Chemical Constituents from the Bark of Garcinia xanthochymus and Their 1,1‐Diphenyl‐2‐picrylhydrazyl (DPPH) Radical‐Scavenging Activities

A new bis‐xanthone (xanthone=9H‐xanthen‐9‐one), named bigarcinenone A (1) which is the first example of a bis‐xanthone with the xanthone–xanthone linkage between an aromatic C‐atom and a C5 side chain from a guttiferae plant, a new phloroglucinol (=benzene‐1,3,5‐triol) derivative, named garcinenone F (2), together with seven known xanthones were isolated from the bark of Garcinia xanthochymus. Their structures were elucidated by spectroscopic methods, especially 2D‐NMR techniques. Bigarcinenone A (1) exhibited potent antioxidant activity in the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical‐scavenging test with a IC50 value of 9.2 μM, compared to the positive control, the well‐known antioxidant butylated hydroxytoluene (BHT) with a IC50 of 20 μM (Table 3).