The Study Of Artemisinin Derivatives Antitumor Activity And Praziquantel Enantiomers Cytotoxicity

1.Antitumor evaluation of artemisinin derivativesCancer is the most dangerous disease in the world. At present, many kinds of the anti-tumor drug have been developed, but lot of them have severe toxic and side-effects to patients. Thus, to find novel drug with higher anticancer activity and less side-effect is very important. Praziquantel and artemisinin have been used in clinical for decades for having little toxic to human. Many studys shows that both of them have many other pharmacological activities.Artemisinin is naturally occurring antimalarials which has shown potent anticancer activity. Recently, artemisinin derivatives plays a very important role in the research of antineoplastic drugs. In the present work, a new kind of artemisinin derivatives with piperazino group were synthesized starting from artemisinin. The antitumor activities of the derivatives 5a-5d were evaluated by MTT assay against ten cell lines. The result showed that all title compounds were more effective in inhibiting cancer cells growth than artemisinin.5d was the most active against human hepatocellular carcinoma cells (HepG2 and PLC/PRF/5), and presented no cytotoxicity on human normal liver cells (L-02). Hoechst 33342 staining and flow cytometry were also used to detected the apoptosis induced by 5d. The results showed that 5d could decrease mitochondrial membrane potential, and up-regulated the levels of Ca2+ and reactive oxygen species (ROS).5d also induced cell cycle arrest in G2/M phase in HepG2 carcinoma cells. Cell cycle arrest and induction of apoptosis were assessed by flow cytometry. Alteration of expression levels in proteins important in the apoptotic cascade was analyzed by western blotting, and the results showed that compound 5d significantly increased the content of p53, bax, caspase-9 and caspase-3 and decrease the protein level of bcl-2, pro-caspase-9, pro-caspase-3 and Apaf-1 in HepG2 cells. These findings indicate that 5d could induced apoptosis in hepatocellular carcinoma cellsctivates through the mitochondria-mediated apoptotic pathway.2.The cytotoxicity study of praziquantel enantiomersPraziquantel (PZQ) is prescribed as a racemic mixture (racemic-PZQ, rac-PZQ), which is composed of (R)-PZQ and (S)-PZQ. In the present work, rac-PZQ and its two enantiomers (R)-PZQ and (S)-PZQ were evaluated for the cytotoxicity on eight cell lines (L-02, HepG2, PLC/PRF/5, SH-SY5Y, HUVEC, A549, HCT-15, Raw264.7) by MTT assay. And the morphology of apoptosis cells were studied by fluorescence microscope by Hoechst 33342 staining, the cytotoxicity of the compounds were also test by LDH assay. Results revealed that (R)-PZQ had negligible cytotoxicity against L-02, SH-SY5Y, HUVEC, A549, HCT-15 and RAW264 cells and negligibly affected the human normal liver cells (L-02) but selectively inhibited tumor cell lines (PLC/PRF/5 and HepG2). However, different from (R)-PZQ, the (S)-isomer showed higher cytotoxicity against L-02 cells and displayed lower inhibition on PLC/PRF/5 and HepG2 cells than (R)-PZQ. Besides,(R)-PZQ showed lower cytotoxicity on SH-SY5Y cells than (S)-PZQ. Meanwhile, (R)-PZQ could promote proliferation of macrophage cells Raw264.7 with the concentration less than 80 μM. Our research revealed that (R)-PZQ has lower cytotoxicity than (S)-PZQ and has similar cytotoxicity with rac-PZQ. (S)-PZQ is the principal enantiomer to cause side effects on human definitive hosts. The findings gave the reasonable reasons for WHO to make (R)-PZQ as a replacement for rac-PZQ for the treatment of Schistosomiasis.