was observed in comparison with normal cells. Compounds 6 and 7
were found to be strongly cytotoxic against DLD-1 cells (IC50 =
0.6–0.7 lM) and their activities were significantly higher than
etoposide and compounds 1, 2, 8 and slightly lower than the camptothecin.
The results showed that new withanolides 1 and known
compound 8 were moderately active against DLD-1 with IC50 values
of 17 and 24 lM, respectively. Interestingly, the new compound
2 was also found to be strongly active against DLD-1
(IC50: 2lM) with a cytotoxicity higher than etoposide (IC50:
4 lM). Unfortunately, cytotoxicities of the aglycone of glycosides
1, 2, 6 and 8 were not assessed because isolated quantities were
not sufficient.