In Vitro Antiproliferative Activity of Palladium(II) Thiosemicarbazone Complexes and the Corresponding Functionalized Chitosan Coated Magnetite Nanoparticles

This work reports the synthesis and characterization of palladium(II) complexes Pd(L1)2 (1), Pd(L2)2
(2), Pd(L3)2 (3) and Pd(L4)2 (4), where L1H: 1‐naphthaldehyde thiosemicarbazone; L2H: 4‐phenyl‐(1‐
naphthaldehyde) thiosemicarbazone; L3H: (2‐hydroxy‐1‐naphthaldehyde) thiosemicarbazone; L4H: 4‐
phenyl‐1‐(2‐hydroxy‐1‐naphthaldehyde) thiosemicarbazone. All four complexes show in vitro
antiproliferative activity against the following human tumor cell lines: H460, DU145, MCF‐7, M14,
HT‐29, K562, HuTu 80. In particular Pd(L1)2 has the most potent activity for all the studied cell lines
(IC50 ~ 1 μM), with the exception of H460. Pd(L2)2 is a promising candidate as pharmacological agent,
since it presents a significant activity and is more innocuous than cisplatin against mouse fibroblast
normal cells, 3T3. Pd(L4)2 is the complex which exhibits the lowest activity against the same cell lines
(IC50 ~ 11 μM), being ten times lower than that of Pd(L1)2. These complexes were used to
functionalize chitosan coated superparamagnetic magnetite nanoparticles with a metallic core of 11‐
13 nm, and the activity of these functionalized nanoparticles (NPs) against diverse human tumor cell
lines was also tested. The nanoparticles, functionalized with Pd(L1)2, Pd(L3)2
and Pd(L4)2 show
antiproliferative activity against DU‐145, while those with Pd(L2)2, Pd(L3)2
and Pd(L4)2
against
HuTu80.