Giovanna Simonetti

Non-Cancer Uses of Histone Deacetylase Inhibitors: Effects on Infectious Diseases and β-Hemoglobinopathies+

After the approval of suberoylanilide hydroxamic acid (SAHA, vorinostat, Zolinza) for the treatment of cutaneous T cell lymphoma (CTCL), a number of HDAC inhibitors (HDACi) are currently in Phase II or III clinical trials (alone or in combination) for the treatment of a great number of tumors. In addition to these cancer uses, HDACi can be successfully used in non-cancer diseases. In this review we focused on the uses of HDACi in some infectious diseases and beta-hemoglobinopaties. In C. albicans cultures, HDACi increased the frequency of cell switching (a relevant virulence trait) in the white-to-opaque transition, reduced the azole trailing effect through reduction in azole-dependent upregulation of CDR and ERG genes, and inhibited the fluconazole-dependent resistance induction. Moreover, they inhibited germination in several strains, and caused 90% reduction in the adherence of C. albicans to human cultured pneumocytes. In HIV-1-infected cells, the treatment with HDACi reactivates the HIV-1 expression in latent cellular reservoirs. Thus, the use of HDACi as adjuvant to highly active antiretroviral therapy (HAART) can represent a new potential therapeutic strategy to eradicate the viral infection. A number of HDACi have been reported as active against P. falciparum infection. Two recent papers show some 2-aminosuberic acid-based compounds as well as a series of phenylthiazolyl suberoyl hydroxamates as very potent and selective antimalarial agents. Among the many agents capable to perform post-natal reactivation of fetal hemoglobin production, HDACi for their capacity to de-repress gamma-globin gene expression in adult red cell, are presently considered promising molecules for personalized therapy of beta-hemoglobinopathies.

Plant tissue electrode for the determination of atrazine

Abstract This work presents a new method for the simple and inexpensive determination of atrazine. The method is based on the use of a novel, partially disposable, plant tissue bioelectrode, which is sensitive to a variety of mono- and polyphenols. The biosensor is obtained by coupling a thin slice of potato ( Solanum tuberosum ) tissue, which contains high levels of the enzyme polyphenoloxidase (PPO), to a commercial O 2 -selective Clark electrode. The concentration of atrazine in aqueous samples can be determined thanks to its inhibitory power toward the catalytic activity of PPO. The low cost of this device and its good analytical performance suggest its application in the field of environmental analysis, especially in the continuous monitoring of atrazine in risk areas.

Synthesis and antifungal activity of a new series of 2-(1H-imidazol-1-yl)- 1-phenylethanol derivatives

A new series of aromatic ester and carbamate derivatives of 2-(1H-imidazol-1-yl)-1-phenylethanol were synthesized and evaluated for their antifungal activity towards Candida albicans and non-albicans Candida species strains. The aromatic biphenyl ester derivatives 6a-c were more active than the reference compound fluconazole. 6c possesses a MIC mean values of 1.7 ± 1.4 μg mL(-1)vs C. albicans and 1.9 ± 2.0 μg mL(-1)vs non-albicans Candida species strains. The racemic mixtures of 6a, b were purified to afford the pure enantiomers. The (-) isomers were up to 500 times more active than (+) isomers. (-)-6a and (-)-6b were thirty and ninety times more active than fluconazole towards C. krusei strain respectively. The racemates of 6a-c showed low cytotoxicity against human monocytic cell line (U937) with 6a demonstrating a CC(50) greater than 128 μg mL(-1).

Activity of caffeic acid derivatives against Candida albicans biofilm

The aim of this study was to evaluate the caffeic acid (1) and ester derivatives (2-10) against Candida albicans biofilm and to investigate whether these compounds are able to inhibit the biofilm formation or destroy pre-formed biofilm. Caffeic acid ester 7, cinnamic acid ester 8 and 3,4-dihydroxybenzoic acid ester 10 are more active than fluconazole, used as reference drug, both on biofilm in formation with MIC50 values of 32, 32 and 16μg/mL, respectively, and in the early stage of biofilm formation (4h) with MIC50 values of 64, 32 and 64μg/mL, respectively. These esters result also more active than fluconazole on mature biofilm (24h), especially 8 and 10 with MIC50 values of 64μg/mL.

Cholinesterase based bioreactor for determination of pesticides

Abstract A novel analytical system for the in-flow quantitative determination of acetylcholine (ACh) and acetylcholinesterase (AChE) inhibitors is presented. Reliable and reproducible values in the monitoring of ACh, of carbamic acid derivatives and of organophosphorous compounds have been obtained thanks to a device realized by coupling an AChE-based whole plant tissue column bioreactor with a traditional choline oxidase (ChO) biosensor. AChE was extracted from the inner part of a grapefuit shell (Albedum pomi citreum), coupled to chitin by glutaraldehyde and immobilized into a glass column bioreactor, whose outlet was connected to a thermostated flow-through cell incorporating the ChO biosensor. A sharp improvement in the sensitivity limits was obtained by recycling the sample solution into the bioreactor. The efficacy of the analytical system here presented was checked on standard solutions of ACh and on three of the most commonly used inhibitors of AChE (aldicarb, malathion and paraoxon), widely employed mainly as the active components of pesticides and insecticides.

Increased microbicidal activity of green tea (Camellia sinensis) in combination with butylated hydroxyanisole.

Abstract We have demonstrated that green tea (Camellia sinensis) shows increased antimicrobial activity against bacteria and fungi when used in combination with butylated hydroxyanisole (BHA). Glycolic extract taken from green tea showed only limited activity against Streptococcus mutans and no activity against Candida albicans and certain strains of Escherichia coli. BHA, at non inhibitory concentrations, increased the microbicidal activity of green tea against 1010 S. mutans (p<0.01), non-susceptible E. coli (p<0.01) and C. albicans (p<0.01). Green tea in combination with BHA reduced the hydrophobicity of S. mutans (p<0.01) and greatly inhibited (p<0.001) the formation of hyphae in C. albicans. The increased antimicrobial activity of green tea is related to an impairment of the barrier function in microorganisms and a depletion of thiol groups. The increased activity of green tea as an oral antimicrobial product is discussed.

A three-step culture system to increase the xanthone production and antifungal activity of Hypericum perforatum subsp. angustifolium in vitro roots

Hypericum perforatum is a well-known medicinal plant. Among all secondary metabolites produced by this species, xanthones are very interesting for their antifungal activity. In the present study, with the aim to improve xanthone production and antifungal activity of H. perforatum subsp. angustifolium (sin. Fröhlich) Borkh in vitro roots, a new methodology consisting of a three-step culture system, has been developed. Regenerated roots of H. perforatum were cultured in a three-step culture system: in the first step, to increase biomass, the roots were cultured in half-strength liquid Murashige and Skoog (MS) medium supplemented with 1 mg L(-1) indole butyric acid (IBA) and 1.5% sucrose. In the second and third steps, to stimulate secondary metabolism, the roots were cultured with 1.1 mg L(-1) 2,4-dichlorophenoxyacetic acid (2,4-D), 0.215 mg L(-1) kinetin (KIN), and 0.186 mg L(-1) 1-naphthalenacetic acid (NAA). In the third step, some of the roots were treated with chitosan. Xanthone production increased 2.7 times following the three-step method. The mean minimal inhibitory concentration (MIC) values were of 36.9, 26.7, and 65 μg mL(-1), against Candida species, Cryptococcus neoformans and dermatophytes, respectively. A positive correlation between xanthone accumulation and antifungal activity has been shown.

Chemical composition and antifungal activity of Hypericum perforatum subsp. angustifolium roots from wild plants and plants grown under controlled conditions

The medicinal properties of the aerial parts of Hypericum perforatum subsp. angustifolium have been extensively investigated, yet little is known about the chemical composition or potential uses of the root extracts. In this study, xanthone production in wild plants and plants grown under controlled conditions was investigated. Chemical analyses carried out on wild plants revealed that xanthones were mainly accumulated in the roots. We mainly detected 1,7-dihydroxyxanthone, paxanthone, 5-O-methyl-2-deprenylrheediaxanthone B, kielcorin. The roots of wild plants showed low xanthone accumulation. In the roots of plants grown under controlled conditions, xanthone accumulation was 27 times greater than that in the roots of wild-grown plants. Kielcorin was not detected in the roots of plants grown under controlled conditions. As xanthones are known for their antifungal activity, the extracts from both samples were tested against the human fungal pathogens Candida albicans, non-albicansCandida species, Cryptococcus neoformans, and dermatophytes. The root extracts from plants grown under controlled conditions showed greater antifungal activity, probably correlated with higher xanthone accumulation.

In vitro antifungal activity of extracts obtained from Hypericum perforatum adventitious roots cultured in a mist bioreactor against planktonic cells and biofilm of Malassezia furfur

Xanthone-rich extracts from Hypericum perforatum root cultures grown in a Mist Bioreactor as antifungal agents against Malassezia furfur. Extracts of Hypericum perforatum roots grown in a bioreactor showed activity against planktonic cells and biofilm of Malassezia furfur. Dried biomass, obtained from roots grown under controlled conditions in a ROOTec mist bioreactor, has been extracted with solvents of increasing polarity (i.e. chloroform, ethyl acetate and methanol). The methanolic fraction was the richest in xanthones (2.86 ± 0.43 mg g− 1 DW) as revealed by HPLC. The minimal inhibitory concentration of the methanol extract against M. furfur planktonic cells was 16 μg mL− 1. The inhibition percentage of biofilm formation, at a concentration of 16 μg mL− 1, ranged from 14% to 39%. The results show that H. perforatum root extracts could be used as new antifungal agents in the treatment of Malassezia infections.

Evaluation of Anti-Candida Activity of Vitis vinifera L. Seed Extracts Obtained from Wine and Table Cultivars

For the first time, grape seed extracts (GSEs), obtained from wine and table cultivars of Vitis vinifera L., cultured in experimental fields of Lazio and Puglia regions of Italy and grown in different agronomic conditions, have been tested on 43 Candida species strains. We demonstrated a significant correlation between the content of the flavan-3-ols in GSEs extracts, with a polymerization degree ≥4, and anti-Candida activity. Moreover, we demonstrated that GSEs, obtained from plants cultured with reduced irrigation, showed a content of polymeric flavan-3-ols >250 mg/g with geometric mean MIC values between 5.7 and 20.2 mg/L against Candida albicans reference strains. GSE, showing 573 mg/g of polymeric flavan-3-ols, has been tested in an experimental murine model of vaginal candidiasis by using noninvasive in vivo imaging technique. The results pointed out a significant inhibition of Candida albicans load 5 days after challenge. These findings indicate that GSEs with high content of polymeric flavan-3-ols can be used in mucosal infection as vaginal candidiasis.