Clausenlanins A and B,Two Leucine-Rich Cyclic Nonapeptides from Clausena lansium

摘要

Two new cyclic nonapeptides,named clausenlanins A(1)and B(2),were isolated from the roots and rhizomes of Clausena lansium.Their structures were elucidated as cyclo-(Gly^(1)-L-Leu^(2)-L-Ile^(3)-L-Leu^(4)-L-Leu^(5)-L-Leu^(6)-L-Leu^(7)-L-Leu^(8)-L-Leu^(9))(1)and cyclo-(Gly^(1)-L-Leu^(2)-L-Val^(3)-L-Leu^(4)-L-Leu^(5)-L-Leu^(6)-L-Leu^(7)-L-Leu^(8)-L-Leu^(9))(2)respectively on the basis of extensive spectroscopic analysis,particularly 2D NMR spectra taken at the temperature of 338 or 303 K and MS.