Antileukemic Effect of Palladium Nanoparticles Mediated by White Tea (<i>Camellia sinensis</i>) Extract <i>In Vitro</i> and in WEHI‐3B‐Induced Leukemia <i>In Vivo</i>

Abstract

This study investigated the in vivo antileukemic activity of palladium nanoparticles (Pd@W.tea‐NPs) mediated by white tea extract in a murine model. The cell viability effect of Pd@W.tea‐NPs, “blank” Pd nanoparticles, and white tea extract alone was determined in murine leukemia WEHI‐3B cells and normal mouse fibroblasts (3T3 cells). Apoptotic and cell cycle arrest effects of Pd@W.tea‐NPs in WEHI‐3B cells were evaluated. The effects of Pd@W.tea‐NPs administered orally to leukemic mice at 50 and 100 mg/kg daily over 28 days were evaluated. Pd@W.tea‐NPs reduced the viability of WHEI‐3B cells with IC 50 7.55 μ g/ml at 72 h. Blank Pd nanoparticles and white tea extract alone had smaller effects on WHEI‐3B viability and on normal fibroblasts. Pd@W.tea‐NPs increased the proportion of Annexin V‐positive WHEI‐3B cells and induced G2/M cell cycle arrest. Leukemic cells in the spleen were reduced by Pd@W.tea‐NPs with an increase in Bax/Bcl‐2 and cytochrome‐C protein and mRNA levels indicating the activation of the mitochondrial apoptotic pathway. These effects replicated the effects of ATRA and were not observed using blank Pd nanoparticles. Pd@W.tea‐NPs afford therapeutic efficacy against leukemia likely to pivot on activation of the mitochondrial pathway of apoptotic signaling and hence appear attractive potential candidates for development as a novel anticancer agent.