[Chemical constituents of cyclic peptides from fibrous roots of Pseudostellaria heterophylla].

Four cyclic peptides were isolated from the 75% ethanol extract of the fibrous roots of Pseudostellaria heterophylla by silica gel, Sephadex LH-20 column chromatography, and semi-preparative HPLC. Through mass spectrometry, NMR and other methods, they were identified as pseudostellarin L(1), heterophyllin B(2), pseudostellarin B(3), and pseudostellarin C(4). Among them, compound 1 was a new cyclic peptide, and compounds 2-4 were isolated from the fibrous roots of P. heterophylla for the first time. None of these compounds displayed cytotoxic activities against MCF-7, A549, HCT-116, and SGC-7901 cells.

A new cyclic peptide from the fibrous root of Pseudostellaria heterophylla.

A new cyclic peptide, Pseudostellarin K (1), together with thirteen known compounds, including two cyclic peptides (2 and 3), one ß-carboline alkaloid (4), two amides (5 and 6), three phenylpropanoids (7-9) and other compounds (10-14), were isolated from the fibrous root of Pseudostellaria heterophylla. Their structures were elucidated by extensive spectroscopic analysis. Compounds 1, 4-6, 10 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.