A new diantheramide and a new cyclic peptide from the seeds of Vaccaria hispanica

Abstract A new diantheramide, 4,4′-dihydroxy-2′-methoxydianthramide ( 1 ), and a new cyclic peptide, named segelin I ( 2 ) were isolated from the seeds of Vaccaria hispanica . Their structures were elucidated by detailed spectroscopic analysis and chemical methods. Compounds 1 and 2 were revealed to show significantly in vitro α-glucosidase inhibitory activity with IC 50 values of 0.080 ± 0.002 mM and 0.28 ± 0.002 mM, respectively, which were more potent than the reference compound acarbose (IC 50 0.410 ± 0.001 mM).