Background: The combretastatin-A4(1) is a phenolic cis-stilbene, natural product, and was
isolated from the stem wood of the South African tree Combretum caffrum in the 1980. Combretastatin
A-4 (CA - 4) has received special attention in the last few years. It showed strong antitumor activity by
inhibiting tubulin polymerization and interacting with the colchicine binding site on tubulin. CA-4 also
acts as Vascular Disrupting Agent (VDAs), and preferentially cut off the blood supply of immature
tumors leading to their death. So we designed, synthesized and screened the anticancer activities of
pyrazole amides fused combretastatin derivatives.
Method: The anticancer activity of the compounds was determined using MTT (3-(4, 5-dimethylthiazol-
2-yl)-2, 5-diphenyl tetrazolium bromide) reduction assay.
Results: The compounds 11b, 11c and 11d exhibited potent anticancer activities than the standard drug
doxorubicin against three cancer cell lines A375, MCF-7 and Colon-205 with IC50 values ranging from
0.18 µM to 3.78 µM. The compounds 11g, 11h, 11i and 11j also showed potent anticancer activities
than the positive control doxorubicin against A375 with IC50 values of 1.78 µM, 0.34 µM, 2.67 µM and
1.67 µM, respectively.
Conclusion: From these results, the compound 11d was identified as a promising drug lead which
showed promising anticancer activity with IC50 value of 0.18 µM towards A375 breast cancer cell line
as compared to the standard drug doxorubicin (IC50 value 5.51 µM).