New Isoflavones with Antioxidant Activity Isolated from Cornulaca monacantha.

In the course of phytochemical and chemotaxonomical investigations of Cornulaca monacantha (Amaranthaceae), two new isoflavones, 3-(2-hydroxyphenyl)-5,7-dimethoxy-6-(methoxymethyl)-4H-1-benzopyran-4-one (1) and 7-hydroxy-3-(4-hydroxyphenyl)-5-methoxy-6-(methoxymethyl)-4H-1-benzopyran-4-one (2) were isolated from the fresh aerial parts of C. monacantha among with three known compounds named vanillic acid (3), N-cis-feruloyltyramine (4) and N-trans-feruloyltyramine (5). Their structures were elucidated by means of spectroscopic methods including one- and two-dimensional NMR and HR-ESI-MS techniques. The isolated compounds exhibited interesting antioxidant activity determined by DPPH, ABTS and TAC tests.