Curcumenol from Curcuma zedoaria: a second monoclinic modification

Omer Abdalla Ahmed Hamdi; Khalijah Awang; A Hamid A Hadi; Devi Rosmy Syamsir; Seik Weng Ng

doi:10.1107/S1600536810040559

. 2010 Oct 20;66(Pt 11):o2844. doi: 10.1107/S1600536810040559

Curcumenol from Curcuma zedoaria: a second monoclinic modification

Omer Abdalla Ahmed Hamdi ^a, Khalijah Awang ^a, A Hamid A Hadi ^a, Devi Rosmy Syamsir ^a, Seik Weng Ng ^a,^*

PMCID: PMC3009189 PMID: 21589030

Abstract

The title compound, systematic name 9-isopropylidene-2,6-dimethyl-11-oxatricyclo[6.2.1.0^1,5]undec-6-en-8-ol, C₁₅H₂₂O₂, which crystallizes with two molecules of similar conformation in the asymmetric unit, features three fused rings, two of which are five-membered and the third six-membered. Of the two five-membered rings, the one with an O atom has a distinct envelope shape (with the O atom representing the flap). The six-membered ring is also envelope-shaped as it shares a common O atom with the five-membered ring. In the crystal, the two independent molecules are linked by a pair of O—H⋯O hydrogen bonds, generating a dimer.

Related literature

For the C2 modification isolated from Globba malaccensis Ridl, see: Muangsin et al. (2004 ▶).

Experimental

Crystal data

C₁₅H₂₂O₂
M _r = 234.33
Monoclinic,
a = 9.3495 (7) Å
b = 12.535 (1) Å
c = 11.7727 (9) Å
β = 96.532 (1)°
V = 1370.76 (18) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 100 K
0.40 × 0.05 × 0.05 mm

Data collection

Bruker SMART APEX diffractometer
13257 measured reflections
3298 independent reflections
2882 reflections with I > 2σ(I)
R _int = 0.046

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.090
S = 1.03
3298 reflections
323 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810040559/hb5676sup1.cif

e-66-o2844-sup1.cif^{(26.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810040559/hb5676Isup2.hkl

e-66-o2844-Isup2.hkl^{(161.8KB, hkl)}

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
O1—H1⋯O4	0.89 (3)	1.92 (3)	2.799 (2)	168 (3)
O3—H3⋯O2	0.86 (3)	1.92 (3)	2.771 (2)	171 (3)

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Acknowledgments

We thank the University of Malaya for supporting this study.

supplementary crystallographic information

Comment

Zingerberaceae is a herbaceous plant found in tropical forests that comprises of 52 genera with 1500 species. Most species are found in the South East Asian region. Curcuma zedoaria, also known as white turmeric, is a species that is a rich source of terpenoids.

Curcumenol, isolated from Globba malaccensis Ridl, belongs to the monoclinic, space group C2, with a 16.8467 (4), b 7.6799 (2), c 11.8613 (10) Å and β 115.997 (1) °. This modification is less dense, as noted from its calculated density of 1.28 (Muangsin et al., 2004). The present modification (I), (Fig. 1) shows nearly identical bond dimensions in the two independent molecules. The two molecules form a dimer in the crystal, being linked by two O—H···O hydrogen bonds.

Experimental

The rhizome of Curcuma zedoaria was collected from Tawangmangu, Indonesia.

Dried rhizomes (1 kg) were powdered and extracted three times with n-hexane and after this, with dichloromethane, ethylacetate, and methanol. The extracts were concentrated under reduced pressure given several fractions.

The n-hexane crude extract (20 g) was subjected to column chromatography over silica gel 60(0.063–0.200 mm, 70–230 mesh ASTM) eluted with a mixture of n-hexane: ethyl acetate with increasing polarity. Separation by TLC gave 21 fractions.

Fraction 10 (1.41 g) was chromatographed over silica gel (0.040–0.063 mm, mesh 230–400 ASTM) eluted with a gradient solvent system of n-hexane: ethyl aceate to give 5 fractions. The second fraction was further purified by high performance thin layerchromatography and using petroleum ether: ethyl acetate: acidified methanol in a 85:14:1 ratio as the developing solvent. Slow evaporation of the solvent gave (I) as colorless prisms.