The enzymatic hydrolysis of glucosinolates (GLs), typical compounds of
Cruciferae, produces
molecules with fungitoxic activity. Eleven GLs and their enzymatic
hydrolysis products obtained
by myrosinase were tested in vitro against Fusarium
culmorum. Toxicity of hydrolysis products
from glucoiberin, glucotropaeolin, sinigrin, and epiprogoitrin were
assayed on eight plant pathogenic
fungi. The results showed (i) the native GLs showed no fungitoxic
activity, whereas their hydrolysis
products inhibited fungal growth depending on their chemical structure;
(ii) the hydrolysis products
from glucoiberin, glucoerucin, glucocheirolin, and glucotropaeolin were
the most effective, with 50%
inhibition of fungal growth at 0.1 mg/mL; (iii) the fungitoxic activity
of hydrolysis products obtained
from glucoiberin, glucotropaeolin, sinigrin, and epiprogoitrin was
confirmed on eight pathogenic
fungi, with different responses depending on their chemical structure;
(iv) the most effective
hydrolysis products were those from glucoiberin, showing
EC50 values of 0.05 mg/mL on Rhizoctonia
solani, Sclerotinia sclerotiorum, Diaporthe
phaseolorum, and Pythium irregulare and a
minimum
inhibitory concentration varying from 0.1 to 1.2 mg/mL.
Keywords: Cruciferae; isothiocyanates; Fusarium culmorum;
myrosinase
The root-knot nematode Meloidogyne incognita (Kofoid et White) Chitw. is responsible for large yield losses in several horticultural crops. Fumigation with chemicals has been efficient in fighting this soil pest, but it clearly shows a negative environmental impact. Thus, it is necessary to find an environmentally friendly alternative to control this nematode and meet the requirements imposed by world regulation to ban some chemical fumigants in the world after 2005. The glucosinolate-myrosinase system, typical of the Brassicaceae family, appears to be an important natural alternative for the control of several soilborne pests and pathogens. The aim of this study was to evaluate, in vitro, the biocidal activity of 11 glucosinolates and their degradation products on second-stage juveniles of the root-knot nematode M. incognita expressed by the nematicidal (LD(50)) and immobilization effects, after 24 and 48 h. None of the intact glucosinolates had any biological effect. After myrosinase addition, their hydrolysis products (essentially isothiocyanates) resulted in highly different biocidal activities. Among the hydrolysis products of the tested glucosinolates, 2-phenylethyl, benzyl, 4-methylthiobutyl, and prop-2-enyl isothiocyanate showed the stronger activity, with an LD(50) at concentrations of 11, 15, 21, and 34 microM, respectively. On the basis of the in vitro test results, new genotypes of Brassicaceae had been selected for high content in the roots of the glucosinolates generating the more active isothiocyanates and their agronomic performances verified in view of a full-field application as catch crop plants. With this aim, the qualitative and quantitative glucosinolate contents in the roots of these potentially nematicidal plants are also reported and discussed.
Background and Purpose
Hydrogen sulfide (H2S)‐releasing agents are viewed as potential antihypertensive drugs. Recently, natural isothiocyanates emerged as original H2S‐donor agents. Among them, erucin, present in some edible cruciferous plants, shows suitable H2S‐releasing properties and features of “druggability.” The aim of this work was to investigate the erucin‐mediated release of H2S inside vascular cells, its vasorelaxing effects, and activity on BP of normo and hypertensive animals.
Experimental Approach
Intracellular H2S‐release and the hyperpolarizing effect of erucin were tested using fluorescent dye, in human aortic smooth muscle cells (HASMCs). Its direct vasorelaxing effect and ability to inhibit noradrenaline‐induced vasoconstriction were evaluated on endothelium‐intact or ‐denuded rat aortic rings. Its vasodilator properties were tested in coronary arteries using Langendorff‐perfused rat hearts. Finally, erucin's antihypertensive activity was evaluated in vivo in normotensive and spontaneously hypertensive rats (SHRs) by recording systolic BP using the tail‐cuff method.
Key Results
Erucin induced the release of H2S inside HASMCs. Moreover, erucin hyperpolarized the membrane of HASMCs membrane in a concentration‐dependent manner. It induced vasodilatation of rat aortic rings, in endothelium‐denuded vessels. This effect was further improved by the presence of endothelial NO. When pre‐incubated with rat aortic rings, erucin induced concentration‐dependent inhibition of noradrenaline‐induced vasoconstriction. Erucin did not affect basal coronary flow but restored the flow to normal in pre‐contracted coronary vessels. Finally, in vivo, erucin decreased systolic BP in SHRs by about 25%, and restored the BP to values observed in normotensive rats.
Conclusions and Implications
Erucin is an H2S donor endowed with vasorelaxing and antihypertensive effects.
Linked Articles
This article is part of a themed section on Hydrogen Sulfide in Biology & Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.4/issuetoc
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