Antifungal activity of 5 new synthetic compounds vs. Trichophyton rubrum and Epidermophyton floccosum

Four new phenolic constituents from the roots of Rumex dentatus L

Four new phenolic compounds, including two naphthalenes, musizin-8-O-β-D-(6'-O-malonyl-3''-methoxy)glucopyranoside (1) and 2-acetyl-3-methyl-1,4-naphtho-quinone-8-O-β-D-glucopyranoside (2), one chromone, (2'R)-7-hydroxy-2-(2'-hydroxypropyl)-5-methyl acetate chromone (3), and one xanthone, 2,8-dimethyl-3,6-dihydroxyxanthone (4) were isolated from the roots of Rumex dentatus L. (Polygonaceae). In addition, five known including four naphthalenes (5-8) and one chromone (9) were also obtained. Their structures were determined by means of extensive spectroscopic analysis and acidic hydrolysis. Compound 1 showed moderate antifungal activity against Epidermophyton floccosum, with inhibitory rate of 39.539 ± 0.412% at a concentration of 100 μM.

Antidermatophytic activity of some newly synthesized arylhydrazonothiazoles conjugated with monoclonal antibody

A new series of 5-arylhydrazonothiazole derivatives 5a–d has been synthesized, elucidated, and evaluated for their antidermatophytic activity. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the newly synthesized products were investigated against 18 dermatophyte fungal isolates related to Epidermophyton floccosum, Microsporum canis, and Trichophyton rubrum. The morphological alterations induced by the synthesized derivatives singly or conjugated with the monoclonal antibody were examined on spores of T. rubrum using a scanning electron microscope. The efficacy of synthesized derivative 5a applied at its respective MFC alone or conjugated with anti-dermatophyte monoclonal antibody 0014 in skin infection treatment of guinea pigs due to inoculation with one of the examined dermatophytes, in comparison with fluconazole as standard reference drug was evaluated. In an in vivo experiment, the efficiency of 5a derivative conjugated with the antibody induced 100% healing after 45 days in the case of T. rubrum and M. canis-infected guinea pigs.

Synthesis and Crystal Structures of 4,5-Dihydroimidazo[1,5-b]pyrazol-6-ones

The synthesis of previously unattainable 2,5-disubstituted 4,5-dihydroimidazo[1,5-b]pyrazol-6-ones has been developed. Electrochemical reductions of readily available 2,2,2-trichloroethylideneacetophenones were followed by reaction with hydrazine, leading to 3-aryl-5-dichloromethyl-2-pyrazolines. These were treated with isocyanates to obtain the corresponding aminocarbonyl derivatives, which were found to be able to form an otherwise almost inaccessible imidazo[1,5-b]pyrazole ring system via a one-step reaction involving internal condensation followed by hydrogen chloride elimination and aromatization. The molecular­ structures of 2-(4-methylphenyl)-5-tosyl-4,5-dihydro­imidazo[1,5-b]pyrazol-6-one, 5-dichloromethyl-N-(4-chlorophenyl)-4,5-dihydro-3-p-tolylpyrazole-1-carboxamide, and 5-(4-bromophenyl)-2-p-tolyl-4,5-dihydroimidazo[1,5-b]pyrazol-6-one were determined by X-ray crystallographic analysis.

Antifungal activity and mechanism of heat-transformed ginsenosides from notoginseng against Epidermophyton floccosum, Trichophyton rubrum, and Trichophyton mentagrophytes

The improved antifungal activity of notoginseng can be attributed to the formation of less polar ginsenosides by heat transformation.

Novel in vivo observations on double acting points of luliconazole on Trichophyton rubrum: an ultrastructural study

Scales from lesional skin of 12 patients with tinea pedis were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to gain an insight into the spatial and morphological changes of dermatophytes after application of a clinical dosage of topical luliconazole 1% cream (Lulicon® cream 1%). In all cases, Trichophyton rubrum was identified. The scales from the lesions collected before and after topical luliconazole application were fixed with glutaraldehyde and subjected to SEM and TEM. For SEM, fixed specimens were first placed in 1N-KOH and then post-fixed and observed. SEM showed a swollen appearance of fungal hyphae as an early change, and then shrinkage of them showing a flattened and twisted appearance as a later change. TEM showed cell wall alterations with initial development of and accumulation of a granular structure in the outermost layer and subsequent amorphous and electron-lucent change of the thickened inner part of the cell wall. This is the first report of dramatic morphological changes of T. rubrum before and after topical luliconazole application in vivo demonstrated by SEM and TEM. We hypothesize that luliconazole has double acting points, on the plasma membrane and cell wall, of dermatophyte hyphae.

Efficacy of some synthesized thiazoles against dermatophytes

Twelve thiazoles and their fused derivatives were tested for their antimicrobial activity against Trichophyton rubrum, T. terrestre, Epidermophyton floccosum, and Microsporum gypseum. Most of the synthesized compounds were inhibitory to the tested fungi. The most effective compound was 5-(4-ethoxybenzylidene-4,5-dihydro-4-oxothiazol-2-yl)-N,3-diphenylbut-2-namide (3c) followed by 2-(4-oxo-4,5-dihydrothiazol-2-yl)-3-phenyl-but-2-enoic acid-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-amide (2b). These compounds were more efficacious than terbinafine, the reference drug. The tested compounds caused variable reduction in the activity of keratinase of the dermatophytes, depending on the azole derivative and the test fungus. Thiazole derivatives (2b) and (3c) exhibited the highest efficacy in decreasing ergosterol biosynthesis of the tested dermatophytes. The treatment of guinea pigs with compound (3c) induced complete curing in the case of all the test dermatophytes 30days post-treatment. The percent curing for compounds (3c) and (2b) was better than the reference drug.

Synthesis of new pyrazolyl-2, 4-thiazolidinediones as antibacterial and antifungal agents

BACKGROUND

Thiazolidine-2, 4-diones (TZDs) have become a pharmacologically important class of heterocyclic compounds since their introduction in the form of glitazones into the clinical use for the treatment of type 2 diabetes. TZDs lower the plasma glucose levels by acting as ligands for gamma peroxisome proliferators-activated receptors. In addition, this class of heterocyclic compounds possesses various other biological activities such as antihyperglycemic, antimicrobial, anti-inflammatory, anticonvulsant, insecticidal, etc. TZDs are also known for lowering the blood pressure thereby reducing the chances of heart failure and micro-albuminuria in the patients with type 2 diabetes.

RESULTS

We have described herein the synthesis of three series of compounds, namely, ethyl 2-((Z)-5-((3-aryl-1-phenyl-1H-pyrazol-4-yl)methylene)-2, 4-dioxothiazolidin-3-yl)acetates (4), methyl 2-((Z)-5-((3-aryl-1-phenyl-1H-pyrazol-4-yl)methylene)-2, 4-dioxothiazolidin-3-yl)acetates (5), and 2-((Z)-5-((3-aryl-1-phenyl-1H-pyrazol-4-yl)methylene)-2, 4-dioxothiazolidin-3-yl)acetic acids (6). The compounds 4 and 5 were synthesized by Knoevenagel condensation between 3-aryl-1-phenyl-1H-pyrazole-4-carbaldehydes (1) and ethyl/methyl 2-(2, 4-dioxothiazolidin-3-yl)acetates (3, 2) in alcohol using piperidine as a catalyst. The resultant compounds 4 and 5 having ester functionality were subjected to acidic hydrolysis to obtain 6. All the new compounds were tested for their in vitro antibacterial and antifungal activity.

CONCLUSIONS

Knoevenagel condensation approach has offered an easy access to new compounds 4-6. Antimicrobial evaluation of the compounds has shown that some of the compounds are associated with remarkable antifungal activity. In case of antibacterial activity, these were found to be effective against Gram-positive bacteria. However, none of the compounds were found to be effective against Gram-negative bacteria.

Synthesis and antifungal activity of some new 3-hydroxy-2-(1-phenyl-3-aryl-4-pyrazolyl) chromones

Seven new 3-hydroxy-2-(1-phenyl-3-aryl-4-pyrazolyl) chromones 4a-g have been synthesized by the oxidation of 2-hydroxychalcone analogues of pyrazole 3a-g with hydrogen peroxide (H(2)O(2)) in KOH-MeOH by Algar Flynn Oymanda (AFO) reaction. The structures of the compounds 4 were established by the combined use of (1)H NMR, IR and mass spectra. All the seven compounds were tested in vitro for their antifungal activity against three phytopathogenic fungi, namely Helminthosporium species, Fusarium oxysporum and Alternaria alternata. Five compounds 4a, 4b, 4c, 4e and 4f were associated with substantially higher antifungal activity than commercial antifungal compound Actidione (cycloheximide) against all three phytopathogenic fungi.