Isolobetyol, a new polyacetylene derivative from Platycodon grandiflorum root

A new polyacetylene, namely isolobetyol (1), was isolated from the root of Platycodon grandiflorum (Jacq.) A. DC., together with lobetyol (2), lobetyolin (3), and trans-2-hexenyl β-D-glucoside (4). The structures of the isolated natural products were identified by high-resolution mass spectrometric (HR-MS) and nuclear magnetic resonance (NMR) spectroscopic analyses. The obtained spectroscopic data was in good agreement with the data previously reported in the literature. The anti-proliferative effects of the isolated compounds were examined using the PC-3 prostate cancer cell line. Compounds 1-3 considerably reduced the proliferation of the PC-3 cells with IC₅₀ values of 6.76, 12.72, and 5.73 μM, respectively.