Comparative Antibacterial and Efflux Pump Inhibitory Activity of Isolated Nerolidol, Farnesol, and α-Bisabolol Sesquiterpenes and Their Liposomal Nanoformulations.

The efflux systems are considered important mechanisms of bacterial resistance due to their ability to extrude various antibiotics. Several naturally occurring compounds, such as sesquiterpenes, have demonstrated antibacterial activity and the ability to inhibit efflux pumps in resistant strains. Therefore, the objective of this research was to analyze the antibacterial and inhibitory activity of the efflux systems NorA, Tet(K), MsrA, and MepA by sesquiterpenes nerolidol, farnesol, and α-bisabolol, used either individually or in liposomal nanoformulation, against multi-resistant Staphylococcus aureus strains. The methodology consisted of in vitro testing of the ability of sesquiterpenes to reduce the Minimum Inhibitory Concentration (MIC) and enhance the action of antibiotics and ethidium bromide (EtBr) in broth microdilution assays. The following strains were used: S. aureus 1199B carrying the NorA efflux pump, resistant to norfloxacin; IS-58 strain carrying Tet(K), resistant to tetracyclines; RN4220 carrying MsrA, conferring resistance to erythromycin. For the EtBr fluorescence measurement test, K2068 carrying MepA was used. It was observed the individual sesquiterpenes exhibited better antibacterial activity as well as efflux pump inhibition. Farnesol showed the lowest MIC of 16.5 µg/mL against the S. aureus RN4220 strain. Isolated nerolidol stood out for reducing the MIC of EtBr to 5 µg/mL in the 1199B strain, yielding better results than the positive control CCCP, indicating strong evidence of NorA inhibition. The liposome formulations did not show promising results, except for liposome/farnesol, which reduced the MIC of EtBr against 1199B and RN4220. Further research is needed to evaluate the mechanisms of action involved in the inhibition of resistance mechanisms by the tested compounds.

Antiparasitary and antiproliferative activities in vitro of a 1,2,4-oxadiazole derivative on Trypanosoma cruzi.

Chagas disease (CD) is a neglected disease, prevalent and endemic in Latin America, but also present in Europe and North America. The main treatment used for this disease is benznidazole, but its efficacy is variable in the chronic phase and presents high toxicity. So, there is a need for the development of new therapeutic agents. The five-membered heterocyclic 1,2,4-oxadiazole ring has received attention for its unique properties and a broad spectrum of biological activities and is therefore a potential candidate for the development of new drugs. Thus, the aim of this study was to evaluate the activity of the N-cyclohexyl-3-(3-methylphenyl)-1,2,4-oxadiazol-5-amine (2) on the evolutionary forms of Trypanosoma cruzi strain Y, as well as its mechanisms of action and in silico theoretical approach. The results by computational method showed an interaction of the 1,2,4-oxadiazole (2) with TcGAPDH, cruzain, and trypanothione reductase, showing good charge distribution and affinity in those three targets. Furthermore, cytotoxicity in LLC-MK2 cells was performed by the MTT method. In the assays with different parasite forms, the tested compound showed similar time-dependent concentration effect. The evaluation of the antiamastigote effect between the two concentrations tested showed a reduction in the number of infected cells and also in the number of amastigotes per infected cell. By flow cytometry, the compound (2) displayed alterations suggestive of necrotic events. Finally, in scanning electron microscopy structural alterations were present, characteristic of necrosisin the epimastigote forms. Overall, the 1,2,4-oxadiazole derivative (2) here evaluated opens perspectives to the development of new antichagasic agents.

A natural cell-penetrating nanopeptide combined with pentavalent antimonial as experimental therapy against cutaneous leishmaniasis.

The inadequacy of available treatments for leishmaniasis has presented up to 40% therapeutic failure. This fact suggests an urgency in the discovery of new drugs or alternative approaches for treating this disease. The objective of this study was to evaluate the antileishmanial activity of combined therapy between crotamine (CTA) from Crotalus durissus terrificus and the pentavalent antimonial Glucantime® (GLU). The assays were in vitro performed measuring the inhibition of Leishmania amazonensis amastigotes, followed by the evaluation of cellular production of cytokines and nitrites. After that, analytical methods were performed in order to characterize the molecules involved in the study by Mass Spectrometry, molecular affinity through an in silico assay and Surface Plasmon Resonance. In vivo experiments with BALB/c mice were performed by analyzing parasitemia, lesion size and immunological mediators. In the in vitro experiments, the pharmacological association improved the inhibition of the amastigotes, modulated the production of cytokines and nitric oxide. The therapy improved the effectiveness of the GLU, demonstrating a decreased parasitemia in the infected tissues. Altogether, the results suggest that the combined approach with CTA and GLU may be a promising alternative for the treatment of cutaneous leishmaniasis.

Evaluation of the antileishmanial activity of biodegradable microparticles containing a hexanic eluate subfraction of Maytenus guianensis bark.

Leishmaniases, caused by Leishmania spp., are among the most prevalent infectious diseases in the world and their treatment may present high toxicity and side/adverse effects. This study evaluated the antileishmanial activity of the Hexanic Eluate subfraction from Maytenus guianensis bark (HEMg) incorporated in microparticles of PLGA. One batch of microparticles produced contained HEMg (HEMgP) and another contained the PLGA polymer alone (PCTE). The microparticles were characterized in regards to diameter, Zeta potential, encapsulation rate and morphology and their cytotoxicity was evaluated against J774 macrophages. The infection assay employing peritoneal macrophages witth L. amazonensis and cytokine dosages were performed on the cell supernatants. The groups of infected BALB/C mice were treated, euthanized and the parasite load and cytokine production were evaluated. The diameters and zeta potential were: 4 µm and -11.6 mV (PCTE) and 7.8 µm and -26.7 mV (HEMgP). The encapsulation rate was ≅ 15% and the morphology of the particles was spherical and homogeneous. In the infection assay, HEMgP inhibited the amastigotes by 70% (24 h) and 59% (48 h) and induced IL-12 and TNF-α production. HEMg in solution reduced the number of parasites in the lymph nodes by 50% and HEMgP administration increased the levels of IL-12 and TNF-α cytokines in lymph nodes and in the lesion site. When encapsulated, HEMg maintained its antileishmanial activity, but in a more attenuated and sustained form over time, showing promise as complementary/alternative therapy against cutaneous leishmaniasis.

Anti-Inflammatory Effects of a Pomegranate Leaf Extract in LPS-Induced Peritonitis.

Folk medicine suggests that pomegranate (peels, seeds and leaves) has anti-inflammatory properties; however, the precise mechanisms by which this plant affects the inflammatory process remain unclear. Herein, we analyzed the anti-inflammatory properties of a hydroalcoholic extract prepared from pomegranate leaves using a rat model of lipopolysaccharide-induced acute peritonitis. Male Wistar rats were treated with either the hydroalcoholic extract, sodium diclofenac, or saline, and 1 h later received an intraperitoneal injection of lipopolysaccharides. Saline-injected animals (i. p.) were used as controls. Animals were culled 4 h after peritonitis induction, and peritoneal lavage and peripheral blood samples were collected. Serum and peritoneal lavage levels of TNF-α as well as TNF-α mRNA expression in peritoneal lavage leukocytes were quantified. Total and differential leukocyte populations were analyzed in peritoneal lavage samples. Lipopolysaccharide-induced increases of both TNF-α mRNA and protein levels were diminished by treatment with either pomegranate leaf hydroalcoholic extract (57 % and 48 % mean reduction, respectively) or sodium diclofenac (41 % and 33 % reduction, respectively). Additionally, the numbers of peritoneal leukocytes, especially neutrophils, were markedly reduced in hydroalcoholic extract-treated rats with acute peritonitis. These results demonstrate that pomegranate leaf extract may be used as an anti-inflammatory drug which suppresses the levels of TNF-α in acute inflammation.

Correlation between TH1 response standard cytokines as biomarkers in patients with the delta virus in the western Brazilian Amazon.

Hepatitis D virus (HDV) is endemic in the Amazon Region and its pathophysiology is the most severe among viral hepatitis. Treatment is performed with pegylated interferon and the immune response appears to be important for infection control. HDV patients were studied: untreated and polymerase chain reaction (PCR) positive (n = 9), anti-HDV positive and PCR negative (n = 8), and responders to treatment (n = 12). The cytokines, interleukin (IL)-2 (p = 0.0008) and IL-12 (p = 0.02) were differentially expressed among the groups and were also correlated (p = 0.0143). Future studies will be conducted with patients at different stages of treatment, associating the viral load with serum cytokines produced, thereby attempting to establish a prognostic indicator of the infection.

Antimalarial potential of leaves of Chenopodium ambrosioides L.

In an effort to identify novel therapeutic alternatives for the treatment of malaria, the present study evaluated the antimalarial effect of the crude hydroalcoholic extract (HCE) from the leaves of Chenopodium ambrosioides L. For this purpose, the molecular affinity between the total proteins from erythrocytes infected with Plasmodium falciparum and HCE or chloroquine was evaluated by surface plasmon resonance (SPR). Subsequently, the plasmodicidal potential of HCE was assessed in a P. falciparum culture. Using BALB/c mice infected with Plasmodium berghei intraperitoneally (ip.), we evaluated the effects of ip. treatment, for three consecutive days (day 7, 8, and 9 after infection), with chloroquine (45 mg/kg) or HCE (5 mg/kg), considering the survival index and the parasitaemia. The groups were compared to an untreated control group that receives only PBS at the same periods. The results indicated that HCE could bind to the total proteins of infected erythrocytes and could inhibit the parasite growth in vitro (IC50 = 25.4 g/mL). The in vivo therapeutic treatment with HCE increased the survival and decreased the parasitaemia in the infected animals. Therefore, the HCE treatment exhibited a significant antiplasmodial effect and may be considered as a potential candidate for the development of new antimalarial drugs.

Biodegradable microparticles containing crotamine isolated from Crotalus durissus terrificus display antileishmanial activity in vitro.

BACKGROUND/AIMS: To evaluate antileishmanial activity of crotamine, a toxin isolated from Crotalus durissus terrificus, in solution form and encapsulated in biodegradable microparticles in vitro. METHODS: Particles were analyzed on-chip by surface plasmon resonance and characterized by testing their diameters, zeta potential and encapsulation rate. The viability of promastigotes as well as murine macrophages was assessed. Furthermore, the phagocytic index was determined for macrophages, and cell supernatants were collected for the determination of TNF-α levels. An infection assay using Leishmania amazonensis-infected macrophages was also conducted. RESULTS: The diameters and zeta potential of control particles (1.35 µm; -12.3 mV) and of those containing crotamine (3.09 µm; -20.9 mV) were adequate for the assays conducted. Crotamine-loaded particles were better captured by macrophages than control particles (increase of 12% in the phagocytic index), leading to increased TNF-α levels (196 pg/ml), and they also induced a significant decrease in the numbers of amastigotes compared to infected macrophages only. CONCLUSION: The approach presented here opens the possibility of working with safe concentrations of encapsulated toxins to reach antileishmanial effects.

Immune system cells modulation in patients with reproductive issues: A systematic review approach.

The aim of this study was to carry out a systematic literature review to investigate the main immune cells responsible for implantation failures. We selected papers from PubMed, Embase and Virtual Health Library databases. Eligible articles included publications between January 1, 2010 and April 24, 2022. Inclusion criteria were: observational and case-control studies; and the exclusion criteria were: review papers, letters to the editor, abstracts, animal studies and case reports. We extracted the following information: day of collection, number of patients, control group, age of patients, type of sample used, immune cells and cytokines. As main findings in our mapping, we found that in peripheral blood, CD3+, CD4+, CD8+, CD16+, CD56+, CD57+, CD69+, CD154+, CD158a+, NKp46 cells were increased and the CD4+, CD45+, Foxp3 and NKp46 markers were reduced. From the endometrial biopsies, there was an increase in CD3+, CD4+, CD5+, CD8+, CD16+, CD25+, CD45+, CD56+, CD57+, CD68+, CD127+ and a reduction in CD45+, CD56+, NKp46 and FoxP3 cells. Cytokines found increased in peripheral blood included IL-6, IL-10, IL-17, INF-γ, TGF-ß, TNF-α; while IL-4, IL-6, IL-10, IL-35, FoxP3, TGF-ß, SOCS3 were reduced. As for the biopsies, there was an increase in IL-2, IL-6, IL-17, IL-22, IL-23, INF-A1, INF-B1, INF-γ, TNF-R and a reduction in IL-6, IL-10, INF-γ, TGFß, TNF-α. We concluded that immune cells can be modulated during pregnancy failure, but further studies are needed to elucidate the modulating effect of the immune system on the endometrium of these patients.

Immunological Activity of Vaccine Systems Containing Liposomal Nanocarriers against Protozoan-Induced Diseases: A Systematic Review.

BACKGROUND: Neglected parasitic diseases constitute a broad spectrum of clinical conditions that, in the chronic phase, lack effective therapies for the target population. The utilization of vaccines based on liposomal nanocarrier systems is emerging, thereby enhancing clinical outcomes in various comorbidities. Consequently, this study aims to assess the immunological activity induced by liposomal nanocarriers against neglected parasitic diseases. METHODS: For the review, the Pubmed, Embase, and Lilacs databases were used using the descriptors vaccine, parasite, and liposome. The following inclusion criteria were adopted: in vivo and in vitro experimental articles. As exclusion criteria: book chapters, editorials, literature reviews and duplicate articles found during the database search. RESULTS: A total of 226 articles were identified, from which 34 were selected for review. The primary diseases identified included Babesia bovis, Entamoeba histolytica, Leishmania braziliensis, Leishmania donovani, Leishmania major, Leishmania infantum, Plasmodium falciparum, Plasmodium chabaudi, Plasmodium chabaudi, Plasmodium yoelii, Toxoplasma gondii and Trypanosoma cruzi. An elevation in cytokines such as GM-CSF, MCP-1, INF-γ, TNF-α, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, and IL-17 was observed in the studies evaluated regarding the parasitic diseases. Furthermore, cytokines such as IL-4, IL-10, and TGF-ß were diminished with the administration of the vaccine systems in those studies. CONCLUSION: Therefore, the administration of liposomal nanovaccine systems can effectively ameliorate the clinical condition of patients by modulating their immunological profile.

Assessment of differentially expressed genes from in vitro matured human oocytes: A bioinformatics approach.

OBJECTIVE: One of the techniques that has gained much attention is the in vitro maturation of oocytes for patients who use assisted reproduction techniques. However, its results are still inferior to controlled ovarian stimulation methodologies. Understanding the maturation mechanisms based on analyses can help improve this methodology's results. The work aims to identify the central genes differentially expressed in oocytes after in vitro maturation in the germinal vesicle and metaphase II stages. METHODS: This work is a computational analysis. The entire search will be conducted using the Gene Expression Omnibus (GEO) database. To carry out and obtain the data present in the work, an advanced research search was carried out in the GEO database within the period from January 1, 2013, to January 1, 2023. A total of 27 genomic data were available in the GEO database, of which only two were used. RESULTS: Two datasets were identified on the Gene Expression Omnibus database platform: registration data GSE158802 and GSE95477. From the analysis, we identified five downregulated and thirty-six upregulated genes; the central genes that correlated with the main gene proteins found were CLTA and PANK1. CONCLUSIONS: There was a differential regulation of gene expression. The most central ones are related to energy capture.

Liposomal nanoformulations with trans-caryophyllene and caryophyllene oxide: do they have an inhibitory action on the efflux pumps NorA, Tet(K), MsrA, and MepA?

This study aimed to evaluate the antibacterial and inhibitory action of NorA, Tet(K), MsrA and MepA efflux pumps in S. aureus strains using the sesquiterpenes named trans-caryophyllene and caryophyllene oxide, both isolated and encapsulated in liposomes. The antibacterial and inhibitory action of these efflux pumps was evaluated through the serial microdilution test in 96-well microplates. Each sesquiterpene and liposome/sesquiterpene was combined with antibiotics and ethidium bromide (EtBr). The antibiotics named norfloxacin, tetracycline and erythromycin were used. The 1199 B, IS-58, RN4220 and K2068 S. aureus strains carrying NorA, Tet(K), MsrA and MepA, respectively, were tested. In the fluorescence measurement test, K2068 S. aureus was incubated with the sesquiterpenes and EtBr, and the fluorescence emission by EtBr was measured. The tested substances did not show direct antibacterial activity, with MIC >1024 µg/mL. Nonetheless, the isolated trans-caryophyllene and caryophyllene oxide reduced the MIC of antibiotics and EtBr, indicating inhibition of NorA, Tet(K) and MsrA. In the fluorescence test, these same sesquiterpenes increased fluorescence emission, indicating inhibition of MepA. Therefore, the sesquiterpenes named trans-caryophyllene and caryophyllene oxide did not show direct antibacterial action; however, in their isolated form, they showed possible inhibitory action on NorA, Tet(K), MsrA and MepA efflux pumps. They may also act in antibiotic potentiation. Further studies are needed to identify the mechanisms involved in antibiotic potentiation and efflux pump inhibitory action.

Therapeutic potential of biodegradable microparticles containing Punica granatum L. (pomegranate) in murine model of asthma.

OBJECTIVE AND DESIGN: Among the options for treatment of diseases affecting the respiratory system, especially asthma, drug delivering systems for intranasal application represent an important therapeutic approach at the site of inflammation. The present study aimed to evaluate the therapeutic effect of biodegradable microparticles formed by poly lactic-co-glycolic acid (PLGA) containing encapsulated pomegranate extract on a murine model of asthma. MATERIAL: The extract was acquired from the leaves of P. granatum and characterized qualitatively by HPLC. A w/o/w emulsion solvent extraction-evaporation method was chosen to prepare the microparticles containing pomegranate encapsulated extract (MP). TREATMENT: OVA-sensitized BALB/c mice were used as asthma model and treated with dexamethasone and P. granatum extract in solution form or encapsulated into microparticles. RESULTS: MP were able to inhibit leukocytes' recruitment to bronchoalveolar fluid, especially, eosinophils, decreasing cytokines (IL-1ß and IL-5) and protein levels in the lungs. CONCLUSIONS: This approach can be used as an alternative/supplementary therapy based on the biological effects of P. granatum for managing inflammatory processes, especially those with pulmonary complications.

Liposomal-lupane system as alternative chemotherapy against cutaneous leishmaniasis: macrophage as target cell.

Leishmania amazonensis causes human diseases that range from self-healing to diffusion cutaneous lesions. The chemotherapy of leishmaniasis requires long-term treatment and has been based on the use of pentavalent antimonials. Liposomes have been used as antileishmanial drug carries and have adjuvant activity in vaccines against several microorganisms, representing an important option to the development of new therapeutics for the disease. In this study, we developed a liposomal formulation containing lupane [3ß,6ß,16ß-trihydroxylup-20(29)-ene], isolated from fruits of Combretum leprosum with pharmacological properties as antinociceptive, anti-inflammatory, antiulcerogenic and antileishmanial activities. The aim of the present study was to evaluate the efficacy of liposomal-lupane in L. amazonensis-infection model. Liposomes were prepared by the extrusion method with DPPC, DPPS and cholesterol at 5:1:4 weight ratio. The lupane (2 mg/mL) was added to the lipid mixture, solubilized in chloroform and dried under nitrogen flow. The activity of liposomal-lupane was conducted in vitro with mouse peritoneal infected macrophages. Furthermore, mice were infected in the right hind footpad with 10(5) stationary growth phase of L. amazonensis promastigotes. After 6 weeks, animals were treated with liposomal-lupane for 15 days by intraperitoneal injection. The evolution of disease was monitored weekly by measuring footpad thickness with a caliper. Three days after the treatment, peritoneal macrophages were collected, plated and production of the cytokines IL-10 and IL-12 was evaluated in supernatants of the cultures after 24 h. The results indicate that the liposomal system containing lupane achieved here is a promising tool to confer antileishmanial activity to infected macrophages.

Celecoxib improves host defense through prostaglandin inhibition during Histoplasma capsulatum infection.

Prostaglandins act as mediators of inflammation and, similar to cytokines, function as immune modulators during innate and adaptive immune responses. Therefore, using a pharmacological inhibitor, celecoxib, we investigated the role of prostaglandins in host defense against Histoplasma capsulatum infection in C57BL/6 mice. Our results showed that treatment with celecoxib inhibited cyclooxygenase 2, reduced the total fungal burden, and reduced the concentration of PGE2, cytokines, lymphocytes, neutrophils, and mononuclear cells in the bronchoalveolar space and lung parenchyma. In addition, celecoxib treatment increased the synthesis of nitric oxide, IFN- γ, LTB4, and the phagocytic capacity of alveolar macrophages. Moreover, celecoxib treatment increased the survival of mice after infection with a lethal inoculum of H. capsulatum. These results suggest that prostaglandins alter the host immune response and play an important role in the pathogenesis of histoplasmosis. Thus, the inhibition of prostaglandins could be a valuable immunomodulatory strategy and antifungal therapy for histoplasmosis treatment.

Oxadiazole Derivatives as Anticancer and Immunomodulatory Agents: A Systematic Review.

BACKGROUND: Tumor plasticity processes impact the treatment of different types of cancer; as an effect of this, the bioprospecting of therapies from natural and/or synthetic compounds that can regulate or modulate the immune system has increased considerably. Oxadiazole derivatives are structures that exhibit diverse biological activities. Therefore, this review aimed to evaluate the activity of oxadiazole compounds against tumor cell lines and their possible immune-mediated mechanisms. METHODS: A search in PubMed, Web of Science, and Science Direct databases was carried out on studies published from January 1, 2004, to January 31, 2022, using "oxadiazole" in combination with the other descriptors "cancer" and "macrophage". Only experimental in vitro and in vivo articles were included. A similar search strategy was used in the Derwent Innovation Index database for technology mapping. The search was performed on Drugbank using the descriptor oxadiazole for commercial mapping. RESULTS: 23 oxadiazole studies were included in this review, and some biological activities linked to antitumoral and immunomodulation were listed. Oxadiazole derivatives inhibited tumor cell growth and proliferation, blocked cell cycle, modulated mitochondrial membrane potential, presented immunoregulatory activity by different mechanisms reducing proinflammatory cytokines levels and acted directly as selective inhibitors of the COX enzyme. There was an increase in oxadiazole patent publications in the last 11 years, with emphasis on chemistry, pharmacy and biotechnology applied to microbiology areas. Compounds with 1,2,4-oxadiazole isomer are predominant in patent publications and approved drugs as observed in the technological and commercial mapping. CONCLUSION: Therefore, oxadiazole derivatives are therapeutic molecules that can be considered promising for the development of cancer therapies.

Molecular Dynamics of a N-Cyclohexyl-1,2,4-Oxadiazole Derivative as a Reversible Cruzain Inhibitor in Trypanosoma cruzi.

BACKGROUND: Chagas disease kills around 10,000 people yearly, primarily in Latin America, where it is prevalent. Current treatment has limited chronic effectiveness, is unsafe, and has substantial side effects. As a result, the use of oxadiazole derivatives and similar heterocyclic compounds as bioisosteres are well known, and they are prospective candidates in the hunt for novel anti-Trypanosoma cruzi chemicals. Recent research has revealed that the cysteine protease cruzain from T. cruzi is a validated target for disease treatment. OBJECTIVE: Thus, using a molecular dynamics simulation, the current study attempted to determine if a significant interaction occurred between the enzyme cruzain and its ligand. RESULTS: Interactions with the catalytic site and other critical locations were observed. Also, the RMSD values suggested that the molecule under research had stable interactions with its target. CONCLUSION: Finally, the findings indicate that the investigated molecule 2b can interfere enzymatic activity of cruzain, indicating that it might be a promising antichagasic drug.

Evaluation of the skin whitening and antioxidant activity of Myracrodruon urundeuva extract (aroeira-do-sertão).

Myracrodruon urundeuva, popularly known as 'aroeira-do-sertão', a large tree, with a tall trunk. Belonging to the Anacardiaceae family, it occurs in the 'caatinga' and dry forests of Brazil, from Ceará to the states of Paraná and Mato Grosso do Sul. The present study aimed to analyse the whitening and antioxidant activities of the aqueous extract of the leaves of Myracrodruon urundeuva (AELMU). Inhibition of the tyrosinase enzyme, as well as its copper chelating capacity and antioxidant effect were evaluated. The AELMU (at 2000 µg/mL) showed excellent inhibitory action (83.76%) on tyrosinase by chelating the copper ion while kojic acid at the same concentration inhibited 97.81%. Moreover, the extract displayed important antioxidant activity (inhibited 76,46% of the 2,2-diphenyl-1-picrylhydrazyl radical - DPPH; 49,59% of thiobarbituric acid reactive substances and 51,07% of the hydroxyl radical). Thus, the extract under study is promising for use in cosmetics, given its multifactorial action.

Valencene, Nootkatone and Their Liposomal Nanoformulations as Potential Inhibitors of NorA, Tet(K), MsrA, and MepA Efflux Pumps in Staphylococcus aureus Strains.

Valencene and nootkatone are aromatic sesquiterpenes with known biological activities, such as antimicrobial, antioxidant, anti-inflammatory, and antitumor. Given the evidence that encapsulation into nanosystems, such as liposomes, could improve the properties of several compounds, the present study aimed to evaluate the activity of these sesquiterpenes in their isolated state or in liposomal formulations against strains of Staphylococcus aureus carrying efflux pumps. The broth microdilution method evaluated the antibiotic-enhancing activity associated with antibiotics and ethidium bromide (EtBr). The minimum inhibitory concentration was assessed in strains of S. aureus 1199B, IS-58, and RN4220, which carry the efflux proteins NorA, Tet(K), and MsrA. In tests with strain 1199B, valencene reduced the MIC of norfloxacin and EtBr by 50%, while the liposomal formulation of this compound did not show a significant effect. Regarding the strain IS-58, valencene, and its nanoformulation reduced norfloxacin MIC by 60.3% and 50%, respectively. In the non-liposomal form, the sesquiterpene reduced the MIC of EtBr by 90%. Against the RN4220 strain, valencene reduced the MIC of the antibiotic and EtBr by 99% and 93.7%, respectively. Nootkatone and its nanoformulation showed significant activity against the 1199B strain, reducing the EtBr MIC by 21.9%. Against the IS-58 strain, isolated nootkatone reduced the EtBr MIC by 20%. The results indicate that valencene and nootkatone potentiate the action of antibiotics and efflux inhibitors in strains carrying NorA, Tet(K), and MsrA proteins, which suggests that these sesquiterpenes act as efflux pump inhibitors in S. aureus. Therefore, further studies are needed to assess the impact of incorporation into liposomes on the activity of these compounds in vivo.

Upregulation of hsa-miR-125b in HTLV-1 asymptomatic carriers and HTLV-1-associated myelopathy/tropical spastic paraparesis patients.

The retrovirus human T lymphotropic virus type 1 (HTLV-1) promotes spastic paraparesis, adult T cell leukaemia and other diseases. Recently, some human microRNAs (miRNAs) have been described as important factors in host-virus interactions. This study compared miRNA expression in control individuals, asymptomatic HTLV-1 carriers and HTLV-1 associated myelopathy (HAM)/tropical spastic paraparesis patients. The proviral load and Tax protein expression were measured in order to characterize the patients. hsa-miR-125b expression was significantly higher in patients than in controls (p = 0.0285) or in the HAM group (p = 0.0312). Therefore, our findings suggest that miR-125b expression can be used to elucidate the mechanisms of viral replication and pathogenic processes.