768 research outputs found
Screening of Traditionally Used Plants for in Vivo Antimalarial Activity in Mice.
No full textAqueous ethanol (80%) extracts of six plants used traditionally for treatment of malaria, Vepris glomerata (F.Hoffm.) Engl (Rutaceae), Maranthus floribunda (Bak.) F.White (Chrysobalanaceae), Strophanthus eminii Asch. & Pax ex Pax (Apocynaceae), Cassia abbreviata Oliv. (Leguminosae) and Caesalpinia bonducella L. Fleming (Fabaceae) were screened for antimalarial activity to establish validity of their claims. The extracts exhibited antimalarial activity in the 4-day Peter's suppressive antimalarial assay in mice inoculated with red blood cells parasitized with Plasmodium berghei. The extracts gave ID(50) values of 42.8, 111.0, 639.3 and 1560 mg/kg body wt for C. bonducella, C. abbreviata, T. furialis and S. eminii, respectively. The ID(50) values for V. glomerata and M. floribunda were above 2400 mg/kg body wt, above which point solubility was a problem. All the tested extracts were innocuous to the mice, up to 2400 mg/kg body wt, suggesting they may be safe for short-term use
Antimicrobial Activity and Brine shrimp Toxicity of Extracts of Terminalia Brownii Roots and Stem.
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Ternimalia brownii Fresen (Combretaceae) is widely used in traditional medicine to treat bacterial, fungal and viral infections. There is a need to evaluate extracts of this plant in order to provide scientific proof for it's wide application in traditional medicine system. Extraction of stem bark, wood and whole roots of T. brownii using solvents of increasing polarity, namely, Pet ether, dichloromethane, dichloromethane: methanol (1:1), methanol and aqua, respectively, afforded dry extracts. The extracts were tested for antifungal and antibacterial activity and for brine shrimp toxicity test. Extracts of the stem bark, wood and whole roots of T. brownii exhibited antibacterial activity against standard strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, and Bacillus anthracis and the fungi, Candida albicans and Cryptococcus neoformans. Aqueous extracts exhibited the strongest activity against both bacteria and fungi. Extracts of the roots and stem bark exhibited relatively mild cytotoxic activity against brine shrimp larvae with LC50 values ranging from 113.75-4356.76 and 36.12-1458.81 microg/ml, respectively. The stem wood extracts exhibited the highest toxicity against the shrimps (LC50 values 2.58-14.88 microg/ml), while that of cyclophosphamide, a standard anticancer drug, was 16.33 (10.60-25.15) microg/ml. These test results support traditional medicinal use of, especially, aqueous extracts for the treatment of conditions such as diarrhea, and gonorrhea. The brine shrimp results depict the general trend among plants of the genus Terminalia, which are known to contain cytotoxic compounds such as hydrolysable tannins. These results warrant follow-up through bioassay-directed isolation of the active principles
Screening Of Traditionally Used Plants For In Vivo Antimalarial Activity In Mice
No full textAqueous ethanol (80%) extracts of six plants used traditionally for
treatment of malaria, Vepris glomerata (F.Hoffm.) Engl (Rutaceae),
Maranthus floribunda (Bak.) F.White (Chrysobalanaceae), Strophanthus
eminii Asch. & Pax ex Pax (Apocynaceae), Cassia abbreviata
Oliv. (Leguminosae) and Caesalpinia bonducella L. Fleming (Fabaceae)
were screened for antimalarial activity to establish validity of their
claims. The extracts exhibited antimalarial activity in the 4-day
Peter s suppressive antimalarial assay in mice inoculated with red
blood cells parasitized with Plasmodium berghei . The extracts gave
ID50 values of 42.8, 111.0, 639.3 and 1560 mg/kg body wt for C.
bonducella, C. abbreviata, T. furialis and S. eminii, respectively. The
ID50 values for V. glomerata and M. floribunda were above 2400 mg/kg
body wt, above which point solubility was a problem. All the tested
extracts were innocuous to the mice, up to 2400 mg/kg body wt,
suggesting they may be safe for short-term use
THE GEOMETRY OF H-C-C-N
No full textAuthor Institution: Department of Chemistry, Michigan State UniversityThe geometry of HCCN in its lowest triplet state has been studied with the restricted open shell SCF technique followed by a modest configuration interaction. The SCF results predict minima corresponding to a linear nitrene and a bent carbene with the allylic structure being the transition state. In contrast, the CI results predict that the allylic structure is the only minimum on the surface
Everyday conceptions of modesty: a prototype analysis
No full textGood theoretical definitions of psychological phenomena not only are rigorously formulated but also provide ample conceptual coverage. To assess the latter, we empirically surveyed everyday conceptions of modesty in a combined U.S./U.K. sample. In Study 1, participants freely generated multiple exemplars of modesty that judges subsequently sorted into superordinate categories. Exemplar frequency and priority served, respectively, as primary and secondary indices of category prototypicality that enabled central, peripheral, and marginal clusters to be identified. Follow-up studies then confirmed the ordinal prototypicality of these clusters with the aid of both explicit (Studies 2 and 3) and implicit (Study 3) methodologies. Modest people emerged centrally as humble, shy, solicitous, and not boastful and peripherally as honest, likeable, not arrogant, attention-avoiding, plain, and gracious. Everyday conceptions of modesty also spanned both mind and behavior, emphasized agreeableness and introversion, and predictably incorporated an element of humility
Are mitochondria subject to evolutionary temperature adaptation?
No full textThermal tolerance and the respiratory properties of isolated red muscle mitochondria were investigated in Oreochromis alcalicus grahami from the alkaline hot-springs, Lake Magadi, Kenya. Populations of O. a. grahami were resident in pools at 42.8 deg C and migrated into water reaching temperatures of 44.8 °C for short periods. The maximum respiration rates of mitochondria with pyruvate as substrate were 217 and 284 natom O mg-1 mitochondrial protein min-1 at 37 deg C and 42 deg C, respectively (Q10=1.71). Fatty acyl carnitines (chain lengths C8, C12 and C16), malate and glutamate were oxidised at 7080 % of the rate for pyruvate. In order to assess evolutionary temperature adaptation of maximum mitochondrial oxidative capacities, the rates of pyruvate and palmitoyl carnitine utilisation in red muscle mitochondria were measured from species living at other temperatures: Notothenia coriiceps from Antarctica (-1.5 to +1 deg; C); summer-caught Myoxocephalus scorpius from the North Sea (1015 °C); and Oreochromis andersoni from African lakes and rivers (2230 °C). State 3 respiration rates had Q10 values in the range 1.82.7. At the lower lethal temperature of O. andersoni (12.5 °C), isolated mitochondria utilised pyruvate at a similar rate to mitochondria from N. coriiceps at 2.5 °C (30 natom O mg-1 mitochondrial protein min-1). Rates of pyruvate oxidation by mitochondria from M. scorpius and N. coriiceps were similar and were higher at a given temperature than for O. andersoni. At their normal body temperature (-1.2 °C), mitochondria from the Antarctic fish oxidised pyruvate at 5.5 % and palmitoyl-dl-carnitine at 8.8 % of the rates of mitochondria from the hot-spring species at 42 °C. The results indicate only modest evolutionary adjustments in the maximal rates of mitochondrial respiration in fish living at different temperatures
Polyethylene glycol promotes autoxidation of cytochrome c
No full textCytochrome c (Cyt c) was rapidly oxidized by molecular oxygen in the presence, but not absence of PEG. The redox potential of heme c was determined by the potentiometric titration to be +236 ± 3 mV in the absence of PEG, which was negatively shifted to +200 ± 4 mV in the presence of PEG. The underlying the rapid oxidation was explored by examining the structural changes in Cyt c in the presence of PEG using UV–visible absorption, circular dichroism, resonance Raman, and fluorescence spectroscopies. These spectroscopic analyses suggested that heme oxidation was induced by a modest tertiary structural change accompanied by a slight shift in the heme position (<1.0 Å) rather than by partial denaturation, as is observed in the presence of cardiolipin. The near-infrared spectra showed that PEG induced dehydration from Cyt c, which triggered heme displacement. The primary dehydration site was estimated to be around surface-exposed hydrophobic residues near the heme center: Ile81 and Val83. These findings and our previous studies, which showed that hydrated water molecules around Ile81 and Val83 are expelled when Cyt c forms a complex with CcO, proposed that dehydration of these residues is functionally significant to electron transfer from Cyt c to CcO
Robust organic radical molecular junctions using acetylene terminated groups for c-au bond formation
No full textOrganic paramagnetic and electroactive molecules are attracting interest as core components of molecular electronic and spintronic devices. Currently, further progress is hindered by the modest stability and reproducibility of the molecule/electrode contact. We report the synthesis of a persistent organic radical bearing one and two terminal alkyne groups to form Au-C σ bonds. The formation and stability of self-assembled monolayers and the electron transport through single-molecule junctions at room temperature have been studied. The combined analysis of both systems demonstrates that this linker forms a robust covalent bond with gold and a better-defined contact when compared to traditional sulfur-based linkers. Density functional theory and quantum transport calculations support the experimental observation highlighting a reduced variability of conductance values for the C-Au based junction. Our findings advance the quest for robustness and reproducibility of devices based on electroactive molecules.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.QN/van der Zant LabQN/Afdelingsburea
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