Anti-plasmodial and antioxidant activities of constituents of the seed shells of Symphonia globulifera Linn f.

A xanthone derivative, named gaboxanthone (1), has been isolated from the seed shells of Symphonia globulifera, together with known compounds, symphonin (2), globuliferin (3), guttiferone A (4), sistosterol, oleanolic acid and methyl citrate. The structure of the compound was assigned as 5,10-dihydroxy-8,9-dimethoxy-2,2-dimethyl-12-(3-methylbut-2-enyl) pyrano [3,2-b]xanthen-6(2H)-one, by means of spectroscopic analysis. The anti-plasmodial and antioxidant activities of the phenolic compounds were evaluated, respectively, in culture against W2 strain of Plasmodium falciparum and using the free radical scavenging activity of the DPPH radical, respectively. Compounds 1-4 were found to be active against the Plasmodium parasites (IC50 of 3.53, 1.29, 3.86 and 3.17 mu M, respectively). Guttiferone A (4) showed a potent free radical scavenging activity compared to the well-known antioxidant caffeic acid. (c) 2005 Elsevier Ltd. All rights reserved.