Chemical Composition and Antimicrobial Activity of Essential Oil and Solvent Extracts of Torch Ginger Inflorescence (Etlingera elatior Jack.)

Figures & data

Table 1 Chemical composition of essential oils of E. elatior inflorescence.^z

Chemical compound		RT	%
	Terpene hydrocarbons
1	Monoterpene hydrocarbon	−	−
2	Sesquiterpene hydrocarbon	−	0.99 ± 0.01
3	β-Caryophyllene	16.06	0.38 ± 0.01
4	Farnesyl alcohol	19.31	0.61 ± 0.01
5	Bicyclo[3.1.1]hept-2-ene, 2,6,6-trimethyl/α-Pinene	4.23	tr
6	Bicyclo[3.1.1]hept-3-en-2-one, 4,6,6-trimethyl-, (1S)/1-Verbenone	9.98	tr
7	1,6,10-Dodecatrien-3-ol, 3,7,11-trimethyl-, (E)-/(E)-Nerolidol	21.13	tr
Oxygenated compounds		RT	%
	Aldehydes (total)		19.54 ± 1.5
8	Decanal/Caprinaldehyde	10.2	2.04 ± 0.2
9	Dodecanal	15.72	17.5 ± 1.35
10	Benzaldehyde, 3,5-bis(phenylmethoxy)-	4.53	tr
11	4-Methylpentanal	12.57	tr
12	10-Undecenal	15.10	tr
13	Cyclohexanepropanal, 1-nitro-2-oxo-, (.+-.)-	30.58	tr
	Alcohols (total)		44.25 ± 2.5
14	1-Nonanol	12.24	1.55 ± 0.4
15	1-Dodecanol	17.46	25.17 ± 3.4
16	8-Dodecen-1-ol, (z)-/Guava oil	21.55	4.03 ± 0.8
17	Hexadecen-1-ol, trans-9-	21.94	12.73 ± 1.2
18	Cis-7-dodecen-1-ol/Looplure inhibitor	25.55	0.21 ± 0.01
19	1-Tetradecanol/Myristic alcohol	26.07	0.24 ± 0.01
20	1-Propanol, 2-methyl-/Isobutanol	1.29	tr
21	1-Hexen-3-ol/Propylvinylcarbinol	1.75	tr
22	1,2-Propanediol/Methylethylene glycol	2.29	tr
23	10-Undecyn-1-ol	21.22	tr
24	13-Tetradece-11-yn-1-ol	21.22	tr
25	11-Dodecen-1-ol	21.78	tr
26	10-Undecen-1-ol/ω-Undecenyl alcohol	24.13	tr
27	2-Propyldecan-1-ol	24.85	tr
28	6H-Dibenzo[B,D]pyran-1-ol, 3-hexyl-6A,7,7,10A-tetrahydro-6,6,9-trimethyl-,(6AR-trans)-	25.34	tr
^zData represents mean ± standard deviation of three independent determinants.
RT: retention time; tr: percent in trace amounts.
Oxygenated compound		RT	%
29	Isooctanol	25.34	tr
30	13-Tetradece-11-yn-1-ol	25.76	tr
31	(8E)-8-Dodecen-1-ol	26.9	tr
32	Decitol,1,2:4,5:9,10-trianhydro-2,6,7,8-tetradeoxy-	27.32	tr
	Ketones (total)		tr
33	2,3-Hexanedione/Acetylbutyryl	2.0	tr
34	2-Undecanone	12.57	tr
35	2-Hexanone, 5-methyl-	17.71	tr
36	2H-Pyran-2-one, 3-acetyl-4-hydroxy-6-[2-(4-nitrophenyl]-, (E)-	27.47	tr
37	Cyclododecanone, 2-nitro-, (.+-.)-	37.68	tr
38	2,4,6-Trimethyl-1-nonene	40.67	tr
	Esters (total)		10.51 ± 1.4
39	Cis-7-tetradecan-1-ol	21.44	0.54 ± 0.02
40	Dodecan-1-yl acetate	2.44	8.51 ± 1.2
41	9-Tetradecen-1-ol, acetate, (z)-	24.35	0.42 ± 0.01
42	1-Tetradecyl acetate/Myristyl acetate	24.69	1.04 ± 0.01
43	Vinyl butyrate/Butyric acid, vinyl ester	1.25	tr
44	Butyl ester of hydroxyacetic acid/butyl glycolate	1.75	tr
45	Acetic acid ethyl ester/Ethyl acetate	2.29	tr
46	Hexadecanoic acid, methyl ester	27.10	tr
47	Heptadecanoic acid, ethyl ester	28.31	tr
48	Ethyl nonadecanoate	28.31	tr
49	Isopropenyl dodecanoate	35.66	tr
50	Dodecanoic acid, 8-nitro-11-oxo-, methyl ester	37.68	tr
51	Undecyl ester of dodecanoic acid	37.85	tr
	Acids (total)		24.42 ± 2.8
52	Dodecanoic acid/Lauric acid	19.98	20.40 ± 2.1
53	Z-7-Tetradecenoic acid	23.38	0.49 ± 0.02
54	Tetradecanoic acid/Myristic acid	23.79	3.58 ± 0.02
55	Hexadecanoic acid/Palmitic acid	27.62	0.32 ± 0.01
56	Propanoic acid, 2-methyl-, 1-methylethyl ester/Isobutyric acid	1.25	tr
	Others (total)
57	Cyclobutane, methyl-/Methylcyclobutane	1.72	tr
58	Butane	1.99	tr
59	1,3,6-Octatriene, 3,7-dimethyl-, (E)-/Trans ocimene	4.23	tr
60	1,3,5-Cycloheptatriene/Tropilidene	4.53	tr
61	Tricycle[3.1.0.02,6]hexane, 1-butyl	8.70	tr
62	3-Heptyne-2,6-diol, 5,5-dimethyl-	8.70	tr
63	2,4-Cyclohexadiene-1-methanol, α,α,4-trimethyl	9.14	tr
64	2,4,6,-Trimethyl-1-nonene	12.91	tr
65	Phenanthrene, 1,4,5,8,9,10-hexamethyl-	18.0	tr
66	1-Hexadecyne	24.13	tr
67	Dodecane, 1,1-difluoro	24.85	tr
68	9,10,11-Trioxabicyclo[6.2.1]undecane	27.47	tr
69	Cyclooctanone, 2-nitro-, (.+-.)-	30.58	tr
70	2-Furancarboxaldehyde, 5-ethoxytetrahydro-2-(1-methylethyl)-	30.80	tr
71	Ethyl (1R*, 2R*)-2-allyl-2-hydroxycyclopentane-1-carboxyate	30.80	tr
72	Isoxazole, 3-(3-butenyl)-5-methyl	34.61	tr
73	5,8,9,10-Tetrahydro-10-hydroxymethyl-2-methyl-2-methoxy-3,6-dimethylbenzocyclooctene	34.61	tr
74	2-Tridecene, 1-bromo-2-chloro-1, 1-difluoro-, (Z)	40.67	tr

Table 2 Antimicrobial activity of torch ginger essential oil, ethanolic, and water extracts against some selected foodborne pathogens. ^z

	Inhibition zone (mm)
Microorganism	Essential oils	Water extract	Ethanol (50%)	Ethanol (100%)	Ampicillin
Gram-positive bacteria
Bacillus cereus	50.33 ± 0.57^d	10 ± 0.0^c	12.67 ± 0.6^d	9.0 ± 0.0^c	13.0 ± 0.6^b
Bacillus subtilis	81.3 ± 1.53^e	8.0 ± 0.0^b	10 ± 0.0^b	7.0 ± 0.0^a	23.3 ± 0.6^d
Staphylococcus aureus	11.0 ± 1.0^a	16.67 ± 0.58^e	11.33 ± 0.6^c	9.0 ± 0^c	36.0 ± 1.0^f
Listeria monocytogenes	26.67 ± 0.6^b	7.0 ± 0.0^a	8.0 ± 0.0^a	8.0 ± 0.0^b	12.67 ± 0.6^b
Gram-negative bacteria
Escherichia coli	NA	NA	NA	NA	23.33 ± 0.6^c
Salmonella typhimurium	NA	NA	NA	NA	30.67 ± 0.5^e
Salmonella enteritidis	NA	NA	NA	NA	21.1 ± 1.0^c
Klebsiella pneumoniae	40.33 ± 0.58^c	11.33 ± 0.58^d	11.0 ± 1^c	9.0 ± 0.0^c	11.33 ± 0.58^a
^zMeans with different letters in the same column differ significantly (p < 0.05). Each data is expressed as mean ± standard deviation of three independent experiments in triplicates (including the 6 mm of the diameter of the paper disc).
NA: no activity.
Concentration of essential oil 50 mg/ml; water 100 mg/ml; 50% ethanol 100 mg/ml; 100% ethanol 100 mg/ml; ampicillin 1 mg/ml.

Table 3 Minimum inhibitory concentration (MIC) levels of the essential oil and the extracts of torch ginger inflorescence against Gram-positive bacteria and Gram-negative bacteria

	Minimum inhibitory concentration (MIC)
Microorganism	Essential oils	Water	Ethanol 50%	Ampicillin
Gram-positive bacteria
Bacillus cereus	1.56	3.1	1.56	<3
Bacillus subtilis	0.78	ND	1.56	<3
Staphylococcus aureus	1.56	1.56	1.56	<3
Listeria monocytogenes	1.56	ND	ND	<3
Gram-negative bacteria
Escherichia coli	ND	ND	ND	<3
Salmonella typhimurium	ND	ND	ND	<3
Salmonella enteritidis	ND	ND	ND	<3
Klebsiella pneumoniae	1.56	3.1	1.60	<3
MIC: minimum inhibitory concentration; ND: not determined (no activity recorded in the disc diffusion assay).
Concentration series: 100–0.78 mg/ml for water, 50% ethanol and 100% ethanol; essential oil 50–0.39 mg/ml; ampicillin 1000–7.8 μg/ml.