Chiara Beatrice Vicentini

Chemical characterization and antifungal activity of essential oil of capitula from wild Indian Tagetes patula L

Summary.The essential oil extracted by steam distillation from the capitula of Indian Tagetes patula, Asteraceae, was evaluated for its antifungal properties and analyzed by gas chromatography and gas chromatography–mass spectrometry. Thirty compounds were identified, representing 89.1% of the total detected. The main components were piperitone (24.74%), piperitenone (22.93%), terpinolene (7.8%), dihydro tagetone (4.91%), cis-tagetone (4.62%), limonene (4.52%), and allo-ocimene (3.66%). The oil exerted a good antifungal activity against two phytopathogenic fungi, Botrytis cinerea and Penicillium digitatum, providing complete growth inhibition at 10 µl/ml and 1.25 µl/ml, respectively. The contribution of the two main compounds, piperitone and piperitenone, to the antifungal efficacy was also evaluated and ultrastructural modifications in mycelia were observed via electron microscopy, evidencing large alterations in hyphal morphology and a multisite mechanism of action.

Pyrazolo-triazoles as light activable dna cleaving agents

In view of the continuous interest in new DNA cleaving compounds, both for the development of new therapeutic agents and for the possible use as reagents in nucleic acids research, a few pyrazolo[3,4-d][1,2,3]triazole derivatives have been obtained and investigated for their antiproliferative activity and capability to cleave DNA, after light-activation. A possible in situ activation, i.e. in neoplastic tissues, of less cytotoxic derivatives, may lead to potential antitumor compounds endowed with high therapeutic indexes.

A facile synthesis of pyrazole, isoxazole and pyrimidine ortho-dicarboxylic acid derivatives via β-enaminoketoesters

Abstract β-Alkoxycarbonyl-β-enaminoketoesters 1a,b react with hydrazines to give pyrazole ortho -dicarboxylic acid derivatives 3, 4 and 5 . Similarly 1a reacts with hydroxylamine to give isoxazole 6 and with amidines and guanidine to give pyrimidine ortho -dicarboxylic acid monoesters 7a-c . The total or partial hydrolysis of selected heterocycles afforded the dicarboxylic acids 8, 9 and 10 and the dicarboxylic acid monoesters 11 and 12 .

Mannan changes induced by 3-methyl-5-aminoisoxazole-4-thiocyanate, a new azole derivative, on Epidermophyton floccosum

The antifungal activity of 3-methyl-5-aminoisoxazole-4-thiocyanate, a new azole derivative, was studied on the dermatophyte Epidermophyton floccosum. The compound strongly inhibited the in vitro growth of two different strains of the fungus and even induced profound morphogenetic anomalies. Optical and electron microscopy showed that such treatment targets the endomembrane system, particularly the plasmalemma, causing abnormal extrusion of the wall mannans. This results in improper arrangement of the different parietal materials; the walls are thus weak and subject to subapical rupture which terminates cell growth and elongation of the hypha. The morphological results and the preliminary biochemical data on fungal sterols suggest that this compound employs an action mechanism similar to that of other azoles used in therapy.

Synthesis, antioxidant and antimicrobial activity of a new phloridzin derivative for dermo-cosmetic applications.

The phenolic compound phloridzin (phloretin 2′-O-glucoside, variously named phlorizin, phlorrhizin, phlorhizin or phlorizoside) is a prominent member of the chemical class of dihydrochalcones, which are phenylpropanoids. Phloridzin is specifically found in apple and apple juice and known for its biological properties. In particular we were attracted by potential dermo-cosmetic applications. Here we report the synthesis, stability studies and antimicrobial activity of compound F2, a new semi-synthetic derivative of phloridzin. The new derivative was also included in finished formulations to evaluate its stability with a view to a potential topical use. Stability studies were performed by HPLC; PCL assay and ORAC tests were used to determine the antioxidant activity. F2 presented an antioxidant activity very close to that of the parent phloridzin, but, unlike the latter, was more stable in formulations. To further explore potential health claims, antifungal activity of phloridzin and its derivative F2 were determined; the results, however, were rather low; the highest value was 31,6% of inhibition reached by F2 on Microsporum canis at the highest dose.

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

The antifungal activity of five new synthetic compounds was evaluated on two dermatophytes: Epidermophyton floccosum and Trichophyton rubrum. The data showed that the imidazo-pyrazole and pyrazolo-thiazoles were not particularly effective, while the two pyrazole-thiocyanates proved highly active on both fungi. The most active 5-amino-3-methyl-1-phenylpyrazolo-4-thiocyanate was chosen to perform SEM and TEM morphological studies on both fungi. Both SEM and TEM observations revealed interesting alterations on the two dermatophytes, particularly involving the endomembrane system.

A new general and efficient synthesis of imidazo[4,5-c]pyrazole derivatives

Abstract A new general and efficient synthesis of imidazo[4,5-c]pyrazoles ( 5 ) is reported. The key step of this synthetic procedure is the intramolecular cyclodehydration of 5 -alkylamino- 4 -nitrosopyrazoles ( 4 ), which affords the title compounds ( 5 ) in good yields.

Synthesis of a novel series of imidazo[4,5-c]pyrazole derivatives and their evaluation as herbicidal agents

Ever changing problems in agricultural weed control require periodic introduction of new herbicides. Imidazo[4,5‐c]pyrazoles, which were considered of interest as potential herbicides, were synthesized and examined for the pre‐emergence, post‐emergence, and post‐transplant control of weeds in rice against broadleaf and grass weed species. The data obtained suggest that some imidazo[4,5‐c]pyrazoles have potential herbicidal activity against a wide range of weeds, with 5‐methyl, 5‐thiomethyl, and 5‐unsubstituted derivatives being the most effective. No herbicidal activity was observed in the 5‐methylsulfonylimidazo[4,5‐c]pyrazole and imidazo[4,5‐c]pyrazolone series.

A new route to the synthesis of imidazo [4,5-c]pyrazoles

Abstract A new synthesis of imidazo [4,5-c] pyrazoles, obtained through cyclisation of 4-nitroso-5-alkylamino-pyrazoles, is described.

Synthesis and biological evaluation of a series of substituted pyrazolo[3,4-d]-1,2,3-triazoles and pyrazolo[3,4-d]oxazoles.

In view of the biological relevance of triazole‐based heterocyclic structures as antifungal, antiviral, and antitumor agents, we have synthesized a series of substituted pyrazolo[3,4‐d]‐1,2,3‐triazoles (2e–h, 2j, 4b) which we evaluated for their cytostatic and antiviral (HIV‐1 included) activity and for their capability to inhibit the multiplication of various human pathogenic fungi and bacteria. Moreover, the biological activities of a few compounds, namely pyrazolo[3,4‐d]oxazoles (3a–e) and pyrazolo[3,4‐d]‐1,2,3‐triazoles (2a–d, 4a, 5), previously obtained by us but not investigated for their biological activity, were also studied. Only compounds 3a–e were endowed with a significative antiproliferative activity on the human lymphoblastoid cell line MT‐4 cells. All pyrazole derivatives proved ineffective in protecting cell cultures against the HIV‐1‐induced cytopathogenicity, and none of the compounds was active against the bacteria and fungi tested.