Reactive radical scavenging and xanthine oxidase inhibition of proanthocyanidins from Carallia brachiata.

Antioxidant-guided separation of Carallia brachiata bark led to a new A-type trimeric proanthocyanidin named carallidin (1), along with mahuannin A (2) and p-hydroxy benzoic acid (3). The structure of 1 was fully characterized by interpretation of spectroscopic data and chemical means. Compounds 1 and 2 exhibited radical scavenging against DPPH (IC(50) 102 and 182 microm) and superoxide radical (IC(50) 1.47 and 9.74 microm). In addition, 1 and 2 also inhibited xanthine oxidase with IC(50) values of 12.9 and 16.0 microm.