Identification of chemical compounds, antioxidant potential and antimicrobial effect of Echinophora platyloba extract on some bacteria causing infection and food poisoning

Echinophora platyloba as a valuable medicinal plant is widely used in traditional medicine to treat infectious diseases. In addition, the herb is used to flavor dairy products. The aim of this study was to extract and identify the chemical compounds, investigate the antioxidant property, determination of total phenolic and flavonoid content and the antibacterial effect of Echinophora platyloba extract (EPE) on some foodborne bacteria. Maceration method was used for extract of aerial parts of Echinophora platyloba. Chemical compounds of the extract were identified by high performance liquid chromatography (HPLC). Antioxidant properties of EPE was measured by DPPH free radical scavenging method (IC 50), total phenolic compounds were determined by using Folin-ciocalteu and total flavonoid content by aluminum chloride reagent, respectively. Antimicrobial activity was determined by Microdilution broth method, minimum bactericidal concentration (MBC), diffusion in agar by disk and well method. Chlorogenic acid and Pyrocatechol were the most abundant compounds in EPE. Total phenolic compounds, total flavonoids and IC50 of EPE were 100.30 ± 0.45 mg GAE/g, 126.26 ± 0.52 mg QE/g and 263.95 ± 0.61 mg/ml, respectively. The minimum inhibitory concentrations for Staphylococcus aureus, Listeria inocoua, Pseudomonas aeruginosa and Escherichia coli were 16, 32, 128 and 128 mg/ml, respectively. The MBC for all bacteria was greater than 512 mg/ml for all bacteria. The diameter of the microbial inhibitory zone of the EPE in disc and well diffusion methods for Staphylococcus aureus (most sensitive) was 24.14 mm and 19.70 mm, respectively. The results of this study revealed that EPE has an acceptable antibacterial activity against the pathogenic microorganisms. However, Gram-positive bacteria obtained higher antimicrobial activity of the extract, compared to Gram-negative bacteria. It is recommended that further studies be conducted to investigate the clinical application of EPE.