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Isolasi dan Uji Bioaktivitas Senyawa dari Mangifera rufocostata dan Mangifera foetida
No full textTumbuhan dari genus mangifera yaitu Mangifera rufocostata dan Mangifera foetida dimanfaatkan masyarakat Kalimantan Selatan. M. rufocostata dan M. foetida tumbuh di Kalimantan Selatan dengan nama lokal masing-masing adalah Asem Tanduy dan Hambawang. Eksplorasi pada kedua tanaman tersebut melalui metabolit profiling ekstrak metanol kedua tanaman dengan LC-MS/MS, mengetahui kandungan total fenolat (TPC) dan total flavonoid (TFC), uji bioaktivitas untuk mengetahui aktivitas antioksidan (ABTS, DPPH, FRAP) dan aktivitas penghambatan enzim α-glukosidase (in vitro dan in silico), serta aktivitas sitotoksik terhadap sel kanker HT-29, HeLa, dan MCF-7. Isolasi senyawa dengan metode ekstraksi, fraksinasi dan pemurnian menggunakan kromatografi, dilanjutkan penentuan struktur dengan spektrometer 1H-NMR, 13C-NMR, HMBC, dan COSY. Uji penghambatan isolat terhadap enzim α-glukosidase (in vitro dan in silico). Derivatisasi struktur senyawa hasil isolasi dengan metode esterifikasi, produknya diidentifikasi dengan LC-MS/MS dan diuji aktivitas penghambatannya terhadap enzim α-glukosidase (in vitro dan in silico). Hasil LC-MS/MS menunjukkan bahwa ekstrak metanol kulit batang M. rufocostata mengandung senyawa utama mangiferin (17,25%) dan asam kuinat (12,83%), sedangkan ekstrak metanol M. foetida mengandung senyawa utama asam 3,4-dihidroksimandelat (7,67%) dan mangiferin (6,16%). Ekstrak metanol kulit batang M. rufocostata mempunyai TPC dan TFC, antioksidan (ABTS, DPPH, FRAP), dan penghambatan enzim α-glukosidase secara in vitro lebih besar daripada ekstrak M. foetida. Beberapa fraksi polar dari ekstrak M. rufocostata dan M. foetida serta isolat mangiferin aktif menghambat enzim α-glukosidase secara in vitro. Mangiferin, irisanton, 7-Hidroksi-2-(4-hidroksifenil)-4-okso-3,4-dihidro-2H-kromen-5-il β-D-glukopiranosida dan kuersetin, berpotensi menghambat enzim α-glukosidase secara in silico. Hasil uji sitotoksisitas menunjukkan ekstrak metanol M. rufocostata bersifat sitotoksik terhadap sel kanker HT-29 dengan IC50 0,25 ± 2,74 µg/mL. Isolat yang diperoleh dari M. rufocostata adalah friedelin, 2-propilpentil galat, dan mangiferin, sedangkan yang diperoleh dari M. foetida adalah mangiferin. Isolat mangiferin aktif menghambat enzim α-glukosidase secara in vitro dengan IC50 22,82±5,87 µg/mL, sedangkan friedelin dan 2-propilpentil galat berturut-turut hanya menghambat sebesar 45,56±2,67 dan 42,71±3,36%. Isolat tersebut berpotensi menghambat enzim α-glukosidase secara in silico. Derivatisasi struktur mangiferin menghasilkan mangiferin pentapentanoat, mangiferin isopentanoat, dan mangiferin butaheksanoat dengan rendemen di bawah 10%. Senyawa derivatisasi tersebut berpotensi menghambat enzim α-glukosidase secara in silico.
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Plants from the mangifera genus such as Mangifera rufocostata and Mangifera foetida have been widely used by the people of South Kalimantan. M. rufocostata and M. foetida grow in South Kalimantan, locally known as Asem Tanduy and Hambawang respectively. This research explored the properties of the two plants through the metabolite profiles of the methanol extracts of the two plants using LC-MS/MS and to determine the total phenolic (TPC) and total flavonoid (TFC) content, bioactivity test was conducted to determine antioxidant activity (ABTS, DPPH, FRAP), and inhibitory activity of the α-glucosidase enzyme (in vitro and in silico), as well as cytotoxic activity against HT-29, Hela, and MCF-7 cancer cells. The compounds isolated through extraction, fractionation and purification methods using various chromatography techniques, followed by structure determination using 1H-NMR, 13C-NMR, HMBC and COSY spectrometers. Inhibition test of isolates against the α-glucosidase enzyme (in vitro and in silico). The structure of the isolated compound was modified using the esterification method, and identify the product using LC-MS/MS, as well as inhibition tests of modified products against the α-glucosidase enzyme (in vitro and in silico). The results of LC-MS/MS showed that the methanol stem extract of M. rufocostata bark contained the major compounds mangiferin (17.25%) and quinic acid (12.83%), while the methanol extract of M. foetida contained the major compound 3,4-Dihydroxymandelic acid (7.67 %) and mangiferin (6.16%). The methanol extract of M. rufocostata stem bark has greater TPC, TFC, antioxidant activity (ABTS, DPPH, FRAP) and inhibition of the α-glucosidase enzyme in vitro than M. foetida extract. Several polar fractions from M. rufocostata and M. foetida extracts as well as mangiferin isolates actively inhibit the α-glucosidase enzyme in vitro. Mangiferin, irisxhantone, 7-hydroxy-2-(4-hydroxyphenyl)-4-oxu-3,4-dihydro-2H-chromen-5-yl-D-glucopyranoside, and Kuersetin have the potential to inhibit the α-glucosidase enzyme in silico. The results of the cytotoxicity test showed that the methanol extract of M. rufocostata was cytotoxic to HT-29 cancer cells with an IC50 of 0.25 ± 2.74 µg/mL. The isolates obtained from M. rufocostata were friedelin, 2-propylpentyl gallate, and mangiferin, while those obtained from M. foetida were mangiferin. Mangiferin actively inhibits the α-glucosidase enzyme in vitro with an IC50 of 22.82 ± 5.87 µg/mL, while friedelin and 2-propylpentyl gallate only inhibit 45.56 ± 2.67 and 42.71 ± 3.36% respectively. This isolate has the potential to inhibit the α-glucosidase enzyme in silico. Modification of the mangiferin structure produces mangiferin pentapentanoate, mangiferin isopentanoate, and mangiferin butahexanoate with yields below 10%. This modified compound has the potential to inhibit the α-glucosidase enzyme in silico
3,3’-Di(5,7-dibromoindol-3-il)-indolin-2-on: Sintesis dan Uji Sitotoksik terhadap Sel Kanker Kolon WiDr
Get PDFColon cancer is one of the causes of death in the world of concern, because until now there has not been found specific drug for its treatment. Therefore, the study aimed to synthesize compounds that have the potential as a novel anticancer compound derivative such as 3,3’-di (indol-3-yl) indolin-2-one is required. Synthesis was done by reacting 5,7-dibromoindole and isatin in methanol with an acid catalyst to produce 3,3’-di (5,7-dibromoindol-3-yl)-indolin-2-one compound with a yield of 48%. 3,3 ‘-di (5,7-dibromoindol-3-yl)-indolin-2-one is cytotoxic against colon cancer cell line WiDr with IC50 of 6.64 μM.Kanker kolon merupakan salah satu penyebab kematian yang menjadi pusat perhatian di dunia, karena hingga saat ini belum ditemukan obat yang spesifik untuk pengobatannya. Oleh sebab itu, penelitian yang bertujuan untuk mensintesis senyawa yang berpotensi sebagai anti kanker baru seperti senyawa turunan 3,3’-di(indol-3-il)indolin-2-on sangat diperlukan. Sintesis dilakukan dengan mereaksikan 5,7-dibromoindol dan isatin dalam metanol dengan katalis asam menghasilkan senyawa 3,3’-di(5,7-dibromoindol-3-il)-indolin-2-on dengan rendemen 48%. 3,3’-Di(5,7-dibromoindol-3-il)-indolin-2-on bersifat sitotoksik terhadap sel kanker kolon WiDr dengan IC50 6,64 μM
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
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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