Fungicidal action

The a,(3-unsaturated aldehyde moiety in these molecules was responsible for their fungicidal action (5). This was described to result from the structural disruption of the cell membrane (6). (Adapted from Kubo et ah, 2001)... 

W. Koller, Antifungal Agents with Target Sites in Sterol Function and Biosynthesis , in Target Sites of Fungicide Action , ed. W. Koller, CRC Press, Boca Raton, FL, 1992, pp. 119-206. 

Certain selenium compounds exhibit bactericidal and fungicidal action,4 and selenious acid may be used as a herbicide against dandelion, Canada thistle and burdock. 

W. Knller, ed., Target Sites of Fungicide Action, CRC Press, Boca Raton, Fla., 1992. 

As indicated above, although less data is available that for herbicides, fungicides also have been implicated in the appearance of variations in phenolic metabolism. Molina et al. [116] have demostrated that the systemic acquired resistance signal transduction pathway, a salicylic acid-dependent plant-defence mechanism, mediates fungicide action in the plant. 

Yeasts (including Candida albicans) and dermatophytes are usually sensitive, although chlorhexidine fungicidal action is subject to species variation, as are other agents. The effective concentrations of chlorhexidine agents for bactericidal, bacteriostatic, sporicidal, and sporostatic organisms are listed in Table 2.13. 

Owing to its broad spectrum of activity and fungicidal action, amphotericin B remains the drug of choice for nearly all life-threatening mycotic infections. It is often used as the initial induction... 

The chemical variability of the 1-substituted azoles can already be recognized from the subgroups presented thus far, Including the N-tritylazoles and their analogues, the N-diphenylmethylazoles, the phenethylazoles and the azolyl-0,N-acetals. The only essential feature is the imidazole or 1,2,4-triazole ring. The quality of the fungicidal action and of the properties necessary for practical use are determined only by the selection of a suitable substituent R. 

The chlorinated phenols, particularly pentachlorophenol (Figure 16.7) and the trichlorophenol isomers, have been widely used as wood preservatives. Applied to wood, these compounds prevent wood rot through their fungicidal action and prevent termite infestation because of their insecticidal properties. Both cause liver malfunction and dermatitis. Contaminant polychlorinated dibenzodiox-ins may be responsible for some of the observed effects. 

The use of pyrazole derivatives in medicine is undoubtedly the principal practical application. Certain alkylpyrazoles have shown quite significant bacteriostatic, bacteriocidal, and fungicidal actions.12-16 In this respect sulfonamides based on pyrazole are of particular interest, e. g. Orisul (1) which has a prolonged bacteriostatic action in vivo.17-20... 

Cl Cl germinating fungal cells, leading to disruption of glycolysis and energy production, fungistasis and fungicidal action... 

Horsfall, J. G., Principles of Fungicidal Action, Chronica Botanica Co.,... 

The majority of phenols, especially those containing chlorine, are too phytotoxic to permit their use as agricultural fungicides. They are widely used as industrial fungicides. Cresols contribute to the fungicidal action of creosote which is used as a timber preservative. Pentachlorophenol, another chlorinated phenol, and its esters are widely used as industrial biocides for the protection of such materials as wood and textiles. 

The spectrum of biological activity displayed by tetramic acid-containing natural products is remarkable in its diversity it includes potent antibiotic, antiviral and antiulcerative properties, cytotoxicity and mycotoxicity, the inhibition of tumors (in mice and humans) as well as fungicidal action." Other members of this class are responsible for the pigmentation of certain molds and sponges. 

Thiophanate methyl (74) is, like thiabendazole (54), a member of the benzimidazole group of fungicides since it is metabolised in vivo to carbendazim (83), which is the active entity. Thiophanate methyl is synthesised by condensation of o-phenylenediamine (82) with potassium thiocyanate and methyl chloroformate (Scheme 17). The benzimidazoles owe their fungicidal action to the inhibition of cell division in the fungus due to interference with the microtubular assembly. 

Its fungicidal action is based on ergosterol depletion and the accumulation of ignosterol in fungal cytoplasmic membrane, which causes the fungal cell wall to thicken and chitin to be deposited. 

Knowledge on the structure of the receptor and the molecular interactions involved in binding of phenylamides is a prerequisite to understand their fungicidal action at the molecular level. Once a three-dimensional model of the receptor can be constructed, it may be possible to redesign phenylamide structures or even design completely new structures that fit into the binding site. 

The possibility that fungicidal action may arise from the liberation of an aglycone from its glycoside within the tissues of the fungus provides an approach to systemic fungicides which is... 

According to the investigations of Fattinger (1950), the fungicidal action of copper is enhanced by cadmium, cobalt, nickel and zinc compounds in Alternaria tenuis and Trichothecium roseum cultures. Zinc sulfate (ZnSO 7HjO) was tried in place of copper sulfate its effect however was inferior to that of the copper compound. Nevertheless, it is still used against rosette disease a physiological disease caused by zinc deficiency. 

McCallan and Wilcoxon (1936) were the first to report that fungal spores can solubilise copper. In the bathing medium of Neurospora sitophilus spores they detected malic acid and certain amine acids which were able to dissolve copper even from dry deposits of Bordeaux mixture. In this case, complex compounds of the copper(II) ions are formed and, as shown already by the investigations of Bodnar and Terenyi (1930), the fungicidal action of copper(II) complexes proved to be superior to that of copper(II) ions. Horsfall et al. (1937) made similar observations. This phenomenon can be explained by the much higher lipoid solubility of copper(II) complexes (Horsfall, 1957 Durkee, 1958) which allows them to penetrate the cell more easily. They dissociate in the cell, and copper(II) ions are liberated. Thus, complex-forming compounds seem to aid the transport of the... 

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