共查询到16条相似文献,搜索用时 15 毫秒
1.
2.
Identification of some Bioactive Metabolites in a Fractionated Methanol Extract from Ipomoea aquatica (Aerial Parts) through TLC,HPLC, UPLC‐ESI‐QTOF‐MS and LC‐SPE‐NMR Fingerprints Analyses 下载免费PDF全文
Mahmoud Hefny Gad Emmy Tuenter Nagwa El‐Sawi Sabry Younes El‐Mewafy El‐Ghadban Kristiaan Demeyer Luc Pieters Yvan Vander Heyden Debby Mangelings 《Phytochemical analysis : PCA》2018,29(1):5-15
Introduction
The plant species Ipomoea aquatica contains various bioactive constituents, e.g. phenols and flavonoids, which have several medical uses. All previous studies were executed in Asia; however, no reports are available from Africa, and the secondary metabolites of this plant species from Africa are still unknown.Objective
The present study aims finding suitable conditions to identify the bioactive compounds from different fractions.Methodology
Chromatographic fingerprint profiles of different fractions were developed using high‐performance liquid chromatography (HPLC) and then these conditions were transferred to thin‐layer chromatography (TLC). Subsequently, the chemical structure of some bioactive compounds was elucidated using ultra‐performance liquid chromatography‐quadrupole time of flight‐tandem mass spectrometry (UPLC‐QTOF‐MS) and liquid chromatography‐solid phase extraction‐nuclear magnetic resonance (LC‐SPE‐NMR) spectroscopy.Results
The HPLC fingerprints, developed on two coupled Chromolith RP‐18e columns, using a gradient mobile phase (methanol/water/trifluoroacetic acid, 5:95:0.05, v/v/v), showed more peaks than the TLC profile. The TLC fingerprint allows the identification of the types of chemical constituents, e.g. flavonoids. Two flavonoids (nicotiflorin and ramnazin‐3‐O‐rutinoside) and two phenolic compounds (dihydroxybenzoic acid pentoside and di‐pentoside) were tentatively identified by QTOF‐MS, while NMR confirmed the structure of rutin and nicotiflorin.Conclusion
The HPLC and TLC results showed that HPLC fingerprints give more and better separated peaks, but TLC helped in determining the class of the active compounds in some fractions. Bioactive constituents were identified as well using MS and NMR analyses. Two flavonoids and two phenolic compounds were tentatively identified in this species for the first time, to the best of our knowledge. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献3.
4.
5.
6.
Simultaneous Qualitative and Quantitative Analyses of Triterpenoids in Ilex pubescens by Ultra‐High‐Performance Liquid Chromatography Coupled with Quadrupole Time‐of‐Flight Mass Spectrometry 下载免费PDF全文
Jing Jin Maosong Qiu Lian Zhou Xinghong Zhou Hui Li Zhongxiang Zhao 《Phytochemical analysis : PCA》2018,29(2):168-179
7.
8.
Simultaneous Determination of Four Triterpenoid Saponins in Aralia elata Leaves by HPLC‐ELSD Combined with Hierarchical Clustering Analysis 下载免费PDF全文
Yichun Sun Baimei Li Xiaoting Lin Juan Xue Zhibin Wang Hongwei Zhang Hai Jiang Qiuhong Wang Haixue Kuang 《Phytochemical analysis : PCA》2017,28(3):202-209
9.
10.
11.
Dereplication by HPLC‐DAD‐ESI‐MS/MS and Screening for Biological Activities of Byrsonima Species (Malpighiaceae) 下载免费PDF全文
Karina Fraige Alessandra Cristina Dametto Maria Luiza Zeraik Larissa de Freitas Amanda Correia Saraiva Alexandra Ivo Medeiros Ian Castro‐Gamboa Alberto José Cavalheiro Dulce Helena S. Silva Norberto Peporine Lopes Vanderlan S. Bolzani 《Phytochemical analysis : PCA》2018,29(2):196-204
12.
An advanced and reliable HPLC-MS method was developed for the simultaneous quantification of eight active components (ginsenosides Rf, Rg(2), Rg(3), Rh(1) and Rh(2), gomisin A, methylophioponanone B and schizandrin) in Sheng-Mai San, a traditional Chinese medicine. The elution of multiple components was performed using a C(18) column with stepwise gradient elution. The detection of individual analytes was monitored by electrospray MS scanning from 300 to 1000 m/z in the positive ion mode, with the limits of detection of these components ranging from 0.06 to 1 microg/mL at a signal-to-noise ratio of > or =5. The intra- and inter-day accuracies ranged from 95.1 to 104.4%, and the overall precision was less than 9.3%. The recoveries of the analytes were > or =96.6%. The method was validated and found suitable for the determination of active components present in Sheng-Mai San preparation. 相似文献
13.
Gerd Rippin 《Biometrical journal. Biometrische Zeitschrift》2000,42(7):887-894
When a case‐control study is planned to include an internal validation study, the sample size of the study and the proportion of validated observations has to be calculated. There are a variety of alternative methods to accomplish this. In this article some possible procedures will be compared in order to clarify whether considerable differences in the suggested optimal designs occur, dependent on the used method. 相似文献
14.
Yingfeng Du Yiran Jin Pengwei Liu Xiaowei Zhang Xiaona Sheng Xiaowei Shi Qiao Wang Lantong Zhang 《Phytochemical analysis : PCA》2010,21(5):416-427
Introduction – Isodon nervosa is a commonly used traditional Chinese medicine including diterpenoids, phenolic acids, triterpenoids and volatile oil. Qualitative and quantitative analysis of multi‐components is important for its quality control. Objective – To establish a liquid chromatography–electrospray ionisation–mass spectrometry method for simultaneous analysis of 20 bioactive constituents of Isodon nervosa in different places of China and different parts of this herb. Methodology – The optimal chromatographic conditions were achieved on a C18 column (250 × 4.6 mm, 5 µm) with with linear gradient elution with 0.1% aqueous formic acid : methanol containing 0.1% formic acid at a flow‐rate of 0.7 mL/min in 15 min. The identification and quantification of those analytes were achieved on a hybrid quadrupole linear ion trap mass spectrometer. Multiple‐reaction monitoring scanning was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run. Full validation of the method was carried out (linearity, precision, accuracy, limit of detection and limit of quantification). Results – The results indicated that the method was simple, rapid, specific and reliable. The proposed method was successfully applied for the qualitative and quantitative analysis of 20 chemical compositions in Isodon nervosa samples. Conclusion – Twenty chemical compositions in 21 batches of wild and cultivated Isodon nervosa samples from different sources had great variation in the contents. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
15.
16.
Control of the pattern‐recognition receptor EFR by an ER protein complex in plant immunity 下载免费PDF全文
Martine Batoux Milena Roux Alejandra Rougon Pascal Bittel Marta Kiss‐Papp Delphine Chinchilla H Peter van Esse Lucia Jorda Benjamin Schwessinger Valerie Nicaise Bart P H J Thomma Antonio Molina Jonathan D G Jones Cyril Zipfel 《The EMBO journal》2009,28(21):3428-3438
In plant innate immunity, the surface‐exposed leucine‐rich repeat receptor kinases EFR and FLS2 mediate recognition of the bacterial pathogen‐associated molecular patterns EF‐Tu and flagellin, respectively. We identified the Arabidopsis stromal‐derived factor‐2 (SDF2) as being required for EFR function, and to a lesser extent FLS2 function. SDF2 resides in an endoplasmic reticulum (ER) protein complex with the Hsp40 ERdj3B and the Hsp70 BiP, which are components of the ER‐quality control (ER‐QC). Loss of SDF2 results in ER retention and degradation of EFR. The differential requirement for ER‐QC components by EFR and FLS2 could be linked to N‐glycosylation mediated by STT3a, a catalytic subunit of the oligosaccharyltransferase complex involved in co‐translational N‐glycosylation. Our results show that the plasma membrane EFR requires the ER complex SDF2–ERdj3B–BiP for its proper accumulation, and provide a demonstration of a physiological requirement for ER‐QC in transmembrane receptor function in plants. They also provide an unexpected differential requirement for ER‐QC and N‐glycosylation components by two closely related receptors. 相似文献