Antibacterial properties of essential oils and methanol extracts of sweet basil Ocimum basilicum occurring in Bangladesh

Figures & data

Table 1.  Chemical composition of the essential leaf and stem oils of Ocimum basilicum L.

No.	Rt (min)^a	Compound	Leaf (%)	Stem (%)
1	7.29	3-Octanol	tr	tr
2	8.07	Eucalyptol	0.1	0.1
3	8.79	Tetrahydrofuran-2-ol,3,4-di(1-butyl)	tr	tr
4	9.09	Mequinol	1.6	1.8
5	9.26	Santolinatriene	tr	tr
6	9.58	Phenylethyl alcohol	0.7	0.5
7	10.33	Camphor	0.5	0.4
8	10.81	(Z)-5,7-Octadine-4-one-2,6-dimethyl	7.6	10.5
9	12.11	2-Isopropylidene-5-methylhexa-4-enal	tr	tr
10	12.32	Octadecane	tr	tr
11	12.54	Phenol-4-ethyl-2-methyl	0.2	tr
12	12.83	Nonadecane	0.1	tr
13	12.83	Heptadecane	0.1	0.1
14	13.78	α-Cubebene	tr	tr
15	14.13	Trimethoquinol	10.3	8.4
16	14.65	(–)-Caryophyllene	2.0	1.9
17	14.65	β-Guaiene	3.7	4.1
18	14.09	Methyl chavicol	36.7	29.9
19	15.47	γ-Elemene	0.5	0.4
20	15.51	γ-Neoclovene	0.2	0.6
21	15.74	Azulene	1.0	0.9
22	15.75	Naphthaline	2.2	3.8
23	15.81	Agarospirol	tr	tr
24	15.94	Cycloisolongifolene	1.2	1.4
25	16.10	Isoledene	0.9	1.0
26	16.12	Hexadecane	0.2	0.1
27	16.13	1-Chloroeicosane	0.4	0.2
28	16.24	Patchoulene	1.0	1.1
29	16.34	Aciphyllene	3.4	3.0
30	16.57	Epizonarene	1.2	1.1
31	17.06	Hinesol	0.4	0.1
32	17.11	Cubenol	0.2	0.9
33	17.19	(–)-Spathulenol	tr	tr
34	17.73	Gitoxigenin	9.3	10.2
35	17.77	β-Myristoylolene	0.9	0.6
36	18.08	Calarene epoxide	0.2	tr
37	18.11	Farnesyl bromide	0.4	0.8
38	18.17	Selina-6-en-4-ol	0.1	tr
39	18.45	γ-Himachalene	0.7	0.9
40	18.76	Agarospirol	1.2	1.0
41	19.40	Leolene alcohol	0.8	0.4
42	20.02	Ledene oxide	0.4	tr
43	20.16	Calarene epoxide	tr	0.9
44	21.06	Globulol	0.5	0.9
45	21.12	Phytol	0.2	tr
46	22.37	Longifolenaldehyde	tr	0.1
47	24.49	Dotriacontane	0.3	0.1
48	27.68	Hetadacane	0.1	0.9
49	28.08	9-Eicosyne	tr	0.2
50	28.09	3-Eicosyne	0.1	0.1
51	30.40	Octadeccanoic acid	tr	1.1
52	32.93	9-Octadecyne	tr	tr
53	43.22	Tritetracontane	0.1	0.2
54	46.74	1-Decanol-2-hexyl	tr	tr
55	46.93	Caryophyllene oxide	tr	0.9
56	47.87	Alizarin	3.2	4.4
57	49.31	Carotene	tr	0.1
		Total	94.9	96.1

^aRetention time (min) of authentic compounds on VF-5 capillary column.

tr, trace (< 0.1%).

Table 2.  Antibacterial activity of essential oils and methanolic extracts of Ocimum basilicum L. against food-borne pathogenic bacteria.

Microorganism	Zone of inhibition (mm)^a
	Essential oil^b		MeOH extract^c	Subfraction of MeOH extract^d			SM^e
	Leaf	Stem		Hexane	CHCl3	EtOAc
B. cereus	18.3 ± 1.6	20.1 ± 1.6	20.1 ± 0.5	14.2 ± 0.7	20.2 ± 1.1	21.1 ± 1.2	20.2 ± 0.5
B. subtilis	16.3 ± 1.2	18.3 ± 0.6	17.2 ± 1.1	15.1 ± 0.6	16.1 ± 1.5	19.3 ± 1.2	16.1 ± 0.7
B. megaterium	15.3 ± 1.2	17.2 ± 1.2	18.1 ± 1.0	13.2 ± 1.2	15.1 ± 0.5	18.2 ± 1.1	17.4 ± 1.2
S. aureus	16.2 ± 0.7	15.1 ± 1.2	16.1 ± 0.5	13.2 ± 1.1	15.1 ± 1.2	17.1 ± 1.2	16.2 ± 1.3
L. monocytogenes	15.1 ± 1.5	17.1 ± 1.2	16.2 ± 1.1	12.3 ± 1.4	14.0 ± 1.2	15.3 ± 1.6	17.3 ± 0.6
E. coli	11.2 ± 0.5	12.2 ± 1.1	14.1 ± 0.5	nd	12.1 ± 1.2	14.2 ± 0.6	16.3 ± 0.6
S. boydii	12.3 ± 1.2	13.3 ± 1.2	13.1 ± 1.4	nd	12.2 ± 1.1	13.0 ± 0.9	20.1 ± 0.5
S. dysenteriae	11.2 ± 1.1	12.3 ± 1.2	14.2 ± 0.7	12.3 ± 0.5	14.2 ± 0.9	15.2 ± 0.6	17.0 ± 0.5
V. parahaemolyticus	14.3 ± 1.2	15.3 ± 1.2	15.4 ± 0.5	nd	15.5 ± 0.7	16.2 ± 0.6	19.3 ± 1.1
V. mimicus	12.2 ± 1.2	13.1 ± 0.6	15.2 ± 1.1	nd	15.2 ± 1.5	15.2 ± 1.7	21.0 ± 0.7
S. typhi	14.0 ± 1.2	14.2 ± 1.2	13.1 ± 0.7	11.3 ± 0.6	14.2 ± 1.5	14.2 ± 1.7	16.3 ± 0.6
S. paratyphi	nd	nd	nd	nd	nd	nd	18.2 ± 0.8
P. aeruginosa	nd	nd	nd	nd	nd	nd	15.3 ± 1.1

^aDiameter of inhibition zone (mm) around disc (6 mm).

^b10 μL/disc, oil was diluted with MeOH, 1:5 (v/v).

^cMeOH extract (300 μg/disc).

^dSubfraction of MeOH extract (300 μg/disc).

^eStandard antibiotic: streptomycin (20 μg/disc).

nd, not detectable inhibition zone. Values are given as mean ± SD (n = 3).

Table 3.  Minimum inhibitory concentrations of essential oils and methanolic extracts of Ocimum basilicum L. against food-borne pathogenic bacteria.

Microorganism	Minimum inhibitory concentration (MIC)^a
	Essential oil		MeOH extract	Subfraction of MeOH extract
	Leaf	Stem		Hexane	CHCl3	EtOAc
B. cereus	62.5	62.5	62.5	125	62.5	62.5
B. subtilis	125	125	125	250	125	125
B. megaterium	125	125	62.5	250	125	62.5
S. aureus	125	62.5	62.5	250	62.5	62.5
L. monocytogenes	125	125	125	500	125	125
E. coli	500	250	125	>1000	250	125
S. boydii	250	250	500	>1000	250	250
S. dysenteriae	500	250	250	500	250	250
V. parahaemolyticus	500	250	500	>1000	500	250
V. mimicus	500	250	500	>1000	500	500
S. typhi	250	500	500	>1000	500	250
S. paratyphi	>1000	>1000	>1000	>1000	>1000	>1000
P. aeruginosa	>1000	>1000	>1000	>1000	>1000	>1000

^aMinimum inhibitory concentration (values in μg/mL).