Abstract:In order to understand the chemical constituents ofBidens pilosavar. radiate, the four polyacetylenes were isolated from ethyl acetate extract of B. pilosavar. radiate by using multiple column chromatography, and their biological activities were studied. Four polyacetylenes were identified as 5-acetoxy-2-phenylethinyl- thiophene (1), 1-phenylhepta-1,3,5-triyne (2), 5-phenyl-2-(1-propynyl)-thiophene (3), and icthyothereol acetate (4). In vitro activity screening, all these compounds showed moderate anti-MRSA activity, and were not toxic to human liver LO2 cells. The NMR spectroscopic data along with the detailed elucidation of compound 1 was firstly presented, besides, compounds 3 and 4 were isolated from Bidens genus for the first time.