TLC-Bioautography as a fast and cheap screening method for the detection of α-chymotrypsin inhibitors in crude plant extracts

Antimicrobial effects of plant extracts against Clostridium perfringens with respect to food-relevant influencing factors

Journal of Food Protection ◽

10.4315/jfp-21-139 ◽

2021 ◽

Author(s):

Ulrike Friedlein ◽

Samart Dorn-In ◽

Karin Schwaiger

Keyword(s):

Influencing Factors ◽

Plant Extract ◽

Plant Extracts ◽

Pathogenic Bacteria ◽

Screening Method ◽

Extrinsic Factors ◽

Antimicrobial Effects ◽

Extract Concentration ◽

Microdilution Method

The application of plant extracts (PEs) could be a promising option to satisfy consumers’ demand for natural additives to inhibit growth of variable pathogenic bacteria. Thus, the aim of this study was to develop a standardized microdilution method to examine the antimicrobial effects of ten hydrophilic plant extracts against two strains of C. perfringens facing various food-relevant influencing factors. Due to the high opacity of PEs, resazurin was used as an indicator for bacterial growth instead of pellet formation. The highest value of the minimum inhibitory concentration (MIC) of the replications of each PE was defined as effective plant extract concentration (EPC), whereas the next concentration beneath the lowest MIC value was defined as the ineffective plant extract concentration (IEPC). The EPC of seven PEs: allspice, cardamom, cinnamon, clove, coriander, ginger and mace were between 0.625 - 10 g/kg, whereas extracts of caravey, nutmeg and thyme showed no antimicrobial activity up to the maximum concentration tested (10 g/kg) against C. perfringens in vitro. Two intrinsic factors, sodium chloride and sodium nitrite, displayed either synergistic/additive effects or no interaction with most PEs. By combination with PEs at its ineffective plant concentration (IEPC, 0.08 – 1.25 g/kg), MIC of NaCl and NaNO2 decreased from 25 – 50 g/kg to 6 – 25 g/kg and > 200 mg/kg to 0.2 – 100 mg/kg respectively. On the contrary, lipid (sun flower oil) at a low concentration inhibited the antimicrobial effects of all tested PEs. For extrinsic factors, only allspice, ginger and coriander could maintain their antimicrobial effects after being heated to 78 °C for 30 min. The synergistic effect between PEs and pH values (5.0 and 5.5) was also found for all PEs. The established screening method with resazurin and defining EPC and IEPC values allows the verification of antimicrobial effects of PEs under various food-relevant influencing factors in a fast and reproducible way.

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Comparative Study of NMR Spectral Profiling for the Characterization and Authentication of Cannabis

Journal of AOAC International ◽

10.5740/jaoacint.17-0089 ◽

2017 ◽

Vol 100 (5) ◽

pp. 1356-1364 ◽

Cited By ~ 3

Author(s):

Xinyi Wang ◽

Peter de B Harrington ◽

Steven F Baugh

Keyword(s):

Discriminant Analysis ◽

Nmr Spectroscopy ◽

Plant Extracts ◽

Screening Method ◽

Fuzzy Rule ◽

Classification Performance ◽

Support Vector ◽

Classification Methods ◽

Linear Discriminant ◽

Projected Difference Resolution

Abstract For the authentication of botanical materials, itis difficult to obtain representative reference materials because botanicals vary significantly with respect to cultivation conditions. Chemical profiling of plant extracts or spectral fingerprinting can differentiate botanicals and group them by their chemical profiles. NMR spectroscopy yields a powerful and useful method for profiling plant extracts. Both 500 MHz 1H and 1H-1H correlation NMR spectroscopy coupled with pattern recognition were used to discriminate among Cannabis samples. A rapid method of analysis was achieved by extracting directly into the deuterated solvent. Spectral ranges including or excluding the downfield region were compared to evaluate the effect on classification accuracy by projected difference resolution. Six classification methods—fuzzy rule-building expert system, linear discriminant analysis (LDA), super partial least-squares discriminant analysis, support vector machine (SVM), and SVMclassification trees (SVMTrees)—all gave better classification performance for proton NMR spectrathan for proton-proton correlation NMR spectra for seven Cannabis samples. Among the classification methods for a set of 25 Cannabis samples, the 0.5–7.2 plus 7.4–13.0 ppm ranges gave higher prediction rates of greater than 96% when compared to the reduced range of 0.5–7.2 ppm that excluded the downfield range. The LDA method had the best prediction accuracy of 99.8 ± 0.4%. SVMTree methods provide a robust tool, and classification trees are amenable to interpretation. Hence, NMR spectroscopy combined withchemometrics could be used as a fast screening method for the authentication of Cannabis samples.

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A Nanoparticle-Based Label-Free Sensor for Screening the Relative Antioxidant Capacity of Hydrosoluble Plant Extracts

Sensors ◽

10.3390/s19030590 ◽

2019 ◽

Vol 19 (3) ◽

pp. 590 ◽

Cited By ~ 2

Author(s):

Melinda David ◽

Adrian Şerban ◽

Claudia Popa ◽

Monica Florescu

Keyword(s):

Antioxidant Capacity ◽

Gold Nanoparticle ◽

Plant Extracts ◽

Screening Method ◽

Amperometric Detection ◽

Electrical Signal ◽

Antioxidant Compounds ◽

Label Free ◽

Quenching Effect ◽

Working Parameters

One of the most important aspects of the detection of antioxidant compounds is developing a fast screening method. The screening of the overall relative antioxidant capacity (RAC) of several Romanian hydrosoluble plant extracts is the focus of this work. This is important because of the presence of increasing levels of reactive oxygen species (such as H2O2) generates oxidative stress in the human body. The consequences are a large number of medical conditions that can be helped by a larger consumption of plant extracts as food supplements, which do not necessarily contain the specified antioxidant contents. By exploiting the catalytic properties of gold nanoparticles, a specific and sensitive nanoparticle-based label-free electrochemical sensor was developed, where the working parameters were optimized for RAC screening of hydrosoluble plant extracts. First, electrochemical measurements (cyclic voltammetry and amperometry) were used to characterize different nanoparticle-based sensors, revealing the best performance of gold nanoparticle-based sensors, obtaining a RAC of 98% for lavender extracts. The sensing principle is based on the quenching effect of antioxidants for H2O2 amperometric detection, where the decrease in electrical signal suggests an increasing antioxidant capacity. The obtained results were expressed in terms of ascorbic acid and Trolox equivalents in order to be able to correlate our results with classical methods like chemiluminescence and UV-Vis spectrophotometry, where a correlation coefficient of 0.907 was achieved, suggesting a good correlation between electrochemistry and spectrophotometry. Considering these results, the optimized gold nanoparticle-based label-free sensor can be used as a simple, rapid alternative towards classical methods for relative antioxidant capacity detection of hydrosoluble plant extracts.

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A Photometric Screening Method for Dimeric Naphthylisoquinoline Alkaloids and Complete On-Line Structural Elucidation of a Dimer in Crude Plant Extracts, by the LC−MS/LC−NMR/LC−CD Triad

Analytical Chemistry ◽

10.1021/ac001503q ◽

2001 ◽

Vol 73 (11) ◽

pp. 2571-2577 ◽

Cited By ~ 33

Author(s):

Gerhard Bringmann ◽

Michael Wohlfarth ◽

Heiko Rischer ◽

Markus Heubes ◽

Wael Saeb ◽

...

Keyword(s):

Plant Extracts ◽

Screening Method ◽

Structural Elucidation ◽

Naphthylisoquinoline Alkaloids ◽

On Line

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An integrated screening method for evaluating the pulmonary toxicity of inhaled particulates: Role of microscopic techniques in assessing pulmonary macrophage clearance functions

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161692 ◽

1990 ◽

Vol 48 (3) ◽

pp. 826-827

Author(s):

David B. Warheit ◽

Lena Achinko ◽

Mark A. Hartsky

Keyword(s):

Bronchoalveolar Lavage ◽

Pulmonary Toxicity ◽

Screening Method ◽

Pulmonary Response ◽

Inhaled Particles ◽

Cytochemical Analysis ◽

Pulmonary Macrophages ◽

Integrated Screening

There is a great need for the development of a rapid and reliable bioassay to evaluate the pulmonary toxicity of inhaled particles. A number of methods have been proposed, including lung clearance studies, bronchoalveolar lavage analysis, and in vitro cytotoxicity tests. These methods are often limited in scope inasmuch as they measure only one dimension of the pulmonary response to inhaled, instilled or incubated dusts. Accordingly, a comprehensive approach to lung toxicity studies has been developed.To validate the method, rats were exposed for 6 hours or 3 days to various concentrations of either aerosolized alpha quartz silica (Si) or carbonyl iron (CI) particles. Cells and fluids from groups of sham and dust-exposed animals were recovered by bronchoalveolar lavage (BAL). Alkaline phosphatase, LDH and protein values were measured in BAL fluids at several time points postexposure. Cells were counted and evaluated for viability, as well as differential and cytochemical analysis. In addition, pulmonary macrophages (PM) were cultured and studied for morphology, chemotaxis, and phagocytosis by scanning electron microscopy.

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