Gertrud E. Morlock

University of Giessen

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Wolfgang Schwack

University of Giessen

Elena S. Chernetsova

University of Giessen

ÁM

Ágnes M. Móricz

Plant Protection Institute

Tim T. Häbe

Boehringer Ingelheim (Germany)

Petar Ristivojević

University of Belgrade

Ines Klingelhöfer

University of Giessen

Péter G. Ott

Centre for Agricultural Research

Julia Heil

University of Giessen

Annabel Mehl

University of Giessen

Stephanie Krüger

University of Giessen

Cooperative Institutions

University of Giessen

145

University of Hohenheim

TransMIT (Germany)

University of Bonn

Giessen School of Theology

University of Belgrade

Centre National de la Recherche Scientifique

Chinese Academy of Sciences

Nestlé (Switzerland)

Universidad de Zaragoza

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Effect-directed analysis of fresh and dried elderberry (Sambucus nigra L.) via hyphenated planar chromatography

Journal of Chromatography A (2015)

Stephanie Krüger Małgorzata Mirgos Gertrud E. Morlock

Sambucus nigra

Ursolic acid

10.1016/j.chroma.2015.11.021

Cite

Citations (42)

Werden planare Assays in‐vitro‐Assays ersetzen?

Lebensmittelchemie (2023)

Gertrud E. Morlock

10.1002/lemi.202359029

Cite

Citations (0)

Production of cyathane type secondary metabolites by submerged cultures of Hericium erinaceus and evaluation of their antibacterial activity by direct bioautography

Fungal Biology and Biotechnology (2015)

Tian Shen Gertrud E. Morlock Holger Zorn

Fungi of the phylum Basidiomycota are well-known to form a broad spectrum of biologically active secondary metabolites, especially low molecular weight compounds such as terpenoids. Hericium erinaceus produces various cyathane type diterpenoids including erinacines. However, no quantitative data and production kinetics have been reported on the biosynthesis of the erinacines C and P in submerged cultures. In the present study, the production of erinacine C was optimized, and the product formation kinetics as well as the antimicrobial activity were studied by high-performance liquid chromatography (HPLC), high-performance thin-layer chromatography (HPTLC) and direct bioautography. Oatmeal and Edamin® K were identified to be crucial media components for an efficient production of erinacine C. The highest concentrations of erinacine C were obtained in the optimized culture medium on the 9th culture day (approximately 260 mg L−1). The production of erinacine P was strongly time dependent. The maximum concentration of erinacine P of 184 mg L−1 was observed on the third culture day. Afterwards, the concentrations of erinacine P decreased while the concentrations of erinacine C steadily increased. Comparable results were obtained by HPTLC with UV detection and HPLC with diode-array detection (DAD) analyses. Direct bioautography allowed for an additional analysis of the antimicrobial activity of the secondary metabolites. The C and N sources oatmeal and Edamin® K induced the formation of erinacine C. Detailed product formation kinetics of the erinacines C and P have been reported for the first time. HPTLC combined with the Aliivibrio fischeri bioassay allowed for an instant detection of cyathane diterpenoids in crude extracts and for an evaluation of the antimicrobial activity of the secondary metabolites directly on the plate.

Hericium erinaceus

10.1186/s40694-015-0018-y

Cite

Citations (22)

Profiling and classification of French propolis by combined multivariate data analysis of planar chromatograms and scanning direct analysis in real time mass spectra

Journal of Chromatography A (2016)

Thibaut Chasset Tim T. Häbe Petar Ristivojević Gertrud E. Morlock

Propolis

DART ion source

Pinocembrin

Galangin

10.1016/j.chroma.2016.08.045

Cite

Citations (48)

Bioprofiling of Cosmetics with Focus on Streamlined Coumarin Analysis

ACS Omega (2017)

Constanze Stiefel Tina Schubert Gertrud E. Morlock

Facing the widespread use of cosmetic products in daily use and recognizing the very limited information obtained by target analysis, a method suited for comprehensive characterization of cosmetics was aimed at. The biological activity of ingredients of 20 cosmetics taken from 16 different product groups and their coumarin contents were investigated via chromatography linked to bioassays (direct bioautography) and mass spectrometry. It allows for screening a large number of cosmetic products within a short time to generate a more valid database on their coumarin content and their contribution to the overall exposure. Bioactivity profiling of cosmetics with regard to bioactive ingredients opens new avenues for a comprehensive characterization of important substances in products of daily use, helpful for the legally required safety and risk assessment of cosmetic products, especially for multiple product usage. As for coumarin, a ubiquitary fragrance compound of allergenic potential, which is under recurrent discussion due to its hepatoxic properties, it is necessary to be able to estimate the regular intake via cosmetics for a valid risk assessment. This newly developed bioprofiling method allowed a selective determination of coumarin down to 1.3 mg kg–1, even for very matrix-rich cosmetics despite minimalism in sample preparation. The declaration limits according to European Cosmetics Regulation were completely covered. Mean coumarin contents of 20 cosmetic products reached up to 2218 mg kg–1. The repeatabilities (%RSD, n = 3) were between 1.1 and 2.9%, and the mean recoveries (n = 5) were between 96 and 102% for the different cosmetic matrices.

10.1021/acsomega.7b00562

Cite

Citations (44)

Antidiabetic and antioxidant profiling of 67 African trifoliate yam accessions by planar on-surface assays versus in vitro assays

Fitoterapia (2024)

Priscilla Oluwakemi Aiyedun Mubo Adeola Sonibare Badara Guèye Dirk C. Albach Julia Heil

Trifoliate yam (Dioscorea dumetorum) is traditionally used to treat diabetics in Nigeria. However, almost no information is available on its antidiabetic constituents and their natural variance. Hence, the activity of methanolic tuber extracts of 67 trifoliate yam accessions from the largest collection in Africa was proven by four colorimetric antidiabetic and antioxidant in vitro assays, as diabetes is also linked with oxidative stress. For the first time, selected accessions were also analyzed by planar bioactivity profiling. It has a comparatively higher, more differentiated information content, is more sustainable in terms of material consumption, and enables straightforward compound prioritization and characterization. Up to a dozen individual antioxidant zones were revealed as well as one prominent zone inhibiting α-glucosidase and α-amylase. The latter inhibition zone was tentatively assigned to palmitic, linoleic, oleic, linolenic, oxo-nonanoic fatty acids by direct elution to heated electrospray ionization high-resolution mass spectrometry.

10.1016/j.fitote.2024.106299

Cite

Citations (0)

Comparison of high-performance thin-layer with overpressured layer chromatography combined with direct bioautography and direct analysis in real time mass spectrometry for tansy root

Journal of Chromatography A (2019)

Ágnes M. Móricz Tim T. Häbe Péter G. Ott Gertrud E. Morlock

DART ion source

Dart

10.1016/j.chroma.2019.03.068

Cite

Citations (26)

Aspects of surface scanning by direct analysis in real time mass spectrometry employing plasma glow visualization

Rapid Communications in Mass Spectrometry (2015)

Elena S. Chernetsova Gertrud E. Morlock

Rationale Visual monitoring of the Direct Analysis in Real Time (DART) gas impact region during sampling was demonstrated via its metastable plasma glow. It is known that adding neon into helium for DART leads to plasma glow, but this effect has not been used in practice and discussed in the literature so far. Methods A single quadrupole mass spectrometer with a DART SVPA ion source was used for recording of DART mass spectra from different surfaces, using galangin and p ‐coumaric acid as model analytes. In specific cases, the composition of the mass spectra was clarified using an Orbitrap mass spectrometer. Results Plasma glow visualization made it possible to track the metastable gas distributions during surface scanning. The influence on the composition of the mass spectra was studied for different carrier gases, i.e. pure helium versus a helium–neon mixture, and for the vacuum pumping rate. The spatial resolution was substantially improved via a DART cap with a narrowed internal diameter, but impaired by a decreased sensitivity. Comparably low signal intensities were obtained for analytes on porous layers due to analyte penetration and metastable gas scattering. Conclusions Visualization through the plasma glow enables the optimal selection of the coordinates for DART‐MS analysis and thus it will support scanning and imaging MS on surfaces, including porous planar chromatographic separation materials. Copyright © 2015 John Wiley & Sons, Ltd.

DART ion source

Dart

Glow discharge

Quadrupole mass analyzer

10.1002/rcm.7221

Cite

Citations (12)

Determination of Sucralose in Soft Drinks by High-Performance Thin-Layer Chromatography: Interlaboratory Study

Journal of AOAC International (2009)

Joerg Stroka Ivanka Doncheva Bernd Spangenberg Katrien Bouten R Braemer

An interlaboratory comparison was carried out to evaluate the effectiveness of a method based on HPTLC in which reagent-free derivatization is followed by UV/fluorescence detection. The method was tested for the determination of sucralose (C12H19C13O8; (2R,3R,4R,5S,6R)-2-[(2R,3S,4S,5S)-2,5-bis(chloromethyl)-3,4-dihydroxyoxolan-2-yl]oxy-5-chloro-6-hydroxymethyl)oxane-3, 4-diol; CAS Registry No. 56038-13-2) in carbonated and still beverages at the proposed European regulatory limits. For still beverages, a portion of the sample was diluted with methanol-water. For carbonated beverages, a portion of the sample was degassed in an ultrasonic bath before dilution. Turbid beverages were filtered after dilution through an HPLC syringe filter. The separation of sucralose was performed by direct application on amino-bonded (NH2) silica gel HPTLC plates (no cleanup needed) with the mobile phase acetonitrile-water. Sucralose was determined after reagent-free derivatization at 190 degrees C; it was quantified by measurements of both UV absorption and fluorescence. The samples, both spiked and containing sucralose, were sent to 14 laboratories in five different countries. Test portions of a sample found to contain no sucralose were spiked at levels of 30.5, 100.7, and 299 mg/L. Recoveries ranged from 104.3 to 124.6% and averaged 112% for determination by UV detection; recoveries ranged from 98.4 to 101.3% and averaged 99.9% for determination by fluorescence detection. On the basis of the results for spiked samples (blind duplicates at three levels), as well as sucralose-containing samples (blind duplicates at three levels and one split level), the values for the RSDr ranged from 10.3 to 31.4% for determinations by UV detection and from 8.9 to 15.9% for determinations by fluorescence detection. The values for the RSDR values ranged from 13.5 to 31.4% for determinations by UV detection and from 8.9 to 20.7% for determinations by fluorescence detection.

Sucralose

Soft drink

10.1093/jaoac/92.4.1153

Cite

Citations (11)

Analysis of unauthorized Sudan dyes in food by high-performance thin-layer chromatography

Analytical and Bioanalytical Chemistry (2018)

Wolfgang Schwack Elodie Pellissier Gertrud E. Morlock

10.1007/s00216-018-0945-6

Cite

Citations (46)