Cyclopeptides from Vaccaria segetalis

From the seeds of Vaccaria segetalis, a well-known traditional Chinese medicine named “wang bu liu xing”, four cyclopeptides vaccarins A-D were isolated in which only vaccarin A is a new cyclopeptide. Their structures were elucidated by spectral and chemical methods as vaccarin A ——cyclo-(Trp-Ala 1 -Gly-Val-Ala 2 ), vaccarin B ——cyclo-(Pro-Gly-Leu-Ser-Phe 1 -Ala-Phe 2 ), vaccarin C——cyclo-(Pro 1 -Gly-Tyr-Val-Pro 2 -Leu-Trp), vaccarin D——cyclo-(Pro-Val 1 -Trp-Ala-Gly-Val 2 ).