Xanthone, 1-5-dihydroxy

P-mangostin, y-mangostin, garcinone E, l,5-dihydroxy-2-(3methylbut-2-enyl)-3-methoxy-xanthone and l,7-dihydroxy-2-(3-methylbut-2-enyl) 3-methoxyxanthone (Asai et al., 1995). 

Wood Garciniaxanthone D and 1,4,5-trihydroxyxanthone (Minami et al, 1995). 2,5-Dihydroxy-l-methoxyl xanthone, l-o-methylsympho-xanthone, Garciniaxanthone E, symphoxanthone and subelliptenone A (Minami et al, 1996). A new benzophenone derivative, 2, 3, 6-trihydroxy-2,4-dimethoxy-benzo-phenone and a new xanthone, 1,6-0-... 

Capsaicin (= qms-8-Methyl-Js- [(4-hydroxy-3-methoxyphenyl) methyl] -6-nonenamide tem-8-Methyl-A-vanillyl-6-nonenamide) (vanilloid phenolic) l,7-Dihydroxy-2,3-dimethoxyxanthone (xanthone)... 

Dihydroxyxanthones.1 KF in DMF is a more efficient catalyst than K2C03 for condensation of methyl salicylates with chlorobenzoquinones to provide phenoxybenzo-quinones (1). The products on reduction (Na2S204) and cyclization (H2S04) afford 1,4-dihydroxy xanthones (2) with high regioselectivity (equation I). 

Besides these groups, some xanthones with unusual substitutions have been isolated from different plant sources including hchens, which could not be classified in the usual manner. These compounds have been grouped as miscellaneous. We can show a chloride compound, 4-chloro-3,8-dihydroxy-... 

Recently, 59 xanthones (= 9H-xanthen-9-ones) of natural or synthetic origin were investigated for their inhibitory activity toward MAO-A and MAO-B. The majority of the compounds demonstrated reversible, time-independent activities, with selectivity toward MAO-A. The most active inhibitor (1,5-dihydroxy-3-methoxyxanthone) had an IC50 of 40 nM. 3D-QSAR studies revealed the importance of an OH substituent in position 1 or 5 instead of a MeO substituent and the contrary is true for position 3, where MeO... 

Swerchirin Swertia chirayita Karst/ Gentianaceae Whole plant A xanthone was isolated from the hexane fraction of the Swertia chirayita and identified as l.8,-dihydroxy-3,5-dimethoxy xanthone (swerchirin). It has a very significant blood sugar lowering effect in fasted, fed, glucose loaded and tolbutamide pretreated albino rat models [113]. 

New oxygenated xanthones were characterized from heartwood, root and leaf extracts of H. geminiflorum [74,75], namely a) 2, 3-dihydroxy-... 

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