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Antimicrobial Isothiocyanates from Brassicaceae Glucosinolates: Analysis, Reactivity, And Quantitative Structure-Activity Relationships.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Antimicrobial Isothiocyanates from Brassicaceae Glucosinolates: Analysis, Reactivity, And Quantitative Structure-Activity Relationships.
Author:	Andini, Silvia.
Published:	Ann Arbor : ProQuest Dissertations & Theses, 2020
Description:	225 p.
Notes:	Source: Dissertations Abstracts International, Volume: 83-05, Section: B.
Notes:	Advisor: Vincken, J. P. ;Araya-Cloutier, C. .
Contained By:	Dissertations Abstracts International83-05B.
Subject:	Flowers & plants.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28760881
ISBN:	9798494443571

Antimicrobial Isothiocyanates from Brassicaceae Glucosinolates: Analysis, Reactivity, And Quantitative Structure-Activity Relationships.
Andini, Silvia.

Antimicrobial Isothiocyanates from Brassicaceae Glucosinolates: Analysis, Reactivity, And Quantitative Structure-Activity Relationships. - Ann Arbor : ProQuest Dissertations & Theses, 2020 - 225 p.

Source: Dissertations Abstracts International, Volume: 83-05, Section: B.

Thesis (Ph.D.)--Wageningen University and Research, 2020.

This item must not be sold to any third party vendors.

Isothiocyanates (ITCs) are electrophilic phytochemicals naturally originating from glucosinolates (GSLs), the major phytochemicals in the plant family of Brassicaceae. ITCs are released when GSLs come in contact with myrosinase. This is part of the Brassicaceae defence system against their natural enemies. The aim of this thesis was to explore the potential of ITCs as natural antimicrobials, e.g. as food preservatives. For this, their production, analysis, reactivity, and (quantitative) structure-activity relationships were studied.Fungal elicitation was studied as an attempt to increase content and structural diversity of GSLs. (Non-)pathogenic fungal elicitation, during Brassicaceae seed germination, did not increase structural diversity nor content of GSLs further than what could be obtained by germination alone. Meanwhile, non-elicited seedlings contained higher or equal GSL content compared to the untreated seeds. As GSLs were present in high abundance in Brassicaceae seeds, the seeds were employed as the source of antimicrobial ITCs via extraction of GSLs, followed by a myrosinase treatment. For this, a method to analyze GSLs and ITCs simultaneously using RP-UHPLC-ESI-MSn was developed and validated with 14 GSLs and 15 ITCs, consisting of 8 subclasses differing in side chain configuration. The method enabled monitoring the in vitro enzymatic conversion of GSLs to ITCs. Due to their electrophilicity, antimicrobial activity of ITCs was negatively affected by nucleophile richness of growth media. In nucleophile-poor growth media, antimicrobial activity of ITCs, particularly x-(methylsulfinyl)alkyl ITC (MSITC) and x-(methylsulfonyl)alkyl ITC (MSoITC), was remarkably improved by a factor of at least 4, compared to that in the nucleophile-rich. Of 9 ITC subclasses tested, MSITC and MSoITC were the most promising ones. Antimicrobial activity of MSITC and MSoITC was dependent on chain length. The short-chained MSITC and MSoITC had good antimicrobial activity (minimum inhibitory concentration, MIC ≤ 25 µg/mL) against Gram– bacteria and Gram+ bacteria, whereas the long-chained ones had good antimicrobial activity against Gram+ bacteria and fungi. A QSAR study revealed that partial charge, polarity, reactivity, and shape were the main physicochemical properties defining the antimicrobial activity of ITCs. The developed QSAR models had good internal prediction power (Q2adj > 0.80) and successfully predicted activity of ITC-rich Brassicaceae extracts.

ISBN: 9798494443571Subjects--Topical Terms:

915830
Flowers & plants.

Antimicrobial Isothiocyanates from Brassicaceae Glucosinolates: Analysis, Reactivity, And Quantitative Structure-Activity Relationships.
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500 $a Source: Dissertations Abstracts International, Volume: 83-05, Section: B.
500 $a Advisor: Vincken, J. P. ;Araya-Cloutier, C. .
502 $a Thesis (Ph.D.)--Wageningen University and Research, 2020.
506 $a This item must not be sold to any third party vendors.
520 $a Isothiocyanates (ITCs) are electrophilic phytochemicals naturally originating from glucosinolates (GSLs), the major phytochemicals in the plant family of Brassicaceae. ITCs are released when GSLs come in contact with myrosinase. This is part of the Brassicaceae defence system against their natural enemies. The aim of this thesis was to explore the potential of ITCs as natural antimicrobials, e.g. as food preservatives. For this, their production, analysis, reactivity, and (quantitative) structure-activity relationships were studied.Fungal elicitation was studied as an attempt to increase content and structural diversity of GSLs. (Non-)pathogenic fungal elicitation, during Brassicaceae seed germination, did not increase structural diversity nor content of GSLs further than what could be obtained by germination alone. Meanwhile, non-elicited seedlings contained higher or equal GSL content compared to the untreated seeds. As GSLs were present in high abundance in Brassicaceae seeds, the seeds were employed as the source of antimicrobial ITCs via extraction of GSLs, followed by a myrosinase treatment. For this, a method to analyze GSLs and ITCs simultaneously using RP-UHPLC-ESI-MSn was developed and validated with 14 GSLs and 15 ITCs, consisting of 8 subclasses differing in side chain configuration. The method enabled monitoring the in vitro enzymatic conversion of GSLs to ITCs. Due to their electrophilicity, antimicrobial activity of ITCs was negatively affected by nucleophile richness of growth media. In nucleophile-poor growth media, antimicrobial activity of ITCs, particularly x-(methylsulfinyl)alkyl ITC (MSITC) and x-(methylsulfonyl)alkyl ITC (MSoITC), was remarkably improved by a factor of at least 4, compared to that in the nucleophile-rich. Of 9 ITC subclasses tested, MSITC and MSoITC were the most promising ones. Antimicrobial activity of MSITC and MSoITC was dependent on chain length. The short-chained MSITC and MSoITC had good antimicrobial activity (minimum inhibitory concentration, MIC ≤ 25 µg/mL) against Gram– bacteria and Gram+ bacteria, whereas the long-chained ones had good antimicrobial activity against Gram+ bacteria and fungi. A QSAR study revealed that partial charge, polarity, reactivity, and shape were the main physicochemical properties defining the antimicrobial activity of ITCs. The developed QSAR models had good internal prediction power (Q2adj > 0.80) and successfully predicted activity of ITC-rich Brassicaceae extracts.
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