Objective: [corrected] To study the cyclic peptides from Psammosilene tunicoides.
Method: The constituents were separated and purified with chromatographic methods, identified by NMR, MS, UV and IR.
Result: Three cyclic dipeptides: cyclo(-Pro-Val-) (1), cyclo(-Pro-Ala-) (2) and cyclo(-Pro-Pro-) (3), were isolated and identified.
Conclusion: Compound 1 and 2 are new natural products, compound 3 was isolated for the first time from Psammosilene tunicoides.