Cyclopalladated and cycloplatinated benzophenone imines: Antitumor, antibacterial and antioxidant activities, DNA interaction and cathepsin B inhibition

Abstract The antitumor, antibacterial and antioxidant activity, DNA interaction and cathepsin B inhibition of cyclo- ortho -palladated and -platinated compounds [Pd(C,N)] 2 (μ-X) 2 [X = OAc ( 1 ), X = Cl ( 2 )] and trans - N , P -[M(C,N)X(PPh 3 )] [M = Pd, X = OAc ( 3 ), M = Pd, X = Cl ( 4 ), M = Pt, X = Cl ( 5 )] are discussed [(C,N) = cyclo- ortho -metallated benzophenone imine]. The cytotoxicity of compound 5 has been evaluated towards human breast (MDA-MB-231 and MCF-7) and colon (HCT-116) cancer cell lines and that of compounds 1 – 4 towards the HCT-116 human colon cancer cell line. These cytotoxicities have been compared with those previously reported for compounds 1 – 4 towards MDA-MB-231 and MCF-7 cancer cell lines. Compound 3 and 4 were approximately four times more active than cisplatin against the MDA-MB-231 and MCF-7 cancer cell lines, and compound 5 , was approximately four times more potent than cisplatin against the HCT-116 cancer cell line. The antibacterial activity of compounds 1 – 5 was in between the ranges of activity of the commercial antibiotic compounds cefixime and roxithromycin. Complexes 1 – 2 and 4 – 5 presented also antioxidant activity. Compounds 1 – 5 alter the DNA tertiary structure in a similar way to cisplatin , but at higher concentration, and do not present a high efficiency as cathepsin B inhibitors. Compound 5 has not been previously described, and its preparation, characterization, and X-ray crystal structure are reported.