Synthesis of Novel Glycerol-Derived 1,2,3-Triazoles and Evaluation of Their Fungicide, Phytotoxic and Cytotoxic Activities.

The synthesis of a series of 1,2,3-triazoles using glycerol as starting material is described. The key step in the preparation of these triazolic derivatives is the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC), also known as click reaction, between 4-(azidomethyl)-2,2-dimethyl-1,3-dioxolane (3) and different terminal alkynes. The eight prepared derivatives were evaluated with regard to their fungicide, phytotoxic and cytotoxic activities. The fungicidal activity was assessed in vitro against Colletotrichum gloeosporioides, the causative agent of papaya anthracnose. It was found that the compounds 1-(1-((2,2-dimethyl-1,3-dioxolan-4-yl)methyl)-1H-1,2,3-triazol-4-yl)-cyclo-hexanol (4g) and 2-(1-((2,2-dimethyl-1,3-dioxolan-4-yl)methyl)-1H-1,2,3-triazol-4-yl)propan-2-ol (4h) demonstrated high efficiency in controlling C. gloeosporioides when compared to the commercial fungicide tebuconazole. The triazoles did not present any phytotoxic effect when evaluated against Lactuca sativa. However, five derivatives were mitodepressive, inducing cell death detected by the presence of condensed nuclei and acted as aneugenic agents in the cell cycle of L. sativa. It is believed that glycerol derivatives bearing 1,2,3-triazole functionalities may represent a promising scaffold to be explored for the development of new agents to control C. gloeosporioides.

New Perspective on the Use of α-Bisabolol for Weed Control.

The indiscriminate use of synthetic herbicides reduces its effectiveness. Bioherbicides produced with metabolites emerge as an alternative to managing weeds. We aimed to analyze the phytotoxic potential of the essential oil of Vanillosmopsis arborea (EOVA) and the α-bisabolol molecule, its main component. We evaluated the effects of EOVA and α-bisabolol at different concentrations on the germination, growth, antioxidant metabolism, and photosynthesis of different species. EOVA and α-bisabolol showed promising phytotoxic effects on the germination and initial growth of the weed Senna occidentalis, inhibiting the activity of the antioxidant enzymes and increasing lipid peroxidation. α-Bisabolol reduced the weed seedling growth by inducing oxidative stress, which suggests a greater role in postemergence. Moreover, in the weed postemergence, both EOVA and α-bisabolol caused damage in the shoots, reduced the chlorophyll content, and increased lipid peroxidation besides reducing photosynthesis in S. occidentalis. Overall, we suggest the promising action of α-bisabolol and EOVA as bioherbicides for weed control.

Anxiety-associated behavior and genotoxicity found in adult Danio rerio exposed to tebuconazole-based commercial product.

The effects of different concentrations of commercial product based on tebuconazole, on adults of Danio rerio, were evaluated through novel tank diving test and micronucleus and comet assay tests. A total of 320 adult D. rerio were divided into eight tanks and exposed to concentrations of 0; 100; 200 and 300 µg/L the commercial product based on tebuconazole, with their respective replicates at 24, 72 and 96 h. The results showed a behavioral deviation of zebrafish and a significant (p < 0.05) increase in DNA damage as a function of exposed time and different concentrations of the commercial product in relation to the negative control. The results obtained in this study allow to conclude that tebuconazole has effects on adults of Danio rerio, inducing genotoxicity and mutagenicity, as well as altering neurological functions related to the change in the behavior of adults.

Acute toxicity of Jatropha curcas oil on plant cell cycle / Toxicidade aguda do óleo de jatropha curcas no ciclo celular de plantas

Today, a great interest in Jatropha-based products exists worldwide, mainly for the production of biofuel.However, the oil obtained from this plant is known to be toxic due to contained curcins andphorbol esters. Bioassays, including plant cytogenetic assays based on cell cycle observation, are useful for determining the toxicity of J. curcas oil. Hence, the aim of this study was to describe the mechanism of action of J. curcas oil by cell cycle analysis using Lactuca sativa as plant testing model. A decrease in root growth was observed, closely related to the reduction in mitotic index, along with an increase in condensed nuclei. J. curcas chemicals act both as aneugenic agents, leading to the formation of lagged, sticky chromosomes and c-metaphase cells, as well as clastogenic agents, inducing the formation of chromosome bridges and fragments. The cytotoxicity and genotoxicity of phorbol esters and other chemical components of J. curcas oil was determined and discussed.

Um grande interesse mundial existe em produtos à base de pinhão manso, principalmente para a produção de biocombustíveis. No entanto, o óleo obtido a partir desta planta é conhecidamente tóxico por conter curcina e ésteres de forbol. Bioensaios, incluindo ensaios citogenéticos em plantas-modelo com base na observação do ciclo celular, são úteis para determinar a toxicidade do óleo de J. curcas. Assim, o objetivo deste estudo foi descrever o mecanismo de ação do óleo de J. curcas por análise do ciclo celular usando Lactuca sativa como modelo de teste em plantas. Foi observada uma redução no crescimento das raízes, intimamente relacionada com a redução do índice mitótico e com um aumento de núcleos condensados. Os constituintes químicos de J. curcas atuam simultaneamente como agentes aneugênicos, levando à formação de cromossomos perdidos e pegajosos e células em c-metáfase, bem como agentes clastogênicos, induzindo a formação de pontes e fragmentos cromossômicos. A citotoxicidade e genotoxicidade do éster de forbol e outros componentes químicos do óleo de J. curcas foram determinados e discutidos.