Table 3.
Percent inhibition of the formation of biofilm exhibited by myrtle EO and its main components
| 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 |
7.20 (± 1.05) |
13.9 (± 1.33) |
26.25 (± 1.67) |
0 (± 0) |
2.01 (± 0.02) |
3.45 (± 0.05) |
0 (± 0) |
6.11 (± 0.57) |
13.75 (± 0.57) |
0 (± 0) |
6.19 (± 0.57) |
20.76 (± 0.57) |
0 (± 0) |
3.12 (± 0.16) |
33.68 (± 0.44)**** |
| LM |
2.03 (± 0.03) |
34.79 (± 1.33) |
64.55 (± 1.15) |
0 (± 0) |
2.97 (± 0.03) |
39.03 (± 1.67) |
0 (± 0.0) |
0 (± 0) |
17.7 (± 1.67) |
17.72 (± 1.56)**** |
29.83 (± 1.67) |
44.49 (± 1.67) |
0 (± 0) |
5.44 (± 0.04) |
7.12 (± 0.08) |
| PC |
0 (± 0) |
44.27 (± 1.57) |
47.28 (± 1.57) |
0 (± 0) |
0 (± 0) |
2.08 (± 0.09) |
0 (± 0) |
0 (± 0) |
36.81 (± 1.67) |
0 (± 0) |
0 (± 0) |
39.65 (± 2.25) |
0 (± 0) |
36.95 (± 1.12) |
55.46 (± 1.44****) |
| PA |
0 (± 0) |
3.33 (± 0.57) |
66.67 (± 1.33) |
14.11 (± 0.89)**** |
57.46 (± 1.33)**** |
57.86 (± 2.13) |
0 (± 0) |
0 (± 0) |
40.22 (± 1.57) |
20.44 (± 2.26)**** |
33.32 (± 1.57)**** |
77.45 (± 2.33)**** |
0 (± 0) |
16.91 (± 0.97)**** |
17.57 (± 0.67) |
| SA |
42.1 (± 1.57) |
43.55 (± 1.25) |
56.7 (± 1.33) |
0 (± 0) |
54.54 (± 2.67) **** |
49.08 (± 2.33) |
0 (± 0.0) |
32.03 (± 2.33) |
59.41 (± 1.67) |
26.23 (± 1.56) |
28.07 (± 2.16) |
91.39 (± 1.67)**** |
0 (± 0) |
22.50 (± 1.57) |
23.07 (± 1.43) |
| 24 h | |||||||||||||||
| EC |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
| LM |
0 (± 0) |
13.65 (± 1.25) |
15.93 (± 1.24) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
7.14 (± 1.67) |
18.48 (± 1.67) |
28.99 (± 1.57) |
0 (± 0) |
9.2 (± 0.04) |
44.13 (± 1.14) |
| PC |
0 (± 0) |
0 (± 0) |
2.8 (± 1.57) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
2.51 (± 0.16) |
0 (± 0) |
0 (± 0) |
2.59 (± 1.67) |
0 (± 0) |
0 (± 0) |
5.37 (± 1.67) |
| PA |
0 (± 0) |
0 (± 0.57) |
4.97 (± 1.33) |
0 (± 0) |
0 (± 0) |
6.33 (± 0.57) |
0 (± 0) |
0 (± 0) |
16.61 (± 1.57) |
0 (± 0) |
0 (± 0) |
14.66 (± 2.33)**** |
0 (± 0) |
5.43 (± 0.57) |
7.07 (± 0.67) |
| SA |
0 (± 0) |
0 (± 0) |
1.1 (± 0.02) |
12.34 (± 0) |
19.92 (± 1.44) |
50.62 (± 1.67) |
0 (± 0) |
9.82 (± 0.57) |
18.09 (± 1.13) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
35.68 (± 1.43) |
| 48 h | |||||||||||||||
| EC |
12.24 (± 1.13) |
32.07 (± 1.67) |
42.49 (± 2.24) |
14.07 (± 0.57) |
50.42 (± 1.14) |
52.15 (± 2.25) |
23.56 (± 1.67) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
15.67 (± 1.07) |
49.51 (± 1.23) |
50.45 (± 1.15) |
| LM |
0 (± 0) |
0 (± 0) |
4.09 (± 0.07) |
0 (± 0) |
0 (± 0) |
9.66 (± 0.04) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
6.05 (± 0) |
30.15 (± 0.65) |
75.77 (± 1.23) |
| PC |
0 (± 0) |
0 (± 0) |
8.29 (± 0.57) |
0 (± 0) |
0 (± 0) |
23.70 (± 0.57) |
0 (± 0) |
0 (± 0) |
36.81 (± 1.67) |
0 (± 0) |
0 (± 0) |
2.59 (± 0.02) |
0 (± 0) |
0 (± 0) |
24.10 (± 1.4) |
| PA |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
11.73 (± 0.57) |
0 (± 0) |
0 (± 0) |
10.23 (± 0.57) |
0 (± 0) |
0 (± 0) |
0 (± 0) |
4.95 (± 0.05) |
19.98 (± 1.67) |
20.45 (± 1.57) |
| SA |
0 (± 0) |
0 (± 0) |
22.06 (± 1.12) |
0 (± 0) |
0 (± 0) |
44.78 (± 1.12) |
0 (± 0) |
0 (± 0) |
41.53 (± 1.57) |
7.65 (± 0.15) |
35.82 (± 1.44) |
36.48 (± 1.22) |
25.43 (± 1.57) |
60.01 (± 1.67) |
64.66 (± 1.24) |
Data 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 < 0.0001 compared with values obtained with EO (ANOVA followed by Dunnett’s multiple comparison test)