Tunicyclin A, the First Plant Tricyclic Ring Cycloheptapeptide from Psammosilene tunicoides
摘要:
A novel cycloheptapeptide, tunicyclin A, with a unique tricyclic ring cyclopeptide skeleton, was isolated from Psammosilene tunicoides. Its structure was elucidated by extensive NMR and MS analysis. Biogenetically, tunicyclin A might be derived from cyclo-(Pro(1)-Ser(2)-(gamma-keto-delta-aldehedyl-Glu(3))-Leu(4)-Val(5)-Gly(6)-Ser(7)) via two steps of nucleophilic addition.