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Evaluation of the Antiplasmodial and Antimicrobial Properties of the Medicinal Plants Rumex nepalensis Spreng and Centella asiatica L
No full textInfectious diseases are the major health problems in the world particularly in developing
countries. To combat this problem various drugs, antibiotics and vaccines have been developed
through time, but these successes have been challenged by the emergence of drug resistant
pathogens. In Ethiopia, most people use traditional medicinal plants which are the natural source
of medicine to treat different diseases. However, traditional healers in this country apply
medicinal plants to heal different infections without scientific prescription and optimization of
the right doses. This study was conducted to investigate antiplasmodial, antibacterial, antifungal
properties, evaluate acute toxicity and possibly isolate the active compounds of two widely used
medicinal plants: Rumex nepalensis Spreng and Centella asiatica L. The two plants were
collected from Dejen District, Northen part of Ethiopia, and air dried in shade. The specific plant
parts (leaves, roots. aerial parts) were separately ground into powder. Each plant powder was
soaked in water, methanol and hexane in separate Erlenmeyer flasks and placed on shaker of 120
rpm for 72 hours. The extracts were concentrated in rotary evaporator and by lyophilizer
(aqueous extract). The crude extracts of water, methanol and hexane of the two plants were
tested for antiplasmodial, antimicrobial activities, acute toxicity and screened for
phytochemicals. The higher antimicrobial performing extract, methanol extracts of the roots of
R. nepalensis and further fractionnated by solvent-solvent extraction (hexane, chloroform,
ethanol, water and methanol) and these fractions were evaluated on pathogenic microorganisms
(Plasmodium berghei, Esherchia coli, Pseudomonas aeruginosa, Shigella flexneri and
Salmonella typhimurium, Klebsiella pneumonia, Candida albicans). Similarly the best fraction,
ethanol fraction, was further fractionnated by column chromatography (CC) and tested for
antiplasmodial and antimicrobial activities. Furthermore, column Chromatographic profiles of the roots of R. nepalensis were analyzed by thin layer chromatography (TLC). The crude
methanol and hexane extracts of the root, the leaf extracts of R. nepalensis and the aerial parts of
C. asiatica at the highest concentration of 5000 mg/kg BW was not toxic to the albino mice.
Furthermore the phytochemical screening of the R. nepalensis revealed the presence of
flavonoids, alkaloids, glycosides, triterpenoids, sterols, saponin and tannin. On the other hand,
phytochemical screening of C. asiatica showed the presence of flavonoids, alkaloids, glycosides
and saponin, triterpenoids and sterols but tannins were not clearly observed. CC and TLC
profiles of ethanol fraction of the roots of R. nepalensis showed the presence of chrysophanol,
emodin and 5 undefined compounds. The crude extracts of water, methanol and hexane of the
two plants had shown suppression to Plasmodium berghei in vivo in mice. Particularly, the crude
extracts of water, methanol and hexane of the roots of R. nepalensis had significantly higher day-
4 suppressive effect 52.00 %, 59.90 % and 39.30 % respectively than the negative control (2%
DMSO). But all extracts had significantly lower day-4 suppressive level than the positive
control, chloroquine in P. berghei infected albino mice. The ethanol fraction of the roots of R.
nepalensis showed higher plasmodium percent suppression in vivo in albino mice (70.08 %)
compared to water (54.31 %), chloroform (19.61 %) and methanol (10.27 %) suppression at 500
mg/kg body weight (BW). Similarly the mean survival time value of the mice administered with
ethanol fraction was significantly higher than all extracts (water, chloroform and methanol) at
500 mg/kg BW and negative control, 2% DMSO treated mice. More specificaly the ethanol
fraction of the roots of R. nepalensis fractionnated by column chromatography in ethyl acetate:
methanol (1:1) v/v showed 73.66% plasmodium suppression in vivo in albino mice at 300 mg/kg
BW. The re-fractionnated ethyl acetate: methanol fraction by column chromatography in
methanol increased its suppression to 79.66% at 150 mg/kg BW. In the antimicrobial test, the ethanol fraction of the roots of R. nepalensis showed zone of inhibition for P. aeruginosa
(19.33±0.33 mm), S. aureus (18.03±0.14 mm) and S. flexneri (12.77±0.15 mm) and S.
typhimurium (8.33±0.33 mm) at 6 mg/well by using agar well diffusion method compared to the
negative control (2% DMSO) which have no inhibition zone on the tested bacteria. However, the
positive control (teteracyclin and chloramphenicol) significantly higher bacterial inhibition than
ethanol fraction of the roots of R. nepalensis. From the result obtained it can be concluded that
the five undefined compounds played a role in synergizing the atiplasmodial, antibacterial and
antifungal activities of the roots of R. nepalensis. In conclusion this work has demonstrated the
high potential of R. nepalensis and C. asiatica as sources for further exploitation of
antiplasmodial, antibacterial and for use in herbal medicine
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
ANTIMALARIAL POTENTIAL OF THE LEAVES OF Rumex nepalensis IN MICE INFECTED WITH Plasmodium berghei
No full textMalaria is one the major world public health problem especially, in Africa. In spite of malaria therapy progress, the therapy is threatened by the emergence of multi-drug-resistant malaria parasite. As a result, medicinal plants which are the natural sources of medicine can be used as the alternative means to treat malaria. This study is aimed at evaluating the anti-malarial activity of methanol, water and hexane extracts of R. nepalinsis leaves. The methanol, aqueous and hexane crude extracts of the leaves R. nepalinsis were prepared for phytochemical screening, oral acute toxicity and for the evaluation of anti-malarial efficacy against Plasmodium berghei in the infected Swiss albino mice. The crude extracts of the leaves of R. nepalinsis were not toxic to Swiss albino mice at the highest dose level of 5000 mg/kg body weight. The phytochemical test showed the presence of secondary metabolites (alkaloids, flavonoids, tannins, terpenoids, saponin, steroids and glycosides). Thus, the plant extracts significantly prevented the loss of body weight, packed cell volume of the infected mice compared to the negative control (2% DMSO). Similarly the methanol extracts had significantly higher percent suppression (41.6, 42.4 and 44.8%) of P. berghei in mice at dose level of 200, 400 and 500 mg/kg body weight respectively than the negative control (2% DMSO). In conclusion, the leaves of R. nepalinsis was not toxic to mice at dose of 5000mg/kg to mice and it had antimalarial potentials in vivo in albino mice thus further studies are required to isolate and identify the responsible active compounds in this plant
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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