Antimicrobial activity and composition of the essential oils of Echinacea species cultivated under organic farming conditions in Turkey

The aim of the present study was to investigate the antimicrobial activity of the essential oils from the flower part of Echinacea purpurea and Echinacea pallida by a semiquantative disc-diffusion method. The minimum inhibitory concentration (MIC) were determined based on a micro-well dilution method against the strains of E. coli, S. enteritidis, S.cholerasuis, P. aeruginosa, S. aureus, B. cereus, S.lutea, C. albicans. E. purpurea and E. pallida cultivated in the experimental farm of Selcuk University under the organic farming conditions and analysis of essential oils was performed by GC and GC-MS. Essential oil compositions of two species were found to be significantly different from each other. The essential oil of E. purpurea was found remarkably rich in germacrene D (11.20%), spathulenol (8.83%), caryophyllene oxide (8.46%) and 1,5-epoxysalvial-4(14)-ene (5.76%). On the other hand essential oil of E. pallida was found rich in caryophyllene oxide (9.35%), germacrene D (7.25%) and α-cadinol (6.40%). When compared with the previous work, results varied significantly [1,2]. The antimicrobial activity of essential oils from E. purpurea and E. pallida were examined against micro-organisms and the results are presented in Table 1.

Plant		E. coli	S. enteritidis	S. cholera suis	P. aeruginosa	S. aureus	B. cereus	S. lutea	C.albicans
E. pallida	mm	19	17	15	17	16	10	15	18
	MIC mg/ml	31.25	31.25	31.25	62.50	125	62.50	62.50	31.25
E. purpurea	mm	15	13	13	12	20	18	19	19
	MIC mg/ml	62.50	62.50	31.25	125	31.25	62.50	62.50	62.50

References: 1. Chicca, A. Et al. (2007)J. of Ethnopharm. 110: 148–153. 2. Mirialili, M.H. Et al. (2006) Flav. and Frag. J. 21: 355–358.