RESUMO
Human louse Pediculus humanus is a cosmopolitan obligatory blood-feeding ectoparasite causing pediculosis and transmitting many bacterial pathogens. Control of infestation is difficult due to the developed resistance to insecticides that mainly target GABA (γ-aminobutyric acid) receptors. Previous work showed that Pediculus humanus humanus (Phh) GABA receptor subunit resistance to dieldrin (RDL) is the target of lotilaner, a synthetic molecule of the isoxazoline chemical class. To enhance our understanding of how insecticides act on GABA receptors, two other GABA receptor subunits were cloned and characterized: three variants of Phh-grd (glycine-like receptor of Drosophila) and one variant of Phh-lcch3 (ligand-gated chloride channel homolog 3). Relative mRNA expression levels of Phh-rdl, Phh-grd, and Phh-lcch3 revealed that they were expressed throughout the developmental stages (eggs, larvae, adults) and in the different parts of adult lice (head, thorax, and abdomen). When expressed individually in the Xenopus oocyte heterologous expression system, Phh-GRD1, Phh-GRD2, Phh-GRD3, and Phh-LCCH3 were unable to reconstitute functional channels, whereas the subunit combinations Phh-GRD1/Phh-LCCH3, Phh-GRD1/Phh-RDL, and Phh-LCCH3/Phh-RDL responded to GABA in a concentration-dependent manner. The three heteromeric receptors were similarly sensitive to the antagonistic effect of picrotoxin and fipronil, whereas Phh-GRD1/Phh-RDL and Phh-LCCH3/Phh-RDL were respectively about 2.5-fold and 5-fold more sensitive to ivermectin than Phh-GRD1/Phh-LCCH3. Moreover, the heteropentameric receptor constituted by Phh-GRD1/Phh-LCCH3 was found to be permeable and highly sensitive to the extracellular sodium concentration. These findings provided valuable additions to our knowledge of the complex nature of GABA receptors in human louse that could help in understanding the resistance pattern to commonly used pediculicides. SIGNIFICANCE STATEMENT: Human louse is an ectoparasite that causes pediculosis and transmits several bacterial pathogens. Emerging strains developed resistance to the commonly used insecticides, especially those targeting GABA receptors. To understand the molecular mechanisms underlying this resistance, two subunits of GABA receptors were cloned and described: Phh-grd and Phh-lcch3. The heteromeric receptor reconstituted with the two subunits was functional in Xenopus oocytes and sensitive to commercially available insecticides. Moreover, both subunits were transcribed throughout the parasite lifecycle.
Assuntos
Inseticidas , Infestações por Piolhos , Pediculus , Ftirápteros , Animais , Drosophila/metabolismo , Humanos , Inseticidas/farmacologia , Pediculus/genética , Pediculus/metabolismo , Ftirápteros/metabolismo , Receptores de GABA , Ácido gama-AminobutíricoRESUMO
This study on Buddleja polystachya highlights its phytochemical composition, antimicrobial activity, and cytotoxic impacts. The study emphasizes the plant's potential to treat ocular diseases by identifying important compounds involved in the bioactivity through GC-MS analysis. This study explores the antimicrobial and cytotoxic potential of Buddleja polystachya (stem and leaves) extracts, with a focus on their application in treating bacterial ocular infections and their efficacy against MCF7, HT29, and HepG2 cancer cells. Through comprehensive GC-MS analysis, a diverse array of phytochemicals was identified within Buddleja polystachya stem and leaves extracts, including carbohydrates, phenolic derivatives, fatty acids, and steroidal components. The extracts were then evaluated for their biological activities, revealing significant antimicrobial properties against a range of bacterial strains implicated in ocular infections. The research findings demonstrate that stem extracts derived from Buddleja polystachya demonstrated high to moderate cytotoxic effects on cancer cell lines MCF7, HT29, and HepG2. Notably, these effects were characterized by varying IC50 values, which suggest distinct levels of sensitivity. In contrast, leaf extracts exhibited reduced cytotoxicity when tested against all these cell lines, although they did so with a significantly higher cytotoxicity aganist HepG2 cells. The results of this investigation highlight the potential therapeutic utilization of Buddleja polystachya extracts in the management of ocular infections and cancer. These results support the need for additional research to elucidate the underlying mechanisms of action of these extracts and explore their potential as drugs.
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The human louse (Pediculus humanus) is an obligatory blood feeding ectoparasite with two ecotypes: the human body louse (Pediculus humanus humanus), a competent vector of several bacterial pathogens, and the human head louse (Pediculus humanus capitis), responsible for pediculosis and affecting millions of people around the globe. GABA (γ-aminobutyric acid) receptors, members of the cys-loop ligand gated ion channel superfamily, are among the main pharmacological targets for insecticides. In insects, there are four subunits of GABA receptors: resistant-to-dieldrin (RDL), glycin-like receptor of drosophila (GRD), ligand-gated chloride channel homologue3 (LCCH3), and 8916 are well described and form distinct phylogenetic clades revealing orthologous relationships. Our previous studies in the human body louse confirmed that subunits Phh-RDL, Phh-GRD, and Phh-LCCH3 are well clustered in their corresponding clades. In the present work, we cloned and characterized a putative new GABA receptor subunit in the human body louse that we named HoCas, for Homologous to Cys-loop α like subunit. Extending our analysis to arthropods, HoCas was found to be conserved and clustered in a new (fifth) phylogenetic clade. Interestingly, the gene encoding this subunit is ancestral and has been lost in some insect orders. Compared to the other studied GABA receptor subunits, HoCas exhibited a relatively higher expression level in all development stages and in different tissues of human body louse. These findings improved our understanding of the complex nature of GABA receptors in Pediculus humanus and more generally in arthropods.
Assuntos
Pediculus , Filogenia , Receptores de GABA , Animais , Pediculus/genética , Pediculus/metabolismo , Receptores de GABA/genética , Receptores de GABA/metabolismo , Humanos , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Sequência de AminoácidosRESUMO
BACKGROUND: Metastatic secondary ocular tumors spread from systemic malignancies, including breast cancer. This study aimed to evaluate the cytotoxicity of extracts from 5 medicinal plants native to Saudi Arabia. METHODS: For preliminary activity screening, cytotoxicity using the MTT assay and selectivity index determinations were made for medicinal plant extracts against various cancer cell-lines. The most promising extract was subjected to GC-MS analysis to determine the phytochemical composition. Clonogenic assays were performed using the most promising extract to confirm the initial results. Finally, western blot analysis was used to determine the modulation in expression of survivin and P27 suppressor genes in the human breast adenocarcinoma (MCF7) cell-line to understand the potential mechanistic properties of the active plant extract. RESULTS: The 5 plant extracts showed various cytotoxic activity levels using IC50. The most active extract was found to be the leaves of Capparis spinosa L. (BEP-07 extract) against the MCF7 breast cancer cell-line (IC50 = 3.61 ± 0.99 µg/ml) and selectivity index of 1.17 compared to the normal human fetal lung fibroblast (MRC5) cells. BEP-07 extract showed a dose dependent clonogenic effect against the MCF7 colonies which was comparable with the effect of doxorubicin. BEP-07 extract caused a significant decrease of survivin and increase in P27 expression compared to control GAPDH at its highest dose (14 µg/ml). The GC-MS chromatogram of Capparis spinosa L. (BEP-07 extract) revealed the existence of 145 compounds, belonging to the diverse classes of phytoconstituents. Fatty acids and their derivatives represent 15.4%, whilst octadecanoic acid, 2,3-dihydroxypropyl ester was the principal component (7.9%) detected. CONCLUSION: Leaves of Capparis spinosa L. (BEP-07 extract) exhibited a significant cytotoxic effect particularly against breast cancer cells. It exhibited this effect through survivin inhibition and via P27 upregulation. The detected phytoconstituents in the plant extract might be involved in tested cytotoxic activity, while further investigations are required to complete the drug candidate profile.
Assuntos
Extratos Vegetais , Plantas Medicinais , Humanos , Arábia Saudita , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Células MCF-7 , Linhagem Celular Tumoral , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Feminino , Survivina/metabolismo , Antineoplásicos Fitogênicos/farmacologia , Cromatografia Gasosa-Espectrometria de Massas/métodos , Compostos Fitoquímicos/farmacologiaRESUMO
Purpose: This study aimed to assess and compile the available research articles about medicinal plants used for ocular diseases. Principal results: A total of 2949 articles were retrieved, 35 full-text articles were assessed for eligibility, and seven studies (4 observational and three experimental) with low to moderate quality were eligible and involved in the systematic review, with a total of 600 plants from 4 countries. Among the 600 plants, only 24 (4%) were used to assess the status. Both the fixed and random models of the studies showed that the included studies tended to predict the results for the observational studies (OR = 0.062, CI = 0.043-0.090 OR = 0.039, CI = 0.012-0.122) for different plants used for ocular diseases. High heterogeneity (estimated as I2 = 87.078, Tau2 = 1.161 and Q-value = 23.217 with a p-value of 0.000), while for experimental studies (I2 = 94.928, Tau2 = 23.211 and Q-value = 39.434 with a p-value of 0.000) and publication bias were reported. Conclusion: Few articles representing approximately 600 plants of low to moderate quality reported using medicinal plants for ocular diseases. The meta-analysis confirmed the systematic review findings regarding the plants' traditional use with high heterogeneity and publication bias. A considerable gap was proven in the use of medicinal plants in ocular diseases requiring intensive research.
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BACKGROUND: Captopril is an important drug and is used to control hypertensive urgency world-wide. But there is very little data available regarding the evaluation of its outcomes in hypertensive urgency among African patients. This study aimed to evaluate the clinical outcomes of captopril use for hypertensive urgency at a selection of Sudanese emergency centres. METHODS: This was a cross-sectional study, conducted between 15 to 30 November 2015. A total of 50 patients, attending a selection of Khartoum State hospital emergency centres, with a clinical diagnosis of hypertensive urgency were approached by investigators for the study. Dose regimen, prognosis, and reduction in systolic and diastolic blood pressure were collected alongside a questionaire to patients regarding their care (compliance, etc.). Data were analysed using the Chi-square Test to compare the mean differences for various results. Differences were considered to be significant at P < 0.05. RESULTS: Around two-thirds (60%) of participants were female, and 28% were non-compliant with treatment. A 25mg dose of captopril was the most frequently used dose. Most of the patients (66%) did not have pre-existing disease. The majority of patients showed an improved blood pressure: both systolic and diastolic blood pressures were reduced by 16-25% and 5-15%, respectively. CONCLUSION: The study concluded that the dose of 25 mg of captopril is effective in managing hypertensive urgency and controlling the blood pressure. We also recommend that patients receiving captopril must be observed in the emergency centre for further evaluation.
RESUMO
6-Methoxykaempferol-3-O-glucoside (6-MKG) was isolated from a Sudanese herb (El-hazha). The pharmacological effects of 6-MKG were tested on isolated non-pregnant or late-pregnant rat uteri in vitro, whilst docking studies were carried out modelling of the binding of 6-MKG to the rat ß(2)-adrenoceptor in silico. In vitro studies revealed that 6-MKG was able to relax both the non-pregnant and the late-pregnant uterine contractility with 50% of the E(max) of terbutaline, whilst the EC(50) for 6-MKG was at least half than that of terbutaline. The ß(2)-adrenoceptors antagonist 3-(isopropylamino)-1-[(7-methyl-4-indanyl)oxy]butan-2-ol(ICI118,551) competitively antagonised the relaxing effect of 6-MKG. Radioligand binding and cAMP studies confirmed the ß(2)-adrenoceptors agonistic property of the compound. In in silico docking studies, 6-MKG bound to rat ß(2)-adrenoceptors with low ∆G(bind) value (-11.53±0.06 kcal/mol) and it interacted with four residues of the active site (Asp(113), Asn(312), Cys(191)and Tyr(316)). It is concluded that 6-MKG exerts weak ß(2)-adrenoceptor agonistic activity and can be considered a natural compound with potential therapeutic significance in the field of premature pregnant uterine contractions and asthmatic problems.