Publication type: Conference poster
Type of review: Peer review (abstract)
Title: Screening for active substances with TLC bioautography : challenges with artefacts
Authors: Merki, Rebekka
Schönborn, Andreas
Pihan, Lisa-Anna-Maria
Wolfram, Evelyn
et. al: No
Proceedings: 12th BioDetectors Conference 2019 : Abstract book
Conference details: 12th BioDetectors Conference 2019, Vienna, Austria, 26-27 September 2019
Issue Date: 2019
Publisher / Ed. Institution: BioDetection Systems
Publisher / Ed. Institution: Vienna
Language: English
Subject (DDC): 540: Chemistry
Abstract: TLC, and its modern form HPTLC, is a standard method for identification and quality control of herbals [1]. Its combination with bioassays offers simultaneous separation and screening of plant extracts and other multi-compound mixtures for active substances. The intriguing simplicity and rapidness of the method might lead to underestimation of potential artefacts, first reported by Taibon et al. for HPTLC-Tyrosinase Inhibition [2]. In assays based on cells or enzymes in hydrophilic media, high lipophilic substances prevent contact with the potentially active substance and might lead to false-positive or false-negative results. Additionally, diffusion problems from the layer to the biological assay agents can also lead to wrong interpretation of results, due to difference in the physico-chemical properties of the molecules in the sample mixture. The planar Yeast Estrogen Screen Assay (pYES) is used for detection of human estrogen receptor alpha agonists in mixtures [3]. The hER-alpha is expressing beta-galactosidase in presence of estrogenic substances. Substances with a strong blue autofluorescence at 366 nm detection and low estrogenic activity are difficult to differentiate from real estrogenic activity, when using the blue fluorescent dye 4-methylumbelliferyl-beta-D-galactopyranosid (MUG) as substarte for beta galactosidase. Results of blue fluorescing phenolic acid rich plant extracts with known estrogen activity are demonstrated and a control assay using beta-D-galactopyranoside (RGP) as substrate is proposed [4]. The poster summarizes potential artefacts from pYES and other antimicrobial assays and reviews the theoretical considerations and suggests further investigation to overcome the challenges and improve bioautographic methods.
Fulltext version: Published version
License (according to publishing contract): Not specified
Departement: Life Sciences and Facility Management
Organisational Unit: Institute of Chemistry and Biotechnology (ICBT)
Appears in collections:Publikationen Life Sciences und Facility Management

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