[Simultaneous determination of eleven components in Ginkgo biloba leaves by high performance liquid chromatography method].

To study Ginkgo biloba leaves in different producing area, we establish an HPLC method for the simultaneously determination of seven flavonoids glycosides and four biflavonoids in G. biloba leaves. The analysis was performed on an Agilent ZORBAX SB-C18 column(4.6 mm×250 mm, 5 µm) wich acetonitrile, and 0.4% phosphoric acid as mobile phase at flow rate of 1 mL•min⁻¹ in a gradient edution, and the detection was carried out at 254 nm.The calibration curves of the seven flavonoids glycosides and four biflavonoids had a good linearitiy with good recoveries. The established HPLC method is simple, rapid, accurate, reliable, and sensitive, and can be applied to the identification and quality control of G. biloba leaves.

[Simultaneous determination of thirteen components in Tong'an injection by LC-MS/MS].

The aim of this study was to develop a simple, sensitive ultra performance liquid chromatography mass spectrometry (UPLC-MS/MS) method for the determination of syringaresinol, N-trans-feruloyltyramine, chelerythrine chloride, sinomenine, coptisine chloride, sanguinarine, chelidonine, magnolflorine, allocryptopine, protopine, farrerol, stylopine and dihydrosanguin-arine in Tong'an injection (TAI), which could be used for the quality control of TAI. The UPLC analysis was performed on Agilent Zorbax SB-Aq column (2.1 mm×150 mm,3.5 µm), with 0.1% formic acid solution (A) -acetonitrile (B) as the mobile phase for gradient elution (0.01-2 min, 5%B; 2-8 min, 5%-30%B; 8-11 min, 30%-95%B; 11-13 min, 95%B; 13-13.1 min, 95%-5%B; 13.1-14 min, 5%B). The flow rate was 0.5 mL•min⁻¹, and the column temperature was 25 ℃; multiple reaction monitoring (MRM) was performed in electrospray ion source positive ion mode for quantitative determination. The calibration curves for the above thirteen compounds showed good linear relationship in corresponding mass concentration range (r>0.999 0). The average recovery rate of the compounds ranged from 95.70% to 104.8%, with RSD of less than 1.9%. The contents of thirteen active components in 10 batches of TAI were 0.021 2-0.029 0, 0.001 7-0.002 3, 0.000 9-0.001 3, 5.952-6.205 2, 0.195 4-0.240 5, 0.002 0-0.002 9, 0.693-0.798 2, 0.069 3-0.078 2, 0.089 29-0.102 9, 0.386 5-0.420 1, 0.014 3-0.015 9, 0.755 3-0.842 1, and 0.008 2-0.011 2 g•L⁻¹ respectively. Methodology validation proved that this method was simple, rapid, sensitive and accurate, which can be used to provide reference for the comprehensive evaluation of TAI quality. The determination results of 10 batches of TAI showed the content of each batch had no significant difference. The results may provide a basis for the quality control of TAI.

[Effect of rat intestinal flora on in vitro metabolic transformation of pumiloside].

To study the metabolic transformation of pumiloside by rat intestinal flora in vitro and identify its metabolites. Pumiloside was incubated in the rat intestinal flora in vitro. HPLC was used to monitor the metabolic process, and HPLC-Q-TOF-MS was used to identify the structures of biotransformation products. In vitro, pumiloside was easily metabolized by rat intestinal flora, and with the prolongation of metabolic time, pumiloside was transformed into several metabolites. Three metabolites were initially identified in this experiment. The study indicated that pumiloside could be extensively metabolized in the rat intestinal flora in vitro.

[Traditional Chinese medicine pairs (III)--effect of extract of Ginseng Radix et Rhizoma and Puerariae Lobatae Radix on intestinal absorption in rats].

This study focused on the intestinal absorption of traditional Chinese medicines (TCM) to reveal the scientific connotation of the compatibility of TCM pairs. The single pass intestinal perfusion (SPIP) was used in rats to compare the absorption of single extracts from Puerariae Lobatae Radix, single extracts from Ginseng Radix et Rhizoma, combined extracts from Puerariae Lobatae Radix and Ginseng Radix et Rhizoma and Puerariae Lobatae Radix and Ginseng Radix et Rhizoma mixture in rats. The content of puerarin, ginsenoside Rg1, ginsenoside Re and ginsenoside Rb1 in liquid were tested by HPLC. The speed constant (Ka) and apparent permeability coefficients (Papp) were calculated and compared. Specifically, the order of puerarin Ka and Papp values from high to low was Ginseng Radix et Rhizoma and Puerariae Lobatae Radix mixture > single extracts from Puerariae Lobatae Radix > combined extracts from Ginseng Radix et Rhizoma and Puerariae Lobatae Radix; the order of ginsenosides Ka and Papp values from high to low was Ginseng Radix et Rhizoma and Puerariae Lobatae Radix mixture > single extracts from Ginseng Radix et Rhizoma > combined extracts from Ginseng Radix et Rhizoma and Puerariae Lobatae Radix. The combined administration of Ginseng Radix et Rhizoma and Puerariae Lobatae Radix may improve the absorption in the intestinal tract.

Boosting oxygen evolution by nickel nitrate hydroxide with abundant grain boundaries via segregated high-valence molybdenum.

High-valence metal doping and abundant grain boundaries (GBs) have been proved to be effective strategies to promote the oxygen evolution reaction (OER). However, the reasonable design of the two to facilitate OER collaboratively is challenging. Herein, a convenient and novel one-step molten salt decomposition strategy is proposed to fabricate segregated-Mo doped nickle nitrate hydroxide with substantial GBs on MoNi foam (Mo-NNOH@MNF). When processed in molten salt, the Mo species on the conductive substrate migrates unevenly to the surface of Mo-NNOH@MNF, which not only induces the formation of abundant GBs to modulate electronic structure, but also improves the intrinsic activity as high-valence dopants, synergistically elevating OER activity. As verification, the optimized Mo-NNOH@MNF-10h exhibits low overpotential of 150 mV at 10 mA cm-2, which can be attributed to the reduced valence charge transition energy of Ni by high-valence Mo dopant, coupled with the fine-tuning of d-band center bond and corresponding local electron density by induced GBs and Mo doping, as DFT calculations revealed. Moreover, the intrinsic robustness and strong adhesion ensure the long-term stability of 6 h at 500 mA cm-2. This work provides a promising molten salt decomposition approach to synthesize advanced materials with unique structures.

Promoting Oxygen Evolution by Deep Reconstruction via Dynamic Migration of Fluorine Anions.

Promoting the reconstruction of electrocatalysts during the oxygen evolution reaction (OER) is generally regarded as a promising strategy for enhanced activity. F anions with strong electronegativity are predicted to enhance this transformation. Herein, a fluorine-anion doping route is proposed to convert the well-latticed NiMoO4@MNF to amorphous F-NiMoO4@MNF by a facile and versatile molten salt strategy. The well-defined nanorod arrays guarantee abundant exposed active sites, rapid mass transfer, and fast gas bubble release. Moreover, the emerged loose amorphous structure is conducive to the dynamic migration of F species and effective penetration of the electrolyte; therefore, the resulting exchange between F and hydroxide anions induces the formation of an active oxy(hydroxide) layer, thus finally optimizing the electronic structure and absorption/desorption energy on the surface of F-NiMoO4@MNF. The boosted OER performance of reconstructed F-NiMoO4@MNF is reliably confirmed by a low overpotential of 188 mV at 50 mA cm-2, a small Tafel slope of 33.8 mV dec-1, and favorable long-term stability. In addition, accelerated hydrogen evolution is observed, which is ascribed to the finely tuned electron distribution. This work would provide a new reconstruction route assisted by F-anion doping to the development of high-performance catalysts.

Ultrahigh activity of molybdenum/vanadium-doped Ni-Co phosphides nanoneedles based on ion-exchange for hydrogen evolution at large current density.

Heteroatom doping is a promising strategy to optimize the electronic structure of transition metal phosphides so enhancing the hydrogen evolution reaction (HER). However, complex and harsh experimental design is often required to achieve homogeneous doping of corresponding elements while achieving the best regulating effect. Herein, a facile ion-exchange (IE) strategy is applied to dope Mo/V species evenly into Ni-Co phosphides under mild conditions while maintaining the nanoneedle morphology. The electrochemical characterization verifies Mo dopants have a better electronic regulation effect on NiCoP crystal than V dopants, corresponding to the better hydrogen evolution performance of Mo-NiCoP/NF. Notably, due to the highly dispersed nanoneedle morphology, the synergistic effect of Ni-Co phosphides, and the optimized electronic structure, Mo-NiCoP/NF demonstrates a higher activity than that of the noble metal Pt/C at the high current density (>99 mA cm-2). The present work is supposed to open new sights for the development of high-performance catalysts by ion-exchange strategy.

Two new estertin modified tungstosilicates: synthesis, catalytic activity and photoelectrochemical property.

Two new tungstosilicates (C(NH2)3)5KNa2H3[Sn(CH2CH2COOCH3)Co(H2O)2Si2W19O69]·10H2O (Si2W19-Co-SnRCOOCH3) and (C(NH2)3)5KNa2H3[Sn(CH2CH2COOCH3)Mn(H2O)2Si2W19O69]·13H2O (Si2W19-Mn-SnRCOOCH3) modified by organometal (OM) and transition metal (TM) ions were obtained, and they were self-assembled from mono-TM-containing (TM = Co, Mn) γ-[SiW10O35]6- (γ-SiW10)-based dimeric tungstosilicate and estertin Cl3SnCH2CH2COOCH3 in an acetate buffer solution, respectively. Their structures were determined with a series of physico-chemical and spectroscopic methods including X-ray crystallography, XRPD, etc. The estertin functional position in the tungstosilicate skeleton was analyzed by theoretical calculations using density functional theory (DFT). These two compounds have good catalytic activity for the oxidation of cyclohexanol to cyclohexanone. Meanwhile, they were composited with TiO2 using a facial layer-by-layer (LBL) method. The assembled composite films {Si2W19-TM-SnRCOOCH3/TiO2}n (TM = Co, Mn; n is the bilayer number, n = 1-6) exhibit efficient photoelectrocatalytic activity for the oxidation of methanol under irradiation of 100 mW cm-2 using a Xe lamp as a light source. And the {Si2W19-Co-SnRCOOCH3/TiO2}4 film produces the highest photocurrent among the composite films studied in this work. Combining the dark current measurement, surface photovoltage spectroscopy (SPV) and electrochemical impedance spectroscopy (EIS), the enhanced photoelectrocatalytic activity of {Si2W19-Co-SnRCOOCH3/TiO2}4 composite film for the oxidation of methanol is attributed to the suppressed electron-hole recombination, increased carrier separation efficiency and interfacial charge transfer.

Two new labdane diterpenoids from aerial parts of Leonurus japonicus and their anti-inflammatory activity.

Two new labdane diterpenoids, Leojaponin E (1) and F (2), together with three known compounds were isolated from the dried herb of Leonurus japonicus Houtt., Lamiaceae. Their structures were determined based on extensive spectroscopic analyses. The absolute configurations of 1 and 2 were elucidated on the basis of experimental and calculated electronic circular dichroism spectra. In addition, compounds 1 and 2 exerted inhibition of LPS-induced PGE2 production in a dose-dependent manner at concentrations ranging from 5 to 20 µM.

Transformation of strictosamide to vincoside lactam by acid catalysis.

AIM: To identify the structure of the acid-catalyzed product of strictosamide and explore the reaction mechanism. METHODS: The acid-catalyzed reaction process of strictosamide was monitored by HPLC, and a macroporous resin was used to purify the reaction solution. The structure of the product was confirmed by MS, NMR, and ROESY spectra. RESULTS: The acid-catalyzed transformation yield from strictosamide to vincoside lactam was 52%. CONCLUSION: The reaction mechanism of the transformation from strictosamide to vincoside lactam may be related to the stability of the three-dimensional configuration of the compound. These results offer a new way to obtain vincoside lactam from the widely distributed indole alkaloid strictosamide by acid-catalysis.