17βH-Periplogenin, a cardiac aglycone from the root bark of Periploca sepium Bunge

Yu-Wei Zhang; Yong-Li Bao; Yin Wu; Chun-Lei Yu; Yu-Xin Li

doi:10.1107/S1600536812018521

. 2012 May 2;68(Pt 6):o1582–o1583. doi: 10.1107/S1600536812018521

17βH-Periplogenin, a cardiac aglycone from the root bark of Periploca sepium Bunge

Yu-Wei Zhang ^a, Yong-Li Bao ^a, Yin Wu ^b,^*, Chun-Lei Yu ^c, Yu-Xin Li ^a,^*

PMCID: PMC3379196 PMID: 22719394

Abstract

The title compound {systematic name: 4-[(3S,5S,8R,9S,10R,13R,14S,17S)-3,5,14-trihydroxy-10,13-dimethylhexadecahydro-1H-cyclopenta[a]phenanthren-17-yl]furan-2(5H)-one}, C₂₃H₃₄O₅, was isolated from the roots of Periploca sepium Bunge, a famous Chinese traditional herbal medicine. The three six-membered rings adopt chair conformations, the cyclopentane ring displays an approximate envelope conformation (with the C atom bearing the methyl substituent at the flap) and the five-membered lactone ring adopts an essentially planar [maximum deviation of 0.004 (8) Å] conformation. In the crystal, molecules are linked into helical chains along [010] by O—H⋯O hydrogen bonds and weak C—H⋯O interactions. Two intramolecular O—H⋯O hydrogen bonds are also present.

Related literature

For the botanical and medicinal background to Periploca sepium Bunge, see: Li & Liu (2004 ▶); Yang et al. (2006 ▶). For the previous preparation and chemical structure determination of the title compound, see: Furuya et al. (1988 ▶); Kawaguchi et al. (1998 ▶).

Experimental

Crystal data

C₂₃H₃₄O₅
M _r = 390.50
Monoclinic,
a = 7.434 (3) Å
b = 10.554 (4) Å
c = 13.537 (5) Å
β = 103.118 (5)°
V = 1034.4 (6) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 296 K
0.26 × 0.24 × 0.02 mm

Data collection

Bruker APEX CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.978, T _max = 0.998
5262 measured reflections
1927 independent reflections
1097 reflections with I > 2σ(I)
R _int = 0.077

Refinement

R[F ² > 2σ(F ²)] = 0.053
wR(F ²) = 0.126
S = 1.01
1927 reflections
254 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: SMART (Bruker, 1997 ▶); 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 datablock(s) I, global. DOI: 10.1107/S1600536812018521/wn2470sup1.cif

e-68-o1582-sup1.cif^{(21.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812018521/wn2470Isup2.hkl

e-68-o1582-Isup2.hkl^{(96.7KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812018521/wn2470Isup3.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
O1—H1C⋯O2	0.82	2.06	2.778 (5)	147
O2—H2C⋯O1	0.82	2.05	2.778 (5)	147
O3—H3B⋯O2ⁱ	0.82	2.16	2.977 (5)	175
C11—H11A⋯O5ⁱⁱ	0.97	2.57	3.393 (7)	143

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

Acknowledgments

This research was supported by the National Natural Science Foundation of China (Nos. 31170324 and 31070318), the Fundamental Research Funds for the Central Universities, grants from the Jilin Province Science & Technology Committee, China (Nos. 20100911, 20102203, 20110938 and 20110711), as well as the Scientific and Technical Project of the Administration of Traditional Chinese Medicine of Jilin Province (No. 2010pt069).

supplementary crystallographic information

Comment

Periploca sepium Bunge (Asclepiadaceae) is native and widespread in the Loess hilly regions of northwest China (Li and Liu, 2004; Yang et al., 2006). Its root bark, which is officially listed in the Chinese Pharmacopoeia under the name Cortex Periploca (Xiangjiapi in Chinese), has been frequently used to treat rheumatism and strengthen tendons and bones. The title compound, 17βH-periplogenin, which has been previously obtained as a biotransformation product of digitoxigenin (Furuya et al., 1988; Kawaguchi et al., 1998), was isolated from the root bark of Periploca sepium Bunge in our recent investigation. To the best of our knowledge, this is its first isolation from plant material. The isolated compound was identified by NMR spectra, which were compared with the previous report (Furuya et al., 1988).

The crystal structure of 17βH-periplogenin has not yet been reported. In view of this, the crystal structure determination of the title compound was carried out and the results are presented here.

As shown in Fig. 1, the molecule consists of three six-membered rings (A, B and C), one cyclopentane ring (D) and one five-membered lactone ring. Rings A:B, B:C and C:D are cis-, trans- and cis- fused, respectively. The three six-membered rings adopt chair conformations, the cyclopentane ring displays an approximate envelope conformation with C13 as the flap atom, and the five-membered lactone ring adopts a planar conformation.

In the crystal structure, molecules are linked into helical chains along [010] through O3—H3B···O2 hydrogen bonds and C11—H11A···O5 weak interactions (Fig. 2 and Table 1). Two intramolecular O—H···O hydrogen bonds are also present (Table 1).

Experimental

The air-dried and powdered roots of Periploca sepium Bunge (2.0 kg) were extracted with 70% EtOH (3×10 l, 3×2.0 h, 85 °C) under reflux conditions to give a crude extract, which was suspended in H₂O and successively partitioned with CHCl₃, EtOAc and n-butanol. A part of the CHCl₃ fraction (50.0 g) was subjected to CC [SiO₂, 200–300 mesh, CHCl₃/MeOH (100:0, 95:5, 90:10, 80:20, 70:30, 60:40, 50:50 and 0:100(v/v)] to yield 8 fractions: Fr.1–8. Fr.3 was resubjected to CC (SiO₂, 200–300 mesh, gradient of CHCl₃/MeOH) and was further chromatographed on Sephadex LH-20 (CHCl₃/MeOH, 1:1) to give 6 subfractions: SFr. 1–6. SFr. 4 (0.9 g) was then subjected to reverse phase preparative HPLC [Waters preparative HPLC system; XTERRA PREP MS C18 column, 5 µm, 19 mm × 150 mm; sample loading 30 - 60 mg/injection; the column was eluted with CH₃OH/H₂O system (52:48) at a flow rate of 16 ml/min] to provide the title compound (t_R = 4.81 min, 26 mg). ¹H and ¹³C NMR spectroscopic data of this compound were recorded on a Bruker-AV-400 spectrometer, using CD₃OD as solvent and Me₄Si as internal standard. The stereochemistry was established by the X-ray diffraction experiment.