Composition and Antibacterial Activity of Essential Oils of Flos Sophorae Immaturus

Figures & data

Table 1 Comparison of the chemical composition of essential oil of Flos Sophorae Immaturus extracted by simultaneous -distilling extraction (SDE) or vapor-distillation extraction (VDE)

			Peak area percentage (%) ^a
Peak no.	Molecular formula	Name	SDE	VDE
1	C6H12O	Hexanal	—	1.49
2	C7H14O	Heptanal	0.51	—
3	C7H12O	2-Heptenal	0.35	—
4	C6H6O2	5-Methyl-2-furancarboxaldehyde	0.79	10.18
5	C5H4O2	Furaldehyde	—	9.21
6	C6H6O3	1-(3-Hydroxy-2-furanyl)-ethanone	1.17	—
7	C9H14O	2-Pentyl-furan	0.59	—
8	C6H10O	Trans-2-hexenal	—	1.12
9	C6H12O2	Hexanoic acid	0.56	1.57
10	C6H7NO	3-Methoxy-pyridine	0.77	—
11	C7H8O	Benzyl alcohol	0.47	—
12	C8H8O	Benzeneacetaldehyde	0.59	1.03
13	C6H7NO	1-(1H-Pyrrol-2-yl)-ethanone	0.63	—
14	C7H14O2	Heptanoic acid	0.31	—
15	C10H18O	Linalool	Trace	—
16	C9H18O	Nonanal	1.76	—
17	C6H6O3	2-Hydroxy-3-methyl-4H-pyran-4-one	3.49	—
18	C9H14O	2,6-Nonadienal	0.37	—
19	C9H16O	Nonenal	0.36	—
20	C8H16O2	Octanoic acid	0.51	—
21	C6H7ON	1-(1H-Pyrrol-2-yl)-ethanone	—	0.91
22	C8H8O	2,3-Dihydro-benzofuran	1.08	—
23	C7H8O2	Guaiacol	0.64	2.08
24	C9H18O2	Nonanoic acid	1.55	—
25	C9H10O2	4-Vinyl-guaiacol	1.82	2.21
26	C10H12O2	Eugenol	6.71	6.22
27	C10H12O2	Isoeugenol	—	3.38
28	C10H12O2	2-Methoxy-4-(2-propenyl)-phenol	—	1.77
29	C7H4Cl2SN2	Benzothiazole	—	1.41
30	C15H24	Trans-caryophyllene	0.40	1.87
31	C12H20O2	Geranyl acetate	0.36	—
32	C13H20O	Trans-β-ionone	0.60	Trace
34	C8H16	3,4-Dimethyl-2-hexene	1.49	—
35	C12H24O2	Dodecanoic acid	0.43	—
36	C15H24O	Caryophyllene oxide	1.22	3.04
37	C11H14O2	Eugenol methyl ether	—	1.60
38	C10H16	Junipene	—	0.95
39	C9H10O3	2,5-Dihydroxy-4-methyl-acetophenone	—	0.91
40	C17H34	8-Heptadecene	2.44	3.01
41	C11H16O2	9-Methyl-cis-decalin-1,8-dione	—	1.30
42	C11H16O2	Tetrohydro-4,4,7a-trimethyl-2(4H)-benzofuranone	0.54	1.39
43	C14H28O2	Myristic acid	1.30	—
44	C18H36O	6,10,14-Trimethyl-2-pentadecanone	1.85	2.11
45	C12H10O2S	Sulfone	2.44	—
46	C17H34O2	Hexadecanoic acid methyl ester	0.39	—
47	C16H32O2	Hexadecanoic acid	38.69	13.92
48	C19H34O2	9,12-Octadecadienoic acid methyl ester	10.47	—
49	C19H32O2	9,12,15-Octadecatrienoic acid methyl ester	0.57	—
50	C20H40O	3,7,11,15-Tetramethyl-2-hexadecen-1-ol	0.91	—
51	C18H32O2	9,12,15-Octadecatrienoic acid	6.35	—
52	C20H42	Eicosane	—	1.97
53	C18H34O2	9-Octadecenoic acid	1.26	—
54	C22H46	Decosane	—	1.23
55	C24H50	Tetracosane	0.52	—
56	C30H62	Triacontane	—	2.10
57	C31H64	Hentriacontane	0.88	—
58	C32H66	Dotriacontane	—	6.55
59	C44H90	Tetratetracontane	1.19	—
^aPeak area percentage (%) means the peak area percentage of each component peak vs. total peak area of FSI essential oil sample by GC/MS analysis.

Table 2 Antibacterial activity of essential oil of Flos Sophorae Immaturus

Strain	Diameter of inhibition zone (mm ± SD)	MLC ^c (μL/mL)
Escherichia coli ATCC ^a 8099	15.50 ± 3.33	0.39
Staphylococcus aureus ATCC 6538	15.67 ± 3.39	0.39
Shigella dysenteriae CMCC ^b 51334	7.33 ± 1.21	1.56
Streptococcus beta-haem CMCC 32210	6.17 ± 0.75	>25.0
Listeria welshimeri ATCC 35897	8.33 ± 1.33	0.78
Listeria monocytogenes ATCC 19116	8.67 ± 1.33	0.39
Salmonella Typhimurium CMCC 50013	6.17 ± 0.75	0.78
Salmonella paratyphi A CMCC 50093	4.17 ± 0.41	>25.0
Salmonella enteritidis ATCC 13076	4.50 ± 0.55	>25.0
Pseudomonas aeruginosa ATCC 14149	3.17 ± 0.41	>25.0
Vibrio parahaemolyticus ATCC17803	3.00 ± 0.00	>25.0
Aspergillus niger ATCC 16404	0.00	—
Candida albicans ATCC 10231	0.00	—
^aATCC: American Type Culture Collection; ^bCMCC: National Center for Medical Culture Collection; ^cMLC: Minimum lethal concentration; 8 μL of essential oil was added to each hole in agar plate with different bacteria. The diameter of the antibacterial circle presented as the average of three tests ± standard error. Acetone and 200,000 units/mL penicillin were used as negative and positive control.

Figure 1 Essential oil of Flos Sophorae Immaturus inhibited the growth of five common pathogenic bacteria in a concentration and treatment time dependent manner.

Table 3 Correlation between different stresses pretreatment before treatment with essential oil of Flos Sophorae Immaturus (FSI) and the number of surviving Staphylococcus aureus.

	1 MLC of FSI essential oil		2 MLC of FSI essential oil
The pretreatment stress (all were further treated with FSI essential oil)	Correlation coefficient, r 1	Significance level, p 1	Correlation coefficient, r2	Significance level, p 2
Heat	0.270	0.959	0.003	0.995
Acid	0.449	0.372	0.115	0.828
Osmosis	0.528	0.282	0.814	0.048 ^a
Sodium benzoate	−0.888	0.018 ^a	−0.797	0.057
potassium sorbate	−0.844	0.035 ^a	−0.941	0.005 ^b
FSI essential oil	−0.854	0.030 ^a	−0.916	0.010 ^b
^a p < 0.05; ^b p < 0.01.