Antioxidant properties and antimicrobial activity of Prosopis farcta root extract on foodborne bacteria

Plants are valuable sources of different antioxidant and antimicrobial compounds. The composition and structure of the functional groups of essential oils and extracts play an important role in their antioxidant and antimicrobial activity. Prosopis farcta is a spice of Leguminosae family and Mimosoideae subfamily, an aborigine to the dry and semi-dried regions of Asia, Africa and America. In this study, the root extract of Prosopis farcta prepared by soxhlet extractor and ethanol 70% solvent. The extraction yield was estimated at 1.85%. Total phenol and flavonoids compounds were calculated 178.14 ± 0.17 mg Gallic acid/g and 94.33 ± 0.77 mg Quercetin/g, respectively. Phenolic compounds comprised 11.98% of the total chemical composition of the extract. IC50 for root extract and BHT (synthetic antioxidant) was determined 2.45 μg/ml and 1.98 μg/ml, respectively. In the β-carotene-linoleic acid system, the average antioxidant activity reported 39.25% for root extract and 57.13% for the BHT. Among 250, 500 and 1000 ppm concentrations of the extract, 1000 ppm showed the best antioxidant effect in soybean oil for 12 days storage at 50°C. Staphylococcus aureus (with MIC 200 µg/ml and MBC 350 µg/ml) showed the most sensitivity in comparison with the two gram-negative bacteria, Salmonella Typhimurium and Escherichia coli. The results of this study showed that the hydro-ethanolic root extract of Prosopis farcta had suitable antimicrobial and antioxidant activity.