Core-functionalised Fréchet-type Rhenium metallodendrimers: Insights into their biological activity as anticancer drug leads

• Core-functionalized Fréchet-type rhenium-based metallodendrimers have been prepared. • Examined for cytotoxicity against a panel of human cancer cell lines. • The lowest generation metallodendrimer showed the greatest cytotoxicity. Cancer remains a major noncommunicable disease and one of the greatest health challenges of the 21st century. Chemotherapy remains a central and effective treatment option, yet the demand for improved therapies has spurred the design of novel chemical entities targeting diverse cancers. Dendrimers have gained attention as versatile drug-delivery platforms. This preliminary study presents the synthesis, characterisation, and cytotoxic assessment of core-functionalized Fréchet-type rhenium metallodendrimers. Reaction of the bidentate dendrimers with [Re(CO)₅Cl] produced three stable, air- and moisture-resistant complexes, characterized by 1 H and 13 C{ 1 H} NMR, FT-IR, and UV-Vis spectroscopy. UV-Vis analysis confirmed their stability in DMSO for up to 48 hours under both ambient and physiological conditions, validating their suitability for biological testing. The synthesized ligands and complexes were examined for cytotoxicity against human breast (MCF-7, MDA-MB-231), cervical (HeLa, CaSki), pancreatic (SW1990, CFPAC-1), and prostate (PC-3) cancer cell lines. Initial single-dose assays identified the lowest-generation metallodendrimer ( 4 ) as the most active, prompting further multidose testing and selectivity studies in cervical cancer models. . Complex 4 displayed IC₅₀ values of 40.4 ± 0.3 μM (SI = 3.76) against HeLa cells and 69.4 ± 0.2 μM (SI = 2.2) against CaSki cells.