A new cyclic peptide, designated as hibispeptin B, has been isolated f
rom the root bark of Hibiscus syriacus. Hibispeptin B has a unique ami
no acid unit assigned as 2-amino-3-(2-hydroxy-5-aminoacetylbenzyl)pent
anoic acid (Ahabpa) in cyclic core. Its structure was established as c
yclo[Ahabpa(-pyro-Glu)-Pro-Leu-Leu-] on the basis of various spectrosc
opic analyses. Configurations of all normal amino acids were determine
d as L by chiral-TLC analysis. (C) 1998 Elsevier Science Ltd. All; rig
hts reserved.