In vitro skin sensitization test methods: Applicability to plant protection products

Nowadays, various industries using nanomaterials are growing rapidly, and in particular, as the commercialization and use of nanomaterials increase in the cosmetic field, the possibility of exposure of nanomaterials to the skin of product producers and consumers is increasing. Due to the unique properties of nanomaterials with a very small size, they can act as hapten and induce immune responses and skin sensitization, so accurate identification of toxicity is required. Therefore, we selected silica nanomaterials used in various fields such as cosmetics and biomaterials and evaluated the skin sensitization potential step-by-step according to in-vitro and in-vivo alternative test methods. KeratinoSensTM cells of modified keratinocyte and THP-1 cells mimicking dendritic-cells were treated with silica nanoparticles, and their potential for skin sensitization and cytotoxicity were evaluated, respectively. We also confirmed the sensitizing ability of silica nanoparticles in the auricle-lymph nodes of BALB/C mice by in-vivo analysis. As a result, silica nanoparticles showed high protein binding and reactive oxygen species (ROS) mediated cytotoxicity, but no significant observation of skin sensitization indicators was observed. Although more studies are needed to elucidate the mechanism of skin sensitization by nanomaterials, the results of this study showed that silica nanoparticles did not induce skin sensitization.

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Screening of Antifungal and Antibacterial Activity of 90 Commercial Essential Oils against 10 Pathogens of Agronomical Importance

Foods ◽

10.3390/foods9101418 ◽

2020 ◽

Vol 9 (10) ◽

pp. 1418

Author(s):

Caroline De Clerck ◽

Simon Dal Maso ◽

Olivier Parisi ◽

Frédéric Dresen ◽

Abdesselam Zhiri ◽

...

Keyword(s):

Antibacterial Activity ◽

Essential Oils ◽

Plant Pathogens ◽

Plant Protection ◽

Fusarium Culmorum ◽

Plant Protection Products ◽

Colletotrichum Lindemuthianum ◽

Alternative Methods ◽

Organosulfur Compounds

Nowadays, the demand for a reduction of chemical pesticides use is growing. In parallel, the development of alternative methods to protect crops from pathogens and pests is also increasing. Essential oil (EO) properties against plant pathogens are well known, and they are recognized as having an interesting potential as alternative plant protection products. In this study, 90 commercially available essential oils have been screened in vitro for antifungal and antibacterial activity against 10 plant pathogens of agronomical importance. EOs have been tested at 500 and 1000 ppm, and measures have been made at three time points for fungi (24, 72 and 120 h of contact) and every two hours for 12 h for bacteria, using Elisa microplates. Among the EOs tested, the ones from Allium sativum, Corydothymus capitatus, Cinnamomum cassia, Cinnamomum zeylanicum, Cymbopogon citratus, Cymbopogon flexuosus, Eugenia caryophyllus, and Litsea citrata were particularly efficient and showed activity on a large panel of pathogens. Among the pathogens tested, Botrytis cinerea, Fusarium culmorum, and Fusarium graminearum were the most sensitive, while Colletotrichum lindemuthianum and Phytophthora infestans were the less sensitive. Some EOs, such as the ones from A. sativum, C. capitatus, C. cassia, C. zeylanicum, C. citratus, C. flexuosus, E. caryophyllus, and L. citrata, have a generalist effect, and are active on several pathogens (7 to 10). These oils are rich in phenols, phenylpropanoids, organosulfur compounds, and/or aldehydes. Others, such as EOs from Citrus sinensis, Melaleucacajputii, and Vanilla fragrans, seem more specific, and are only active on one to three pathogens. These oils are rich in terpenes and aldehydes.

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FEATURES OF TESTING SPRAYERS OF AGRICULTURAL MACHINES

Tekhnicheskiy servis mashin ◽

10.22314/2618-8287-2020-58-4-47-53 ◽

2020 ◽

Vol 4 (141) ◽

pp. 47-53

Author(s):

ROMAN POTEMKIN ◽

◽

ALEKSEY SVIRIDOV

Keyword(s):

Plant Protection ◽

Discharge Rate ◽

Plant Protection Products ◽

Test Methods ◽

Research Purpose ◽

Mineral Fertilizers ◽

Pump System ◽

Initial Stage ◽

Modern Application ◽

Agricultural Machines

Modern application of chemical plant protection products and liquid mineral fertilizers requires a comprehensive approach in compliance with all agricultural standards. Under-watering or overdosing of the introduced fertilizers can adversely affect the yield. Sprayers used on agricultural machines must be carefully selected and tested. (Research purpose) The research purpose is in analyzing the features of testing sprayers used on agricultural machines. (Materials and methods) The article presents reviewed data on the use of various methods of sprayer testing. Authors studied open sources as research materials and conducted a comparative analysis of the information. (Results and discussion) The article describes successive stages and test methods. The initial stage of testing sprayers is to determine the size (diameter) of drops at a certain pressure (1.5-3 bar) of the pump system. The liquid demolition directly depends on the size of the drop. Authors used the method of distribution of the solution into measuring cups on specialized test benches to determine the discharge rate. The article presents an example of the resulting table for testing sprayers.

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Risk Assessment of the Metabolite M44 of Bixafen, One of the Active Substancesin Aviator Xpro EC225

European Journal of Nutrition & Food Safety ◽

10.9734/ejnfs/2019/v9i430077 ◽

2019 ◽

pp. 317-318

Author(s):

Jan Ludvig Lyche ◽

Hubert Dirven ◽

Marit Låg ◽

Asbjørn Magne Nilsen ◽

Katrine Borgå ◽

...

Keyword(s):

Food Safety ◽

Plant Protection ◽

Experimental Studies ◽

Plant Protection Products ◽

Guidance Document ◽

Developmental Effects ◽

Historical Control Data ◽

The Eu

Aviator Xpro EC 225 containing the active substance bixafen was assessed by VKM in spring 2013, and it was concluded that the metabolite M44 has potential for groundwater contamination. Furthermore, VKM assessed in late 2013 the relevance of this metabolite in accordance with the EU guidance document on metabolites in groundwater, and concluded that the malformations observed in rabbits exposed to the metabolite should be considered treatment related. VKM also concluded that the data presented to evaluate the possible genotoxic properties of the metabolite was insufficient to reach a conclusion. Based on this, the Norwegian Food Safety Authority rejected the approval of Aviator Xpro EC 225. The applicant has now submitted results from an in vivo study to strengthen the basis for assessment of genotoxic properties, and also submitted new historical controls in relation to the experimental studies on foetal developmental effects in rabbits. The VKM Panel on Plant Protection Products has discussed the questions raised by The Norwegian Food Safety Authority on the basis of the new data, and has the following opinion: On the assessment of genotoxic properties of the M44 metabolite of bixafen, one of the active ingredients of Aviator Xpro EC 225. It is the view of VKM Panel on Plant Protection Products that the new in vivo mouse micronucleus study, supplemented together with a separate study demonstrating bioavailability, overrides the results of the in vitro clastogenicity studies. Taken together, it is the opinion of VKM that under the conditions studied, M44 should be considered as non-genotoxic. On the assessment of the relevance of the foetal malformations in M44 exposed animals. VKMs Panel on Plant Protection products has assessed the arguments and new historical control data presented by the applicant, intended to show that metabolite M44 is not teratogenic. It is however the opinion of the Panel that the arguments and the new historical data provided by the applicant do not alter the panel’s previous conclusion; that the malformations observed in rabbits exposed to the metabolite M44 should be considered treatment related.

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Scientific Opinion of the Scientific Panel on Plant Protection Products and their Residues (PPR Panel) on testing and interpretation of comparative in vitro metabolism studies

EFSA Journal ◽

10.2903/j.efsa.2021.6970 ◽

2021 ◽

Vol 19 (12) ◽

Author(s):

◽

Antonio F Hernandez‐Jerez ◽

Paulien Adriaanse ◽

Annette Aldrich ◽

Philippe Berny ◽

...

Keyword(s):

Plant Protection ◽

Plant Protection Products ◽

In Vitro Metabolism ◽

Scientific Opinion

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Effects of co-formulants on the absorption and secretion of active substances in plant protection products in vitro

Archives of Toxicology ◽

10.1007/s00204-021-03140-x ◽

2021 ◽

Author(s):

Mawien Karaca ◽

Benjamin Christian Fischer ◽

Christian Tobias Willenbockel ◽

Tewes Tralau ◽

Philip Marx-Stoelting ◽

...

Keyword(s):

Fluorescence Anisotropy ◽

Plant Protection ◽

Plant Protection Products ◽

Qualitative And Quantitative ◽

Mixture Effects ◽

Dependent Inhibition ◽

Surface Active ◽

Active Substances ◽

Do So

AbstractCurrently, the authorisation process for plant protection products (PPPs) relies on the testing of acute and topological toxicity only. Contrastingly, the evaluation of active substances includes a more comprehensive set of toxicity studies. Nevertheless, mixture effects of active ingredients and co-formulants may result in increased toxicity. Therefore, we investigated effects of surface active co-formulants on the toxicity of two PPPs focussing on qualitative and quantitative toxicokinetic effects on absorption and secretion. The respective products are based on the active substances abamectin and fluroxypyr-meptyl and were tested for cytotoxicity in the presence or absence of the corresponding surfactants and co-formulants using Caco-2 cells. In addition, the effect of co-formulants on increased cellular permeation was quantified using LC–MS/MS, while potential kinetic mixture effects were addressed by fluorescence anisotropy measurements and ATPase assays. The results show that surface active co-formulants significantly increase the cytotoxicity of the investigated PPPs, leading to more than additive mixture effects. Moreover, analytical investigations show higher efflux ratios of both active substances and the metabolite fluroxypyr upon combination with certain concentrations of the surfactants. The results further point to a significant and concentration-dependent inhibition of Pgp transporters by most of the surfactants as well as to increased membrane fluidity. Altogether, these findings strongly support the hypothesis that surfactants contribute to increased cytotoxicity of PPPs and do so by increasing the bioavailability of the respective active substances.

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