In addition to the known alkaloids, zizyphine-F, jubanine-A and amphibine-H, a new peptide alkaloid spinanine-A has been isolated from the stem bark of Zizyphus spina-christi. The structure was deduced by spectroscopic methods and chemical degradation. Spinanine-A is a 14-membered cyclopeptide alkaloid of the amphibine-B type.