Antitumor Research on Artemisinin and Its Bioactive Derivatives

Cancer is the leading cause of human death which seriously threatens human life.The antimalarial drug artemisinin and its derivatives have been discovered with considerable anticancer properties.Simultaneously,a variety of target-selective artemisinin-related compounds with high efficiency have been discovered.Many researches indicated that artemisinin-related compounds have cytotoxic effects against a variety of cancer cells through pleiotropic effects,including inhibiting the proliferation of tumor cells,promoting apoptosis,inducing cell cycle arrest,disrupting cancer invasion and metastasis,preventing angiogenesis,mediating the tumor-related signaling pathways,and regulating tumor microenvironment.More importantly,artemisinins demonstrated minor side effects to normal cells and manifested the ability to overcome multidrug-resistance which is widely observed in cancer patients.Therefore,we concentrated on the new advances and development of artemisinin and its derivatives as potential antitumor agents in recent 5 years.It is our hope that this review could be helpful for further exploration of novel artemisinin-related antitumor agents.

Effect of bone marrow stromal cell transplantation to the hippocampal CA1 region on electroencephalographic activity in epileptic rats

BACKGROUND： Animal experiments have confirmed that bone marrow stromal cell （BMSC） transplantation can serve as a treatment for epilepsy. OBJECTIVE： BMSCs derived from green fluorescent protein （GFP） mice were transplanted into the hippocampal CA1 region of epileptic rats. The aim of the study was to record electroencephalogram （EEG）, analyze survival and migration of BMSCs, and validate the effect of BMSC transplantation for the treatment of epilepsy. DESIGN, TIME AND SETTING： A randomized block design experiment was performed at the Institute of Neuroscience, Kunming Medical College from March 2005 to February 2006. MATERIALS： Homozygous C57BL/6CrSlcTgN （acr-EGFP） OsbC 14-Y01-FM 131 mice, 8-12 weeks of age, were selected for preparation of cell suspension. Sprague Dawley rats were selected for establishing epilepsy models. METHODS： Rats were randomly divided into 4 groups： control （n = 8）, model （n = 8）, normal saline （n = 24）, and BMSC （n = 24）. In the model, normal saline, and BMSC groups, epilepsy was established with penicillin （3 × 10^7 U/kg i.p. ×7 days）. Rats in the BMSC group received a BMSC suspension derived from green fluorescent protein mice into the fight hippocampal CA1 region. Rats in the vehicle control group were injected with the same volume of normal saline into the hippocampal CA1 region. MAIN OUTCOME MEASURES： The electroencephalogram was used to monitor brain activity. Survival and migration of the transplanted BMSCs was observed using fluorescence microscopy at 1, 2, and 4 weeks after transplantation. RESULTS： In BMSC group, fluorescent cells were observed at the transplantation site and in the adjacent tissue, as well as in the tissue surrounding the needle tract, indicating the migration of implanted cells. Fluorescent cells were not detected in the vehicle control group. The electroencephalogram of the control animals exhibited 7-9 Hzα waves, with a wave amplitude 〈 50 μV. In the model and vehicle control groups random spike-and-wave discharges of the sharp spike-sharp low wave type were observed. EEG amplitudes were significantly smaller in the BMSC group, compared with the model and vehicle control groups. CONCLUSION： Following transplantation, BMSCs survived and migrated to the injury region of the epileptic rat brain and alleviated epileptic seizures.

N-doping offering higher photodegradation performance of dissolved black carbon for organic pollutants: experimental and theoretical studies

We investigated the influence mechanism of N-doping for dissolved black carbon(DBC)photodegradation of organic pollutants.The degradation performance of N-doped dissolved black carbon(NDBC)for tetracycline(TC)(71%)is better than that for methylene blue(MB)(28%)under irradiation.These levels are both better than DBC degradation performances for TC(68%)and MB(18%)under irradiation.Reactive species quenching experiments suggest that h and-O,are the main reactive species for NDBC photodegraded TC,while-OH and h*are the main reactive species for NDBC photodegraded MB.-OH is not observed during DBC photodegradation of MB.This is likely because N-doping increases valence-band(VB)energy from 1.55 eV in DBC to 2.04 eV in NDBC;the latter is strong enough to oxidize water to form-OH.Additionally,N-doping increases the DBC band gap of 2.29 to 2.62 eV in NDBC,resulting in a higher separation efficiency of photo-generated electrons-holes in NDBC than in DBC.AIl these factors give NDBC stronger photodegradation performance for TC and MB than DBC.High-performance liquid chromatography-mass spectrometry(HPLC-MS)characterization and toxicity evaluation with the quantitative structure-activity relationship(QSAR)method suggest that TC photodegradation intermediates produced by NDBC have less aromatic structure and are less toxic than those produced by DBC.We adopted a theoretical approach to clarify the relationship between the surface groups of NDBC and the photoactive species produced.Our results add to the understanding of the photochemical behavior of NDBC.