The estrane analogue of OSW-1, a potent antitumor natural saponin, was efficiently synthesized from estrone in 12 steps. The cytostatic activity of the compound against several human malignant tumor cells was examined and compared to those of the natural OSW-1 and cisplatin, the results suggesting that the modification of the steroidal component could be an effective approach in the search for new candidates of anticancer drugs. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)