(10E,12E,14E)-9,16-Dioxoocta­deca-10,12,14-trienoic acid

Lise Bréant; Catherine Vonthron-Sénécheau; Lydia Brelot; Annelise Lobstein

doi:10.1107/S1600536812027870

. 2012 Aug 1;68(Pt 9):o2624. doi: 10.1107/S1600536812027870

(10E,12E,14E)-9,16-Dioxooctadeca-10,12,14-trienoic acid

Lise Bréant ^a,^*, Catherine Vonthron-Sénécheau ^a, Lydia Brelot ^b, Annelise Lobstein ^a

PMCID: PMC3435652 PMID: 22969525

Abstract

The title octadecatrienoic acid derivative, C₁₈H₂₆O₄, was isolated from Silene maritima With. (Caryophyllaceae), the first time this natural compound has been found in the Caryophyllales order. This fatty acid has an 18-carbon backbone with three double bonds on trans (E) conformation and two carbonyl. In the crystal, molecules are linked via pairs of O—H⋯O hydrogen bonds, forming inversion dimers.

Related literature

For botanical information about Silene maritima With., see: Baker (1978 ▶); Bremer et al. (2009 ▶). For interactions between heavy-metals and Silene maritima With., see: Price & Abrahams (1994 ▶). For phytochemical investigation on Silene maritima With., see: Adrian-Romero et al. (1998 ▶). For previous descriptions of the title compound, see: Herz & Kulanthaivel (1984 ▶); Li et al. (2011 ▶). For lipoxygenase action on α-linoleic acid, see: Vellosillo et al. (2007 ▶). For environmental-stress-response involvement of oxylipines and their structure similarity with the title compound, see: Browse (2005 ▶); Schaller et al. (2004 ▶); Wasternack (2007 ▶).

Experimental

Crystal data

C₁₈H₂₆O₄
M _r = 306.39
Triclinic,
a = 5.6859 (3) Å
b = 7.7535 (5) Å
c = 19.9045 (16) Å
α = 81.333 (4)°
β = 84.152 (4)°
γ = 87.660 (4)°
V = 862.68 (10) Å³
Z = 2
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 173 K
0.40 × 0.30 × 0.10 mm

Data collection

Nonius KappaCCD diffractometer
8217 measured reflections
3846 independent reflections
2648 reflections with I > 2σ(I)
R _int = 0.063

Refinement

R[F ² > 2σ(F ²)] = 0.065
wR(F ²) = 0.189
S = 1.06
3846 reflections
204 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: COLLECT (Nonius, 1998 ▶); cell refinement: DENZO (Otwinowski & Minor, 1997 ▶); data reduction: DENZO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812027870/zj2081sup1.cif

e-68-o2624-sup1.cif^{(19KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812027870/zj2081Isup2.hkl

e-68-o2624-Isup2.hkl^{(184.7KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812027870/zj2081Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O1ⁱ	0.90 (4)	1.78 (4)	2.658 (2)	167.0 (4)

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank Dr J. Suffert for his help in crystallizing the compound.

supplementary crystallographic information

Comment

Silene maritima With. belongs to the Caryophyllaceae family (Bremer et al., 2009) and is a perennial species found on cliffs and shingle beaches in coastal habitats (Baker, 1978). This species is known to be a heavy-metal indicator (Price & Abrahams, 1994), and the only phytochemical investigation previously carried out on its aerial parts has revealed the presence of glycinebetaine, a compound used by cells for protection against osmotic stress (Adrian-Romero et al., 1998).

This study is the first report of the presence of 9,16-dioxo-10E,12E,14E octadecatrienoic acid in the Caryophyllales order. This compound has previously been described only in the Asteraceae (Herz & Kulanthaivel, 1984) and Lamiaceae (Li et al., 2011) families.

Its molecular structure contains an 18-carbon backbone with three double bonds in the trans conformation and two carbonyls (Fig. 1). The existence of intermolecular hydrogen interactions between two carboxylic functions was also observed (Fig. 2). The structure of this fatty acid might involve a lipoxygenase action on the α-linoleic acid (Vellosillo et al., 2007). Thus suggesting that it could belong to oxylipines, a class of compounds implicated in environmental stress responses (Browse, 2005; Schaller et al., 2004; Wasternack, 2007).

Experimental

The sampling station is situated in the littoral zone of the western coast of Brittany (Brélès 29, France). Sampling was carried out in July 2008. The aerial parts of the plant were collected, air-dried, and grinded into a fine powder using a grinder (Retsch, ZM 200). Hydroalcoholic extract of aerial parts (1 kg) was prepared by soaking it at room temperature in 3 x 10 l of EtOH/H₂O (6/4, v/v) during first 14 h, then 4 h and again 4 h, until exhaustion of raw materials. The extract was then filtered and dried under vacuum using a rotavapor. The amorphous solid, a black-brownish mass, was then dissolved in d-H₂O and extracted sequentially with cyclohexane, CH₂Cl₂, AcOEt and n-BuOH. The CH₂Cl₂ extract (2.496 g) was fractionated on a silica gel column (SI60 0.050–0.16 mm in size, Merck) eluted successively with cyclohexane (500 ml), AcOEt (1170 ml) and MeOH (330 ml) to yield five main fractions. The third fraction (210 mg) was re-dissolved in MeOH and subjected to semi-preparative HPLC purification (Gilson, binary solvent system). The isolation was performed with a reverse phase Nucleodur C18 ec (250 mm x 21 mm, 5 µm) from Macherey-Nagel. Eluent A was H₂O with 0.01% HCOOH, and eluent B was ACN. The flow rate was 10 ml/min and the injection volume was 400 µl at 40 mg ml^-1. The elution conditions applied were: 0–5 min, linear gradient from 10% to 15% B; 5–55 min, 15% to 65% B; 55–60 min, 65% to 100% B; 60–70 min, 100% B isocratic. Simultaneous UV monitoring was set at 316 nm. This experimental procedure allowed us to isolate the title compound C₁₈H₂₆O₄ at the retention time of 26 min. The pure compound (1 mg) was re-dissolved in 0.2 ml of MeOH/CHCl₃ (2/1). The corresponding crystals of 9,16-dioxo-10E,12E,14E octadecatrienoic acid were grown thanks to a slow solubility decrease during two weeks at room temperature after addition of n-heptane (0.4 ml).