Screening, Characterization and Evaluation of Mangiferin Polymorphs

Mangiferin is a compound with many pharmacological activities and exists in many natural products.Anhydrous and hydrate of mangiferin have been reported separately in two literatures,but the polymorphism of this compound has not been realized until this paper.In this study,polymorph screening of mangiferin has been carried out and five forms have been obtained including three new forms never reported.Several solid state characterization methods,such as powder X-ray diffraction,differential scanning calorimetry and thermogravimetry,are used to identify and characterize all of mangiferin forms.The comparison of the crystallographic data and hirshfeld surface analysis were first reported for mangiferin anhydrous and hydrate.Furthermore,the studies on stability,transformation and solubility have been undertaken,the results prompt that form V can be used as the dominant polymorph for the development of innovative pharmaceuticals.

Anomalous refinement and uniformization of grains in metallic thin films

When a laser beam writes on a metallic film,it usually coarsens and deuniformizes grains because of Ostwald ripening,similar to the case of annealing.Here we show an anomalous refinement effect of metal grains:A metallic silver film with large grains melts and breaks into uniform,close-packed,and ultrafine(~10 nm)grains by laser direct writing with a nanoscale laser spot size and nanosecond pulse that causes localized heating and adaptive shock-cooling.This method exhibits high controllability in both grain size and uniformity,which lies in a linear relationship between the film thickness(h)and grain size(D),D∝h.The linear relationship is significantly different from the classical spinodal dewetting theory obeying a nonlinear relationship(D∝h5/3)in common laser heating.We also demonstrate the application of such a silver film with a grain size of~10.9 nm as a surface-enhanced Raman scattering chip,exhibiting superhigh spatial-uniformity and low detection limit down to 10-15 M.This anomalous refinement effect is general and can be extended to many other metallic films.

Inhibition of FOXO3a/BIM signaling pathway contributes to the protective effect of salvianolic acid A against cerebral ischemia/reperfusion injury

Salvianolic acid A(SalA) is an effective compound extracted from traditional Chinese medicine Salvia miltiorrhiza Bunge. The Forkhead box O3a(FOXO3a) signaling pathway plays crucial roles in the modulation of ischemia-induced cell apoptosis. However, no information about the regulatory effect of SalA on FoxO3a is available. To explore the anti-cerebral ischemia effect and clarify the therapeutic mechanism of SalA, SH-SY5Y cells and Sprague–Dawley rats were applied, which were exposed to oxygen glucose deprivation/reoxygenation(OGD/R) and middle cerebral artery occlusion/reperfusion(MCAO/R) injuries, respectively. The involved pathway was identified using the specific inhibitor LY294002. Results showed that SalA concentration-dependently inhibited OGD/R injury triggered cell viability loss. SalA reduced cerebral infarction, lowered brain edema, improved neurological function, and inhibited neuron apoptosis in MCAO/R rats, which were attenuated by the treatment of phosphatidylinositol-4,5-bisphosphate 3-kinase(PI3K) specific inhibitor LY294002. SalA time-and concentration-dependently upregulated the phosphorylation levels of protein kinase B(AKT) and its downstream protein FOXO3a. Moreover, the nuclear translocation of FOXO3a was inhibited by SalA both in vivo and in vitro, which was also reversed by LY294002. The above results indicated that SalA fought against ischemia/reperfusion damage at least partially via the AKT/FOXO3a/BIM pathway.