Spirostanols from the roots and rhizomes of Trillium tschonoskii

Two novel spirostanols, (23S, 24R, 25S)-18-norspirost-1,4,13-triene-21,23,24-triol-3,15-dione (1) and (23S, 24S, 25S)-spirost-5-ene1 beta,3 beta,21,23,24-pentaol (2), a new natural product (3), and two known analogues (4 and 5) were isolated from the ethyl acetate-soluble portion of the ethanolic extract of Trillium tschonoskii Maxim. Their structures were elucidated by extensive spectroscopic analyses, and their cytotoxic activities on four kinds of human tumor cells were studied in vitro. Compound 4 showed significant cytotoxic activity against MCF-7 and A549 with IC50 values of 6.16 +/- 2.21 and 28.5 +/- 11.5 mu M, respectively, while 5 exhibited selective cytotoxicity against A549 with an IC50 value of 13.0 +/- 4.51 mu M. (C) 2015 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.