%0 Journal Article
%T Naturally Occurring Xanthones: Chemistry and Biology
%A J. S. Negi
%A V. K. Bisht
%A P. Singh
%A M. S. M. Rawat
%A G. P. Joshi
%J Journal of Applied Chemistry
%D 2013
%R 10.1155/2013/621459
%X Xanthones are one of the biggest classes of compounds in natural product chemistry. A number of xanthones have been isolated from natural sources of higher plants, fungi, ferns, and lichens. They have gradually risen to great importance because of their medicinal properties. This review focuses on the types, isolation, characterization, biological applications, and biosynthesis of naturally occurring xanthones isolated so far. Different physicochemical and instrumental methods such as liquid-solid and liquid-liquid extraction, TLC, flash chromatography, column chromatography, IR, 1H NMR and 13C NMR spectroscopy, GLC, HPLC, GC, and LCMS have been widely used for isolation and structural elucidation of xanthones. Hepatoprotective, anticarcinogenic, antileprosy, antimalarial, antioxidant, anticholinergic, mutagenicity, radioprotective, immunomodulatory, antibone resorption, antiparasitic, neuraminidase inhibitory, anticomplement, antibacterial, antifungal, algicidal, anti-HIV, cardioprotective, antitumoral, antidiabetes, antihyperlipidemic, antiatherogenic, anti-inflammatory, antiulcer, antidiabetic, hypolipidemic, analgesic, antiasthmatic, antihistaminic, antiamoebic, diuretic, antidiarrheal, larvicidal, and ovicidal activities have been reported for natural occurring xanthones. To a certain extent, this review provides necessary foundation for further research and development of new medicines. 1. Introduction Xanthones are secondary metabolites commonly occurring in higher plant families, fungi, and lichen [1]. Their pharmacological properties have raised great interest. Structures of xanthones are related to that of flavonoids and their chromatographic behaviours are also similar. Flavonoids are frequently encountered in nature, whereas xanthones are found in limited number of families. Xanthones always occur in the families Gentianaceae, Guttiferae, Moraceae, Clusiaceae, and Polygalaceae. Xanthones are sometimes found as the parent polyhydroxylated compounds but most are mono- or polymethyl ethers or are found as glycosides [2]. Unlike iridoids, xanthones are apparently not present in all plant species investigated in the family Gentianaceae. This is documented by the systematic work of Hostettmann et al. [3]. Natural occurrence of 12 xanthones in higher plants and 4 in fungi has been reviewed by Roberts in 1961 and by Dean in 1963 [4, 5]. Gottlieb [6] mentioned the isolation of 60 xanthones from higher plants and 7 from fungi, whereas Carpenter et al. [7] listed 82 xanthones from higher plants. Gunasekera [8] recorded 183 xanthones from 5 families of
%U http://www.hindawi.com/journals/jac/2013/621459/