Synthesis and in vitro cytotoxic activity of novel indazole analogues of curcumin against MCF-7, HeLa, WiDr, and vero cell lines

We prepared six novel curcumin indazole analogs and confirmed their structures by Fourier transform infrared, nuclear magnetic resonance, and mass spectra. Subsequently, their cytotoxicity was tested using the Michigan Cancer Foundation (MCF-7) proliferation assay against the Michigan Cancer Foundation (MCF-7), HeLa, WiDr, and vero cell lines. This study found that the compounds we prepared were more active against WiDr than HeLa and MCF-7. The activity of 3b, 3c, 3d, and 5a against WiDr (colorectal carcinoma) cells was higher than curcumin and tamoxifen. Their selectivity index (SI) indicated that several synthesized compounds showed more selectivity (SI value > 2) than positive controls tamoxifen and doxorubicin (SI value < 2.00). Three compounds (3a, 3b, and 3c) showed high SI against WiDr cells (3.74, 5.27, and 4.39, respectively). Compound 3b produced the highest cytotoxic activity, especially against WiDr cells (IC₅₀ = 27.20 µM) with excellent selectivity (SI = 5.27). Therefore, the compound should be further developed as an anticancer agent for colorectal carcinoma.