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Viveiros M

The activity of 16 new hydantoin compounds on the intrinsic and overexpressed efflux pump system of Staphylococcus aureus.

AIM:
To evaluate a new series of 16 hydantoin derivatives for activity against the intrinsic and overexpressed efflux pumps of the ATTC 25923 Staphylococcus aureus and the clinical Staphylococcus aureus HPV-107 strain, respectively.
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Contribution of efflux activity to isoniazid resistance in the Mycobacterium tuberculosis complex.

Resistance to isoniazid (INH), one of the main drugs used in tuberculosis (TB) therapy, is mostly due to chromosomal mutations in target genes. However, approximately 20-30% of INH resistant Mycobacterium tuberculosis isolates do not have mutations in any of the genes associated with INH resistance.
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Inhibitors of mycobacterial efflux pumps as potential boosters for anti-tubercular drugs.

Tuberculosis is one of the major causes of infection across the world. The emergence of multi-, extensively- and totally drug-resistant strains of Mycobacterium tuberculosis contributes to the lack of therapeutic options available.
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The in vitro activity of products formed from exposure of chlorpromazine to a 266nm laser beam against species of mycobacteria of human interest

Chlorpromazine (CPZ) was exposed to a 266 nm laser beam for different periods of time ranging from minutes to 24 h. At intervals, the products from irradiation were evaluated by thin-layer chromatography (TLC) and evaluated for their activity against mycobacteria of human interest (Mycobacterium tuberculosis, M. avium, M. intracellulare and their corresponding reference strains or clinical isolates).
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Biological activity of twenty-three hydantoin derivatives on intrinsic efflux pump system of Salmonella enterica serovar Enteritidis NCTC 13349.

BACKGROUND:
Hydantoin derivatives have important biochemical and pharmacological properties. In the present study, 23 hydantoin compounds were evaluated for their efflux-modulating effects in Salmonella enterica serovar Enteritidis NCTC 13349 using real-time fluorimetry based on the intracellular accumulation of ethidium bromide (EB), a universal substrate of efflux pumps.
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Thioridazine induces apoptosis of multidrug-resistant mouse lymphoma cells transfected with the human ABCB1 and inhibits the expression of P-glycoprotein.

AIM:
Chlorpromazine has activity against a large variety of cancer types. However, this phenothiazine produces a plethora of serious side-effects. We have studied thioridazine (TZ), a phenothiazine neuroleptic that is much milder, for activity against multidrug-resistant (MDR) cancer cells, as well as against the overexpressed ABCB1 transporter (P-glycoprotein) that is the cause for the MDR phenotype of these cancer cells.
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Modulation of multidrug efflux pump activity by new hydantoin derivatives on colon adenocarcinoma cells without inducing apoptosis.

BACKGROUND:
Hydantoin derivatives are very promising candidates to improve the efficacy of anticancer chemotherapy. Previously, we demonstrated that eight hydantoin derivatives inhibited the P-glycoprotein (ABCB1) efflux pump of mouse T-lymphoma cells, as well as acting synergistically with the anticancer drug doxorubicin.
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Ethidium bromide transport across Mycobacterium smegmatis cell-wall: correlation with antibiotic resistance.

BACKGROUND:
Active efflux systems and reduced cell-wall permeability are considered to be the main causes of mycobacterial intrinsic resistance to many antimicrobials. In this study, we have compared the Mycobacterium smegmatis wild-type strain mc2155 with knockout mutants for porins MspA (the main porin of M. smegmatis) and MspC, the efflux pump LfrA (the main efflux pump system of M. smegmatis) and its repressor LfrR for their ability to transport ethidium bromide (EtBr) on a real-time basis.
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Inhibition of drug efflux in mycobacteria with phenothiazines and other putative efflux inhibitors.

Mycobacteria are responsible for some of the oldest diseases known to man, usually associated with high morbility and mortality rates. An example is tuberculosis (TB), a major public health problem that accounts for eight million new cases each year.
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Inhibition of efflux pumps in methicillin-resistant Staphylococcus aureus and Enterococcus faecalis resistant strains by triterpenoids from Momordica balsamina.

Six cucurbitane-type triterpenoids (1-6) isolated from the aerial parts of Momordica balsamina were evaluated for their ability to inhibit the activity of bacterial efflux pumps of methicillin-resistant Staphylococcus aureus (MRSA) COL(OXA), Enterococcus faecalis ATCC 29212, Salmonella enterica subsp.
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