Acetogenins from Annona cornifolia and their antioxidant capacity

Seed ethanol extract, fractions and acetogenins from Annona cornifolia A. St.-Hil were tested for their antioxidant activities against DPPH. Acetogenins showed a strong DPPH radical-scavenging activity, similar to that of ascorbic acid. Ten acetogenins were isolated in their pure form and two were isolated as a mixture. Five are new acetogenins and are described here for the first time. Their structures were elucidated by NMR and ESI-MS analysis, and relative configurations bearing THF rings were established. The absolute configuration at C-36 of two acetogenins was defined by circular dichroism. This is, to the best of our knowledge, the first description of the antioxidant activity of acetogenins.