• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.1-7
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• 2007

We have developed an efficient synthesis of 2(5H)-furanones using the microwave-promoted Suzuki-Miyaura coupling reaction and evaluated their fungicidal activities against six fungal pathogens in vivo. In addition, 2-cyclopentenones or 2-cyclohexenones possessing one or two additional methylene groups instead of the oxygen in the 2(5H)-furanone skeleton were also prepared by using the similar method. As the results of in vivo fungicidal screening against 6 plant diseases, a few derivatives displayed specific fungicidal activities against rice blast and tomato late blast. Further studies toward the optimization of the chemical structures are necessary for the development of novel fungicides with high potency.

• The Korean Journal of Pesticide Science
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• v.15 no.1
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• pp.1-7
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• 2011

In order to enhance the fungicidal activity of the thifluzamide formulation against rice sheath blight, the surfactants which was able to facilitate the foliar uptake or increase the leaf deposit of thifluzamide on rice plants were selected, and the formulations containing the surfactants were tested to compare the fungicidal efficacy against the rice sheath blight with a control WP formulation. The WP suspension containing dodecaethylene glycol monohexadecyl ether as an activator increased the foliar uptake of thifluzamide on rice plants, but its fungicidal efficacy against rice sheath blight was decreased. The addition of the combined surfactants with either heptaethylene glycol monoisododecy ether or heptaethylene glycol monotridecyl ether and sodium dioctylsulfosuccinate to WP suspension increased the leaf deposition of thif1uzamide at around 5 times of that without a spreader-sticker that median control concentrations of thifluzamide against rice sheath blight were decreased to 4.4 mg $L^{-1}$ and 3.4 mg $L^{-1}$, respectively.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1324-1329
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• 2007

Resveratrol (3,5,4'-trihydroxystilbene) is a naturally occurring, multi-biofunctional chemical existing in grapes and various other plants as a polyphenol type, and it is one of the best known natural anticancer and antiatherosclerosis reagents. In this study, we investigated the antifungal action by resveratrol in Candida albicans, which is a human infectious fungi as an agent of candidiasis. Resveratrol displayed potent fungicidal activity in an energy-dependent manner, without any hemolytic effects against human erythrocytes. It was found that the serum-induced mycelial forms, which playa crucial role in the pathogenesis of C. albicans during host tissue invasion, were disrupted by resveratrol. To understand the correlation between lethal effects and resveratrol action, we examined the physiological changes of C. albicans. A significant accumulation of intracellular trehalose was induced by stress responses to resveratrol action, and a remarkable arrest of cell-cycle processes at the S-phase in C. albicans occured. Therefore, the fungicidal effects of resveratrol demonstrate that this compound is a potential candidate as an antifungal agent in treating infectious diseases by candidal infections.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1703-1706
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• 2012

Rice blast is the most serious disease of rice due to its harmfulness and its world wide distribution. $Magnaporthe$ $grisea$ is the cause of rice blast disease and destroys rice enough to feed several tens of millions of people each year. Fungicides are commonly used to control rice blast. But $M.$ $grisea$ acquires resistance to chemical treatments by genetic mutations. 2-Phenylimino-1,3-thiazolines were proposed as a novel class of fungicides against $M.$ $grisea$ in the previous study. To develop compounds with a higher biological activity, a new series of 2-phenylimino-1,3-thiazolines was synthesized and its fungicidal activity was determined against $M.$ $grisea$. The QSAR analysis was carried out on a series of 2-phenylimino-1,3-thiazolines. The QSAR results showed the dependence of fungicidal activity on the structural and physicochemical features of 2-phenylimino-1,3-thiazolines. Our results could be used as guidelines for the study of the mode of action and further design of optimal fungicides.

• The Korean Journal of Pesticide Science
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• v.9 no.2
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• pp.132-139
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• 2005

New ${\beta}$-methoxyacrylate derivatives 1-4 having thio-enol side chain were prepared and subjected to in vivo screening for fungicidal activity against phytopathogenic fungi and many of them showed good fungicidal activities against especially rice blast and wheat leaf rust at 100 ppm.

• Applied Biological Chemistry
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• v.37 no.3
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• pp.189-193
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• 1994

The hydrolysis of fungicidal N-[1-(benzotriazol-1-yl)benzyl]aniline (BBA) molecule in the presence of cationic cetyltrimethylammonium bromide (CTABr) and anionic sodium laurylsulfate (NaLs) micellar solutions has been studied kinetically. The Micellar catalysis effect shows that the rate is slightly accelerated by the addition of the anionic NaLs at high pH and the binding constant (Ks) is $1.45{\times}10^4M^{-1}$. This result presumably is due to the electrostatic stabilization by the anionic micelle of the developing carbocation in the transition state rather than the hydrophobic character (${\pi}$: 4.93) of (BBA).

• Archives of Pharmacal Research
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• v.28 no.5
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• pp.557-560
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• 2005

Resveratrol, a phenolic antioxidant found in grapes, has been known to mediate various biological activities on the human body. In the present study, we tested the antifungal a ctivity of resveratrol against human pathogenic fungi before carrying out further studies to elucidate the antifungal mechanism(s) of resveratrol. Resveratrol displayed potent antifungal activity against human pathogenic fungi at concentration levels of 10-20 ${\mu}g$/mL. Furthermore, time-kill curve exhibited fungicidal effect of resveratrol on C. albicans, but the compound had no hemolytic activity against human erythrocytes. The destruction of C. albicans cells by resveratrol was confirmed by scanning electron microscopy. These results suggest that resveratrol could be employed as a therapeutic agent to treat fungal infections of humans.

• Applied Biological Chemistry
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• v.50 no.3
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• pp.187-191
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• 2007

Comparative molecular similarity indice analysis (CoMSIA) models on the fungicidal activities of N-phenyl substituents (X) in N-phenyl-O-phenylthionocarbamate derivatives against rice sheath blight (Rhizoctonia solani: RS) and phytophthora blight (Phytophthora capsici: PC) were derived. Also, the characterizations of H-bonds between substrates and ${\beta}-tubulin$ were discussed quantitatively. It was revealed that, from the contour maps of CoMSIA models, the H-bond acceptor field contributed the most highly to fungicidal activity for two fungi in common. It is predicted that the selectivity in the fungicidal activity between two fungi is caused by results from the roles of H-bond donor disfavor functional groups in RS and H-bond acceptor disfavor functional groups in PC when these two groups induced at meta- and para-position on the N-phenyl ring. And also, if the substituents (X) are steric disfavor group, negative charge favor groups are introduced at the metaposition in RS and H-bond acceptor group is introduced at the para-position in PC, the antifungal activity against two fungi will be likely able to be increased.

• The Korean Journal of Pesticide Science
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• v.2 no.2
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• pp.22-28
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• 1998

Twenty six derivatives of bis-aromatic ${\alpha},{\beta}$-unsaturated ketones as substrate(S) were synthesized and their fungicidal activities in vivo against rice blast(Pyricularia oryzae), tomato leaf blight(Phytophtora infestans) and barley powdery mildew(Erysiphe graminis) were examined. The quantitative structure-activity relationship(QSAR) between the fungicidal activities($pI_{50}$) and a physicochemical parameters of substitued($R_{2}$) phenyl backbone group in 2-thienyl and 2-furyl substituents were analyzed with regression equations. The activities of substituted($R_{2}$) phenyl backbone in 2-thienyl substituents, $1{\sim}10$ would depend largely on the resonance(R>0), molecular refractivity($M_{R}<0$) and optimal length of substituent(($L_{1})opt.=5.50{\AA}$). Whereas, in case of 2-furyl substituents, $10{\sim}26$ optimal molar attraction constant ($F_{opt}=0.49{\sim}l.11$), optimal steric($Es_{opt}=1.78$) constant and indicator variables(Io & Ip) for position of substituents. The fungicidal activity relationship of 2-thienyl substituents against Pyricularia oryzae and Phytophtora infestans have been a reciprocal proportioned.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.38-43
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• 2008

3D-QSARs on the fungicidal activity with N-phenylbenzenesulfonamide and N-phenyl-2-thienylsul-fonamide analogues (1-34) against Fusarium wilt (Fusarium oxysporum) were discussed quantitatively using CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indices analysis) methods, respectively. Generally, the CoMFA models have better predictability and fitness than the CoMSIA models. The fungicidal activities, according to the information of the optimized CoMF A 2 model $(r^2\;_{cv.}=0.523\;&\;r^2\;_{ncv.}=0.956)$, were dependent on the electrostatic field of the N-phenylbenzenesulfonamide analogues. Therefore, from the results of graphical analyses on the contour maps with the optimized CoMFA 2 model, it is expected that the characters of $R_4-substituents$ on the N-phenyl ring as steric and positive charge favor will contribute to the fungicidal activity against Fusarium wilt.