Cytotoxic Profiling of 3′,4′,5′‐Trimethoxychalcones Reveals Cell‐Line‐Dependent Cytotoxic Activity: An In Vitro and In Silico Study

Abstract

ABSTRACT Cytotoxic activity of a series of 3′,4′,5′‐trimethoxychalcones ( 1–25 ) was evaluated against multiple human cancer cell lines under uniform experimental conditions. The compounds were designed to bear simple substitutions on ring B to allow direct comparison of substitution effects. Most derivatives showed higher cytotoxic potency than the reference drug melphalan in the more responsive models. Several compounds exhibited submicromolar half‐maximal inhibitory concentration (IC 50 ) values ( 7 , 8 , 12 , 13 , 14 , 17 , 18 , 20 , 23 ). Low‐nanomolar activity was also observed. Compounds 4 , 5 , 9 , 10 , 15 , 16 , and 24 showed particularly high potency. However, cytotoxic responses were strongly cell‐line dependent. MCF‐7 (estrogen receptor–positive breast carcinoma) and SKW‐3 (T‐cell leukemia) cells were highly sensitive, whereas MDA‐MB‐231 (triple‐negative breast carcinoma) and K‐562 (BCR‐ABL–positive leukemia) cells were less responsive. In the doxorubicin‐resistant HL‐60/DOX (multidrug‐resistant promyelocytic leukemia) subline, 10 retained activity. Compound 16 showed a nine‐fold increase in potency relative to HL‐60. Hierarchical clustering, principal component analysis (PCA), and descriptor‐based quantitative structure–activity relationship (QSAR) revealed no transferable trends. Molecular docking showed moderate, non‐selective interactions with multiple targets. Similar binding to human serum albumin was observed. Overall, these findings support cell‐line‐resolved evaluation and context‐aware optimization in 3′,4′,5′‐trimethoxychalcone‐based anticancer research.