Open Access

Characterization of volatile compounds of Daucus crinitusDesf. Headspace Solid Phase Microextraction as alternative technique to Hydrodistillation

  • Mohammed El Amine Dib1,
  • Nassim Djabou1, 2,
  • Jean-Marie Desjobert2,
  • Houcine Allali1,
  • Boufeldja Tabti1,
  • Alain Muselli2Email author and
  • Jean Costa2
Chemistry Central Journal20104:16

DOI: 10.1186/1752-153X-4-16

Received: 30 June 2010

Accepted: 21 September 2010

Published: 21 September 2010

Abstract

Background

Traditionally, the essential oil of aromatic herbs is obtained using hydrodistillation (HD). Because the emitted volatile fraction plays a fundamental role in a plant's life, various novel techniques have been developed for its extraction from plants. Among these, headspace solid phase microextraction (HS-SPME) can be used to obtain a rapid fingerprint of a plant's headspace. Daucus crinitus Desf. is a wild plant that grows along the west coast of Algeria. Only a single study has dealt with the chemical composition of the aerial part oils of Algerian D. crinitus, in which isochavicol isobutyrate (39.0%), octyl acetate (12.3%), and β-caryophyllene (5.4%) were identified. Using GC-RI and GC-MS analysis, the essential oils and the volatiles extracted from separated organs of D. crinitus Desf. were studied using HS-SPME.

Results

GC-RI and GC-MS analysis identified 72 and 79 components in oils extracted using HD and in the volatile fractions extracted using SPME, respectively. Two types of essential oils were produced by the plant: the root oils had aliphatic compounds as the main component (87.0%-90.1%), and the aerial part oils had phenylpropanoids as the main component (43.1%-88.6%). HS-SPME analysis showed a more precise distribution of compounds in the organs studied: oxygenated aliphatic compounds were well represented in the roots (44.3%-84.0%), hydrocarbon aliphatic compounds were in the leaves and stems (22.2%-87.9%), and phenylpropanoids were in the flowers and umbels (47.9%-64.2%). Moreover, HS-SPME allowed the occurrence of isochavicol (29.6 - 34.7%) as main component in D. crinitus leaves, but it was not detected in the oils, probably because of its solubility in water.

Conclusions

This study demonstrates that HD and HS-SPME modes could be complimentary extraction techniques in order to obtain the complete characterization of plant volatiles.

https://static-content.springer.com/image/art%3A10.1186%2F1752-153X-4-16/MediaObjects/13065_2010_Article_257_Figa_HTML.gif

Background

Daucus is a genus belonging to the Apiaceae family and consists of about 600 species that are widely distributed around the world. D. carota (carrot) is the main species of the Daucus genus, and its cultivated form, Daucus carota ssp. sativa, is one of the most popular root vegetable crops in the world. Carrots have been reported to be endowed with medicinal properties, i.e., hypotensive, diuretic, carminative, stomachic, and antilipemic properties [14]. In Algeria, the Daucus genus is represented by species living in dry and uncultivated areas and, among these, D. crinitus Desf. syn. and D. meifolius Brot. are widespread along the Algerian west coast from Tlemcen to Mascara [5]. D. crinitus is characterized by the presence of many subspecies that colonize the sands and cliffs [5]. A survey conducted by herbalists identified that, in folk medicine, a drink made from the roots of D. crinitus is used in decoction to expel the placenta after childbirth, and as a tonic.

Although the phytochemistry of the Daucus genus has been extensively studied (e.g., flavonoids, carotenoids, polyacetylenes, anthocyanins, and volatile constituents), only a single study has dealt with the chemical composition of Algerian D. crinitus oil [6]. The oil obtained from the aerial parts is dominated by phenylpropanoid compounds (45.5%), followed by aliphatic compounds (17.1%), and hydrocarbons sesquiterpenes (16.6%). The main components are isochavicol isobutyrate (39.0%), an uncommon phenylpropanoid associated with octyl acetate (12.3%), and β-caryophyllene (5.4%). Moreover, antibacterial and antifungal activities of separated phenylpropanoid esters of the entire oil have been reported.

The essential oils of aromatic herbs are traditionally obtained using hydrodistillation. Because the emitted volatile fraction plays a fundamental role in a plant's life, various novel techniques have been developed for its extraction from plants. Among these, headspace solid phase microextraction (HS-SPME) allows for the rapid fingerprinting of a plant's headspace [710], and HS sampling requires the optimization of the extraction parameters to be carried out. As has been previously reported in the literature [9, 10], the most effective fibers from vegetable matrices used are those consisting of three polymers: a liquid (PDMS) for the less polar components, and two solids, DVB and CAR, for the more polar components. Several conditions regarding the time and temperature for equilibrium and extraction have been reported, according the plant material analyzed [710].

To obtain a better understanding of the volatiles of D. crinitus, we investigated the chemical composition of Algerian D. crinitus essential oils extracted using hydrodistillation (HD) from separated organs (i.e., the roots, stems, leaves, flowers, and umbels), and the volatile fractions extracted using HS-SPME from the same plant material. In both cases, the analysis was carried out using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS).

Results and Discussion

Composition of the essential oils

An analysis of the essential oils from the roots, stems, leaves, flowers, and umbels of D. crinitus harvested in four locations (A-D) identified 72 components, which accounted for 90.9%-98.3% of the total number. Their retention indices and relative percentages are shown in Table 1. Among these, 22 nonterpenic compounds, 12 monoterpenes, nine sesquiterpenes, and four diterpenes were identified. Identification of 33 components was performed by comparing their EI-MS and retention indices with those from the laboratory-produced "Arômes" library; 13 components were identified by comparing their EI-MS and apolar retention indices with those reported in commercial or literature libraries.
Table 1

Chemical compositions of Daucus crinitus Desf. essential oils from Algeria

No.a

Components£

lRIab

RIac

RIpd

Rootse

Leavese

Stemse

Umbelse

Flowerse

     

A

B

C

D

A

B

C

D

A

B

C

D

A

B

C

D

A

B

C

D

1

Nonane

906

902

907

0.9

0.8

-

-

0.6

0.5

0.5

0.6

tr

tr

tr

-

0.5

0.4

0.2

0.3

-

-

0.1

tr

2

α- Pinene

936

931

1015

-

-

-

-

0.5

0.4

0.1

-

-

tr

tr

-

0.9

0.8

0.6

0.9

0.2

0.1

0.2

0.5

3

Sabinene

973

966

1107

-

-

-

-

0.6

0.5

0.6

-

-

-

-

-

0.1

0.3

0.1

tr

0.3

0.4

0.6

0.2

4

β-Pinene *

978

971

1124

-

-

-

-

0.1

0.1

0.1

-

-

-

-

-

0.6

0.4

0.1

tr

0.1

0.3

1

1.5

5

Myrcene

987

981

1141

-

-

-

-

0.6

0.3

0.5

-

0.7

0.7

0.9

0.9

0.1

0.2

0.3

0.4

0.2

0.1

tr

tr

6

Decane

993

998

999

0.1

0.1

-

-

tr

tr

tr

tr

0.1

tr

0.1

0.1

tr

0.1

tr

tr

tr

0.1

0.1

tr

7

p-Cymene

1015

1012

1247

-

-

-

-

0.2

0.1

-

-

0.1

0.1

6

4.2

0.7

0.4

0.3

tr

-

-

-

-

8

1,8-Cineole *

1024

1020

1199

-

-

-

-

0.1

0.1

tr

tr

tr

-

0.1

-

0.1

0.1

0.2

tr

0.2

0.4

0.3

0.6

9

Limonene

1025

1026

1190

-

-

-

-

0.9

0.6

0.3

-

0.8

0.8

0.9

1.1

1.6

1.2

1.9

2.6

-

-

-

-

10

(E)-β-Ocimene

1041

1037

1224

-

-

-

-

0.6

0.3

0.2

-

0.1

tr

1.1

1.6

0.2

0.1

0.1

tr

-

-

-

-

11

γ-Terpinene

1051

1049

1228

-

-

-

-

1.6

0.8

0.1

-

0.1

0.1

0.2

0.5

0.3

0.2

0.2

tr

-

-

-

-

12

1-Octanol

1061

1056

1390

-

-

-

-

tr

tr

 

tr

0,1

0,1

0,1

tr

0,2

0,2

0,1

0,1

tr

tr

-

-

13

2-Methyl-decane

1068

1065

1146

0.1

0.4

-

-

tr

tr

0.1

0.3

-

-

-

-

-

-

-

-

-

-

-

-

14

Nonanal

1076

1074

1403

-

-

-

-

-

0,2

tr

-

tr

0,1

0,2

0,1

0,1

0,1

0,1

0,1

-

-

-

-

15

α-Terpinolene

1082

1079

1274

-

-

-

-

0.4

0.2

0.1

-

0.3

0.3

0.5

0.4

0.3

0.1

0.2

0.1

0.1

0.2

0.4

0.3

16

Linalool *

1086

1086

1528

-

-

-

-

0.2

0.1

tr

-

tr

tr

tr

0.1

0.1

0.2

0.1

tr

tr

0.1

0.1

0.2

17

Undecane

1100

1098

1101

34.1

30.9

14.4

15.3

4.1

5.1

4.5

14.2

tr

0.3

0.3

0.4

0.3

0.5

0.4

0.6

0.1

0.3

0.2

0.1

18

2-Ethyl hexyl acetate *

1144

1149

1420

-

-

-

-

tr

tr

0.1

tr

0.1

tr

0.2

0.1

-

-

tr

0.1

-

0.2

0.2

0.5

19

Terpinen 4-ol

1164

1161

1586

-

-

-

-

0.1

0.1

tr

-

tr

0.1

0.3

0.4

0.3

0.3

0.1

tr

-

-

-

tr

20

Octyl acetate *

1188

1187

1460

    

2.3

3.0

2.8

1.0

0.2

1.0

1.9

2.5

1.0

1.2

2.2

2.4

    

21

Decanal

1188

1187

1483

0.3

0.2

-

-

1.4

1.0

1.4

0.1

tr

0.1

0.3

1

0.6

0.2

1.0

1.2

-

-

-

0.1

22

Dodecane

1200

1198

1209

0,1

0,2

tr

0,1

tr

tr

-

-

0,1

0,1

0,2

tr

-

-

-

-

-

-

-

-

23

Decanol

1263

1259

1729

-

-

tr

0,1

0,1

0,2

0,3

0,1

0,1

0,2

0,1

0,1

-

-

-

-

0,2

0,1

tr

tr

24

Nonanoic acid

1263

1263

2119

-

-

-

-

-

-

-

-

0,1

0,1

0,2

0,1

-

-

-

-

0,1

0,1

0,1

0,1

25

Undecanal

1290

1280

1610

tr

0,1

0,1

-

tr

tr

tr

0,1

0,2

0,1

0,1

tr

0,2

tr

tr

tr

-

-

-

-

26

Tridecane

1300

1292

1305

0.7

0.5

0.9

0.4

0.1

tr

0.1

0.6

0.1

tr

0.1

0.2

0.2

0.5

0.4

0.5

0.1

0.2

0.1

tr

27

n-Octyl isobutyrate

1329

1325

1535

-

-

-

-

tr

0,1

0,1

0,1

-

-

-

-

0,2

0,1

0,2

0,2

0,1

0,1

0,1

0,1

28

Neryl acetate

1342

1336

1730

-

-

-

tr

-

-

tr

tr

0,1

0,2

0,4

0,2

0,1

0,1

0,1

0,1

0,1

tr

tr

0,1

29

Decanoic acid

1347

1348

2080

tr

0,1

tr

tr

-

-

-

-

-

0,1

0,1

tr

0,1

0,1

tr

0,3

-

-

-

-

30

Benzyl 2-methyl butyrate

1360

1352

1770

-

0,2

-

tr

tr

-

-

-

-

-

-

-

-

-

-

-

0,1

0,2

0,1

0,1

31

Geranyl acetate

1362

1359

1759

-

-

-

-

-

-

-

-

-

0,2

0,1

0,1

0,1

0,1

0,1

0,1

0,2

0,1

0,1

0,2

32

Undecanol *

1363

1367

1816

-

-

-

-

0.1

0.1

tr

0.1

0.1

0.1

0.3

0.4

0.4

0.2

0.1

tr

0.2

0.4

0.2

0.6

33

α-Copaene

1379

1372

1470

-

-

-

-

tr

tr

tr

tr

tr

0.1

0.2

0.4

0.5

0.4

0.3

0.2

0.1

0.1

0.1

0.1

34

β-Bourbonene

1386

1376

1520

-

-

-

-

-

-

-

-

0,1

0,5

0,4

0,1

-

-

-

-

-

-

-

-

35

Dodecanal

1389

1390

1695

16.7

24.6

25.1

26.3

3.1

2.1

2.1

6.7

0.5

4.0

5.0

6.1

0.1

tr

0.1

tr

-

0.1

0.1

tr

36

Tetradecane

1400

1403

1408

-

-

-

-

tr

0,1

0,1

0,1

0,1

0,1

0,2

0,1

tr

tr

tr

tr

-

-

-

-

37

Longifolene

1411

1409

1575

-

-

-

-

tr

tr

0,1

tr

0,1

0,1

0,1

0,1

-

-

-

-

0,1

0,1

0,1

0,1

38

α-Santalene

1422

1415

1569

-

-

-

-

-

-

-

-

tr

0,1

0,1

0,2

-

-

-

-

tr

tr

tr

tr

39

β-Caryophylene

1420

1424

1555

-

-

-

-

0.6

0.4

0.1

0.2

tr

0.4

0.3

0.1

5.4

3.2

3.9

5.1

0.2

0.1

tr

0.1

40

Dauca-3,8-diene

1428

1426

1680

-

-

-

-

tr

tr

tr

0,1

-

-

-

-

-

-

-

-

0,2

tr

0,1

tr

41

trans-α-Bergamotene

1432

1432

1575

-

-

-

-

0,1

0,1

tr

tr

0,1

0,3

0,1

tr

-

-

-

tr

0,2

tr

0,1

0,1

42

(E)-β-Farnesene

1446

1443

1660

-

-

-

-

tr

tr

tr

0,1

0,1

0,1

0,2

tr

tr

tr

0,1

tr

0,2

0,2

0,1

0,2

43

α-Humulene

1455

1451

1648

-

-

-

-

0.7

1.0

1.1

0.2

tr

0.2

0.3

0.2

0.5

0.5

0.6

0.3

tr

0.1

tr

0.2

44

Zizaene *

1456

1463

1860

1.2

1.3

2.9

2.7

tr

tr

tr

1.4

1.0

1.1

1.0

1.0

5.9

5.2

6.0

9.2

6.2

8.1

9.1

8.0

45

Dodecanol

1472

1470

1754

0.2

0.2

-

-

tr

tr

0.1

tr

tr

tr

0.1

tr

tr

0.1

0.1

tr

0.2

0.1

0.1

tr

46

α-Curcumene

1473

1474

1769

-

-

-

-

-

-

-

-

0,1

0,1

0,2

0,2

0,1

0,2

0,2

0,1

0.2

tr

tr

tr

47

Germacrene-D

1479

1478

1710

-

-

-

-

tr

tr

0.1

0.1

0.1

0.5

tr

tr

0.2

0.2

0.1

tr

0.2

0.1

tr

0.2

48

β-Selinene *

1486

1480

1685

-

-

-

-

tr

tr

0.2

0.2

-

0.1

tr

0.1

0.1

0.1

0.2

tr

tr

0.1

tr

0.1

49

Zingiberene

1489

1483

1717

-

-

-

-

-

-

-

-

tr

tr

0,1

tr

-

-

-

tr

0,1

tr

tr

0,1

50

Pentadecane

1500

1497

1502

-

-

-

-

5.1

3.5

4.1

2.2

3.0

6.0

12.6

14.5

8.5

9.5

10.5

15.2

4.1

6.2

7.3

10.1

51

δ-Cadinene

1520

1514

1736

-

-

-

-

tr

tr

0.3

0.1

0.1

0.3

tr

0.1

0.6

0.4

0.3

0.4

-

0.1

tr

0.1

52

Geranyl butyrate

1534

1530

1877

-

0,1

tr

0,1

-

-

-

-

tr

0,1

0,2

0,2

-

0,1

tr

0,1

0,2

tr

tr

0,1

53

Isochavicol isobutyrate

1546

1541

2134

-

-

-

-

44.9

35.2

35.6

25.2

84.1

57.6

41.2

36.5

51.2

50.2

50.2

40.1

65.3

55.3

58.2

62.3

54

(Z)-3-Hexenyl benzoate*

1545

1557

2059

1.9

2.3

0.1

0.1

0.1

0.2

0.1

0.1

0.1

0.4

0.2

0.1

0.5

0.6

0.5

0.6

0.1

0.2

0.3

tr

55

Dodecanoic acid *

1554

1560

2474

1.9

0.3

-

-

1.1

12.3

9.3

5.6

0.1

tr

0.6

1.2

0.5

0.3

0.3

0.2

0.1

0.2

0.6

0.3

56

Caryophyllene oxyde

1578

1572

1980

-

-

-

-

-

-

-

-

tr

tr

tr

tr

tr

tr

0,1

0,1

-

-

-

-

57

Dodecyl acetate

1585

1580

1882

31.7

30.3

48.2

42.3

2.5

1.5

7.2

8.9

0.3

0.2

1.9

2.3

tr

0.1

tr

0.1

1.5

1.6

1.8

1.0

58

α-Cedrol

1603

1596

2115

-

-

-

-

tr

tr

0.2

0.1

tr

tr

0,1

tr

tr

tr

tr

tr

0,1

tr

tr

tr

59

Hexadecane

1600

1599

1598

-

-

-

-

0,1

0,1

0,1

0,2

0,2

0,1

0,1

0,1

tr

tr

tr

0,1

tr

0,1

0,1

tr

60

Isochavicol 2-methyl butyrate

1651

1648

2255

0.2

0.3

1.5

2.3

9.7

8.9

11.3

17.8

4.2

7.8

9.1

13.2

3.2

6.5

5.5

6.1

9.8

12.5

9.6

4.8

61

α-Bisabolol *

1673

1667

2202

-

-

-

-

tr

0.1

1.6

0.2

tr

0.1

0.1

tr

0.1

0.1

0.1

0.1

0.2

0.2

0.1

tr

62

Heptadecane

1700

1703

1699

0.2

0.2

-

-

3.4

2.4

6.2

2.1

0.4

6.5

2.5

2.7

5.8

4.8

3.9

4.1

2.5

1.9

2.4

1.1

63

Benzyl benzoate

1730

1723

2121

0,1

0,1

0,2

tr

0,1

0,2

0,1

0,1

0,1

0,2

0,2

0,2

tr

0,1

tr

tr

tr

0,1

tr

tr

64

Tetradecanoic acid *

1761

1756

2649

0.3

0.2

1.1

2.0

3.1

4.4

0.2

0.8

0.1

0.3

0.7

0.4

0.1

0.5

0.5

0.2

0.3

1.0

2.3

2.0

65

Lactarazulene *

1796

1792

2430

0.1

0.4

2.7

0.4

0.7

0.5

0.1

tr

tr

0.8

tr

0.1

-

-

-

-

-

-

0.1

tr

66

Hexadecanal

1782

1787

2108

0.3

0.2

0.2

0.3

0.1

0.6

tr

0.2

0.1

tr

0.1

0.2

0.1

0.2

0.1

tr

-

0.1

0.3

tr

67

Neophytadiene

1807

1807

1918

-

-

-

-

0.4

0.4

0.5

0.1

tr

tr

0.1

0.3

-

-

-

-

-

0.4

0.8

0.4

68

Phytone *

1833

1835

2131

-

-

-

-

tr

0.7

0.3

tr

tr

-

-

-

-

-

-

-

-

-

-

-

69

Dodecyl pentanoate *

1843

1840

2834

0.5

0.2

-

-

-

-

  

-

-

-

-

-

-

-

-

-

-

-

-

70

Isophytol *

1946

1944

2316

 

-

-

-

tr

tr

0.6

1.1

tr

-

-

-

-

-

-

-

tr

-

-

-

71

Hexadecanoic acid *

1951

1949

2916

0.6

-

-

-

1.1

0.5

0.3

0.1

tr

-

-

-

-

-

-

-

0.2

-

-

-

72

(E)-Phytol *

2114

2102

2620

-

-

-

-

1.7

1.9

2.5

0.7

0.2

-

-

-

-

-

-

-

2.3

-

-

-

 

Total

   

92.2

94.2

97.4

92.4

93.2

90.9

93.8

91.9

98.3

92.5

92.4

95.1

92.7

91.4

91.1

92.3

96.9

92.3

97.5

96.6

 

Hydrocarbon compounds

37.5

34.8

20.9

18.9

21.4

17.4

20.2

22.8

7.5

19.7

28.8

29.7

33.4

29.7

30.9

40.1

15.4

19.2

23.0

23.5

 

Oxygenated compounds

54.7

59.4

76.5

73.5

71.8

73.5

76.2

69.1

90.8

72.8

63.6

65.4

59.3

61.7

60.2

52.2

81.5

73.1

74.6

73.1

 

Aliphatic compounds

88.8

89.9

90.1

87.0

28.4

37.9

39.7

44.2

6.0

19.8

28.6

33.2

19.1

19.5

18.8

26.0

10.3

13.1

16.7

19.5

 

Phenylpropanoid compounds

2.1

2.6

1.7

2.3

54.7

44.3

47.0

43.1

88.6

65.8

50.5

49.8

54.9

57.3

56.2

46.8

75.2

68.0

68.1

64.1

 

Hydrocarbon non-terpenic compounds

36,2

33.1

15.3

15.8

13.4

11.7

15.7

20.3

4.0

13.0

16.0

18.1

15.8

15.8

15.4

20.8

6.8

16.8

10.2

11.3

 

Hydrocarbon monoterpenes

-

1.7

-

-

5.5

3.3

2.0

-

2.1

2.0

9.6

8.7

4.8

3.7

3.8

4.0

0.9

1.1

2.3

2.5

 

Hydrocarbon sesquiterpenes

1.3

-

5.6

3.1

2.1

2.0

2.0

2.4

1.4

4.7

3.1

2.6

12.8

10.2

11.7

15.3

7.7

9.0

9.7

9.3

 

Hydrocarbon diterpenes

-

-

-

-

0.4

0.4

0.5

0.1

-

-

0.1

0.3

-

-

-

-

-

0.4

0.8

0.4

 

Oxygenated non-terpenic compounds

54,7

59.4

76.5

73.5

69.7

70.5

71.0

67.0

90.6

72.6

63.1

64.9

58.7

61.0

59.6

52.0

78.7

72.4

74.1

72.3

 

Oxygenated monoterpenes

-

-

-

-

0.4

0.3

-

-

-

0.1

0.4

0.5

0.5

0.6

0.4

-

0.2

0.5

0.4

0.8

 

Oxygenated sesquiterpenes

-

-

-

-

-

0.1

1.8

0.3

-

0.1

0.1

-

0.1

0.1

0.2

0.2

0.3

0.2

0.1

-

 

Oxygenated diterpenes

-

-

-

-

1.7

2.6

3.4

1.8

0.2

-

-

-

-

-

-

-

2.3

-

-

-

a Order of elution is given on apolar column (Rtx-1). The compounds with an asterisk (*) were only identified in the essential oils.

b Retention indices of literature on the apolar column (lRIa) reported from [1218].

c Retention indices on the apolar Rtx-1 column (RIa).

d Retention indices on the polar Rtx-Wax column (RIp).

e Percentages are given on the apolar column except for components with identical RIa (percentages are given on the polar column), tr = trace (< 0.05%). Sample locations: Bensekrane (A), Sid Abdeli (B), Terni (C) and Beni Snous (D).

£ Compounds identified from commercial data libraries: National Institute of Standards and Technology, 1999 (12, 33, 39, 43, 44); and König WA, Hochmuth DH, Joulain D, 2001 (26, 34, 35, 36, 40, 41, 42, 46).

However, the main component of the oils in the aerial parts of D. crinitus (53, 84.1%-40.1%) remained unidentified, and its identification was carried out using joint information obtained using data from EI-MS and 13C-NMR spectroscopy. The EI-MS data of 53 were close to those of isochavicol 2-methylbutyrate (4-(prop-(1E)-enyl)phenyl 2-methylbutyrate) 60, except for the molecular ion (m/z = 204 vs. m/z = 218, respectively), and for a signal at m/z = 43, replacing a peak occurring at m/z = 57. These signals suggest the occurrence of an isochavicol-derivative compound that had lost a 14 uma fragment from the acyl part. The 13C-NMR spectra acquired from the stem oil from a sample from Bensekrane (53, 84.1%) exhibited 10 signals, of which, three had double the intensity, assigned from the DEPT spectra of three quaternary carbon atoms (175.60, 149.65, and 135.59 ppm), and two aromatic methine carbon atoms (121.46 and 126.65 ppm), two unsaturated methine carbon atoms (130.15 and 125.78 ppm) and two methyl carbon atoms (18.43 and 18.93 ppm). These signals confirm the presence of phenylpropanoid compounds, and the formula of C13H16O2 was deduced from the DEPT spectra. The identification of isochavicol isobutyrate was unambiguously established from a comparison of its 13C-NMR spectral data with those reported in the literature [6, 11] and from the identification of isochavicol as a corresponding alcohol from the LAH reduction of the Bensekrane stem oil sample.

Concerning the plant chemistry, two types of essential oils were produced by D. crinitus. The root oils were mainly composed of aliphatic compounds (87.0%-90.1%), and the aerial part oils (i.e., the leaves, stems, flowers, and umbels) were characterized by the occurrence of phenylpropanoids (43.1%-88.6%). The three main aliphatic compounds in the root oils were: dodecyl acetate 57 (30.3%-48.2%), undecane 17 (14.4%-34.1%), and dodecanal 35 (16.7%-26.3%). It is noticeable that the relative percentage abundance of these compounds differed according to the locality of the sampling; undecane was the major component in the Bensekrane (A) and Sid Abdelli (B) sample oils (34.1% and 30.9%, respectively), whereas dodecyl acetate 57 was identified as the main aliphatic component in the Terni (C) and Beni Snous (D) root oils (48.2% and 42.3%, respectively).

Conversely, in the oils from the aerial parts, the main components were isochavicol esters. These oils were similar qualitatively, but differed in the relative amounts of their major components. We noted that isochavicol isobutyrate 53 was always the major component (84.1%-36.5%), whichever organ was analyzed. The other major components identified were: isochavicol 2-methylbutyrate 60 (1.8%-17.8%), pentadecane 50 (0.4%-15.2%), zizaene 44 (trace-9.2%), and undecane 17 (trace-14.2%). Moreover, except for the stem oil obtained from the Bensekrane (A) sample, it appeared that the sampling locality had a lesser influence on the variability of the component chemicals of the oils. Finally, it should be noted that the relative percentage abundance of the aliphatic and phenylpropanoid compounds was correlated with the position of the organ on the dressed plant. On moving from the bottom to the top of the plant (i.e., the root, leaf, stem, umbel, and then flower), the relative percentage abundance of aliphatic compounds decreased, while the relative percentage abundance of phenylpropanoids increased. In the same way, we noted that the relative percentage abundance of hydrocarbon sesquiterpenes was higher in the umbels and flower oils (10.2%-15.3% and 7.7%-9.7%, respectively) than in the other organs (never more than 5.6%).

HS-SPME analysis of the volatiles

The volatiles emitted from the D. crinitus roots, leaves, stems, umbels, and flowers harvested in different locations were investigated using HS-SPME under optimized parameters. The optimization of the HS-SPME sampling parameters was carried out using fresh plant material based on the sum of the total peak areas obtained using GC-FID. The maximum sum of the total peak area was acquired for a temperature of 70°C, an equilibrium time of 60 min, and an extraction time of 30 min (Table 2). The GC-RI and GC-MS analysis identified 84 components: 45 nonterpenic compounds, 17 monoterpenes, 21 sesquiterpenes, and one diterpene (Tables 3 and 4). Identification of 45 components was performed by comparing their EI-MS and retention indices with those in the laboratory-produced "Arômes" library, and 18 components were identified by comparing their EI-MS data and their apolar retention indices with those reported in commercial or literature libraries.
Table 2

Influence of HS-SPME parameters (temperature extraction, equilibrium and extraction times) on the volatiles of Daucus crinitus Desf

 

HS-SPME parameters

  

Equilibrium time teq min

Extraction time text min

Extraction Temperature Text°C

  

(Text = 70°C - text = 15 min)

(Text = 70°C - teq = 60 min)

(text = 30 min - teq = 60 min)

Class of compounds

20

40

60

80

30

45

30

50

70

90

Hydrocarbon compounds

37.6

58.8

53.8

49.1

69.3

52.3

85.9

76.3

69.3

62.0

Oxygenated compounds

56.8

37.8

44.8

47.6

30.1

38.1

11.3

22.5

30.1

36.1

Aliphatic compounds

74.6

69.3

78.4

72.2

80.2

67.2

74.8

79.3

80.2

76.1

Phenylpropanoid compounds

2.0

3.2

1.2

2.9

0.6

2.5

0.1

0.3

0.6

0.9

Hydrocarbon non-terpenic compounds

23.5

37.5

39.8

29.9

54.8

33.8

67.4

59.5

54.8

45.1

Hydrocarbon monoterpenes

11.9

17.2

13.1

17.6

6.7

12.1

19.3

12.6

6.7

4.1

Hydrocarbon sesquiterpenes

2.2

4.0

0.6

1.5

7.6

6.3

0.8

4.2

7.6

12.5

Hydrocarbon diterpenes

-

0.1

0.3

0.1

0.2

0.1

-

-

0.2

0.3

Oxygenated non-terpenic compounds

52.9

35.0

39.8

45.2

26.0

35.9

9.1

20.1

26.0

31.9

Oxygenated monoterpenes

3.8

2.8

4.9

2.3

1.0

2.1

2.2

2.2

1.0

0.5

Oxygenated sesquiterpenes

0.1

-

0.1

0.1

3.1

0.1

-

0.2

3.1

3.7

Esters

4.9

5.4

5.4

7.0

9.9

4.5

3.2

8.6

9.9

12.8

Alcohols

4.2

2.8

3.9

2.2

4.4

29.0

1.9

3.2

4.4

7.3

Ketones

0.7

0.1

0.6

0.2

0.4

0.3

0.1

0.2

0.4

0.2

Aldehydes

43.0

25.4

28.0

35.3

10.2

25.6

3.2

8.5

10.2

11.2

Total identification (%)

94.6

96.6

98.6

96.7

99.4

90.4

97.2

98.8

99.4

98.1

Total area 105 a

223.2

282.8

351.0

303.1

454.1

426.4

96.8

206.4

454.1

451.2

a Total area is expressed in arbitrary units

Fresh aerial parts of Daucus crinitus Desf. used for this study were harvested in Bensekrane.

Table 3

Volatile components extracted by HS-SPME from roots, leaves and stems of Daucus crinitus Desf

No.a

Components£

lRIab

RIac

Rootsd

Leavesd

Stemsd

    

A

B

C

D

A

B

C

D

A

B

C

D

1a

Heptane

700

702

0.3 ± 0.01

tr

-

-

0.1 ± 0.01

tr

tr

tr

0.3 ± 0.07

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

1b

3-methyl 1-Butanol

717

710

-

-

-

-

tr

-

-

-

0.3 ± 0.01

0.1 ± 0.01

0.3 ± 0.01

0.5 ± 0.07

1c

Hexanal

780

767

tr

tr

tr

-

tr

0.1 ± 0.01

tr

0.6 ± 0.07

0.7 ± 0.07

0.2 ± 0.01

0.8 ± 0.07

1.0 ± 0.14

1d

Hex-5-en-1-ol

820

820

-

-

-

-

0.3 ± 0.07

0.5 ± 0.07

0.2 ± 0.01

0.9 ± 0.07

tr

tr

0.1 ± 0.01

0.1 ± 0.01

1e

2-Heptanone

871

870

tr

-

-

-

tr

0.3 ± 0.01

 

0.3 ± 0.01

tr

-

-

-

1

Nonane

906

902

0.3 ± 0.07

5.5 ± 0.21

-

-

3.7 ± 0.14

2.1 ± 0.14

1.2 ± 0.14

0.8 ± 0.14

1.4 ± 0.14

0.5 ± 0.07

1.4 ± 0.21

1.7 ± 0.28

2

α-Pinene

936

931

-

-

-

-

0.2 ± 0.01

2.8 ± 0.21

0.2 ± 0.01

0.6 ± 0.01

6.1 ± 0.21

1.8 ± 0.21

6.1 ± 0.01

2.6 ± 0.14

2a

Camphene

950

943

-

-

-

-

0.1 ± 0.01

-

-

-

0.2 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

3

Sabinene

973

966

-

0.1 ± 0.01

-

-

0.3 ± 0.01

0.3 ± 0.01

-

tr

0.6 ± 0.07

0.2 ± 0.01

0.4 ± 0.01

0.3 ± 0.01

3a

2-pentyl Furan

981

978

0.3 ± 0.01

-

-

-

tr

-

-

 

0.2 ± 0.01

tr

0.2 ± 0.01

0.1 ± 0.01

5

Myrcene

987

981

-

-

-

-

0.1 ± 0.01

0.6 ± 0.14

-

0.2 ± 0.07

10.6 ± 0.64

10.0 ± 0.64

7.4 ± 0.54

7.5 ± 0.35

5a

α-Phellandrene

1002

991

-

-

-

-

tr

0.2 ± 0.01

-

-

0.3 ± 0.01

0.4 ± 0.07

0.4 ± 0.01

0.4 ± 0.07

5b

3-methyl butyl Isobutyrate

994

997

-

-

-

-

0.2 ± 0.01

tr

0.1 ± 0.01

-

tr

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

6

Decane

993

998

0.2 ± 0.01

1.2 ± 0.14

0.1 ± 0.01

-

tr

tr

 

-

0.1 ± 0.01

0.3 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

6a

2-methyl butyl Isobutyrate

1004

999

-

-

-

-

0.1 ± 0.01

tr

0.2 ± 0.01

-

0.1 ± 0.01

-

-

tr

7

p-Cymene

1015

1012

-

-

-

-

 

3.5 ± 0.21

-

0.1 ± 0.01

2.2 ± 0.14

0.2 ± 0.01

2.7 ± 0.21

3.3 ± 0.21

9

Limonene

1025

1026

-

0.1 ± 0.01

-

-

0.2 ± 0.01

2.0 ± 0.35

0.2 ± 0.01

0.3 ± 0.07

7.5 ± 0.49

11.7 ± 0.64

9.9 ± 0.49

11.1 ± 0.92

10

(E)-β-Ocimene

1041

1037

-

-

-

-

tr

0.7 ± 0.07

0.1 ± 0.01

tr

0.1 ± 0.01

0.5 ± 0.01

0.4 ± 0.01

0.7 ± 0.01

11

γ-Terpinene

1051

1049

-

-

-

-

0.2 ± 0.01

7.4 ± 0.01

-

-

1.6 ± 0.28

2.7 ± 0.21

1.6 ± 0.01

2.3 ± 0.28

12

1-Octanol

1061

1056

-

-

-

-

0.1 ± 0.01

tr

-

tr

0.2 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.07

13

2-methyl Decane

1068

1065

0.4 ± 0.07

6.7 ± 0.71

0.3 ± 0.07

-

0.6 ± 0.07

-

-

-

tr

-

tr

tr

14

Nonanal

1076

1074

-

-

-

-

tr

0.4 ± 0.01

-

-

-

0.3 ± 0.01

0.5 ± 0.01

0.8 ± 0.07

15

α-Terpinolene

1082

1079

-

-

-

-

0.2 ± 0.01

9.4 ± 0.42

-

-

0.2 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

0.5 ± 0.07

15a

2-Nonanol

1085

1080

-

-

-

0.1 ± 0.01

-

-

-

-

0.1 ± 0.01

0.4 ± 0.01

0.4 ± 0.01

0.5 ± 0.01

17

Undecane

1100

1098

43.5 ± 0.85

5.0 ± 0.35

26.2 ± 0.92

2.3 ± 0.21

11.1 ± 0.57

2.9 ± 0.35

1.2 ± 0.07

8.9 ± 0.28

2.7 ± 0.78

2.8 ± 0.14

2.1 ± 0.35

2.6 ± 0.14

17a

Limonene 1,2-epoxide

1117

1113

-

-

-

-

tr

0.1 ± 0.01

-

-

-

-

-

-

17b

Camphor

1123

1120

-

-

-

-

tr

0.5 ± 0.07

0.3 ± 0.01

0.5 ± 0.07

0.1 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

17c

n-hexyl Isobutyrate

1127

1126

-

-

-

-

0.1 ± 0.01

0.1 ± 0.01

-

0.1 ± 0.01

-

0.2 ± 0.01

0.1 ± 0.01

tr

17d

Cryptone

1160

1158

-

-

-

-

tr

0.1 ± 0.01

-

-

0.4 ± 0.07

0.3 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

19

Terpinen-4-ol

1164

1161

-

-

-

-

-

-

-

-

0.3 ± 0.01

0.6 ± 0.07

0.3 ± 0.01

0.4 ± 0.01

19a

3-methyl Undecane

1170

1165

0.1 ± 0.01

0.5 ± 0.07

tr

-

-

-

-

-

-

-

-

-

19b

Estragole

1175

1169

-

-

-

-

0.2 ± 0.01

-

-

-

tr

0.9 ± 0.01

0.8 ± 0.14

1.0 ± 0.14

21

Decanal

1188

1187

-

0.1 ± 0.01

-

-

1.5 ± 0.02

14.8 ± 0.01

7.8 ± 0.57

2.5 ± 0.14

1.1 ± 0.01

1.8 ± 0.21

2.1 ± 0.14

2.5 ± 0.01

22

Dodecane

1200

1198

0.3 ± 0.07

0.3 ± 0.01

tr

-

0.1 ± 0.01

tr

-

-

tr

0.3 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

22a

γ-Octanolide

1208

1208

-

-

-

-

0.1 ± 0.01

0.1 ± 0.01

0.5 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.4 ± 0.01

0.3 ± 0.01

0.4 ± 0.07

22b

Chavicol

1219

1214

-

0.1 ± 0.01

-

-

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

-

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.3 ± 0.01

22c

2-Nonanyl acetate

1224

1220

-

0.7 ± 0.01

-

-

-

-

-

-

tr

0.2 ± 0.01

tr

tr

23

Decanol

1263

1259

-

0.1 ± 0.01

-

0.4 ± 0.07

0.2 ± 0.01

0.8 ± 0.01

1.8 ± 0.21

-

1.8 ± 0.14

2.2 ± 0.14

1.4 ± 0.14

1.5 ± 0.21

23a

trans-Anethol

1262

1260

-

-

-

-

tr

-

-

-

tr

0.1 ± 0.01

tr

tr

24

Nonanoic acid

1263

1263

-

0.1 ± 0.01

-

-

-

-

-

-

0.3 ± 0.07

0.4 ± 0.07

0.4 ± 0.01

0.4 ± 0.01

24a

Benzyl isobutyrate

1269

1266

-

-

-

-

-

-

-

-

-

-

-

-

24b

Undecan-2-one

1273

1268

0.1 ± 0.01

tr

-

1.1 ± 0.14

0.1 ± 0.01

-

-

-

0.2 ± 0.01

0.6 ± 0.07

0.5 ± 0.01

0.5 ± 0.01

25

Undecanal

1290

1280

-

0.7 ± 0.21

0.2 ± 0.01

-

-

tr

0.2 ± 0.01

-

tr

0.3 ± 0.01

0.2 ± 0.01

0.3 ± 0.01

26

Tridecane

1300

1292

3.7 ± 0.21

7.7 ± 0.85

4.0 ± 0.35

0.7 ± 0.07

0.2 ± 0.01

0.1 ± 0.01

0.4 ± 0.01

0.3 ± 0.07

0.2 ± 0.01

0.4 ± 0.01

0.3 ± 0.01

0.4 ± 0.01

26a

Isochavicol

1313

1315

-

-

-

-

0.1 ± 0.01

0.1 ± 0.01

0.7 ± 0.01

-

0.4 ± 0.07

0.1 ± 0.01

0.1 ± 0.01

tr

27

n-Octyl isobutyrate

1329

1325

-

-

-

-

0.1 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

-

-

-

-

-

28

Neryl acetate

1342

1336

-

-

-

0.6 ± 0.01

-

-

0.1 ± 0.01

-

0.2 ± 0.01

1.1 ± 0.21

1.1 ± 0.01

1.0 ± 0.14

29

Decannoic acid

1347

1348

0.2 ± 0.01

0.4 ± 0.01

0.4 ± 0.01

-

-

-

tr

-

tr

0.2 ± 0.01

0.1 ± 0.01

tr

30

Benzyl 2-methyl butyrate

1360

1352

-

0.6 ± 0.07

-

-

tr

-

tr

-

-

-

-

-

31

Geranyl acetate

1362

1359

-

-

-

-

-

-

0.1 ± 0.01

-

tr

0.2 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

33

α-Copaene

1379

1372

-

-

-

-

-

-

-

-

1.6 ± 0.14

2.1 ± 0.14

4.1 ± 0.01

2.6 ± 0.14

34

β-Bourbonene

1386

1376

-

-

-

-

-

-

-

-

4.0 ± 0.42

3.6 ± 0.21

3.7 ± 0.01

3.2 ± 0.28

35

Dodecanal

1389

1390

29.3 ± 1.2

20.6 ± 1.84

45.1 ± 1.27

55.4 ± 0.99

0.4 ± 0.14

1.5 ± 0.21

4.4 ± 0.14

2.1 ± 0.01

2.7 ± 0.28

1.3 ± 0.21

1.2 ± 0.01

1.4 ± 0.07

36

Tetradecane

1400

1403

-

-

-

-

0.1 ± 0.07

0.1 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

37

Longifolene

1411

1409

-

0.2 ± 0.01

tr

-

tr

0.2 ± 0.01

-

2.3 ± 0.21

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

38

α-Santalene

1422

1415

-

-

tr

-

-

-

-

tr

0.1 ± 0.01

tr

tr

tr

39

β-Caryophyllene

1421

1424

-

-

-

-

0.8 ± 0.14

0.1 ± 0.01

-

-

0.7 ± 0.14

1.2 ± 0.07

0.4 ± 0.01

0.8 ± 0.07

40

Dauca-3,8-diene

1428

1426

-

-

-

-

0.1 ± 0.01

-

-

-

-

-

-

-

41

trans-α-bergamotene

1432

1432

-

-

-

-

0.7 ± 0.01

0.2 ± 0.01

  

0.2 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

42

(E)-β-Farnesene

1446

1443

-

-

-

-

0.1 ± 0.01

0.1 ± 0.01

 

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

43

α-Humulene

1455

1451

-

-

-

-

0.4 ± 0.01

0.3 ± 0.01

1.0 ± 0.01

0.3 ± 0.01

0.9 ± 0.01

0.3 ± 0.01

0.4 ± 0.07

0.4 ± 0.01

45

Dodecanol

1472

1470

2.7 ± 0.01

8.8 ± 0.42

1.7 ± 0.28

4.4 ± 0.35

0.2 ± 0.01

-

-

-

0.5 ± 0.01

0.8 ± 0.21

0.9 ± 0.01

0.5 ± 0.07

46

α-Curcumene

1473

1474

-

-

-

-

-

-

-

-

0.8 ± 0.14

0.6 ± 0.01

0.9 ± 0.01

0.4 ± 0.01

47

Germacrene-D

1479

1478

0.2 ± 0.01

-

-

-

-

-

-

-

0.8 ± 0.01

2.1 ± 0.28

3.3 ± 0.01

2.1 ± 0.07

49

Zingiberene

1489

1483

0.2 ± 0.01

0.7 ± 0.14

0.4 ± 0.07

0.6 ± 0.01

-

-

-

-

tr

0.2 ± 0.01

tr

0.1 ± 0.01

50

Pentadecane

1500

1497

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

51.6 ± 1.77

12.8 ± 0.49

41.2 ± 1.34

40.8 ± 0.57

11.9 ± 1.06

13.1 ± 0.78

14.0 ± 0.28

16.0 ± 0.42

51

δ-Cadinene

1520

1514

-

-

-

-

0.1 ± 0.01

tr

1.1 ± 0.01

0.3 ± 0.01

-

-

-

-

52

Geranyl butyrate

1534

1530

tr

0.1 ± 0.01

-

0.2 ± 0.01

-

0.6 ± 0.01

-

-

0.3 ± 0.01

2.0 ± 0.01

1.7 ± 0.01

1.6 ± 0.21

53

Isochavicol isobutyrate

1546

1541

 

0.4 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

19.9 ± 0.85

10.4 ± 1.13

19.0 ± 0.85

0.2 ± 0.01

0.7 ± 0.14

0.4 ± 0.01

0.2 ± 0.01

56

Caryophyllene oxyde

1578

1572

-

-

-

-

-

-

-

-

0.1 ± 0.01

tr

tr

tr

57

Dodecyl acetate

1585

1580

14.2 ± 0.49

32.4 ± 1.70

16.4 ± 1.06

21.7 ± 0.85

0.2 ± 0.01

0.3 ± 0.01

3.6 ± 0.21

5.0 ± 0.21

2.3 ± 0.28

2.0 ± 0.01

2.3 ± 0.21

2.6 ± 0.07

58

α-Cedrol

1603

1596

-

-

-

-

-

0.1 ± 0.01

-

-

1.4 ± 0.21

1.0 ± 0.01

0.9 ± 0.01

0.9 ± 0.07

59

Hexadecane

1600

1599

-

-

-

-

0.3 ± 0.01

0.1 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

0.5 ± 0.01

0.4 ± 0.01

0.2 ± 0.01

0.3 ± 0.01

60

Isochavicol 2-methyl butyrate

1651

1648

-

-

-

0.4 ± 0.01

0.1 ± 0.01

2.7 ± 0.01

2.9 ± 0.01

2.1 ± 0.14

0.1 ± 0.01

0.4 ± 0.01

0.3 ± 0.01

0.1 ± 0.01

60a

Bisabolol oxide B

1654

1650

-

-

-

-

0.2 ± 0.01

 

tr

0.1 ± 0.01

3.9 ± 0.01

2.7 ± 0.01

2.1 ± 0.01

1.1 ± 0.14

62

Heptadecane

1700

1703

0.1 ± 0.01

0.2 ± 0.01

tr

0.2 ± 0.01

20.7 ± 1.56

4.1 ± 0.21

11.9 ± 0.35

6.4 ± 0.57

20.7 ± 0.57

13.2 ± 0.42

9.0 ± 0.35

11.2 ± 0.49

63

Benzyl benzoate

1730

1723

0.1 ± 0.01

0.7 ± 0.01

tr

2.7 ± 0.14

-

-

0.3 ± 0.01

0.7 ± 0.01

0.5 ± 0.07

0.2 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

66

Hexadecanal

1782

1787

0.5 ± 0.01

0.5 ± 0.01

0.5 ± 0.07

0.7 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

tr

0.1 ± 0.01

tr

tr

0.2 ± 0.01

67

Neophytadiene

1807

1807

tr

0.8 ± 0.01

tr

3.2 ± 0.21

0.6 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

0.4 ± 0.01

0.3 ± 0.01

tr

0.1 ± 0.01

0.2 ± 0.01

 

% Identification

  

96.8 ± 0.57

95.4 ± 0.21

95.7 ± 0.28

95.2 ± 0.07

97.3 ± 0.21

93.6 ± 0.64

93.1 ± 0.21

96.3 ± 0.28

95.7 ± 0.35

92.1 ± 0.07

90.9 ± 0.28

92.9 ± 0.49

 

Total area (105)

  

486.4

451.3

445.5

430.2

391.8

351.9

378.3

345.6

312.5

336.1

333.8

342.8

 

Hydrocarbon compounds

  

49.4

28.4

31.2

7.3

92.8

65.1

66.9

65.4

82.8

72.9

73.9

76.4

 

Oxygenated compounds

  

47.4

67.0

64.5

87.9

4.5

28.5

26.2

30.9

12.9

19.2

17.0

16.5

 

Aliphatic compounds

  

96.3

91.8

95.1

88.1

90.8

42.0

75.7

69.3

49.4

46.1

42.6

49.1

 

Phenylpropanoid compounds

  

0.1

1.8

0.2

3.3

0.7

22.8

14.4

21.8

1.3

2.5

1.9

1.8

 

Hydrocarbon non-terpenic compounds

49,0

27,4

30.8

3.5

88.7

37.1

64.2

60.8

43.8

34.2

31.3

37.3

 

Hydrocarbon monoterpenes

  

-

0.2

-

-

1.3

26.9

0.5

1.2

29.4

28.0

29.4

28.9

 

Hydrocarbon sesquiterpenes

  

0.4

0.8

0.4

0.6

2.2

0.9

2.1

3.0

9.3

10.7

13.1

10.0

 

Hydrocarbon diterpenes

  

-

-

-

3.2

0.6

0.2

0.1

0.4

0.3

-

0.1

0.2

 

Oxygenated non-terpenic compounds

 

47,4

66.2

64.5

87.9

4.3

27.7

25.9

30.3

6.9

14.4

13.2

13.6

 

Oxygenated monoterpenes

  

-

 

-

-

-

0.7

0.3

0.5

0.8

1.1

0.8

0.9

 

Oxygenated sesquiterpenes

  

-

0.8

-

-

0.2

0.1

-

0.1

5.2

3.7

3.0

2.0

a Order of elution is given on apolar column (Rtx-1). Numbers correspond to those in table 1. The compounds that the number is followed by a letter were only identified in HS-fractions.

b Retention indices of literature on the apolar column (lRIa) reported from [1218].

c Retention indices on the apolar Rtx-1 column (RIa).

d Percentages (means of three analyses) obtained by GC-FID (on RTX-1: apolar column) with peak-area normalization under optimized HS-SPME parameters: temperature: 70°C; equilibrium time: 60 min; extraction time: 30 min. Sample locations: Bensekrane (A), Sid Abdeli (B), Terni (C) and Beni Snous (D).

e Total area is expressed in arbitrary units.

£ Compounds identified from commercial data libraries: National Institute of Standards and Technology, 1999 (1b, 12, 15c, 17a, 19d, 20b); and literature data: König WA, Hochmuth DH, Joulain D, 2001 (3a, 13a, 19b, 19c, 24a, 32b, 35, 36, 36a, 38a, 41, 42).

Table 4

Volatile components extracted by HS-SPME from umbels and flowers of Daucus crinitus Desf

No.a

Components£

lRIab

RIac

Umbelsd

Flowersd

    

A

B

C

D

A

B

C

D

1a

Heptane

700

702

tr

tr

0.1 ± 0.01

tr

tr

0.1 ± 0.01

tr

tr

1b

3-methyl 1-Butanol

717

710

tr

tr

0.1 ± 0.01

0.1 ± 0.01

-

-

-

-

1c

Hexanal

780

767

0.1 ± 0.01

0.1 ± 0.01

tr

tr

0.2 ± 0.01

0.3 ± 0.07

0.6 ± 0.01

0.8 ± 0.01

1d

Hex-5-en-1-ol

820

820

tr

tr

tr

0.1 ± 0.01

-

-

-

-

1e

2-Heptanone

871

870

-

-

-

-

-

-

-

-

1

Nonane

906

902

0.2 ± 0.07

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.5 ± 0.07

0.4 ± 0.07

2

α-Pinene

936

931

0.2 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

0.7 ± 0.07

0.5 ± 0.14

0.7 ± 0.01

0.8 ± 0.01

2a

Camphene

950

943

0.1 ± 0.01

-

-

-

-

-

-

-

3

Sabinene

973

966

-

-

-

-

-

-

-

-

3a

2-pentyl Furan

981

978

0.1 ± 0.01

-

-

-

-

-

-

-

5

Myrcene

987

981

0.6 ± 0.01

0.2 ± 0.01

0.6 ± 0.07

0.2 ± 0.01

0.6 ± 0.01

0.5 ± 0.07

2.2 ± 0.14

2.1 ± 0.07

5a

α-Phellandrene

1002

991

1.1 ± 0.01

-

-

-

-

-

-

-

5b

3-methyl butyl Isobutyrate

994

997

0.5 ± 0.07

0.3 ± 0.01

0.6 ± 0.07

0.7 ± 0.07

0.4 ± 0.01

0.3 ± 0.01

0.4 ± 0.07

0.3 ± 0.01

6

Decane

993

998

tr

tr

0.1 ± 0.01

tr

-

-

-

-

6a

2- methyl butyl Isobutyrate

1004

999

-

0.2 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

7

p-Cymene

1015

1012

0.8 ± 0.07

9.7 ± 0.14

0.6 ± 0.01

0.6 ± 0.07

0.2 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

9

Limonene

1025

1026

1.8 ± 0.21

1.6 ± 0.07

1.8 ± 0.14

2.3 ± 0.28

0.7 ± 0.14

0.7 ± 0.07

1.1 ± 0.14

2.2 ± 0.28

10

(E)-β-Ocimene

1041

1037

0.1 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

tr

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

11

γ-Terpinene

1051

1049

0.4 ± 0.07

0.7 ± 0.14

0.5 ± 0.01

0.4 ± 0.01

0.1 ± 0.01

tr

0.1 ± 0.01

0.1 ± 0.01

12

1-Octanol

1061

1056

0.2 ± 0.01

0.6 ± 0.07

0.5 ± 0.01

0.6 ± 0.07

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

13

2-methyl Decane

1068

1065

-

-

-

-

-

-

-

-

14

Nonanal

1076

1074

0.3 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.07

-

-

-

-

15

α-Terpinolene

1082

1079

0.3 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

-

-

-

-

15a

2-Nonanol

1085

1080

tr

0.1 ± 0.01

0.1 ± 0.01

tr

-

-

-

-

17

Undecane

1100

1098

0.3 ± 0.07

0.3 ± 0.01

0.3 ± 0.01

0.2 ± 0.07

0.1 ± 0.01

tr

0.1 ± 0.01

0.1 ± 0.01

17a

Limonene 1-2-epoxide

1117

1113

tr

tr

-

tr

tr

0.2 ± 0.01

0.1 ± 0.01

tr

17b

Camphor

1123

1120

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

tr

0.1 ± 0.01

-

tr

17c

n-hexyl Isobutyrate

1127

1126

0.5 ± 0.07

0.5 ± 0.01

0.5 ± 0.01

0.6 ± 0.14

-

-

-

-

17d

Cryptone

1160

1158

tr

tr

0.1 ± 0.01

tr

tr

tr

0.1 ± 0.01

0.1 ± 0.01

19

Terpinen-4-ol

1164

1161

tr

tr

-

0.1 ± 0.01

tr

0.2 ± 0.01

0.3 ± 0.01

0.1 ± 0.01

19a

3-methyl Undecane

1170

1165

-

-

-

-

-

-

-

-

19b

Estragole

1175

1169

0.1 ± 0.01

0.4 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

-

-

-

-

21

Decanal

1188

1187

tr

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

-

-

-

-

22

Dodecane

1200

1198

-

-

-

-

-

-

-

-

22a

γ-Octanolide

1208

1208

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

0.4 ± 0.07

22b

Chavicol

1219

1214

2.3 ± 0.28

1.7 ± 0.01

2.0 ± 0.14

1.7 ± 0.28

tr

0.1 ± 0.01

0.1 ± 0.01

tr

22c

2-Nonanyl acetate

1224

1220

tr

tr

-

0.1 ± 0.01

0.7 ± 0.14

0.9 ± 0.01

0.7 ± 0.01

0.8 ± 0.14

23

Decanol

1263

1259

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.2 ± 0.07

0.5 ± 0.07

0.2 ± 0.01

0.4 ± 0.01

0.4 ± 0.07

23a

Trans-Anethol

1262

1260

0.5 ± 0.01

tr

0.1 ± 0.01

0.5 ± 0.07

0.4 ± 0.01

0.3 ± 0.07

0.6 ± 0.01

0.5 ± 0.01

24

Nonanoic acid

1263

1263

2.3 ± 0.21

0.2 ± 0.07

-

-

0.5 ± 0.14

0.5 ± 0.07

0.7 ± 0.07

0.4 ± 0.01

24a

Benzyl isobutyrate

1269

1266

-

-

-

-

0.3 ± 0.01

0.5 ± 0.01

0.5 ± 0.01

0.5 ± 0.01

24b

Undecan-2-one

1273

1268

0.2 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

0.2 ± 0.01

0.4 ± 0.01

0.2 ± 0.01

25

Undecanal

1290

1280

0.3 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.4 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.4 ± 0.01

26

Tridecane

1300

1292

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.0

0.1 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

26a

Isochavicol

1313

1315

15.2 ± 1.34

9.1 ± 0.57

15.5 ± 0.42

7.1 ± 0.49

31.8 ± 1.34

34.7 ± 1.27

29.6 ± 0.99

32.9 ± 1.13

27

n-Octyl isobutyrate

1329

1325

0.4 ± 0.07

0.2 ± 0.01

0.3 ± 0.01

0.2 ± 0.01

0.8 ± 0.07

0.7 ± 0.01

0.4 ± 0.01

0.5 ± 0.01

28

Neryl acetate

1342

1336

0.2 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

29

Decannoic acid

1347

1348

0.2 ± 0.01

tr

0.1 ± 0.01

0.1 ± 0.01

-

-

-

-

30

Benzyl 2-methyl butyrate

1360

1352

tr

0.2 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.3 ± 0.01

0.1 ± 0.01

0.5 ± 0.01

0.3 ± 0.01

31

Geranyl acetate

1362

1359

0.7 ± 0.14

0.7 ± 0.07

0.7 ± 0.07

0.7 ± 0.07

0.6 ± 0.07

0.3 ± 0.01

0.2 ± 0.01

0.7 ± 0.01

33

α-Copaene

1379

1372

0.3 ± 0.14

0.4 ± 0.01

0.5 ± 0.01

0.4 ± 0.01

0.6 ± 0.14

0.4 ± 0.01

0.6 ± 0.01

0.6 ± 0.07

34

β-Bourbonene

1386

1376

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.2 ± 0.01

0.1 ± 0.01

35

Dodecanal

1389

1390

0.4 ± 0.07

0.6 ± 0.01

0.6 ± 0.01

0.5 ± 0.07

0.5 ± 0.14

0.5 ± 0.01

0.8 ± 0.14

0.4 ± 0.01

36

Tetradecane

1400

1403

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

37

Longifolene

1411

1409

tr

tr

tr

tr

0.6 ± 0.01

0.5 ± 0.01

0.7 ± 0.01

0.3 ± 0.07

38

α-Santalene

1422

1415

-

-

-

-

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

39

β-Caryophyllene

1421

1424

5.1 ± 0.28

5.8 ± 0.01

4.2 ± 0.14

5.4 ± 0.42

0.1 ± 0.01

tr

0.2 ± 0.01

tr

40

Dauca-3,8-diene

1428

1426

tr

tr

tr

tr

0.2 ± 0.01

0.1 ± 0.10

0.3 ± 0.07

0.5 ± 0.07

41

Trans-α-bergamotene

1432

1432

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.2 ± 0.01

0.7 ± 0.07

0.4 ± 0.07

0.6 ± 0.07

0.5 ± 0.07

42

(E)-β-Farnesene

1446

1443

0.4 ± 0.01

tr

0.3 ± 0.01

0.2 ± 0.01

0.7 ± 0.07

0.5 ± 0.07

1.1 ± 0.01

0.7 ± 0.01

43

α-Humulene

1455

1451

tr

0.4 ± 0.01

0.1 ± 0.01

0.2 ± 0.07

0.3 ± 0.01

0.3 ± 0.01

0.3 ± 0.01

0.1 ± 0.01

45

Dodecanol

1472

1470

6.0 ± 0.14

6.8 ± 0.49

7.1 ± 0.35

7.6 ± 0.42

1.9 ± 0.28

3.6 ± 0.14

2.6 ± 0.07

2.0 ± 0.14

46

α-Curcumene

1473

1474

0.8 ± 0.21

tr

0.5 ± 0.01

0.3 ± 0.01

0.5 ± 0.05

0.4 ± 0.01

0.7 ± 0.07

0.3 ± 0.01

47

Germacrene-D

1479

1478

0.2 ± 0.01

1.0 ± 0.01

0.9 ± 0.01

0.7 ± 0.07

0.5 ± 0.01

0.2 ± 0.01

0.5 ± 0.01

0.5 ± 0.01

49

Zingiberene

1489

1483

tr

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.5 ± 0.01

0.3 ± 0.01

0.8 ± 0.07

0.4 ± 0.01

50

Pentadecane

1500

1497

8.9 ± 0.57

5.9 ± 0.20

4.1 ± 0.28

3.6 ± 0.21

14.2 ± 0.49

12.5 ± 0.35

14.0 ± 0.64

12.9 ± 0.49

51

δ-cadinene

1520

1514

0.8 ± 0.01

0.1 ± 0.01

0.6 ± 0.01

0.7 ± 0.07

0.5 ± 0.01

0.2 ± 0.01

0.4 ± 0.01

0.4 ± 0.01

52

Geranyl butyrate

1534

1530

tr

0.4 ± 0.01

0.5 ± 0.01

0.4 ± 0.07

tr

0.1 ± 0.01

tr

0.1 ± 0.01

53

Isochavicol isobutyrate

1546

1541

26.7 ± 1.20

49.4 ± 0.99

40.3 ± 1.70

51.8 ± 0.64

14.3 ± 0.01

15.4 ± 0.64

18.2 ± 0.49

19.7 ± 0.57

56

Caryophyllene oxyde

1578

1572

1.0 ± 0.01

0.6 ± 0.01

1.1 ± 0.01

0.9 ± 0.01

-

-

-

-

57

Dodecyl acetate

1585

1580

0.7 ± 0.14

0.6 ± 0.01

0.6 ± 0.07

0.7 ± 0.07

0.4 ± 0.01

0.5 ± 0.01

0.3 ± 0.01

0.2 ± 0.01

58

α-Cedrol

1603

1596

0.6 ± 0.07

0.3 ± 0.01

0.4 ± 0.01

0.6 ± 0.01

1.9 ± 0.35

1.4 ± 0.01

1.1 ± 0.14

1.4 ± 0.14

59

Hexadecane

1600

1599

0.1 ± 0.01

0.6 ± 0.01

0.3 ± 0.07

0.3 ± 0.01

0.7 ± 0.01

0.5 ± 0.01

0.5 ± 0.01

0.4 ± 0.01

60

Isochavicol 2-methyl Butyrate

1651

1648

3.1 ± 0.21

3.6 ± 0.01

3.4 ± 0.14

2.3 ± 0.21

2.3 ± 0.14

2.3 ± 0.01

2.0 ± 0.07

2.6 ± 0.28

60a

Bisabolol oxide B

1654

1650

0.6 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

0.1 ± 0.01

1.7 ± 0.01

2.5 ± 0.01

1.3 ± 0.01

2.4 ± 0.21

62

Heptadecane

1700

1703

6.0 ± 0.28

1.9 ± 0.28

1.6 ± 0.14

1.7 ± 0.07

7.1 ± 0.35

5.0 ± 0.42

5.1 ± 0.49

4.5 ± 0.57

63

Benzyl benzoate

1730

1723

0.2 ± 0.01

tr

0.1 ± 0.01

0.2 ± 0.07

0.6 ± 0.07

0.5 ± 0.01

0.3 ± 0.01

0.5 ± 0.07

66

Hexadecanal

1782

1787

0.1 ± 0.01

tr

tr

tr

0.1 ± 0.01

tr

tr

tr

67

Neophytadiene

1807

1807

0.1 ± 0.01

tr

0.1 ± 0.01

tr

tr

tr

tr

tr

 

% d'identification

  

92,8 ± 0.35

98,8 ± 0.78

94,8 ± 0.64

98 ± 0.64

91,6 ± 0.64

91,2 ± 0.49

94,2 ± 0.85

97,5 ± 0.35

 

Total area 105 e

  

280,1

247,7

267,9

260,4

524,5

535,7

549,3

558,2

 

Hydrocarbon compounds

  

29,7

21,5

18,8

19,0

30,9

24,7

32,5

29,9

 

Oxygenated compounds

  

63,1

77,3

76,0

79,0

60,7

66,5

61,7

67,6

 

Aliphatic compounds

  

29,0

21,5

20,0

20,2

31,5

27,8

29,2

27,0

 

Phenylpropanoid compounds

  

48,1

64,4

61,6

63,8

48,7

53,4

51,3

56,5

 

Hydrocarbon non-terpenic compounds

16,3

9,7

7,2

6,8

23,1

19,1

21,7

19,9

 

Hydrocarbon monoterpenes

  

5,4

3,9

4,1

3,9

2,4

2,0

4,3

5,5

 

Hydrocarbon sesquiterpenes

  

7,9

7,9

7,4

8,3

5,4

3,6

6,5

4,5

 

Hydrocarbon diterpenes

  

0,1

-

0,1

-

-

-

-

-

 

Oxygenated non-terpenic compounds

 

60,8

76,2

74,4

77,2

57,1

62,1

58,8

63,6

 

Oxygenated monoterpenes

  

0,1

0,1

0,2

0,2

-

0,5

0,5

0,2

 

Oxygenated sesquiterpenes

  

2,2

1,0

1,4

1,6

3,6

3,9

2,4

3,8

a Order of elution is given on apolar column (Rtx-1). Numbers correspond to those in table 1. The compounds that the number is followed by a letter were only identified in HS-fractions.

b Retention indices of literature on the apolar column (lRIa) reported from [1218].

c Retention indices on the apolar Rtx-1 column (RIa).

d Percentages (means of three analyses) obtained by GC-FID (on RTX-1: apolar column) with peak-area normalization under optimized HS-SPME parameters: temperature: 70°C; equilibrium time: 60 min; extraction time: 30 min. Sample locations: Bensekrane (A), Sid Abdeli (B), Terni (C) and Beni Snous (D).

e Total area is expressed in arbitrary units.

£ The volatile components identified exclusively from the HS-fractions were affected by a letter. Compounds identified from commercial data libraries: National Institute of Standards and Technology, 1999 (1b, 12, 15c, 17a, 19d, 20b); and literature data: König WA, Hochmuth DH, Joulain D, 2001 (3a, 13a, 19b, 19c, 24a, 32b, 35, 36, 36a, 38a, 41, 42).

Regarding the organ contribution to the aromatic plant fingerprint, it should be noted that the volatile constituents were more abundant in the flowers than in the other parts of the plant. Our analysis showed that, for the same organ, the chemical composition of the HS fractions obtained from different localities was qualitatively similar, but differed by the relative percentage abundance of the main components. However, a correlation between the class of compounds and the organ studied was observed: the oxygenated aliphatic compounds were well represented in the roots, hydrocarbon aliphatic compounds were present in the leaves and stems, and phenylpropanoids were present in the flowers and umbels. In particular, the main volatiles from the roots were aliphatic compounds (88.1%-96.3%) such as dodecanal 35 (20.6%-55.4%), undecane 17 (2.3%-43.5%), dodecyl acetate 57 (14.2%-32.4%), and dodecanol 45 (1.7%-8.8%).

Regarding the aerial organs, both the leaf and stem volatile fractions were dominated by aliphatic hydrocarbon compounds (22.2%-87.9% and 27.6%-37.9%, respectively) and, in particular, alkanes such as pentadecane 50 (11.9%-16.0% and 19.9%-51.6%, respectively) and heptadecane 62 (9.0%-20.7% and 4.1%-20.7%). In addition, hydrocarbon monoterpenes were identified in stems (28.0%-29.4%), e.g., limonene 9 (7.5%-11.7%) and myrcene 5 (7.4%-10.6%), and isochavicol isobutyrate 53 was identified as a volatile emitted from the leaves (0.2%-19.0%). The occurrence of phenylpropanoids was established from both the volatile fractions emitted from the umbels and flowers (43.1%-88.6%), e.g., isochavicol isobutyrate 53 (26.7%-51.8% and 14.3%-19.7%, respectively) and isochavicol 26a (7.1%-15.2% and 29.6%-34.7%, respectively). In addition, hydrocarbon aliphatic compounds, in particular pentadecane 50 and heptadecane 62, were identified and their relative percentage abundance was higher in the volatile fraction extracted from the flowers (the sum was close to 20%) than from the umbels (the sum was close to 10%).

The identification of isochavicol 26a, a compound not present in our MS libraries, was carried out from a comparison of the retention indices and the EI-MS data with those of laboratory-synthesized compounds obtained from the LAH reduction of isochavicol isobutyrate 53, and it was confirmed by a comparison with the 13C-NMR data reported in the literature [6]. Isochavicol 26a has been reported to exhibit interesting antiplasmodial activity [6], and to the best of our knowledge, this uncommon phenylpropanoid has not been identified in D. crinitus before.

The chemical differences observed between both the essential oils and the volatile fractions extracted using HD and SPME, respectively, can be explained by the fact that the first technique is based on the liquid quasi-total extraction of plant volatiles and the latter technique is controlled by a solid/gas equilibrium step. During hydrodistillation, the most volatile compounds and water-soluble compounds are lost in the gaseous phase and in the hydrolate, respectively, whereas, with HS extraction, it is the fiber affinity of each compound that monitors the sampling of the volatiles. As a consequence, it should be noted that 13 aliphatic compounds (1a-1e, 3a, 5b, 6a, 15a, 17c, 19a, 22c, and 24b) with a low molecular mass and boiling point were identified only in the volatile fractions extracted using HS-SPME. In the same way, isochavicol (26a) was absent in the D. crinitus essential oil, but its occurrence in the leaf HS fractions as a main component (7.1%-34.7%) can be explained by its solubility in water. Twenty-five compounds (identified by a number followed by a letter in Tables 3 and 4) in total were identified only in the volatile fractions extracted using HS-SPME, and 18 compounds (identified by an asterisk in Table 1) were identified only in the essential oils.

Because the experiments were optimized for the SPME extraction parameters, the extraction temperature was the most important parameter in our plant headspace study. The distribution constants of each component were temperature dependent: the extraction of hydrocarbon monoterpenes and oxygenated sesquiterpenes was improved at a medium temperature (50°C) and at a high temperature (90°C), respectively (Table 2). The optimal temperature (70°C) used for the HS extraction was an analytical compromise based on the maximum amount of volatiles extracted. Regarding the comparison of both techniques in terms of the isolation time, HS-SPME was clearly faster (70 min), whereas 300 min was required for hydrodistillation. In the same way, the amount of plant material used for the headspace analysis was less (1 g), whereas the production of D. crinitus oil using hydrodistillation required 200-300 g of plant material. This may be a major reason for the difference in the chemical HS and HD data.

Conclusions

Several conclusions can be drawn concerning the chemistry of D. crinitus from this study.
  1. (i)

    Two types of essential oil were produced: the root oils, which were mainly composed of aliphatic compounds (87.0%-90.1%); and the aerial part oils, which were mainly composed of phenylpropanoids (43.1%-88.6%).

     
  2. (ii)

    HS-SPME analysis showed a more precise distribution of volatiles in the organs studied: oxygenated aliphatic compounds were well represented in the roots (44.3%-84.0%), hydrocarbon aliphatic compounds in the leaves and stems (31.3%-88.7%), and phenylpropanoids in the flowers and umbels (47.9%-64.2%).

     
  3. (iii)

    Except for two samples, the location of the samples had a minor influence on the plant volatile production.

     

Finally, this study has demonstrated that HS-SPME extraction can be considered as an alternative technique for isolating volatiles from aromatic plants.

Experimental

Plant Material and Oil Isolation

Samples of each organ (roots, stems, leaves, flowers and umbels) from D. crinitus Desf., were collected on November 2008, in Bensekrane (A) [260 m, 35°04'N 1°13'O], Sid Abdelli (B) [258 m, 35°05'N 1°12'O], Terni (C) [1199 m, 34°47'N 1°21'O] and Beni Snous (D) [854 m, 34°37'N 1°34'O] forests near Tlemcen, Algeria. Voucher specimens were deposited in the herbarium of the Tlemcen University Botanical Laboratory (Voucher number: UBL 05.09). The oils were isolated by hydrodistillation (200 - 300 g of plant per sample) for 6 h using a Clevenger-type apparatus [12] according to the European Pharmacopoeia and yielded 0.02 for roots and 0.03-0.04% for aerial parts.

HS-SPME Conditions

The single organs of D. crinitus were cut roughly with scissors (1 - 2 cm long) before subjection to HS-SPME. The SPME device (Supelco) coated with divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS, 30 μm) was used for extraction of the plant volatiles. Optimization of conditions was carried out using fresh aerial parts of the plant (1 g in a 20 mL vial) and based on the number and the sum of total peak areas measured on GC-FID. Temperature, equilibration time and extraction time were selected after nine experiments combining four temperatures (30, 50, 70 and 90°C), four equilibration times (20, 40, 60 and 80 min) and three extraction times (15, 30 and 45 min). After sampling, SPME fibre was inserted into the GC and GC-MS injection ports for desorption of volatile components (5 min), both using the splitless injection mode. Before sampling, each fibre was reconditioned for 5 min in the GC injection port at 260°C. HS-SPME and subsequent analyses were performed in triplicate. The coefficient of variation (1.9% < CV < 19.8%) calculated on the basis of total area obtained from the FID-signal for the samples indicated that the HS-SPME method produced reliable results.

Gas Chromatography

GC analyses were carried out using a Perkin Elmer Autosystem GC apparatus (Walhton, MA, USA) equipped with a single injector and two flame ionization detectors (FID). The apparatus was used for simultaneous sampling to two fused-silica capillary columns (60 m × 0.22 mm, film thickness 0.25 μm) with different stationary phases: Rtx-1 (polydimethylsiloxane) and Rtx-Wax (polyethylene glycol). Temperature program: 60 to 230°C at 2°C min-1 and then held isothermal 230°C (30 min). Carrier gas: helium (1 mL.min-1). Injector and detector temperatures were held at 280°C. Split injection was conducted with a ratio split of 1:80. Injected volume: 0.1 μL. For HS-SPME-GC analysis, only Rtx-1 (polydimethylsiloxane) column was used and volatile components were desorbed in a GC injector with a SPME inlet liner (0.75 mm. I.D., Supelco).

Gas Chromatography-Mass Spectrometry

The oils obtained were investigated using a Perkin Elmer TurboMass Quadrupole Detector, directly coupled to a Perkin Elmer Autosystem XL equipped with two fused-silica capillary columns (60 m × 0.22 mm, film thickness 0.25 μm), Rtx-1 (polydimethylsiloxane) and Rtx-Wax (polyethylene glycol). Other GC conditions were the same as described above. Ion source temperature: 150°C; energy ionization: 70 eV; electron ionization mass spectra were acquired with a mass range of 35-350 Da. Oil injected volume: 0.1 μL. The volatile fractions sampling by HS-SPME were analyzed only on a Rtx-1 capillary column and volatile components were desorbed in a GC injector with a SPME inlet liner (0.75 mm. I.D., Supelco).

Component Identification

Identification of the components was based (i) on the comparison of their GC retention indices (RI) on non polar and polar columns, determined relative to the retention time of a series of n-alkanes with linear interpolation, with those of authentic compounds or literature data [1318]; and (ii) on computer matching with commercial mass spectral libraries [1519] and comparison of spectra with those of our personal library. Relative amounts of individual components were calculated on the basis of their GC peak areas on the two capillary Rtx-1 and Rtx-Wax columns, without FID response factor correction.

NMR analysis

13C-NMR spectra of the stem oil from Bensekrane station (isochavicol isobutyrate 53: 84.1 %) were acquired in deuterated chloroform using a Bruker Avance 400 Fourier Transform spectrometer (Wissembourg, France) operating at 100.13 MHz for 13C-NMR and equipped with a 5 mm probe. All shifts were referred to the internal standard tetramethylsilane (TMS). 13C-NMR spectra of the chromatographic fractions were recorded with the following parameters: pulse width, 4 μs (flip angle, 45°); acquisition time, 2.7 s for 128 K Data table with a spectral width of 25,000 Hz (250 ppm); CPD mode decoupling; digital resolution, 0.183 Hz/pt. The number of accumulated scans was 5000 for a sample (around 40 mg of the oil in 0.5 mL of deuterochloroform) depending of the amount of product. Exponential line broadening multiplication (1 Hz) of the tree induction decay was applied before Fourier Transformation.

Reduction of isochavicol isobutyrate 53

The isochavicol isobutyrate-rich stem oil (200 mg) from Bensekrane, was dissolved in dry Et2O (4 mL) and was carefully added to a suspension of lithium aluminum hydride (LAH) (100 mg) in dry Et2O (6 mL) at 0°C. The mixture was stirred at room temperature and then refluxed for 3 h. The reaction mixture was hydrolysed by addition of a solution of NaOH 15 % (2 mL) and cold water. The organic layer was separated, washed with water to neutrality, dried over Na2SO4 and concentrated under vacuum. The mixture (80 mg) exhibited isochavicol (22.3 %) as main components.

Declarations

Acknowledgements

The authors are grateful to Prof. M. Bouazza (Botanical Laboratory, Biology Department, Aboubekr Belkaïd University) for the identification of the vegetable matter and Dr. P. Bradesi (University of Corsica, UMR-CNRS 6134, Equipe Chimie et Biomasse) for NMR data acquisition. They are indebted to the Agence Universitaire de la Francophonie (AUF) for providing a research grant to N.D.

Authors’ Affiliations

(1)
Université de Tlemcen, Laboratoire de Chimie Organique, Substances Naturelles et Analyses
(2)
Université de Corse, UMR CNRS 6134, Laboratoire Chimie des Produits Naturels, Campus Grimaldi

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© El Amine Dib et al 2010