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Manuela Saddi

Publications and source records attributed to Manuela Saddi.

3 recordsLinked to original sources

Ligand-based virtual screening, parallel solution-phase and microwave-assisted synthesis as tools to identify and synthesize new inhibitors of mycobacterium tuberculosis.

In an attempt to identify new inhibitors of the growth of Mycobacterium tuberculosis (MTB), the causative agent of tuberculosis, a procedure for the generation, design, and screening of a ligand-based virtual library was applied. This used both an in silico protocol centered on a recursive partitioning (RP) model described herein, and a pharmacophoric model for antitubercular agents previously generated by our research group. Two candidates emerged from databases of commercially available compounds, both characterized by a minimum inhibitory concentration (MIC) of 25 microg mL(-1). Based on these compounds, two series of derivatives were synthesized by both parallel solution-phase and microwave-assisted synthesis, leading to enhanced antimycobacterial activity. During both the design and synthesis, attention was focused on the efficient allocation of available resources with the aim of reducing the overall costs associated with calculation and synthesis.

Antitubercular Agents↗

In vitro activity of 2-cyclohexylidenhydrazo-4-phenyl-thiazole compared with those of amphotericin B and fluconazole against clinical isolates of Candida spp. and fluconazole-resistant Candida albicans.

OBJECTIVES: The aim of this study was to investigate the in vitro antifungal activity of an isothiosemicarbazone cyclic analogue against isolates of Candida spp. including fluconazole-resistant Candida albicans. METHODS: We investigated the activity of 2-cyclohexylidenhydrazo-4-phenyl-thiazole (EM-01D2) against 114 clinical isolates of Candida spp., representing five different species, by microdilution, according to the NCCLS method 27-A. The activity against C. albicans biofilms was also investigated. Toxicity in vitro was evaluated by MTT reduction assay. RESULTS: EM-01D2 demonstrated low toxicity, broad spectrum, fungicidal activity and was active against C. albicans and Candida krusei at concentrations lower than those shown by amphotericin B and fluconazole (P < 0.05). It maintained potent in vitro activity against fluconazole-resistant C. albicans isolates. Fungicidal activity occurred at concentrations 1-2 doubling dilutions greater than the corresponding MICs, and time-kill analysis indicated that a 99.9% loss of C. albicans viability occurred after 6 h of incubation in the presence of EM-01D2 at concentrations equal to four times the MIC. EM-01D2 was also active in inhibiting the growth of C. albicans ATCC 10231 biofilms, even though such inhibition occurred at concentrations higher than the MICs determined under planktonic growth conditions. However, when C. albicans biofilms were pre-exposed to subinhibitory concentrations of EM-01D2, a reduction of MIC50 of amphotericin B was observed. CONCLUSIONS: Based on these results, EM-01D2 could represent a template for the development of novel fungicidal agents.

Amphotericin B↗

In vitro antimycobacterial activity of newly synthesised S-alkylisothiosemicarbazone derivatives and synergistic interactions in combination with rifamycins against Mycobacterium avium.

The antimycobacterial activities of two new S-alkylisothiosemicarbazone derivatives (1i and 1f) against 32 Mycobacterium avium isolates were investigated. The minimum inhibitory concentrations (MICs) were significantly lower than those of rifampicin and other reference drugs. The two derivatives also showed excellent intracellular activity against M. avium residing in the macrophage-like J774 cells. Interestingly, the combination of subinhibitory concentrations of 1i and rifabutin or rifampicin induced a potent synergistic effect, as determined by the fractional inhibitory concentration indexes (FICIs) ranging between 0.103 and 0.412. Such synergistic effect resulted in a 81-fold and 139-fold reduction of the MICs of rifabutin and rifampicin, respectively. Enhancement of intracellular activity of rifabutin by the S-alkylisothiosemicarbazone derivative 1i was also observed. Results indicate that S-alkylisothiosemicarbazones can be useful in the therapy and prophylaxis of M. avium infections and can represent a template for the development of novel antimycobacterial drugs. Furthermore, as a consequence of their ability to enhance the activity of rifamycins, a reduction of drug interactions following the co-administration of protease inhibitors could be achieved by lower doses of rifampicin and rifabutin.

Animals↗