Design, synthesis and biological evaluation of novel evodiamine and rutaecarpine derivatives against phytopathogenic fungi.

Evodiamine and rutaecarpine are two alkaloids isolated from traditional Chinese herbal medicine Evodia rutaecarpa, which have been reported to have various biological activities in past decades. To explore the potential applications for evodiamine and rutaecarpine alkaloids and their derivatives, various kinds of evodiamine and rutaecarpine derivatives were designed and synthesized. Their antifungal profile against six phytopathogenic fungi Rhizoctonia solani, Botrytis cinerea, Fusarium graminearum, Fusarium oxysporum, Sclerotinia sclerotiorum, and Magnaporthe oryzae were evaluated for the first time. Furthermore, a series of modified imidazole derivatives of rutaecarpine were synthesized to investigate the structure-activity relationship. The results of antifungal activities in vitro showed that imidazole derivative of rutaecarpine A1 exhibited broad-spectrum inhibitory activities against R. solani, B. cinerea, F. oxysporum, S. sclerotiorum, M. oryzae and F. graminearum with EC50 values of 1.97, 5.97, 12.72, 2.87 and 16.58 µg/mL, respectively. Preliminary mechanistic studies showed that compound A1 might cause mycelial abnormalities of S. sclerotiorum, mitochondrial distortion and swelling, and inhibition of sclerotia formation and germination. Moreover, the curative effects of compound A1 were 94.7%, 81.5%, 80.8%, 65.0% at 400, 200, 100, 50 µg/mL in vivo experiments, which was far more effective than the positive control azoxystrobin. Significantly, no phytotoxicity of compound A1 on oilseed rape leaves was observed obviously even at a high concentration of 400 µg/mL. Therefore, compound A1 is expected to be a novel leading structure for the development of new antifungal agents.

Sodium valproate prevents radiation-induced injury in hippocampal neurons via activation of the Nrf2/HO-1 pathway.

PURPOSE: To investigate the neuroprotective role of sodium valproate (VPA) in a hippocampal neuronal cell line (HT22) and the hippocampus of zebrafish after exposure to radiation. METHODS: We investigated whether VPA could protect HT22 hippocampal neurons and the hippocampus of zebrafish from radiation-induced injury. We measured the generation of reactive oxygen species (ROS), the mitochondrial membrane potential, the levels of glutathione (GSH) and malondialdehyde (MDA), and the activity of superoxide dismutase (SOD). The expression of nuclear factor (erythroid-derived 2)-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was also measured. The cognitive behavior of the zebrafish was evaluated 1month after radiation exposure. RESULTS: VPA treatment improved the survival rate (300 mg/kg body weight (BW) VPA: 76.67%; 100 mg/kg BW VPA: 56.7%) of zebrafish 1 month after exposure to a lethal dose of whole-body irradiation (P<0.01). VPA treatment decreased the ROS generation (P<0.01), decreased the MDA levels (P<0.01), increased the GSH levels (P<0.01) and increased the SOD activity (P<0.01). VPA treatment activated the Nrf2/HO-1 pathway, increased the nuclear translocation of Nrf2 and increased the mRNA (P<0.01) and protein expression of HO-1 to prevent radiation-induced neuronal injury. SiRNA knockdown of the Nrf2 gene prevented the VPA-induced attenuation of radiation injury in the HT22 neuronal cells that was found in the control cells (40.09±1.76% vs. 41.14±1.09%, P>0.05). VPA also improved the zebrafish cognitive behavior after radiation-induced neuronal injury as measured by the exploration test (control 5.74±1.42min vs. radiation therapy 16.39±4.03min vs. radiation therapy plus VPA 7.18±1.79min, P<0.05). CONCLUSIONS: ROS generation after radiation exposure contributes to DNA damage in the zebrafish brain. VPA inhibits ROS generation by activating the Nrf2/HO-1 pathway, which improves cognitive behavior following radiation-induced neuronal injury.

Protective effect of tanshinone IIA against radiation-induced ototoxicity in HEI-OC1 cells.

Radiotherapy is a highly efficient treatment method for nasopharyngeal carcinoma that is often accompanied by significant ototoxic side-effects. The inner ear hair cells are particularly prone to serious injury following radiotherapy. Tanshinone IIA is a transcription factor inhibitor that is extracted from the traditional herbal medicine, Salvia miltiorrhiza Bunge. The present study investigated the effects of tanshinone IIA treatment on radiation-induced toxicity in the HEI-OC1 hair cell line. Using an MTT assay and flow cytometry, the radiation-induced weakening of the cells was observed to be alleviated when the cells were pre-treated with tanshinone IIA. Radiation exposure promoted p65/nuclear factor (NF)-κB nuclear translocation and activated the p53/p21 pathway, two processes which play a significant role in radiation-induced cell apoptosis. However, pre-treatment of the cells with tanshinone IIA inhibited p65/NF-κB nuclear translocation and p53/p21 pathway activation. These results demonstrate that tanshinone IIA is capable of protecting cochlear cells from radiation-induced injury through the suppression of p65/NF-κB nuclear translocation and the p53/p21 signaling pathway.

Effects of different concentrations of amino acids in the culture medium on preimplantation mouse embryo development in vitro.

OBJECTIVE: To evaluate the effects of amino acids (AA) on the development of in vitro cultured preimplantation embryos of Kunming mice, and define the optimal AA concentration for embryo culture. METHODS: Totally 630 zygotes were collected from the oviducts of superovulated female Kunming mice, which were cultured in protein-free potassium simplex optimized medium (mKSOM) supplemented with Eagle's essential amino acids and Eagle's non-essential amino acids of different concentrations (mKSOM, mKSOM+1/16AA, mKSOM+1/8AA, mKSOM+1/4AA, mKSOM+1/2AA, mKSOM+AA, and mKSOM+2AA). RESULTS: The embryos cultured with the amino acids showed higher development rate to both 8-cell embryo stage and blastocyst stage than those cultured without amino acids. The correlation of amino acid concentration with 8-cell and blastocyst development rates conformed to the cubic model, with the highest development rate to both of the two stages observed at half of the amino acid concentration. CONCLUSION: Amino acids can promote the development of preimplantation Kunming mouse embryos, but excessively high concentration of amino acids impair embryo development possibly because of metabolic and osmotic pressure changes of the embryos as well as toxicity of ammonium resulting from the metabolism of amino acids.