Abstract
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).
Keywords: Combretastatin-A4, celecoxib, pyrazole, anticancer activity, Combretum caffrum, heterocyclic systems.
Graphical Abstract