Simultaneous determination of eight major bioactive compounds in Dachengqi Tang (DT) by high-performance liquid chromatography

<p>Abstract</p> <p>Background</p> <p><it>Dachengqi Tang </it>(DT) is a common traditional Chinese medicine formula for expelling <it>neire </it>('internal heat') in the stomach and intestines. There was no reliable analytical method available for the quality control of DT.</p> <p>Methods</p> <p>A high-performance liquid chromatography (HPLC) method with a reverse phase C₁₈column (150 × 4.6 mm) was developed. The mobile phase was methanol with 0.2% acetic acid. Eight markers including naringin, hesperidin, aloe emodin, rhein, honokiol, magnolol, emodin and chrysophanol were determined.</p> <p>Results</p> <p>Regression analysis revealed a linear relationship between the concentrations of the markers and the peak area ratio of the standards and internal standard. The limit of detection (S/N = 3) and the limit of qualification (RSD < 20%) ranged from 0.21 to 0.43 ng/μl and 0.76 to 1.74 ng/μl respectively. The recovery was between 95.6% and 103.4%. The tests on the samples from three batches of DT showed that the profiles of the markers did not vary significantly among batches.</p> <p>Conclusion</p> <p>A reliable HPLC method for simultaneous determination of the eight markers in DT was developed.</p

A chromatogram of pure standards: (1) naringin, (2) hesperidin (3) aloe emodin, (4) rhein, (5) honokiol, (6) magnolol, (7) emodin, (8) chrysophanol and the internal standard (IS), 1, 8-dihydroxyanthraquinone

Simultaneous determination of eight markers: (1) naringin, (2) hesperidin (3) aloe emodin, (4) rhein, (5) honokiol, (6) magnolol, (7) emodin, (8) chrysophanol and the internal standard (IS), 1, 8-dihydroxyanthraquinone, in a Dachengqi Tang sample.<p><b>Copyright information:</b></p><p>Taken from "Simultaneous determination of eight major bioactive compounds in Dachengqi Tang (DT) by high-performance liquid chromatography"</p><p>http://www.cmjournal.org/content/3/1/5</p><p>Chinese Medicine 2008;3():5-5.</p><p>Published online 29 Apr 2008</p><p>PMCID:PMC2383911.</p><p></p

Construction of High Tg Bipolar Host Materials with Balanced Electron–Hole Mobility Based on 1,2,4-Thiadiazole for Phosphorescent Organic Light-Emitting Diodes

A novel electron-transporting moiety, 1,2,4-thiadiazole, was first introduced to construct bipolar host molecules for phosphorescent organic light-emitting diodes (PhOLEDs). By incorporating 1,2,4-thiadiazole with typical hole-transporting carbazole moieties, a series of thiadiazole/carbazole hybrids, <i><b>o</b></i><b>-CzTHZ</b>, <i><b>m</b></i><b>-CzTHZ</b>, and <i><b>p</b></i><b>-CzTHZ</b>, were synthesized. All the hybrids exhibit very high glass transition temperatures (<i>T</i>_g ≥ 167 °C) and show good thermal and morphological stability in films. Moreover, these host materials possess good bipolar charge transporting properties; electron and hole mobilities of these bipolar thiadiazole/carbazole hybrids can be tuned by simply adjusting the linkage modes between thiadiazole and carbazole moieties. The maximum external quantum efficiencies (<i>η</i>_EQE, max) in the green PhOLEDs with <i><b>o</b></i><b>-CzTHZ</b>, <i><b>m</b></i><b>-CzTHZ</b>, and <i><b>p</b></i><b>-CzTHZ</b> as the hosts reached 26.1%, 24.0%, and 22.9%, respectively, and their EQE were still over 20% even at the high luminance of 10,000 cd/m². This study demonstrates that 1,2,4-thiadiazole should be an excellent electron-transporting unit for bipolar phosphorescent hosts

Programmable dual responsive system reconstructing nerve interaction with small-diameter tissue-engineered vascular grafts and inhibiting intimal hyperplasia in diabetes

Small-diameter tissue-engineered vascular grafts (sdTEVGs) with hyperglycemia resistance have not been constructed. The intimal hyperplasia caused by hyperglycemia remains problem to hinder the patency of sdTEVGs. Here, inspired by bionic regulation of nerve on vascular, we found the released neural exosomes could inhibit the abnormal phenotype transformation of vascular smooth muscle cells (VSMCs). The transformation was a prime culprit causing the intimal hyperplasia of sdTEVGs. To address this concern, sdTEVGs were modified with an on-demand programmable dual-responsive system of ultrathin hydrogels. An external primary Reactive Oxygen Species (ROS)-responsive Netrin-1 system was initially triggered by local inflammation to induce nerve remolding of the sdTEVGs overcoming the difficulty of nerve regeneration under hyperglycemia. Then, the internal secondary ATP-responsive DENND1A (guanine nucleotide exchange factor) system was turned on by the neurotransmitter ATP from the immigrated nerve fibers to stimulate effective release of neural exosomes. The results showed nerve fibers grow into the sdTEVGs in diabetic rats 30 days after transplantation. At day 90, the abnormal VSMCs phenotype was not detected in the sdTEVGs, which maintained long-time patency without intima hyperplasia. Our study provides new insights to construct vascular grafts resisting hyperglycemia damage