A new cyclic peptide from the fibrous root of .

A new cyclic peptide, Pseudostellarin K (), together with thirteen known compounds, including two cyclic peptides ( and ), one β-carboline alkaloid (), two amides ( and ), three phenylpropanoids () and other compounds (), were isolated from the fibrous root of . Their structures were elucidated by extensive spectroscopic analysis. Compounds , -, were isolated from the genus pseudostellaria for the first time. All compounds were evaluated for cytotoxic activities against MCF-7, A549, HCT-116 and SGC-7901 cell lines by MTT assay. Unfortunately, all these compounds displayed weak cytotoxic activities.