Examples of naturally occurring bioactive cyclopeptides are Segetalins A and B，which were isolated from Vaccaria segetalis (Caryophyllacea) and
were shown to have estrogen-like activity. The seeds of Vaccaria segetalis are used in Chinese folk medicine to activate blood flow, to promote milk secretion, and to
treat amenorrhea and breast infections.
That Segetalin A and Segetalin B have the Try-Ala-Gly-Val (WAGV) sequence in
common indicates this is the biologically active part of the molecules. NMR
studies indicate,however,that the orientation of the Val residue is different in the
molecules.The effect of this amino acid on the activity of the compounds might
not be very important.
