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Table 2 Antimicrobial activity of 21 essential oils against S. aureus, B. subtilis and K. pneumoniae using disc diffusion method

From: In vitro antibacterial activity of some plant essential oils

Oil Name

S. aureus

B. subtilis

K. pneumoniae

Concentration

1:1

1:5

1:10

1:20

1:1

1:5

1:10

1:20

1:1

1:5

1:10

1:20

Aniseed oil

-

-

-

-

12.1 ± 1.0klm

10.8 ± 0.2ij

-

-

-

-

-

-

Calamus oil

-

-

-

-

17.9 ± 0.9def

14.7 ± 0.5cd

12.6 ± 0.5 c

11.3 ± 1.2d

-

-

-

-

Camphor oil

-

-

-

-

-

-

-

-

8.5 ± 0.5e

-

-

-

Cedar wood

-

-

-

-

13.4 ± 0.5jkl

12.2 ± 0.5ghi

99 ± 0fg

-

-

-

-

-

Cinnamon oil

20.8 ± 0.5 a

18.7 ± 0.2a

14.8 ± 0.2b

13.7 ± 0.28b

29.9 ± 0.7 a

27.8 ± 1.1 a

24.1 ± 1.1 a

22.8 ± 0.2b

27.5 ± 0.5a

23.5 ± 0.5a

20.9 ± 0.2a

18.6 ± 0.5a

Citronella oil

15.8 ± 0.3bc

10.3 ± 0.5de

-

-

14.6 ± 0.5ij

12.5 ± 0.5ghi

10.3 ± 0.5de

9.3 ± 0.5ef

-

-

-

-

Clove oil

16.3 ± 0.5 b

14.0 ± 0bc

8.1 ± 1.1d

9.8 ± 0.57c

14.5 ± 0.2hij

13.1 ± 0.2ef

10.1 ± 1.0def

8.9 ± 0.2f

16.2 ± 0.5c

14.4 ± 0.5b

8.4 ± 0.5c

-

Eucalyptus oil

-

-

-

-

-

-

-

-

-

-

-

-

Geranium oil

10.4 ± 0.5e

8.9 ± 0.2e

-

-

17.2 ± 0.2defg

14.7 ± 0.5cde

-

-

10.8 ± 0.2d

9 ± 0c

-

-

Lavender

-

-

-

-

12.5 ± 0.4jk

11.1 ± 0.2hi

-

-

-

-

-

-

Lemon oil

17.5 ± 1.1b

14.5 ± 0.2b

8.3 ± 0.2d

-

16.9 ± 0.2efgh

14.5 ± 0.5cdef

8.9 ± 0.5 g

-

16.5 ± 0.5c

15.3 ± 1.1b

8.7 ± 0.5c

-

Lemongrass oil

11.4 ± 1.0 de

8.9 ± 0.2e

-

-

16.7 ± 0.5fghi

15.1 ± 0.7 c

8.9 ± 1.0fg

-

8.3 ± 0.5e

-

-

-

Lime oil

14.2 ± 0.5cd

12.7 ± .2bcd

10.3 ± 0.

9 ± 0.00c

23.9 ± 1.1 c

20.8 ± 0.7 b

15.8 ± 0.2 b

14.1 ± 1.1c

16.1 ± 1.1c

14.6 ± 0.5b

12.9 ± 0.5b

12.6 ± 0.5b

Nutmeg

11.7 ± 0.8de

9.1 ± 0.2e

-

-

11.5 ± 0.5mn

10.9 ± 0.2hij

-

-

-

-

-

-

Orange oil

12.8 ± 0.2cd

10.6 ± 0.2cde

-

-

18.6 ± 0.8de

15.7 ± 1.2 c

9.4 ± 0.5efg

10.6 ± .5e

11.9 ± 0.7d

9.31.1c

-

-

Palmarosa oil

12.5 ± 0.2cd

10.9 ± 0.5de

8 ± 0d

-

15.4 ± 0.5ghi

14.2 ± 1cdef

12.5 ± 0.4 c

11.3 ± 0.5d

-

-

-

-

Peppermint oil

8.1 ± 0.5f

-

-

-

10.6 ± 0.5mn

8.6 ± 0.4k

-

-

-

-

-

-

Rosemary oil

12.5 ± 1d

10.6 ± 1.0e

8.6 ± 0.2d

-

14.7 ± 1hi

12.8 ± 0.5efg

11.2 ± 0.5cd

8.9 ± 0.2f

11.9 ± 0.5d

9.9 ± 0.7c

-

-

Basil oil

10.3 ± 0.5e

8.3 ± 0.5e

-

-

-

-

-

-

-

-

-

-

Vetiver oil

-

-

-

-

18.9 ± 0.9 d

15.6 ± 0.5c

12.8 ± 0.2 c

11.6 ± 0.7d

-

-

-

-

Wintergreen

8.7 ± 0.51f

-

-

-

9.9 ± 0.5 n

9.1 ± 0.1jk

-

-

-

-

-

-

Streptomycin**

20.9 ± 0.5

   

26.9 ± 0.5

   

20.9 ± 0.9

   

Vehicle control

-

   

-

   

-

   
  1. ** Streptomycin disc (25 μg) as a positive reference standard; Values are mean inhibition zone (mm) ± S.D of three replicates
  2. Means within a column followed by different letters are statistically significant by tukey's test at p = 0.05; - no activity.