Cytotoxic effect of a cyclic nonapeptide from <i>Agrostemma githago</i> L. against non-small cell lung carcinoma H460 cells

One new cyclic nonapeptide, named agroscyclopeptide A (<b>1</b>), was isolated from <i>Agrostemma githago</i> L. The planar structure of agroscyclopeptide A was determined using spectroscopic techniques and MS analyses. The amino acids absolute configurations were identified by advanced Marfey's method. The potential anti-lung-cancer activity of compound <b>1</b> was evaluated using CCK-8 assay, through which its cytotoxic effects on NCl-H460 cells were analysed by assessing cellular viability. The results revealed that the compound <b>1</b> exhibited dose-dependent inhibition of NCL-H460 cells with a calculated IC₅₀ value of 4.6 <i>μ</i>M, demonstrating efficacy comparable to that of cisplatin under identical experimental condition.