Cesare Vitali

The inhibition of Candida species by selected essential oils and their synergism with amphotericin B

In this work we highlight a possible synergistic anti-Candida effect between Melaleuca alternifolia, Origanum vulgare and Pelargonium graveolens essential oils and the antifungal compound Amphotericin B. The antifungal activity was assessed using the agar dilution method in eleven Candida strains. The results obtained indicate the occurrence of a synergistic interaction between the essential oils under study and Amphotericin B. P. graveolens essential oil appeared to be the most effective, inhibiting all the Candida species evaluated by this study.

In vitro synergic efficacy of the combination of Nystatin with the essential oils of Origanum vulgare and Pelargonium graveolens against some Candida species.

In this study we investigated a synergistic effect between the essential oils Origanum vulgare, Pelargonium graveolens and Melaleuca alternifolia and the antifungal compound Nystatin. Nystatin is considered a drug of choice in the treatment of fungal infections, but it can cause some considerable problems through its side effects, such as renal damage. Finding a new product that can reduce the Nystatin dose via combination is very important. Our findings showed an experimental occurrence of a synergistic interaction between two of these essential oils and Nystatin. The essential oil O. vulgare appeared to be the most effective, inhibiting all the Candida species evaluated in this study. Some combinations of Nystatin and P. graveolens essential oil did not have any synergistic interactions for some of the strains considered. Associations of Nystatin with M. alternifolia essential oil had only an additive effect.

Synthesis and Biological Evaluation of 2-Mercapto-1,3-benzothiazole Derivatives with Potential Antimicrobial Activity

The enhancement of bacterial resistance of pathogens to currently available antibiotics constitutes a serious public health threat. So, intensive efforts are underway worldwide to develop new antimicrobial agents. To identify compounds with a potent antimicrobial profile, we designed and synthesized low molecular weight 2‐mercaptobenzothiazole derivatives 2a–2l and 3a–3l. Both series were screened for in‐vitro antibacterial activity against the representative panel of Gram‐positive and Gram‐negative bacteria strains. The biological screening identified compounds 2e and 2l as the most active ones showing an interesting antibacterial activity with MIC values of 3.12 μg/mL against Staphylococcus aureus and 25 μg/mL against Escherichia coli, respectively. The replacement of the S‐H by the S‐Bn moiety resulted in considerable loss of the antibacterial action of the 3a–3l series. The antibiotic action of compounds 2e and 2l was also investigated by testing their activity against some clinical isolates with different antimicrobial resistance profile. Moreover, the involvement of the NorA efflux pump in the antibacterial activity of our molecules was evaluated. Finally, in this paper, we also describe the cytotoxic activity of the most interesting compounds by MTS assay against HeLa and MRC‐5 cell lines.

In Vitro Synergistic Action of Certain Combinations of Gentamicin and Essential Oils

The aim of this study was to verify the existence of synergistic antibacterial effect between four essential oils (Aniba rosaeodora, Melaleuca alternifolia, Origanum vulgare, and Pelargonium graveolens) individually combined with the antibacterial drug Gentamicin. We investigated the effectiveness in vitro of the association of essential oil/Gentamicin, against fifteen different strains of Gram positive and Gram negative bacteria. The antibacterial effects of these oils in combination with Gentamicin were evaluated by using the MHB microdilution method, while gas chromatography (GC) and GC/Mass spectrometry were used to analyze the chemical composition of the oils. A synergistic interaction was observed against all tested strains with the associations between the essential oils Aniba rosaeodora/Gentamicin and Pelargonium graveolens/Gentamicin. In particular a very strong synergistic interaction was observed against Acinetobacter baumannii ATCC 19606 (FIC index = 0.11). In contrast, the essential oils Origanum vulgare and Melaleuca alternifolia in association with Gentamicin were less effective on bacterial species growth. In vitro interaction can improve the antimicrobial effectiveness of the Gentamicin and may contribute to reduce its dose correlated to side effects.

Synthesis and antibacterial activity of pyridazino[4,3-b]indole-4-carboxylic acids carrying different substituents at N-2

The synthesis and the in vitro evaluation of antibacterial activity of new pyridazino[4,3-b]indole-4-carboxylic acids 2-4, 6 against some selected representative of Gram-positive and Gram-negative bacteria are reported. The role of the lipophilicity in the modulation of the antibacterial activity of the tested compounds is discussed. All the synthesized compounds appear quite weak against Gram-positive bacteria, whereas have no significant activity against Gram-negative bacteria. Only derivative 2g possesses an interesting activity against Gram-positive bacteria.

Synthesis and antibacterial activity of 2-aryl-2,5-dihydro-3(3H)-oxo-pyridazino[4,3-b]indole-4-carboxylic acids.

The in vitro antibacterial and antifungal activities of a series of pyridazinoindolonic acids II against some selected representative of Gram-positive, Gram-negative bacteria and fungi have been investigated. Some interesting observations among the structural features necessary for high antibacterial activity are presented and discussed.