A Novel Dibenzofuran and Two New Xanthones from Calophyllum panciflorum.

Antimalarial xanthones from Calophyllum caledonicum and Garcinia vieillardii

“…Fractions 5 to 7 (200 mg) were combined and further chromatographed over Si gel (elution with Cyclohexane-EtOAc 100:0 to 0:100 and EtOAc-MeOH 80:20) and yielded 25 fractions. Further semi-preparative HPLC using an inverse phase column (Kromasil, 5 Am 60 2, 250*10) with a water-CH 3 CN gradient yielded 1,6-dihydroxyxanthone (8) (10 mg, 0.11%, Rt 17.0 min) (Yang et al, 2001) and pancixanthone A (9) (1.3 mg, 0.014%, Rt 23.5 min) (Ito et al, 1996). Crystallization of the fourteenth fraction (70 mg) in CH 3 CN gave isocudraniaxanthone B (10) (50 mg, 0.54%) (Kobayashi et al, 1997).…”

Antimalarial polyoxygenated and prenylated xanthones from the leaves and branches of Garcinia mckeaniana

“…9 The crude acetone extract of the air dried branches of G. mckeaniana was separated by column chromatography resulting in the isolation of two new natural xanthones, mckeanianones D-E (4-5) along with ten known compounds, pancixanthones A and B (10 and 17), 10 neriifolone A (11), 11 1,3,5-trihydroxy-2-(3-methylbut-2-enyl)-9H-xanthen-9-one (12), 12 1,3,6-trihydroxy-7-methoxyxanthone (13) (Table 1) (Table 2). This isoprene unit was at C-3 ( C 167.2) based on the HMBC correlations between H-11 ( H 4.72) and the 13 C NMR resonances for C-3, C-12 ( C 120.0) and C-13 ( C 139.2).…”

“…This plant is locally named "Ma da" and is found in the North of Thailand. This study resulted in the isolation of six new natural products (1-6), together with thirteen known compounds (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). The biological activities of these compounds against the Plasmodium falciparum strains, TM4 and K1 (a multidrug resistant strain) and their cytotoxicities against a Vero cell line are reported.…”

Nitric Oxide Inhibitory Activity of Xanthones from the Green Fruits of Cratoxylum formosum ssp. pruniflorum

“…We propose that compounds 1 and 2 could be derived from pancixanthone A, which was previously isolated from the stem barks of Calophyllum panciflorum. [14] The cyclization of the phenol group with the dimethylallyl group of pancixanthone A furnished a 2,3,3-trimethyldihydrofuran ring, which was reported as pancixanthone B. [14] This transformation was a common pathway occurring in natural products.…”

“…[14] The cyclization of the phenol group with the dimethylallyl group of pancixanthone A furnished a 2,3,3-trimethyldihydrofuran ring, which was reported as pancixanthone B. [14] This transformation was a common pathway occurring in natural products. Compounds 1 and 2 could be formed from different pathway to the pancixanthone B.…”