Antibacterial Activity of Extracts of Myrtus communis Against Food-Borne Pathogenic and Spoilage Bacteria

Figures & data

Table 1 Antibacterial activity of different leaf and berry extracts of Myrtus communis against food-borne and spoiling bacteria. ^a

	Inhibition zones of leaves extracts (mm) ^b			Inhibition zones of berries extracts (mm) ^b
Microorganisms	Methanol	Ethanol	Ethyl acetate	Methanol	Ethanol	Ethyl acetate
Bacillus subtilis DCM 3366	27± 2,12	26 ± 1,41	35 ± 0,00	30 ± 2,68	32 ± 1,48	22 ± 1,67
Enteroccus faecium CECT 410	45± 1,34	30 ± 1,13	36 ± 1,41	30 ± 1,41	35 ± 1,41	8 ± 0,00
Escherchia coli K12	8 ± 0,00	8 ± 0,00	8 ± 0,00	8 ± 0,00	8 ± 0,00	8 ± 0,00
Listeria innocua CECT 4030	23± 0,00	17 ± 0,71	15 ± 0,42	30 ±0,42	23 ± 1,76	11 ± 1,55
Listeria monocytogenes CECT 4032	50± 0,47	30 ± 1,56	35 ± 0,84	30 ±0,00	31 ± 2,89	31 ± 1,96
Proteus vulgaris CECT 484	20± 1,77	15 ± 0,00	8 ± 0,00	15 ± 0,56	19 ± 1,48	8 ± 0,00
Pseudomonas aeruginosa IH	23± 1,41	23 ± 1,27	8 ± 0,00	20 ± 1,27	14 ± 1,27	8 ± 0,00
Pseudomonas aeruginosa CECT 118	22± 0,07	15 ± 0,42	8 ± 0,00	26 ± 0,42	25 ± 1,41	8 ± 0,00
Pseudomonas aeruginosa CECT 110T	22± 0,71	16 ± 1,27	8 ± 0,00	30 ± 2,26	37 ± 0,91	8 ± 0,00
Pseudomonas flourescens CECT 378	12± 0,00	13 ± 0,28	8 ± 0,00	24 ± 2,82	20 ± 0,35	8 ± 0,00
Staphylococcus aureus MBLA	35± 1,41	37 ± 0,00	8 ± 0,00	20 ± 0,00	20 ± 1,83	8 ± 0,00
Staphylococcus aureus CECT 976	35±0,71	37 ± 1,98	32 ± 2,82	27 ± 3,11	22 ± 3,32	35 ± 1,13
Staphylococcus aureus CECT 794	35±0,28	37± 1,61	33 ± 1,13	27 ± 2,96	24 ± 0,70	35 ±2,47
^aValues are means of three replicates. ^bDiameter of inhibition zone including well diameter of 8 mm.

Table 2 Minimum inhibition concentrations (MICs) of different leaf and berry extracts of Myrtus communis against food-borne and spoiling bacteria

	MIC^b of leaves extracts			MIC^b of berries extracts
Microorganisms	Methanol	Ethanol	ethyl acetate	Methanol	Ethanol	ethyl acetate
Bacillus subtilis DCM 3366	0.3	0.3	2.5	2.5	0.625	2.5
Enteroccus faecium CECT 410	2.5	0.3	5	2.5	>5	–
Escherchia coli K12	–	–	–	–	–	–
Listeria innocua CECT 4030	0.15	0.15	0.15	2.5	2.5	2.5
Listeria monocytogenes CECT 4032	0.625	5	>5	1.25	1.25	1.25
Proteus vulgaris CECT 484	>5	>5	–	>5	>5	–
Pseudomonas aeruginosa IH	0.625	0.625	–	1.25	1.25	–
Pseudomonas aeruginosa CECT 118	5	5	–	5	5	–
Pseudomonas aeruginosa CECT 110T	5	5	–	2.5	<5	–
Pseudomonas flourescens CECT 378	0.625	5	–	2.5	2.5	–
Staphylococcus aureus MBLA	0.625	0.625	–	0.3	5	–
Staphylococcus aureus CECT 976	<0.075	0.3	<0.075	<0.075	0.15	0.3
Staphylococcus aureus CECT 794	<0.075	<0.075	<0.075	<0.075	0.15	2.5
(–): no inhibition ^aValues are means of three replicates. ^bMIC, minimum inhibitory concentration (as mg/ml).

Figure 1 Viable count of (a) Listeria monocytogenes CECT 4032 and (b) Pseudomonas aeruginosa IH cells (log CFU/ml) at different times after the addition of three concentrations (▪: control; ♦: MIC; ○: 2 MIC; and Δ: 4 MIC) of methanolic leaf extracts.