A new gallic acid hydrazone, 3,4,5-trihydroxybenzoyl salicylaldehyde hydrazone, and its four rare earth complexes, [LnL (OAc)2] • H2O (Ln = La3+, Sm3+, Tb3+, Dy3+), have been synthesised and characterised on the basis of elemental analyses, molar conductivity, IR and 1H NMR spectra. The antitumour activities of the prepared compounds have also been evaluated. The results indicate that Gallic acid hydrazone and its four complexes synthesised possess antitumour activity to some extent, and the four complexes show higher antitumour activity against the human leukaemia cell line HL-60 than the ligand. The antitumour activity of the gallic acid hydrazone can be improved by the formation of the rare earth complexes.
