1,7-Dihydr­oxy-2,3,4-trimeth­oxy-9H-xanthen-9-one monohydrate from Halenia elliptica

Peizhong Yu; Xiaojuan Shen; Changqi Hu; Edward J Meehan; Liqing Chen

doi:10.1107/S1600536808004832

. 2008 Mar 5;64(Pt 4):o651–o652. doi: 10.1107/S1600536808004832

1,7-Dihydroxy-2,3,4-trimethoxy-9H-xanthen-9-one monohydrate from Halenia elliptica

Peizhong Yu ^a, Xiaojuan Shen ^a, Changqi Hu ^a, Edward J Meehan ^b, Liqing Chen ^b,^*

PMCID: PMC2960944 PMID: 21202049

Abstract

The title compound, C₁₆H₁₄O₇·H₂O, possesses a planar three-ring skeleton; its carbonyl, one of the two hydroxy and two of the three methoxy O atoms and the water molecule form hydrogen bonds, giving rise to a layer structure.

Related literature

For the antidepressant, antitumor, antimicrobial, antifungal, anti-inflammatory, antiviral, cardiotonic, hypoglycemic, antihepatotoxic and immunomodulatory activities of simple xanthones, see: Basnet et al. (1994 ▶); Fernandes et al. (1995 ▶); Karan et al. (1999 ▶); Liou et al. (1993 ▶); Miura et al. (2001 ▶); Parmar et al. (1996 ▶); Pedro et al. (2002 ▶); Sousa et al. (2002 ▶). For the crystal structures of oxygenated xanthones, see: Evans et al. (2004 ▶); Gales et al. (2001 ▶); Jiang et al. (2004 ▶); Kabaleeswaran et al. (2003 ▶); Kato et al. (2005 ▶); Kijjoa et al. (1998 ▶); Shi et al. (2004 ▶, 2005 ▶); Stout et al. (1969 ▶); Vijayalakshmi et al. (1987 ▶).

Experimental

Crystal data

C₁₆H₁₄O₇·H₂O
M _r = 336.29
Monoclinic,
a = 10.9272 (9) Å
b = 10.4511 (8) Å
c = 14.0201 (11) Å
β = 111.6830 (10)°
V = 1487.8 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.12 mm⁻¹
T = 298 K
0.2 × 0.1 × 0.05 mm

Data collection

Bruker SMART 1K CCD diffractometer
Absorption correction: none
8808 measured reflections
3563 independent reflections
2848 reflections with I > 2σ(I)
R _int = 0.052

Refinement

R[F ² > 2σ(F ²)] = 0.046
wR(F ²) = 0.141
S = 1.06
3563 reflections
233 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: SMART (Bruker, 1999 ▶); cell refinement: SAINT (Bruker, 1999 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808004832/ng2424sup1.cif

e-64-0o651-sup1.cif^{(20.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808004832/ng2424Isup2.hkl

e-64-0o651-Isup2.hkl^{(174.7KB, 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
O8ⁱ—H16ⁱ⋯O2	0.73 (3)	2.58 (3)	3.091 (2)	129.4
O8ⁱ—H16ⁱ⋯O3	0.73 (3)	2.46 (3)	3.177 (2)	167.3
O8ⁱⁱ—H15ⁱⁱ⋯O6	0.84 (5)	2.08 (5)	2.923 (2)	172.3
O7—H7⋯O8ⁱⁱⁱ	0.83	1.88	2.706 (2)	169

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

This work was supported in part by the NSF-EPSCoR, USA.

supplementary crystallographic information

Comment

Xanthone compounds commonly occur in several higher plant families, such as Gentianaceae,Guttiferae, Moraceae and Polygalaceae. Simple oxygenated xanthones possess different biological activities such as antidepressant, antitumor, antimicrobial, antifungal, anti-inflammatory, antiviral, cardiotonic, hypoglycemic, antihepatotoxic and immunomodulatory (Liou et al., 1993; Basnet et al., 1994; Fernandes et al., 1995; Parmar et al., 1996; Karan et al., 1999; Miura et al., 2001; Pedro et al., 2002; Sousa et al., 2002). The majority of the xanthones isolated so far are hydroxyl or methoxy substituted in the xanthone skeleton. Up to present, only ten simple oxygenated xanthones were characterized by X-ray diffraction (Stout et al., 1969; Vijayalakshmi et al., 1987; Kijjoa et al., 1998; Gales et al., 2001; Kabaleeswaran et al., 2003; Jiang et al., 2004; Shi et al., 2004; Evans et al., 2004; Kato et al., 2005; Shi et al., 2005). 1,7-dihydroxy-2,3,4-trimethoxyxanthone (I) was first isolated from Halenia elliptica D. Don (Gentianaceae) and has antioxidant activity. Its crystal structure is reported for the first time in this paper. The structure of I (Figure 1) is similar to other xanthones reported with a planar three-ring skeleton. The asymmetric unit of crystal I contains one molecule I plus one water molecule. I forms hydrogen bonds with the water molecule through its carbonyl, one of the two hydroxyl and two of the three methoxyl O atoms (Table 1, Figure 2). The crystal structure is stabilized by the extensive hydrogen bond network.

Experimental

Halenia elliptica D. Don was collected in DALI, Yunnan Province, in April 2005 and was identified by Professor Xiaokuang Ma, Department of Pharmacognosy, School of Pharmacy, DALI University, People's Republic of China.

Extraction and isolation: 1,7-dihydroxy-2,3,4-trimethoxyxanthone (I) was isolated from ethyl acetate fraction of the ethanol extract of the aerial parts of Halenia elliptica with other four 1,7-dihydroxy substituted xanthones by silica gel column chromatography with gradient mixtures of petroleum ether and ethyl acetate. Yellow crystals of I were obtained by slow evaporation of a solution in EtOH. M.p.164–165°C. ESI-MS m/z (rel. %): 319[M+H]^+.1H-NMR (400 MHz, CDCl₃), d12.60 (1H, s, OH-1), 7.60 (1H, d, J=3.0 Hz, H-8), 7.49 (1H, d, J=9.3 Hz, H-5), 7.34 (1H, dd, J=3.0, 9.0 Hz, H-6), 5.32 (1H, br. s, OH-7), 4.15 (3H, s, OCH₃), 3.96 (3H, s, OCH₃), 3.95 (3H, s, OCH₃).