Alkaloids constituents from the roots of Phragmites australis (Cav.) Trin. ex Steud. with their cytotoxic activities.

Two new alkaloids, phranisines A-B (1-2), along with two known compounds, N-p-Coumaroyl serotonin (3) and N-p-coumaroyl-tryptamine (4), were isolated from the roots of Phragmites australis. The structures of 1-4 were established on the basis of extensive spectroscopic. The absolute configuration of compounds 1-2 were identified through quantum-chemical electronic circular dichroism (ECD) calculation compared with their experimental CD. All the isolated compounds were tested for their cytotoxic activities against HeLa and MCF-7 human cancer cell lines, and compounds 2-4 showed moderate cytotoxic activities against HeLa cell lines with IC50 values ranging from 13.2 to 18.6 µM.

Synthesis and evaluation of 26-amino acid methyl ester substituted sarsasapogenin derivatives as neuroprotective agents for Alzheimer's disease.

Sarsasapogenin, extracted from Anemarrhena asphodeloides Bunge., has been reported to protect neurons from H2O2-induced damage. In the current study, four series of 26-amino acid methyl ester substituted sarsasapogenin derivatives (5a-5e, 5f-5j, 6a-6e and 7a-7e) were synthesized and tested for neuroprotective activity by evaluating their neuroprotective ratio against SH-SHY5Y cell lines. Studies showed that most of the target compounds displayed better neuroprotective effects than that of sarsasapogenin. Structure-activity relationship analysis suggested that 3-methoxy derivatives (5f-5j) were more potent than other series and the phenylalanine methyl ester moiety at C-26 was important for exhibiting apparent neuroprotective activity. It was worth noting that compound 5h exhibited optimal neuroprotective activity (102.2%) compared with sarsasapogenin (27.3%) and trolox (40.5%), and this encouraged us to investigate the cellular mechanism of 5h further. Our investigation revealed that 5h could attenuate H2O2-induced cell damage by inhibiting the expression of cleaved poly (ADP-ribose) polymerase (PARP) and cleaved caspase-3 as well as rescuing the downregulation of brain-derived neurotrophic factor (BDNF) and its tyrosine receptor kinase B (TrkB). Taken together, these results suggest that the representative compound 5h is a profound lead compound for further investigation and the sarsasapogenin skeleton could be a promising structural template for the development of new anti-Alzheimer drug candidates.

In vivo and in vitro induction of the apoptotic effects of oxysophoridine on colorectal cancer cells via the Bcl-2/Bax/caspase-3 signaling pathway.

Oxysophoridine (OSR) is a major active alkaloid extracted from Sophoraalopecuroides L. The aim of the present study was to investigate the induction of the apoptotic effects of OSR on colorectal cancer cells in vivo and in vitro. The results of the MTT and colony formation assays demonstrated that the proliferation of HCT116 cells was inhibited by OSR in vitro. The characteristics of cellular apoptosis in OSR-treated HCT116 cells were analyzed by Hoechst 33258 staining. It was also observed that the expression of caspase-3, B-cell lymphoma-2 (Bcl-2) associated X protein (Bax) and cytochrome c increased significantly upon OSR treatment. However, the expression of Bcl-2 and poly ADP-ribose polymerase-1 (PARP-1) was downregulated in OSR-treated cells compared with untreated cells. The in vivo experiments identified that OSR significantly inhibited the growth of the transplanted mouse CT26 tumor tissue, upregulated the expression of caspase-3, Bax and cytochrome c and downregulated the expression of Bcl-2 and PARP-1, as detected by reverse transcription-quantitative polymerase chain reaction and western blotting. It may be concluded that OSR significantly induced apoptotic effects on colorectal cancer cells in vivo and in vitro, and that its mechanism may be associated with the Bcl-2/Bax/caspase-3 signaling pathway.

[Effects of temperature and heating time on armco iron spectral emissivity in atmospheric environment].

The spectral emissivity of pure iron at 1.55 µm was investigated systematically by using our self-designed reflective experimental apparatus based on the Kirchhoff's law, and the influences of temperature and heating time on the spectral emissivity of pure iron were also discussed. The experimental data showed that the spectral emissivity of pure iron increased with temperature rising and its peak value and valley value appeared at certain temperatures. By analyzing the emissivity model of metal with oxidation layer, the variation of the spectral emissivity of pure iron was illustrated. The influence of heating time on the spectral emissivity was different at different temperature. The research results will further enrich pure iron spectral emissivity data, and provide the experimental basis for its application in atmospheric environment.