83(P2-13) 地骨皮のACE,Renin活性阻害ペプチドの構造(ポスター発表の部)  [in Japanese] 83(P2-13) STRUCTURES OF ANTI-ACE AND -RENIN PEPTIDES FROM LYCII RADICIS CORTEX  [in Japanese]

Two new cyclic octapeptides, named lyciumins A (1) and B (2), have been isolated from Lycii Radicis Cortex, the root barks of Lycium chinense Mill. (Solanaceae), which has been used for an antifebrile and a tonic as traditional crude drug. Their structures have been elucidated by chemical (analysis of amino acids produced by hydrolysis using mineral acid, chymotrypsin and proline specific endopeptidase) and spectroscopic (assignments of ^1H-NMR spectra by ^1H-^1H COSY and determination of sequences of amino acids by ROESY) means. The structure of 1 has been characterized as (glycyl^4Cα, tryptophan^8indole N^1)-cyclo-pyroglutaminyl-prolyl-tyrosyl-glycyl-valyl-glycyl-seryl-tryptophan. The structure of 2 has likewise been deduced to be a peptide replaced by Trp in 2 instead of Tyr in 1. These plant origin peptides are unique examples and they are novel in terms of cyclic one with linkage between the indole N^1 of Trp^8 and the Ca of Gly^4. Furthermore, they have been shown to possess inhibiting actions for renin and ACE activities, i.e. inhibitions of renin activities for 1, 19.4% (40μg/ml); for 2, 32% (40μg/ml), inhibitions of ACE activities for 1, 90.9% (100μg/R.M.); for 2, 79.0% (100μg/R.M.).