Xanthone

About: Xanthone is a research topic. Over the lifetime, 1639 publications have been published within this topic receiving 25870 citations. The topic is also known as: 9-oxo-xanthene & Diphenyline ketone oxide.

Anti-oxidant and anti-bacterial activities of 11 Calophyllum species from Indonesia

Abstract: Members of Calophyllum (Calophyllaceae) are commonly used as herbal medicine in Indonesia from the beginning of civilization. Due to their tremendous potential as a source for pharmaceutical industry, we selected 11 Calophyllum species for the current anti-oxidant and anti-bacterial studies, namely, Calophyllum euryphyllum, C. bicolor, C. flavoramulum, C incrassaptum, C. lowei, C. macrophyllum, C. nodosum, C. soulattri, C. tetrapterum, C. teysmannii, and C. tomentosum. The methods include Calophyllum stem bark extraction and separation into n-hexane, ethyl acetate, and butanol fractions, followed by the antioxidant analysis using DPPH (2,2-diphenyl-1-picrylhydrazyl radical scavenging) and the anti-bacterial activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa. The results showed that n-hexane fraction of C. soulattri exhibited the best anti-oxidant activity (IC50 = 2.2 µg/m). This study also showed that a xanthone compound isolated from C. macrophyllum, namely, 1,8 - dihydroxy-6 methoxy xanthone exhibited the anti-oxidant activity with IC50 = 1.56 ppm.

Xanthone C-Glycoside and Acylated Sugar from Polygala tenuifolia.

Abstract: A new xanthone C-glycoside, polygalaxanthone III (1), and a new acylated sugar, tenuifoliside E (2) were isolated from the roots of Polygala tenuifolia. Their structures were characterized as 4-C-[beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranosyl]-1, 3,6-trihydroxy-7-methoxyxanthone (1) and beta-D-(1-O-acetyl-3-O-feruloyl-6-O-sinapoyl)-fructofuranosy l-alpha-D-(2,4,6- O-triacetyl)glucopyranoside (2), respectively, on the basis of chemical and spectral evidence including two dimensional nuclear magnetic resonance (2D-NMR) studies.

Antibacterial and Antioxidative Compounds from Oroxylum indicum

Abstract: Plants are the largest reservoir of secondary metabolites that contribute to combating different diseases from ancient times [1]. Oroxylum indicum (L.) Benth. ex Kurz, a plant belonging to the Bignoniaceae family, is known as an Asian medical plant and is used in folk medicine for the treatment of rheumatism, diarrhea, and dysentery [2, 3]. Considering its wide traditional uses, we have carried out phytochemical studies of O. indicum and evaluated the antibacterial and antioxidative activities of its crude extracts and isolated compounds. Studies of the chemical constituents of the leaves, roots, stems, and twigs of O. indicum show that it possesses flavonoids, xanthones, coumarin, quinine, one cyclohexylethanoid, benzaldehyde, and one phenylpropanoid. Their structures were elucidated by spectroscopic analysis including UV, IR, and NMR. To the best of our knowledge, the 11 compounds (6–16) in O. indicum are reported for the first time. The antibacterial and antioxidative activities of the extracts and isolated compounds were also evaluated using 2-fold serial dilutions and flow injection analysis (FIA) methods, respectively. Isolation and purification of O. indicum extracts led to 16 compounds (1–16), including flavonoids: 5,7-dihydroxy6-methoxyflavone (1) [4], 5,7-dihydroxyflavone (2) [4], 5,7,4 -trihydroxy-6-methoxyflavone (3) [5], 5,7,4 -trihydroxyflavone (4) [6], 5,6,7,4 -tetrahydroxyflavone (5) [7], 5,7,4 -trihydroxy-3 -methoxyflavone (6) [8], and 5,4 -dihydroxy-7-methoxyflavone (7) [9]; four xanthones: 5 -demethoxycadensin G (8) [10], 1,7-dihydroxyxanthone (9) [11], 1,3,6-trihydroxy-7-methoxy-2(3,7-dimethyl-2,6-octadienyl)xanthone (10) [12], and 3,7-dihydroxy-1-methoxyxanthone (11); one coumarin: heraclenin (12) [13]; one quinone: 2-methoxystypandrone (13) [14]; one cyclohexylethanoid: rengyolone (14) [15]; one benzaldehyde: 4-hydroxy-3-methoxybenzaldehyde (15) [16]; and one phenylpropanoid: 1-(4-hydroxyphenyl)propan-1-one (16) [17]. The antibacterial activity of the crude extracts against gram-positive bacteria (B. cereus, S. aureus, and MRSA SK1) and gram-negative bacteria (E. coli, P. aeruginosa, and S. typhimurium) were investigated; and they showed weak to moderate activity against gram-positive bacteria (160–1280 g·mL–1) and gram-negative bacteria (640–1280 g·mL–1). Compounds 8 and 3 exhibited moderate antibacterial activity against B. cereus and MRSA SK1 with MIC values of 16 and 32 g·mL–1, respectively. The other isolated compounds showed weak antibacterial activity with a MIC range of 64–128 g·mL–1. In addition, we studied the antioxidative activity of the compounds by the FIA method; the acetone extracts of the leaves and roots of the plant and compound 5 exhibited strong antioxidative activity with IC50 values of 8.01 0.29 and 9.81 0.09 g·mL –1 and 11.88 0.06 M, respectively. In addition, the acetone extracts of the stems and twigs, the dichloromethane extracts of the roots and twigs, and compound 6 exhibited moderated radical scavenging activity with IC50 values of 28.06 1.66, 34.24 1.77, 31.57 1.08, 32.72 0.41 g·mL–1 and 33.45 1.45 M, respectively. The hexane extract of the leaves, the dichloromethane extract of the leaves, methanolic extracts of the stems and twigs, and isolated compounds 1–4 and 8–16 showed a % inhibition lower than 50% and were not further tested for IC50. Plant Materials. The leaves, roots, stems, and twigs of O. indicum were collected from Lamphun Province, Thailand in April 2011.

Prenylated Xanthones as Potential P-Glycoprotein Modulators.

Abstract: Dimethylallyl (DMA) derivatives of a naturally occurring xanthone (decussatin 1) were prepared. Their activity as potential P-glycoprotein inhibitors was monitored by affinity of direct binding and compared to that of corresponding DMA-flavones. Both classes of compounds exhibited the same structure-activity relationships. Decreasing polarity enhanced the binding affinity for the P-glycoprotein C-terminal cytosolic domain since DMA derivatives were more active, but unsubstituted hydroxyl group close to the carbonyl was required for efficient activity.