Cytotoxic activity of C₁₇ polyacetylenes from the roots of Glehnia littoralis against drug-resistant colorectal and lung cancer cells

In the preliminary screening, falcarinol and falcarindiol, C₁₇ polyacetylenes from the roots of Glehnia littoralis F. Schmidt ex Miq (Umbelliferae), displayed cytotoxic activity both against oxaliplatin-sensitive/resistant colorectal cancer (CRC) and gefitinib-sensitive/resistant non-small cell lung cancer (NSCLC) cells. In this study, 13 polyacetylenes including a new (3R,11R)-11-hyroxy-isofalcarinolone (1) were isolated from G. littoralis, and the chemical structures were elucidated through NMR, HRMS, and optical rotation analysis as well as DP4 plus calculation. (3S,8S)-Oplopandiol (5) showed cytotoxic activities against oxaliplatin-sensitive and -resistant CRC (HCT116 and HCT116-OxR) cells. Unexpectedly, (3R,8S)-falcarindiol (3) and (3S)-falcarinol (12), newly purified from G. littoralis, did not show cytotoxic activity. It was confirmed that both falcarinol and falcarindiol, previously evaluated, were decomposed, which seems to be the cause of inconsistent biological results. These findings indicated that C₁₇ polyacetylene could be a good starting compound for the development of anticancer leads against drug-resistant CRC and NSCLC cells, however, the stability of C₁₇ polyacetylens should be considered for further studies.