تأثیر روش استخراج عصاره اندام هوایی گیاه دارویی سرخارگل (Echinacea Purpurea L.) بر خاصیت ضد میکروبی آن در تعدادی از باکتری‌های بیماری‌زا

Background and Objective: In recent years, it is recommended to use natural materials like plant extracts and essences instead of chemical preservatives in food industry. The main objective of this study was to evaluate the antimicrobial activity of shoot extract of purple coneflower against some gram positive and gram negative bacteria.  Materials and Methods: This Laboratory study was conducted in 2013. Two extraction methods (maceration and microwave-assisted) with three solvents (water, methanol 80% and acetone) were used to extract the phenolic compounds from purple coneflower shoot The micro-organisms investigated in this study were: Bacillus cereus, Listeria monocytogenes, Escherichia coli, Shigella dysenteriae and Pseudomonas aeruginosa. Experimental data were analyzed using ANOVA by the SPSS version 15 software and mean comparison were done using the Duncan's multiple range test. Results: The highest total phenolic content was related to the methanol extract produced by microwave-assisted extraction (MAE), whereas in both extraction methods, the lowest amount of phenolic was obtained by using acetone extract. Comparing the extraction methods showed that MAE had higher extraction efficiency in all three tested solvents. Regarding to antimicrobial activity of purple coneflower shoot extracts, the minimum inhibitory concentration and minimum bactericidal concentration were observed in gram positive bacteria (Bacillus cereus and Listeria monocytogenes). Pseudomonas aeruginosa was the most resistant bacterium against the extracts. Conclusion: The results showed that in most cases, the extracts obtained by MAE method had more antimicrobial activity in comparison to traditional method. In addition the microwave-assisted extract of this plant can be considered as a food preservative. However, more studies, such as examinations in food models are needed to unravel the antimicrobial effects of given plant. Key words: Purple coneflower extract, Antimicrobial properties, Extraction method. Funding: This research was funded by Hamadan University of Medical Sciences and Tarbiat Modares University. Conflict interest: None declared. Ethical approval: This article does not need permission from the Ethics Committee because the information in this article was derived from a non-animal research.   How to cite this article: Izadi Z, Sorooshzadeh A, Modarres Sanavi S.A.M, Esna-Ashari M, AghaAlikhani M, Davoodi P. Effect of Extraction Method on Antimicrobial Properties of Shoot Extract of Purple Coneflower (Echinacea Purpurea l.) Against Some Pathogenic Bacteria?. J Rafsanjan Univ Med Sci 2014 13(3): 267-80. [Farsi]