New cytotoxic quinone analogues from the rhizomes of Arnebia euchroma

Two new quinone analogues, given the trivial names arneromas A–B (1–2) were isolated from the rhizome of Arnebia euchroma. Their structures were elucidated on the basis of extensive spectroscopic analyses. The absolute configurations of both compounds were determined by comparison of their calculated and experimental CD curves. In addition, compounds 1–2 were tested for their cytotoxic activities against HCT-8 and HL-60 cancer cell lines, and both of the compounds showed moderate inhibitory activities against HL-60 cell line with IC50 values of 9.1 and 7.2 μM, respectively.