Peptide alkaloids from Zizyphus species

The isolation of cyclopeptide alkaloids, frangufoline from Zizyphus jujuba and Z. nummularia, amphibine-H and nummularine-K from Z. xylopyra and nummularine-R, a new 13-membered cyclopeptide alkaloid, from Z. nummularia is reported. The structure of the new alkaloid was elucidated by spectroscopic methods and by chemical degradation.