Insight into the Catalytic Activity of Amorphous Multimetallic Catalysts under a Magnetic Field toward the Oxygen Evolution Reaction.

Slow kinetics in the oxygen evolution reaction (OER) remains a Gordian knot to develop an efficient and cost-effective electrocatalyst in electrochemical water splitting. In recent studies, either a synergistic effect on multimetallic catalysts or spin polarization in ferromagnetic materials is considered as a desirable way to improve water electrolysis. Herein, the OER performance of amorphous FeNiCo-based multimetallic catalysts with adjustable composition was investigated from the perspective of atomic structure. Mössbauer spectra results demonstrate that the OER activities exhibit a significant dependence on the local structure of catalysts in which a catalyst with a high content of Fe clusters of low coordination numbers tends to obtain higher activity. Furthermore, benefiting from the spin polarization of these ferromagnetic catalysts, the OER activity is notably enhanced in the presence of a magnetic field. In particular, overpotential reduction exceeding 20 mV (above 100 mA cm-2) in alkaline OER performance is observed for strong ferromagnetic catalysts in comparison with the weak ferromagnetic ones. An increment of 65.2% in turnover frequency is achieved for the catalyst with the strongest ferromagnetism. This magnetic enhancement strategy affords an effective way of improving the water oxidation performance on amorphous ferromagnetic catalysts.

[Phaseoloideside E induces human hepatoma HepG2 cells apoptosis].

OBJECTIVE: To study in vitro anti-tumor activity of phaseoloideside E (PE) with human hepatoma HepG2 cells as the objective. METHOD: MTT assay was adopted to detect the cytotoxic effect of PE of different concentrations on HepG2 cells after being processed for 48 h. Changes in morphology of PE-processed cells were observed under an optical microscope and fluorescence microscope. DNA agrose gel electrophoresis was used to detect the DNA ladder, an important characteristic of cell apoptosis. The expression levels of Bax and Bcl-2 were determined by western blot assay. RESULT: PE dramatically repressed the viability of HepG2 cells. Typical morphological changes of apoptosis had been detected by both direct microscopic observation and Hoechst 33,258 staining. Typical DNA Ladder was also observed by agarose gel electrophoresis in the administration group, but it did not exist in the control group. Western blot showed that the expression of Bax was up-regulated and Bcl-2 was down-regulated. CONCLUSION: Above data demonstrates that PE can induce apoptosis in human hepatoma HepG2 cells, and indicate that PE-induced expression level changes of Bax and Bcl2 may be related to the apoptosis-induction effect.

[Preliminary study on mechanisms of total saponins from Entada phaseoloides against diabetes].

OBJECTIVE: To study the effect of total saponins from Entada phaseoloides (TSEP) on islet morphology and skeletal muscle PI3K pathway-related protein expression of type 2 diabetic rats. METHOD: Type 2 diabetic rats were induced by high-fat diet and low-dose streptozotocin and then randomly divided into 5 groups, i.e. the normal control, the model group, the positive control drug (200 mg x kg(-1) metformin), the low-dose TSEP (25 mg x kg(-1)) group and the high-dose TSEP (50 mg x kg(-1)). Three weeks later, the islet morphology of rat pancreas were observed by HE staining, and protein expressions of insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3-kinase (PI3K), protein tyrosine phosphatase-1B (PTP-1 B) and glucose transporter 4 (GLUT4) in rat skeletal muscle were detected by Western blot. RESULT: Compared with the modal group, TSEP administration groups showed relatively normal structures, clear pancreatic cells and intact capsula structures in pancreatic tissue pathological sections, with the number of pancreatic islets close to the normal control group. Meanwhile, above TSEP administration groups showed increased IRS-1, PI3K and GLUT4 protein expressions in their skeletal muscle tissues and decreased PTP-1B protein expression compared with the model group. CONCLUSION: TSEP has an effect on protecting pancreatic tissues of type 2 diabetic rats and intervening in abnormal expression of proteins in skeletal muscle tissues.

Antidiabetic effect of total saponins from Entada phaseoloides (L.) Merr. in type 2 diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The seed of Entada phaseoloides (L.) Merr. (Entada phaseoloides) has been long used as an effective herb for the treatment of Diabetes mellitus by Dai people, one of the Chinese ethnic minorities. Saponin is an abundant type of secondary metabolic products in the seed of this plant. The aim of this study is to evaluate the potential therapeutic effects of total saponins from Entada phaseoloides (TSEP) in experimental type 2 Diabetes mellitus (T2DM) rats. MATERIALS AND METHODS: T2DM rats were induced by high-fat diet and low-dose streptozotocin (STZ). Then different oral doses of TSEP (25, 50 and 100 mg/kg) were administrated to T2DM rats for 21 days. For comparison, a standard antidiabetic drug, metformin (200 mg/kg), was used as a positive control drug. Then the relative biochemical analysis and histopathological examination were made to evaluate the antidiabetic effect of TSEP. RESULTS: TSEP dramatically reduced fasted blood glucose and serum insulin levels and alleviates hyperglycemia associated oxidative stress in T2DM rats. Moreover, a significantly hypolipidemic effect and an improvement in tissue steatosis could be observed after TSEP administration. Further investigations revealed a possible anti-inflammation effect of TSEP by examining serum levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and C-reactive protein (CRP). The effects of TSEP exhibited a dose-dependent manner and were comparable to metformin. CONCLUSION: Our present study demonstrates both hypoglycemic and hypolipidemic activities of TSEP in T2DM rats, which support its antidiabetic property. This work also implies a possibility that TSEP exerts its therapeutic effect through repressing chronic inflammation responses.