The cytotoxicities of 6,7-modified-5,8-quinoxalinedione derivatives an
d heterocyclic quinoxaline derivatives containing nitrogen, sulfur, an
d oxygen on human lung adenocarcinoma cell (PC 14), human gastric aden
ocarcinoma cell (MKN 45), and human colon adenocarcinoma cell (colon 2
05) were examined in vitro, using MTT assay. Pyrido[1,2-a]imidazo[4,5-
g] quinoxaline-6,11-dione (10) was markedly cytotoxic against MKN 45 c
ompared with adriamycin and cis-platin used as anticancer drugs. The I
C50 value of compound 10 was 0.073 mu M while those of adriamycin and
cis-platin were 0.12 mu M and 2.67 mu M, respectively.