (Cupressaceae), Pistacia atlantica Desf. (Anacardiaceae), and Oudneya africana R. Br. (Brassicaceae), were examined for antimicrobial activity against bacterial food pathogens. Aqueous extracts were prepared and then precipitated with methanol or acetone. Extracted acetone fractions (pH 7.2) showed powerful antimicrobial activity, especially against Listeria monocytogenes, Listeria innocua, and Listeria ivanovii (Gram-positive) and were also active against Gram-negative strains Escherichia coli and Pseudomonas aeruginosa. Extracts selected for high antimicrobial activity were stable in the presence of organic solvents (chloroform, hexane, acetonitrile, methanol, and acetone), and withstand thermal treatments up to 100°C for 30 min. L. monocytogenes LSD530 and E. coli ATCC 25922 appeared to be inhibited by Juniperus and Pistacia extracts with a minimum concentration of 1.56 and 3. 12 mg/mL, respectively. This study established the potential of medicinal plants growing wild in arid regions of Tunisia as a source of antimicrobial agents.

Keywords::

• Food-borne pathogens
• Juniperus phoenicea
• Oudneya africana
• Pistacia atlantica

Acknowledgement

This research was supported by the Ministry of Higher Education, Scientific Research and Technology, Republic of Tunisia.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.