Gao‐Feng Shi, R. Lu, Yun-shang Yang
Feb 1, 2005
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0
Influential Citations
12
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Journal
Journal of Chemical Crystallography
Abstract
AbstractIn order to study the relationship between biological and pharmacological activities with their structures, a series of tri-, tetra-oxygenated xanthones including 1-hydroxyl-2,3,4,7-tetramethoxy xanthone 1, 1-hydroxyl-2,3,4,5-tetramethoxyl xanthone 2, 1-hydroxyl-3,5-dimethoxy xanthone 3, 1,8-dihydroxyl-3,5-dimethoxyl xanthone 4, 1,5,8-trihydroxyl-3-methoxy xanthone 5 has been isolated from Swertia chirayita. Their structures were established on the basis of spectral and chemical evidence. The crystal structure of 5 was also investigated by single crystal X-ray diffraction analysis. It crystallizes in the triclinic system, space group P$$\bar{1}$$, with a = 7.1540(10) Å, b = 7.520(2) Å, c = 10.671(2) Å, V = 562.7(2) Å3, α = 86.50(3)∘, β = 80.06(3)∘, γ = 85.00(3)∘, Z = 2, Dc = 1.618 g m−3, Rint = 0.0230, wR(F2) = 0.1028, F(000) = 284. The molecular structure is nearly plane and four substituents are much closer to the plane of the molecule. Compound 5 also shows three intermolecular hydrogen bonds. A recent study shows that phenolic hydroxyls in xanthones are the main active groups capable of scavenging •OH and O2•.