Table 4.
Capability of M. communis EO and its main components to inhibit the biofilm metabolic activity
| Time | Myrtle EO (mg/ml) | Myrtenyl acetate (mg/ml) | 1,8-Cineole (mg/ml) | α-Pinene (mg/ml) | Linalool (mg/ml) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 0.4 | 1 | 2 | 0.4 | 1 | 2 | 0.4 | 1 | 2 | 0.4 | 1 | 2 | 0.4 | 1 | 2 |
| EC |
21.49 (± 0.57) |
27.15 (± 1.33) |
37.59 (± 0.57) |
0 (± 0) |
0 (± 0) |
61.34 (± 1.67)**** |
0 (± 0) |
0 (± 0) |
0 (± 0.0) |
0 (± 0) |
6.19 (± 0.15) |
33.75 (± 1.33) |
0 (± 0) |
0 (± 0) |
56.72 (± 1.67)**** |
| LM |
6.81 (± 0.57) |
38.74 (± 0.57) |
68.06 (1.57) |
20.05 (± 2.05)**** |
39.25 (± 3.32) |
41.73 (± 2.05) |
0 (± 0) |
39.62 (± 4.56) |
55.17 (± 1.33) |
27.72 (± 1.67)**** |
29.83 (± 0.57) |
67.71 (± 2.33) |
33.42 (± 1.67)**** |
43.42 (± 0.57) |
54.47 (± 3.67) |
| PC |
23.56 (± 1.33) |
57.93 (± 1.67) |
60.82 (± 1.67) |
46.18 (± 1.07)**** |
59.10 (± 2.33) |
60.77 (± 2.57) |
20.38 (± 2.33) |
30.44 (± 4.21) |
35.65 (± 2.33) |
0 (± 0) |
0 (± 0) |
36.81 (± 1.67) |
0 (± 0) |
62.31 (± 3.33) |
77.84 (± 2.67)**** |
| PA |
0 (± 0) |
0 (± 0) |
50.19 (± 1.57) |
95.12 (± 1.33)**** |
95.72 (± 0.57)**** |
96.99 (± 0.57)**** |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
31.32 (± 1.67)**** |
40.22 (± 1.33) |
30.12 (± 1.33)**** |
48.54 (± 2.57) **** |
59.59 (± 3.33) *** |
| SA |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
50.29 (± 1.67)**** |
78.13 (± 1.67)**** |
0 (± 0) |
5.76 (± 0.57)* |
12.03 (± 0.57)*** |
76.23 (± 1.67)**** |
78.07 (± 1.67)**** |
89.41 (± 1.67)**** |
0 (± 0) |
72.34 (± 3.56)**** |
77.05 (± 4.87)**** |
| 24 h | 0.4 | 1 | 2 | 0.4 | 1 | 2 | 0.4 | 1 | 2 | 0.4 | 1 | 2 | 0.4 | 1 | 2 |
| EC |
0 (± 0) |
0 (± 0) |
6.36 (± 1.57) |
0 (± 0) |
0 (± 0) |
32.29 (± 1.67) |
0 (± 0) |
0 (± 0) |
0 (± 0.0) |
0 (± 0) |
0 (± 0) |
16.62 (± 1.33) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
| LM |
24.44 (± 1.57) |
61.65 (± 2.67) |
68.65 (± 1.57) |
0 (± 0) |
0 (± 0) |
50.89 (± 2.67) |
0 (± 0) |
0 (± 0) |
2.59 (± 1.67) |
22.56 (± 1.67) |
42.80 (± 2.25) |
43.73 (± 2.33) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
| PC |
0 (± 0) |
0 (± 0) |
64.11 (± 1.67) |
36.28 (± 1.67) |
52.70 (± 2.25) |
68.70 (± 2.25) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
35.75 (± 1.25) |
63.27 (± 1.67) |
71.59 (± 1.67) |
27.86 (± 0) |
45.04 (± 4.34) |
45.20 (± 2.34) |
| PA |
13.43 (± 1.67) |
32.86 (± 2.24) |
45.44 (± 1.57) |
37.77 (± 1.73) |
53.62 (± 1.57) |
70.79 (± 1.67) |
9.65 (± 0.15) |
20.35 (± 0.65) |
52.79 (± 2.21) |
11.21 (± 0.86) |
30.31 (± 1.57) |
65.31 (± 1.67) |
0 (± 0) |
0 (± 0) |
38.10 (± 0.57) |
| SA |
31.86 (± 1.67) |
51.10 (± 1.45) |
65.30 (± 2.25) |
34.52 (± 0.57) |
63.39 (± 1.67) |
69.77 (± 1.57) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
11.33 (± 1.33) |
26.77 (± 2.67) |
35.88 (± 1.57) |
17.98 (± 0) |
37.44 (± 1.57) |
44.92 (± 3.67) |
| 48 h | 0.4 | 1 | 2 | 0.4 | 1 | 2 | 0.4 | 1 | 2 | 0.4 | 1 | 2 | 0.4 | 1 | 2 |
| EC |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
26.53 (± 1.67) |
0 (± 0) |
0 (± 0) |
31.08 (± 0.0) |
3.44 (± 0) |
10.23 (± 0.15) |
45.84 (± 1.33) |
0 (± 0) |
5.14 (± 0) |
8.77 (± 0.57) |
| LM |
0 (± 0) |
0 (± 0) |
60.63 (1.57) |
17.74 (± 2.06) |
39.17 (± 3.32) |
49.97 (± 2.05) |
0 (± 0) |
0 (± 0) |
53.92 (± 1.33) |
25.67 (± 1.67) |
45.49 (± 0.57) |
61.83 (± 2.33) |
0 (± 0) |
4.19 (± 0.57) |
55.51 (± 3.67) |
| PC |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
4.09 (± 2.33) |
14.07 (± 4.21) |
38.28 (± 2.33) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 3.33) |
24.18 (± 1.67) |
| PA |
0 (± 0) |
0 (± 0) |
23.04 (± 1.57) |
0 (± 0) |
0 (± 0) |
15.73 (± 0.57) |
0 (± 0) |
0 (± 0) |
43.89 (± 0) |
20.56 (± 0) |
40.30 (± 1.67) |
40.71 (± 1.33) |
0 (± 0) |
0 (± 0) |
14.51 (± 1.13) |
| SA |
0 (± 0) |
0 (± 0) |
44.96 (± 0) |
0 (± 0) |
0 (± 0) |
7.37 (± 0.57) |
12.44 (± 0) |
31.36 (± 0.57)* |
32.19 (± 0.57) |
0 (± 0) |
0 (± 0) |
32.19 (± 1.21) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
The test was performed with 0.4, 1 and 2 mg/ml that were added at time zero, on 24 h-biofilms and on 48 h-biofilms, using the MTT assay. Results are reported as percent of inhibition respect to the control (for which the inhibition was assumed = 0). Results are the mean of three experiments (± SD). EC: E. coli; LM: L. monocytogenes; PC: P. carotovorum; PA: P. aeruginosa; SA: S. aureus. * p < 0.05;*** p < 0.001; ****p < 0.0001 compared with values obtained with EO (ANOVA followed by Dunnett’s multiple comparisontest)