RESUMO
A series of 19 novel eugenol derivatives containing a 1,2,3-triazole moiety was synthesized via a two-step process, with the key step being a copper(I)-catalyzed azide-alkyne cycloaddition reaction. The compounds were assessed for their antifungal activities against Colletotrichum gloeosporioides, the causative agent of papaya anthracnose. Triazoles 2k, 2m, 2l, and 2n, at 100 ppm, were the most effective, reducing mycelial growth by 88.3, 85.5, 82.4, and 81.4%, respectively. Molecular docking calculations allowed us to elucidate the binding mode of these derivatives in the catalytic pocket of C. gloeosporioides CYP51. The best-docked compounds bind closely to the heme cofactor and within the channel access of the lanosterol (LAN) substrate, with crucial interactions involving residues Tyr102, Ile355, Met485, and Phe486. From such studies, the antifungal activity is likely attributed to the prevention of substrate LAN entry by the 1,2,3-triazole derivatives. The triazoles derived from natural eugenol represent a novel lead in the search for environmentally safe agents for controlling C. gloeosporioides.
Assuntos
Carica , Colletotrichum , Eugenol , Fungicidas Industriais , Simulação de Acoplamento Molecular , Doenças das Plantas , Triazóis , Colletotrichum/efeitos dos fármacos , Eugenol/farmacologia , Eugenol/química , Carica/química , Fungicidas Industriais/farmacologia , Fungicidas Industriais/química , Fungicidas Industriais/síntese química , Triazóis/química , Triazóis/farmacologia , Triazóis/síntese química , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Relação Estrutura-Atividade , Desenho de Fármacos , Proteínas Fúngicas/química , Estrutura MolecularRESUMO
Botrytis cinerea is a ubiquitous fungus that affects hundreds of plants, resulting in economic losses to the horticulture and fruit industry. The search for new antifungal agents is a matter of current interest. Thus, in this work a series of geranylated phenols in which the side alkyl chain has been hydrated have been synthesized, and their activity against B. cinerea has been evaluated. The coupling of phenol and geraniol has been accomplished under microwave irradiation obtaining the highest reaction yields in the shortest reaction times. Hydration of the side chain was carried out in dioxane with p-toluenesulfonic acid polymer-bound as the catalyst. All synthesized compounds were tested against B. cinerea using the growth inhibition assay and EC50 values were determined. The results show that activity depends on the number and nature of functional groups in the phenol ring and hydration degree of the geranyl chain. The most active compound is 1,4-dihydroquinone with one hydroxyl group attached at the end of the alkyl chain. Results from a molecular docking study suggest that hydroxyl groups in the phenol ring and alkyl chain are important in the binding of compounds to the active site, and that the experimental antifungal activity correlates with the number of H-bond that can be formed in the binding site.
Assuntos
Antifúngicos/farmacologia , Botrytis/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Fenóis/farmacologia , Terpenos/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Botrytis/crescimento & desenvolvimento , Fungicidas Industriais/síntese química , Fungicidas Industriais/química , Simulação de Acoplamento Molecular , Fenóis/síntese química , Fenóis/química , Relação Estrutura-Atividade , Succinato Desidrogenase/antagonistas & inibidores , Succinato Desidrogenase/química , Terpenos/síntese química , Terpenos/químicaRESUMO
A novel chemical conjugate between chitosan (CH) and riboflavin (RF) has been synthesized and characterized via Fourier transform infrared, NMR, and other spectroscopic methods. Photophysical and photochemical properties such as absorption spectra, fluorescence emission, fluorescence anisotropy, and singlet oxygen generation were characterized as well. This new biopolymer-based conjugate was designed to have an antifungal effect enhanced through antimicrobial photodynamic therapy. The antifungal effect of this conjugate (CH-RF) was compared with CH and RF against Penicillium digitatum in vitro. The conjugate showed the highest fungal growth inhibition of all systems tested at a dose of 0.5% w/v. This new biopolymer-based compound could be a promising alternative to fungicides used in citrus fruits postharvest.
Assuntos
Quitosana/química , Quitosana/farmacologia , Fungicidas Industriais/farmacologia , Penicillium/efeitos dos fármacos , Riboflavina/química , Riboflavina/farmacologia , Citrus/microbiologia , Fungicidas Industriais/síntese química , Fungicidas Industriais/química , Luz , Penicillium/crescimento & desenvolvimento , Doenças das Plantas/microbiologiaRESUMO
Invasive candidiasis, such as intra-abdominal candidiasis (IAC), is a significant cause of morbidity and mortality worldwide. IAC is still poorly understood, and its treatment represents a challenge for public health. In this study, we showed the in vitro anti-Candida activity of four alkaloid synthetic derivatives and their antifungal potential in a murine model of IAC. The biological effects of alkaloids were evaluated against Candida spp. through the determination of the minimum inhibitory concentration (MIC). For the alkaloids that showed antifungal activity, the fungicidal concentration, time-kill curve, synergism with azoles and polyenes, phenotypic effects, and the effect against virulence factors were also determined. The most active alkaloids were selected for in vivo assays. The compounds 6a and 6b were active against C. albicans, C. glabrata, and C. tropicalis (MIC 7.8 µg/mL) and showed promising antifungal activity against C. krusei (MIC 3.9 µg/mL). The compound 6a presented a potent fungicidal effect in vitro, eliminating the yeast C. albicans after 8 h of incubation at MIC. An important in vitro synergistic effect with ketoconazole was observed for these two alkaloids. They also induced the lysis of fungal cells by binding to the ergosterol of the membrane. Besides that, 6a and 6b were able to reduce yeast-to-hyphal transition in C. albicans, as well as inhibit the biofilm formation of this pathogen. In the in vivo assay, the compound 6a did not show acute toxicity and was mainly absorbed by the liver, spleen, and lung after a parenteral administration. Also, this analogue significantly reduced the fungal load of C. albicans on the kidney and spleen of animals with IAC. Therefore, these results showed that the compound 6a is a potent anti-Candida agent in vitro and in vivo.
Assuntos
Alcaloides/farmacologia , Antifúngicos/farmacologia , Candida/efeitos dos fármacos , Desenho de Fármacos , Fungicidas Industriais/farmacologia , Alcaloides/síntese química , Alcaloides/química , Antifúngicos/síntese química , Antifúngicos/química , Relação Dose-Resposta a Droga , Fungicidas Industriais/síntese química , Fungicidas Industriais/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
The antifungal activity of pterophyllin 2, pterophyllin 4, a 5-desmethyl analog of the latter and some of their synthetic intermediates, against three postharvest phytopathogenic fungi, was evaluated. The target fungi were Rhizopus stolonifer, Botrytis cinerea and Monilinia fructicola, which affect fruits worldwide, causing important economic losses. The tests were carried out with imazalil and carbendazim as positive controls. Minimum inhibitory concentrations and minimum fungicidal concentrations were determined, and the morphology of the colonies was examined microscopically. In liquid medium, it was found that pterophyllin 4 exhibited selective fungicidal activity toward M. fructicola, whereas its congener pterophyllin 2 proved to be less potent and not selective and the 5-desmethyl analog of pterophyllin 4 displayed a different activity profile. Morphological changes were observed in the colonies exposed to pterophyllin 4. The results highlighted the importance of small structural features for the antifungal behavior and also suggested that, in Nature, the pterophyllins may act as plant defenses against pathogens.
Assuntos
Cumarínicos/síntese química , Cumarínicos/farmacologia , Frutas/microbiologia , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Ascomicetos/efeitos dos fármacos , Botrytis/efeitos dos fármacos , Fungicidas Industriais/síntese química , Meliaceae/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Esporos Fúngicos/efeitos dos fármacosRESUMO
A series of benzyl-substituted thiobenzoazoles were synthesized by an environmentally friendly approach, to search for new antifungal agrochemicals. Compounds were prepared starting from 2-mercaptobenzoazoles, using KOH, benzyl halides, and water, resulting in a simple and ecological method. New antifungals were tested against a group of phytopathogenic fungi. Two compounds showed an interesting activity against Botrytis cinerea, Fusarium oxysporum, and Aspergillus spp.: 2-((4-(trifluoromethyl)benzyl)thio)benzo[d]thiazole, 3ac, and 2-((4-methylbenzyl)thio)benzo[d]thiazole, 3al. Thus, 3ac and 3al can be considered as broad spectrum antifungal agents. Furthermore, two new compounds, 2-((4-iodobenzyl)thio)benzo[d]thiazole, 3aj, and 2-(benzylthio)benzo[d]oxazole, 3ba, showed better inhibitory effect against Botrytis cinerea and Fusarium oxysporum when compared to the commercial fungicide Captan. Thus, 3aj and 3ba can be considered reduced-spectrum antifungals.
Assuntos
Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Aspergillus/efeitos dos fármacos , Azóis/química , Compostos de Benzil/química , Botrytis/efeitos dos fármacos , Fungicidas Industriais/química , Fusarium/efeitos dos fármacos , Química Verde , Testes de Sensibilidade Microbiana , Estrutura MolecularRESUMO
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.
Assuntos
Fungicidas Industriais/síntese química , Glicerol/síntese química , Triazóis/síntese química , Sobrevivência Celular/efeitos dos fármacos , Química Click , Colletotrichum , Reação de Cicloadição , Fungicidas Industriais/toxicidade , Glicerol/toxicidade , Lactuca/efeitos dos fármacos , Triazóis/química , Triazóis/toxicidadeRESUMO
Quantitative Structure-Activity Relationships (QSAR) are established with the aim of analyzing the fungicidal activities of a set of 27 active cinnamate derivatives. The exploration of more than a thousand of constitutional, topological, geometrical and electronic molecular descriptors, which are calculated with Dragon software, leads to predictions of the growth inhibition on Pythium sp and Corticium rolfsii fungi species, in close agreement to the experimental values extracted from the literature. A set containing 21 new structurally related cinnamate compounds is prepared. The developed QSAR models are applied to predict the unknown fungicidal activity of this set, showing that cinnamates like 38, 28 and 42 are expected to be highly active for Pythium sp, while this is also predicted for 28 and 34 in C. rolfsii.
Assuntos
Basidiomycota/efeitos dos fármacos , Cinamatos/química , Cinamatos/farmacologia , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Pythium/efeitos dos fármacos , Basidiomycota/crescimento & desenvolvimento , Cinamatos/síntese química , Fungicidas Industriais/síntese química , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Valor Preditivo dos Testes , Pythium/crescimento & desenvolvimento , Relação Quantitativa Estrutura-Atividade , SoftwareRESUMO
The inhibitory effects on the mycelial growth of plant pathogen Botritys cinerea have been evaluated for a series of geranylphenols substituted with one, two and three methoxy groups in the aromatic ring. The results show that the antifungal activity depends on the structure of the geranylphenols, increasing from 40% to 90% by increasing the number of methoxy groups. On the other hand, the acetylation of the -OH group induces a change of activity that depends on the number of methoxy groups. The biological activity of digeranyl derivatives is lower than that exhibited by the respective monogeranyl compound. All tested geranylphenols have been synthesized by direct coupling of geraniol and the respective phenol. The effect of solvent on yields and product distribution is discussed. For monomethoxyphenols the reaction gives better yields when acetonitrile is used as a solvent and AgNO3 is used as a secondary catalyst. However, for di- and trimethoxyphenols the reaction proceeds only in dioxane.
Assuntos
Acetatos/química , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Fungicidas Industriais/química , Fenóis/química , Terpenos/química , Acetatos/síntese química , Acetatos/farmacologia , Monoterpenos Acíclicos , Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Química Verde , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Fenóis/síntese química , Fenóis/farmacologia , Terpenos/síntese química , Terpenos/farmacologiaRESUMO
Natural geranyl compounds are known to exhibit important biological activities. In this work a series of geranylphenols were synthesized to evaluate their effect on the mycelial growth of Botrytis cinerea. Geranyl derivatives were synthesized by direct geranylation reactions between the corresponding phenol derivatives and geraniol, using BF3.OEt2 as catalyst and AgNO3 as secondary catalyst. Previously reported molecules [geranylhydroquinone (2), geranylhydroquinone diacetate (6) and geranylphloroglucinol (9)], and new substances [(E)-4-(3,7-dimethylocta-2,6-dienyl)benzene-1,2,3-triol (geranyl-pyrogallol, 7), (E)-4-(3,7-dimethylocta-2,6-dienyl)benzene-1,2,3-triyl triacetate (8), (E)-2-(3,7-dimethylocta-2,6-dienyl)benzene-1,3,5-triyl triacetate geranylphloroglucinol triacetate (10), 2,4-bis((E)-3,7-dimethylocta-2,6-dienyl)benzene-1,3,5-triyl triacetate (11), 2,6-bis((E)-3,7-dimethylocta-2,6-dienyl)-3,5-dihydroxyphenyl acetate (12)], were obtained. All compounds were characterized by IR, HRMS and NMR spectroscopic data. The inhibitory effect of the synthesized compounds on the mycelial growth of Botrytis cinerea was tested in vitro. Excepting compound 11, all substances constrained the mycelial growth of Botrytis cinerea. The antifungal activity depends on the chemical structure of geranylphenol derivatives. Compounds 2 and 9 were the more effective substances showing inhibition degrees higher than those obtained with the commercial fungicide Captan, even at lower concentrations. Monosubstitution on the aromatic nucleus by a geranyl chain seems to be more effective for the inhibition of mycelial growth than a double substitution. These results suggest that the new derivatives of geranylphenols have the ability to block the mycelial development of the plant pathogen B. cinerea and that this capacity depends strongly on the structural features and lipophilicity of the compounds.