Xanthones from the Bark of Garcinia xanthochymus and Their 1,1-Diphenyl-2-picrylhydrazyl Radical-Scavenging Activity†

Five new xanthones, garcinenone A (1), B (3), C (4), D (7) and E (8), along with 7 known compounds were isolated from the EtOAc-soluble extract of the bark of Garcinia xanthochymus, and their structures were elucidated by spectroscopic methods, especially 2D-NMR techniques. Jacareubin (2), 1,4,6-trihydroxy-5-methoxy-7-(3-methyl-2-butenyl)xanthone (6), subeliptenone B (11) and symphoxanthone (12) were obtained from this plant for the first time. The isolated compounds exhibited potent antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test with IC50 values in the 6.0–23.2 µmol/L. These results suggested that G. xanthochymus could be a promising rich source of natural antioxidant.