Gypsophin: A novel α-glucosidase inhibitory cyclic peptide from the roots of Gypsophila oldhamiana

An unusual new cyclic peptide with a pyrrolidine-2,5-dione unit, gypsophin (1), was isolated from Gypsophila oldhamiana. Its structure was elucidated by the spectroscopic evidences. The stereochemistry was determined by application of the Marfey’s method and the single-crystal X-ray diffraction. Compound 1 exhibited inhibitory activity against α-glucosidase with IC50 of 305 μM.