Chemical composition of selected aromatic plant essential oils and their antifungal efficacy against toxigenic fungi associated with maize (Zea mays L)

Figures & data

Table 1. Description of plants used for EO extraction.

Common name	Scientific name	Family	Properties
Coriander	Coriandrum sativum	Umbelliferae/Apiaceae	Annual herb
Palmarosa	Cymbopogon martini	Poaceae	Perennial herbaceous
Thyme	Thymus vulgaris	Lamiaceace	Evergreen herb

Table 2. Chemical compositions of the EOs from selected aromatic plants.

			Peak area (%)^d
Compounds^a	Rt (min)^b	RI^c	C. martini	C. sativum	T. vulgaris
Nonane	4.51	900		1.01
α- Thujene	5.07	929			2.70
α -pinene	5.25	937		1.57
ß-Myrcene	6.45	991	4.95
(+)-4-Carene	7.16	1009			3.36
o-cymene	7.36	1022			17.50
Trans – ß-Ocimene	7.63	1049	11.72
ß-cis-Ocimene	7.89	1038	5.50
Gamma-Terpinene	8.22	1060		1.15	16.78
Linalool	9.36	1099	5.03	8.32	2.71
Benzene,2-methoxy-4-methyl-1-(1-methylethyl)-	12.87	1230			9.70
Benzene,1-methoxy-4-methyl-2-(1-methylethyl)-	13.12	1291			7.06
2-Decenal, (E)-	13.69	1263		12.60
Geraniol	13.75	1255	51.44
2-decen-1-ol,(Z)-	13.83	1806		2.97
1-Decanol	13.89	1273		6.11
4-Undecanone	14.08	1208	2.25
Thymol	14.66	1291			34.37
Undecanal	14.48	1307		3.52
Dodecanal	15.79	1409		2.87
2-Dodecenal, (E)-	16.38	1465		4.53
Geranyl acetate	16.90	1382	14.51
Caryophyllene	17.92	1419			1.39
(E)-Tetradec-2-enal	18.19	1673		1.82
Hexanedioicacid,bis(2-ethylhexyl) ester	21.24	2398		46.89
(6R,7R)-Bisabolone	25.26	1747	1.27
Total			96.67%	93.36%	95.57%

Note: ^aThe compounds are listed in the order of elution from the DB-SMS column; ^b RT: retention time of the components calculated on the DB-SMS column; ^cRI: retention index; ^d(%) relative percentage obtained from peak area and compounds with the low value of peak area (<1%) are not listed.

Table 3. Proportion of volatile compound classes in T. vulgaris, C. martini and C. sativum EOs.

Chemical Classes	T. vulgaris	C. martini	C. sativum
Monoterpenes	40	28	25
Oxygenated monoterpenes	20	20	6.25
Aldehyde	4	0	31.25
Ester	4	16	3.12
Sesquiterpenes	12	20	3.13
Oxygenated sesquiterpenes	8	8	6.25
Other	12	8	25

Table 4. Colony growth diameter (mean ± SE) of potentially toxigenic fungi treated with three different doses of EOs after five days of incubation.

		Colony Growth Diameter (mm)*
Name of plant	EO doses µL/mL	A. flavus	A. niger	F. verticillioides	F. graminearum
	Control	41.67 ± 3.18	53.67 ± 1.45	56.33 ± 1.76	90 ± 0.0
C. martini	0.5	17.67 ± 2.40	NG	NG	NG
	1	17.00 ± 0	NG	NG	NG
	1.5	9.67 ± 0.88	NG	NG	NG
T. vulgaris	0.5	NG	NG	NG	NG
	1	NG	NG	NG	NG
	1.5	NG	NG	NG	NG
C. sativum	0.5	8.66 ± 8.66	2.33 ± 1.2	NG	NG
	1	7 ± 6.03	NG	NG	NG
	1.5	NG	NG	NG	NG

Note.Values are average of three replications; NG: No growth; 0.5 µL/mL, 1 µL/mL, 1.5 µL/mL.

Table 5. Spores number (mean ± SE) of A. flavus on maize grains treated with three doses of EOs after 15 days.

Essential oil	EO’s doses µL/plate	Spore number after 15 days (spores/g)^a
Cymbopogon martini	5	7.5 x 10^5±2.8 x 10^4
	10	2.5 x 10^5±2.8 x 10^4
	15	0
Thymus vulgaris	5	0
	10	0
	15	0
C. sativum	5	5 x 10^5 ± 1.1 x 10^5
	10	2 x 10^4 ± 5.7 x 10^3
	15	0
	Control	3.9 x 10^9 ± 2.52 x 10^8

Note:*Average of three replications.

Figure 1. GC profiles of essential oil from Thymus vulgaris (a), Coriandrum sativum (b) and Cymbopogon martini (c).

Table A1. Chemical Composition of T. vulgaris essential oil.

Compounds^a	Rt (min)^b	Peak area (%)^c
α- Thujene	5.07	2.70
α -pinene	5.25	0.52
Furaldehyde phenylhydrazone	5.47	0.05
Camphene	5.62	0.05
ß-Phellandrene	6.11	0.31
Sabinene	6.24	0.16
ß-Myrcene	6.45	0.80
α -phelliandrene	6.61	0.23
(+)-4-Carene	7.16	3.36
o-cymene	7.36	17.50
Gamma-terpinene	8.22	16.78
Linalool	9.36	2.71
Camphor	10.71	0.08
Terpinen-4-ol	11.63	0.34
L-alpha-terpineol	12.05	0.56
Decanal	12.30	0.30
Benzene,2-methoxy-4-methyl-1-(1-methylethyl)-	12.87	9.70
Benzene,1-methoxy-4-methyl-2-(1-methylethyl)-	13.13	7.06
Thymol	14.66	34.37
Thymol acetate	16.02	0.03
Caryophyllene	17.92	1.39
ß-copaene	19.46	0.14
γ -Elemene	19.81	0.18
lH-cycloprop(e)azulen-7-ol,decahydro-1,1,7-trimethylene-	21.86	0.14
Caryophyllene oxide	22.00	0.38

Note: ^aThe compounds are listed in the order of elution from the DB-SMS column; ^b RT: retention time of the components calculated on the DB-SMS column; ^c (%) relative percentage obtained from peak area.

Table A2. Chemical composition of C. martini essential oil.

Compounds^a	Rt (min)^b	Peak area (%)^c
Tricyclene	5.04	0.06
α -pinene	5.25	0.11
Camphene	5.63	0.20
ß-Myrcene	6.45	4.95
D-Limonene	7.48	0.21
Trans – ß-Ocimene	7.63	11.72
ß-cis-Ocimene	7.89	5.50
Linalool	9.36	5.03
2,4,6-Octatriene,2,6-dimethyl-(E,Z)-	10.08	0.26
Alpha-terpineol	12.08	0.03
Citronellol	12.88	0.87
Citral	13.19	0.05
Geraniol	13.75	51.44
4-Undecanone	14.08	2.25
Bornyl acetate	14.43	0.04
Citronellol acetate	16.10	0.25
Geranyl acetate	16.90	14.51
(2E,6E)-3,7,11-trimethyldideca-2,6,10-trienyl propionate	17.14	0.09
Caryophyllene	17.93	0.63
Humulene	18.83	0.07
Germacrene D	19.46	0.10
(Z)-1-methyl-4-(6-methylhept-5-en-2-ylidene)cyclohex-1-ene	20.17	0.03
ß-sesquiphellandrene	20.48	0.09
zingibereno	24.27	0.22
(6R,7R)-Bisabolone	25.26	1.27

Note: ^aThe compounds are listed in the order of elution from the DB-SMS column; ^b RT: retention time of the components calculated on the DB-SMS column; ^c (%) relative percentage obtained from peak area.

Table A3. Chemical composition of C. sativum essential oil.

Compounds^a	Rt(min)^b	Peak area (%)^c
Nonane	4.51	1.01
α -pinene	5.25	1.57
Camphene	5.63	0.16
Sabinene	6.25	0.11
ß-Myrcene	6.45	0.08
Decane	6.68	0.22
octanal	6.83	0.51
o-cymene	7.36	0.24
D-Limonene	7.48	0.25
Trifluoroacetly- α-terpineol	7.60	0.08
Trans – ß-Ocimene	7.89	0.13
Gamma-Terpinene	8.22	1.15
Linalool	9.36	8.32
Camphor	10.71	0.70
Decanal	12.89	0.08
2-Decenal, (E)-	13.69	12.60
2-decen-1-ol,(Z)-	13.83	2.97
1-Decanol	13.90	6.11
Undecanal	14.48	3.52
2-Undecenal	15.29	1.89
Dodecanal	15.79	2.87
2-Dodecenal, (E)-	16.38	4.53
17-Octadecynoic acid	16.77	0.21
8-Hexadecenal,14-methyl-,(Z)-	17.32	0.15
Tetradecanal	17.66	0.55
Epicubebol	17.85	0.16
Tau-cadinol	18.15	0.55
(E)-tetradec-2-enal	18.19	1.82
cis-Neocnidilide	18.79	0.32
9,12-Octadecadienoic acid(Z,Z)-	19.52	0.10
Hexanedioicacid,bis(2-ethylhexyl) ester	21.24	46.89
Oleic Acid	21.88	0.12

Note: ^aThe compounds are listed in the order of elution from the DB-SMS column; ^b RT: retention time of the components calculated on the DB-SMS column; ^c (%) relative percentage obtained from peak area.

Table A4. Volatile compound class of T. vulgaris, C.martini and C.sativum.

			Peak area (%)
Compounds	Volatile compound classes	Rt(min)	T. vulgaris	C. martini	C. sativum
	Hydrocarbon Monoterpenes		40	28	25
Tricyclene		5.04	–	0.06	–
α- Thujene		5.07	2.70	–	–
α -pinene		5.25	0.52	0.11	1.57
Camphene		5.62	0.05	0.20	0.16
ß-Phellandrene		6.11	0.31	–	–
Sabinene		6.25	0.16	–	0.11
ß-Myrcene		6.45	0.80	4.95	0.08
α -phellandrene		6.61	0.23	–	–
(+)-4-Carene		7.16	3.36	–	–
o-Cymene		7.36	17.50	–	0.24
D-Limonene		7.48	–	0.21	0.25
Trans – ß-Ocimene		7.64	–	11.72	–
Trans – ß-Ocimene		7.89	–	–	0.13
ß-cis-Ocimene		7.90	–	5.50	–
Gamma-terpinene		8.22	16.78	–	1.15
	Oxygenated monoterpenes		20	20	6.25
Linalool		9.36	2.71	5.03	8.32
Camphor		10.71	0.08	–	0.70
Terpinen-4-ol		11.63	0.34	–	–
L-alpha-terpineol		12.05	0.56	–	–
Alpha-terpineol		12.08	–	0.03	–
Citronellol		12.88	–	0.87	–
Citral		13.19	–	0.05	–
Geraniol		13.75	–	51.44	–
Thymol		14.66	34.37
	Aldehyde		4%	0	31.25
Octanal		6.83	–		0.51
Decanal		12.30	0.30		–
Decanal		12.89	–		0.08
2-Decenal, (E)-		13.69	–		12.60
Undecanal		14.48	–		3.52
2-Undecenal		15.29	–		1.89
Dodecanal		15.79	–		2.87
2-Dodecenal, (E)-		16.38	–		4.53
8-Hexadecenal,14-methyl-,(Z)-		17.32	–		0.15
Tetradecanal		17.66	–		0.55
(E)-Tetradec-2-enal		18.19	–		1.82
	Ester		4	16	3.13
Bornyl acetate		14.43	–	0.04	–
Thymol acetate		16.02	0.03	–	–
Citronellol acetate		16.10	–	0.25	–
Geranyl acetate		16.90	–	14.51	–
(2E,6E)-3,7,11-Trimethyldodeca-2,6,10-trienyl propionate		17.14	–	0.09	–
Hexanedioicacid,bis(2-ethylhexyl) ester		21.24	–	–	46.89
	Hydrocarbon Sesquiterpenes		12	20	3.13
		17.85	-	-	0.16
Caryophyllene		17.92	1.39	0.63	–
Humulene		18.83	–	0.07	–
Germacrene D		19.41	–	0.10	–
ß-copaene		19.46	0.14	–	–
γ -Elemene		19.81	0.18	–	–
(Z)-1-methyl-4-(6-methylhept-5-en-2-ylidene) cyclohex-1-ene		20.17	–	0.03	–
ß-Sesquiphellandrene		20.48	–	0.09	–
	Oxygenated sesquiterpenoids		8	8	6.25
Epicubebol		21.86	0.14	–	–
Tau-cadinol		18.15	–	–	0.55
cis-Neocnidilide		18.79	–	–	0.32
Caryophyllene oxide		22.00	0.38	–	–
Zingiberenol		24.27	–	0.22	–
(6R,7R)-Bisabolone		25.26	–	1.27	–
	Others		12	8	28.13
Nonane		4.51	-	-	1.01
Furaldehyde phenylhydrazone		5.47	0.05	-	-
Decane		6.68	-	-	0.22
Trifluoroacetyl- α-terpineol		7.60	–	–	0.08
2,4,6-Octatriene,2,6-dimethyl-(E,Z)-		10.08	–	0.26	–
Benzene,2-methoxy-4-methyl-1-(1-methylethyl)-		12.87	9.70	–	–
Benzene,1-methoxy-4-methyl-2-(1-methylethyl)-		13.13	7.06	–	–
2-Decen-1-ol,(Z)-		13.83	–	–	2.97
1-Decanol		13.90	–	–	6.11
4-Undecanone		14.08	–	2.25	–
17-Octadecynoic acid		16.77	–	–	0.21
9,12-Octadecadienoic acid(Z,Z)-		19.52	–	–	0.10
Oleic Acid		21.88	–	–	0.12