Antibacterial and Antioxidant Properties of Methanolic Extracts of Some Native Edible Plants Collected from Kermanshah, Western Iran

Background: There is growing demand to improve physicochemical, microbiological, and sensory properties of fresh foods using natural herbal antimicrobial and antioxidant compounds. The aim of the present study was to investigate antioxidant and antibacterial properties of some native edible plants of Kermanshah, Western Iran. Methods: The methanolic extracts of leaves of Falcaria vulgaris, Allium rotundum, Tragopogon graminifolius, and Mentha longifolia plants were prepared. The antibacterial effects of these four plant extracts were determined on Salmonella typhimurium, Bacillus subtilis, B. cereus, Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157:H7 using micro-broth dilution and agar disk diffusion assays. Also, the 2,2-diphenyl-1-picrylhydrazyl hydrate assay was used for determination of antioxidant properties of the plant extracts. The analysis was performed using SPSS 16.0 (Chicago, IL, USA) software package. Results: The most antibacterial effectiveness was significantly (p<0.05) found for M. longifolia extract. The following sequence inhibition effect on investigated bacterial strains was observed: M. longifolia>T. graminifolius>A. rotundum>F. vulgaris. Moreover, Gram-negative bacteria were more resistant to the presence of methanolic plant extracts than Gram-positive bacteria. The highest antioxidant activity (based on IC50) was significantly (p<0.05) found for M. longifolia (0.88&plusmn;0.12 mg/ml); as well as these rates for T. graminifolius, A. rotundum, and F. vulgaris extracts were 0.45&plusmn;0.78, 0.26&plusmn;0.07, and 0.14&plusmn;0.23 mg/ml, respectively. Conclusion: The studied edible plants had antimicrobial and antioxidant activities that recommend as potential preservatives in food products. However, methanolic extract of M. longifolia had the best antibacterial and antioxidant properties in vitro.