Quantitative analysis of two isoflavones in Pueraria lobata flowers from eleven Chinese provinces using high performance liquid chromatography

<p>Abstract</p> <p>Background</p> <p><it>Pueraria lobata </it>flower (<it>Gehua</it>) is a medicinal herb to treat intoxication, hepatic and gastrointestinal tract lesion induced by alcohol. This study aims to develop a new HPLC method for the determination of two major isoflavones in <it>P. lobata </it>flowers, namely tectoridin and 6"-O-xylosyl-tectoridin.</p> <p>Methods</p> <p>A high performance liquid chromatography (HPLC) method with a C₁₈column (250 mm × 4.6 mm, 5 μm) was developed for the quantitative analysis of tectoridin and 6"-O-xylosyl-tectoridin, the main isoflavone components in <it>P. lobata </it>flower. A simple gradient of acetonitrile/water (0 min 15:85; 35 min 50:50; 36 min 15:85; 40 min 15:85; v/v) was used, and 265 nm was selected as detection wavelength. Tectoridin and 6"-O-xylosyl-tectoridin were used as the external standards in quality control of <it>P. lobata </it>flower for the first time. The method was applied to practical use in quality assessment of eleven batches of <it>P. lobata </it>flower samples in Chinese herbal medicine market.</p> <p>Results</p> <p>The peak area response was linear for tectoridin in the 11.8-236.4 μg/mL range with a correlation coefficient of 0.9996 (P < 0.001), and for 6"-O-xylosyl-tectoridin in the 10.33-185.99 μg/mL range with a correlation coefficient of 0.9984 (P < 0.001) respectively. The average recoveries were 102.7-103.7% for tectoridin and 95.7-103.2% for 6"-O-xylosyl-tectoridin (RSDs < 3%), and the intra-day and inter-day RSDs of the two components were less than 2%. This HPLC method was applied to assess the quality of <it>P. lobata </it>flower from eleven provinces in China. <it>P. lobata </it>flowers from northern China contained 26.46-43.28 mg/g of tectoridin and 30.90-48.23 mg/g of 6"-O-xylosyl-tectoridin comparing to 10.00-19.81 mg/g of tectoridin and 11.08-37.03 mg/g of 6"-O-xylosyl-tectoridin in those from southern China.</p> <p>Conclusion</p> <p>The results showed that <it>P. lobata </it>flowers from northern China contained more tectoridin and 6"-O-xylosyl-tectoridin than those from southern China.</p

Grouping, spectrum-effect relationship and antioxidant compounds of Chinese propolis from different regions using multivariate analyses and off-line anti-DPPH assay

49 samples of propolis from different regions in China were collected and analyzed for their chemical compositions, contents of total flavonoids (TFC), total phenolic acid (TPC) and antioxidant activity. High-performance liquid chromatography (HPLC) analysis identified 15 common components, including key marker compounds pinocembrin, 3-O-acetylpinobanksin, galangin, chrysin, benzyl p-coumarate, pinobanksin and caffeic acid phenethyl ester (CAPE). Cluster analysis (CA) and correlation coefficients (CC) analysis showed that these propolis could be divided into three distinct groups. Principal component analysis (PCA) and multiple linear regression analysis (MLRA) revealed that the contents of isoferulic acid, caffeic acid, CAPE, 3,4-dimethoxycinnamic acid, chrysin and apigenin are closely related to the antioxidant properties of propolis. In addition, eight peak areas decreased after reacting with 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals, indicating that these compounds have antioxidant activity. The results indicate that the grouping and spectrum-effect relationship of Chinese propolis are related to their chemical compositions, and several compounds may serve as a better marker for the antioxidant activity of Chinese propolis than TFC and TPC. The findings may help to develop better methods to evaluate the quality of propolis from different geographic origins

Attenuation of methylglyoxal-induced glycation and cellular dysfunction in wound healing by Centella cordifolia

Current pre-clinical evidences of Centella focus on its pharmacological effects on normal wound healing but there are limited studies on the bioactivity of Centella in cellular dysfunction associated with diabetic wounds. Hence we planned to examine the potential of Centella cordifolia in inhibiting methylglyoxal (MGO)-induced extracellular matrix (ECM) glycation and promoting the related cellular functions. A Cell-ECM adhesion assay examined the ECM glycation induced by MGO. Different cell types that contribute to the healing process (fibroblasts, keratinocytes and endothelial cells) were evaluated for their ability to adhere to the glycated ECM. Methanolic extract of Centella species was prepared and partitioned to yield different solvent fractions which were further analysed by high performance liquid chromatography equipped with photodiode array detector (HPLC-PDA) method. Based on the antioxidant [2,2-diphenyl-1-picrylhydrazyl (DPPH) assay] screening, anti-glycation activity and total phenolic content (TPC) of the different Centella species and fractions, the ethyl acetate fraction of C. cordifolia was selected for further investigating its ability to inhibit MGO-induced ECM glycation and promote cellular distribution and adhesion. Out of the three Centella species (C. asiatica, C. cordifolia and C. erecta), the methanolic extract of C. cordifolia showed maximum inhibition of Advanced glycation end products (AGE) fluorescence (20.20 ± 4.69 %, 25.00 ± 3.58 % and 16.18 ± 1.40 %, respectively). Its ethyl acetate fraction was enriched with phenolic compounds (3.91 ± 0.12 mg CAE/μg fraction) and showed strong antioxidant (59.95 ± 7.18 μM TE/μg fraction) and antiglycation activities. Improvement of cells spreading and adhesion of endothelial cells, fibroblasts and keratinocytes was observed for ethyl acetate treated MGO-glycated extracellular matrix. Significant reduction in attachment capacity of EA.hy926 cells seeded on MGO-glycated fibronectin (41.2%) and attachment reduction of NIH3t3 and HaCaT cells seeded on MGO-glycated collagen (33.7% and 24.1%, respectively) were observed. Our findings demonstrate that ethyl acetate fraction of C. cordifolia was effective in attenuating MGO-induced glycation and cellular dysfunction in the in-vitro wound healing models suggesting that C. cordifolia could be a potential candidate for diabetic wound healing. It could be subjected for further isolation of new phytoconstituents having potential diabetic wound healing properties

CHANG-ES VI: Probing Supernova Energy Deposition in Spiral Galaxies Through Multi-Wavelength Relationships

How a galaxy regulates its SNe energy into different interstellar/circumgalactic medium components strongly affects galaxy evolution. Based on the JVLA D-configuration C- (6 GHz) and L-band (1.6 GHz) continuum observations, we perform statistical analysis comparing multi-wavelength properties of the CHANG-ES galaxies. The high-quality JVLA data and edge-on orientation enable us for the first time to include the halo into the energy budget for a complete radio-flux-limited sample. We find tight correlations of $L_{\rm radio}$ with the mid-IR-based SFR. The normalization of our $I_{\rm 1.6GHz}/{\rm W~Hz^{-1}}-{\rm SFR}$ relation is $\sim$2-3 times of those obtained for face-on galaxies, probably a result of enhanced IR extinction at high inclination. We also find tight correlations between $L_{\rm radio}$ and the SNe energy injection rate $\dot{E}_{\rm SN(Ia+CC)}$, indicating the energy loss via synchrotron radio continuum accounts for $\sim0.1\%$ of $\dot{E}_{\rm SN}$, comparable to the energy contained in CR electrons. The integrated C-to-L-band spectral index is $\alpha\sim0.5-1.1$ for non-AGN galaxies, indicating a dominance by the diffuse synchrotron component. The low-scatter $L_{\rm radio}-{\rm SFR}$/$L_{\rm radio}-\dot{E}_{\rm SN (Ia+CC)}$ relationships have super-linear logarithmic slopes at $\sim2~\sigma$ in L-band ($1.132\pm0.067$/$1.175\pm0.102$) while consistent with linear in C-band ($1.057\pm0.075$/$1.100\pm0.123$). The super-linearity could be naturally reproduced with non-calorimeter models for galaxy disks. Using Chandra halo X-ray measurements, we find sub-linear $L_{\rm X}-L_{\rm radio}$ relations. These results indicate that the observed radio halo of a starburst galaxy is close to electron calorimeter, and a galaxy with higher SFR tends to distribute an increased fraction of SNe energy into radio emission (than X-ray).Comment: 16 pages, 6 figures, 1 table, MNRAS in pres

Conductivity of Strongly Coupled Striped Superconductor

We study the conductivity of a strongly coupled striped superconductor using gauge/gravity duality (holography). The study is done analytically, in the large modulation regime. We show that the optical conductivity is inhomogeneous but isotropic at low temperatures. Near but below the critical temperature, we calculate the conductivity analytically at small frequency \omega, and find it to be both inhomogeneous and anisotropic. The anisotropy is imaginary and scales like 1/\omega. We also calculate analytically the speed of the second sound and the thermodynamic susceptibility.Comment: 32 page

Fluid and Diffusion Limits for Bike Sharing Systems

Bike sharing systems have rapidly developed around the world, and they are served as a promising strategy to improve urban traffic congestion and to decrease polluting gas emissions. So far performance analysis of bike sharing systems always exists many difficulties and challenges under some more general factors. In this paper, a more general large-scale bike sharing system is discussed by means of heavy traffic approximation of multiclass closed queueing networks with non-exponential factors. Based on this, the fluid scaled equations and the diffusion scaled equations are established by means of the numbers of bikes both at the stations and on the roads, respectively. Furthermore, the scaling processes for the numbers of bikes both at the stations and on the roads are proved to converge in distribution to a semimartingale reflecting Brownian motion (SRBM) in a $N^{2}$-dimensional box, and also the fluid and diffusion limit theorems are obtained. Furthermore, performance analysis of the bike sharing system is provided. Thus the results and methodology of this paper provide new highlight in the study of more general large-scale bike sharing systems.Comment: 34 pages, 1 figure

CHANG-ES XI: Circular Polarization in the Cores of Nearby Galaxies

We detect 5 galaxies in the CHANG-ES (Continuum Halos in Nearby Galaxies -- an EVLA Survey) sample that show circular polarization (CP) at L-band in our high resolution data sets. Two of the galaxies (NGC~4388 and NGC~4845) show strong Stokes $V/I\,\equiv\,m_C\,\sim\,2$\%, two (NGC~660 and NGC~3628) have values of $m_C\sim \,0.3$\%, and NGC~3079 is a marginal detection at $m_C\sim \,0.2$\%. The two strongest $m_C$ galaxies also have the most luminous X-ray cores and the strongest internal absorption in X-rays. We have expanded on our previous Faraday conversion interpretation and analysis and provide analytical expressions for the expected $V$ signal for a general case in which the cosmic ray electron energy spectral index can take on any value. We provide examples as to how such expressions could be used to estimate magnetic field strengths and the lower energy cutoff for CR electrons. Four out of our detections are {\it resolved}, showing unique structures, including a {\it jet} in NGC~4388 and a CP `conversion disk' in NGC~4845. The conversion disk is inclined to the galactic disk but is perpendicular to a possible outflow direction. Such CP structures have never before been seen in any galaxy to our knowledge. None of the galaxy cores show linear polarization at L-band. Thus CP may provide a unique probe of physical conditions deep into radio AGNs.Comment: 30 pages, 4 figures, accepted to MNRA

CHANG-ES IV: Radio continuum emission of 35 edge-on galaxies observed with the Karl G. Jansky Very Large Array in D-configuration, Data Release 1

We present the first part of the observations made for the Continuum Halos in Nearby Galaxies, an EVLA Survey (CHANG-ES) project. The aim of the CHANG-ES project is to study and characterize the nature of radio halos, their prevalence as well as their magnetic fields, and the cosmic rays illuminating these fields. This paper reports observations with the compact D configuration of the Karl G. Jansky Very Large Array (VLA) for the sample of 35 nearby edge-on galaxies of CHANG-ES. With the new wide bandwidth capabilities of the VLA, an unprecedented sensitivity was achieved for all polarization products. The beam resolution is an average of 9.6" and 36" with noise levels reaching approximately 6 and 30 microJy per beam for C- and L-bands, respectively (robust weighting). We present intensity maps in these two frequency bands (C and L), with different weightings, as well as spectral index maps, polarization maps, and new measurements of star formation rates (SFRs). The data products described herein are available to the public in the CHANG-ES data release available at www.queensu.ca/changes. We also present evidence of a trend among galaxies with larger halos having higher SFR surface density, and we show, for the first time, a radio continuum image of the median galaxy, taking advantage of the collective signal-to-noise ratio of 30 of our galaxies. This image shows clearly that a typical spiral galaxy is surrounded by a halo of magnetic fields and cosmic rays.Comment: 70 pages, of which 35 pages present the data of each galax

Medium effect on photon production in ultrarelativistic nuclear collisions

The effect of in-medium vector and axial-vector meson masses on photon production is studied. We assume that the effective mass of a vector meson in hot nuclear matter decreases according to a universal scaling law, while that of an axial-vector meson is given by Weinberg's mass formula. We find that the thermal production rate of photons increases with reduced masses, and is enhanced by an order of magnitude at T=160 MeV with $m_\rho=300$ MeV. Assuming a hydrodynamic evolution, we estimate the effect of the reduced masses on photon production in nucleus-nucleus collisions. The result is compared to experimental data from the WA80/WA98 collaboration.Comment: 21 pages, REVTEX + 9 figures (ps file