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Phytochemical Composition And Oxidative Stability Of Cold-Pressed Butternut Squash (Cucurbita Moschata) And Pumpkin (Cucurbita Pepo L.) Seed Oils
Get PDFPumpkin (Cucurbita spp.), a crop native to America, represents a profitable opportunity in the Northeast. In the US, production of pumpkin has expanded greatly particularly in Illinois, Michigan, Pennsylvania, New Jersey and New York. With the appreciable volume of production intended mainly for utilization of the flesh for food processing, it is also expected that significant amounts of seeds, as part of the processing wastes, are being generated. Pumpkin seeds have been reported to contain a significant amount of highly unsaturated oil. Therefore, utilization of pumpkin seeds for oil production may add value to this crop and could help reduce food-processing waste. We studied the phytochemical composition, oxidative stability and behavior of the natural antioxidants of cold-pressed pumpkin (PSO) and butternut squash (BSO) seed oils. Experiments included quantification of carotenoid, tocopherol and phenolic content by HPLC analyses and determination of the effect of packaging light transmission properties and storage temperatures on the oxidative stability of the oils and the retention of their major antioxidant compounds. The predominant carotenoid in BSO was -carotene (21.8 mg/kg) while lutein+zeaxanthin (16.76 mg/kg) was the most abundant in PSO. [alpha]-carotene and cryptoxanthin were detected at lower concentrations but the latter was not detected in BSO. The total carotenoid content of PSO (32.4 mg/kg) was slightly lower than that of BSO (27.1 mg/kg). Significant concentrations of tocopherols ([alpha], [gamma], and [delta]) were found with [gamma]-tocopherol showing preponderance (>90%) in both oils. The total tocopherol content of BSO (563 mg/kg) was not significantly different compared to that of PSO (553 mg/kg). Two isomers ([gamma] and [delta]) of tocotrienol were also detected. The individual phenolics were tyrosol, luteolin, vanillin, vanillic acid, and trans-cinnamic acid. The oils were stable for at least 20 weeks when stored in amber bottles at temperature below 300C and we estimated a shelf-life for both oils of over 15 months based on accelerated storage test. Oxidation was most pronounced in clear bottles while green bottles provided only partial protection when exposed to 15W fluorescent light at 200C. The antioxidant compounds were better retained in amber bottles while significant reductions (p -tocopherol; lutein > -carotene. Phenolics exhibited only minor losses suggesting excellent stability of these compounds. Because of their high content of natural antioxidants and good storage stability, cold-pressed butternut squash and pumpkin seed oils demonstrate potential for valueadded uses such as production of specialty oils as natural sources of dietary antioxidants and in pharmaceutical and cosmetic applications. i
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S-Alk(en)ylmercaptocysteine suppresses LPS-induced pro-inflammatory responses in murine macrophages through inhibition of NF-κB pathway and modulation of thiol redox status
No full textThe Allium vegetable-derived metabolite, S-alk(en)ylmercaptocysteine (CySSR), has been reported to modulate oxidative stress and inflammatory responses. However, the underlying mechanisms of action and structure-activity relationships are not completely understood. We investigated the mechanistic basis of the protective effects of CySSR on pro-inflammatory responses involving redox/oxidative stress induced by E. coli lipopolysaccharide (LPS) using RAW 264.7 cells. CySSR (R = allyl, “A” or 1-propenyl, “Pe”) pre-treatments conferred concentration-dependent reductions in cytokines (TNF-α, IL-1β and IL-6), NO production and iNOS (inducible nitric synthase) overexpression, and attenuated oxidant production in LPS-stimulated RAW 264.7 cells where viability remained > 90%. These protective effects were manifested through inhibited activation of the nuclear factor-kappa B (NF-κB) signaling pathway via suppression of the IκB kinases (IKK) phosphorylation possibly by transforming growth factor β-activated kinase 1 or a kinase further upstream the canonical NF-κB signaling pathway. The attenuation of LPS-induced inflammation by CySSRs was associated with enhanced levels of cellular cysteine (CySH) and glutathione (GSH) mediated by cellular import/reduction of CySSR and the induction of glutamate cysteine ligase (GCL), one of > 200 nuclear factor erythroid 2-related factor 2 (Nrf2) regulated proteins. The reduction of anti-inflammatory effect of CySSR following pretreatment of cells with L-buthionine-S,R-sulfoximine (BSO) implicates GSH having a major role in reducing inflammation, likely in the context of other Nrf2-regulated antioxidant enzymes that scavenge H2O2 and peroxides using GSH as co-substrate. The anti-inflammatory effect of CySSPe was significantly greater than CySSA for almost all indicators measured, and cell metabolites of CySSRs may have a role in attenuating NF-κB signaling
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S-1-propenylmercaptocysteine protects murine hepatocytes against oxidative stress via persulfidation of Keap1 and activation of Nrf2
No full textThe onion-derived metabolite, S-1-propenylmercaptocysteine (CySSPe), protects against oxidative stress and exhibits anti-inflammatory effects by modulating cellular redox homeostasis. We sought to establish whether CySSPe activates nuclear factor erythroid 2–related factor 2 (Nrf2) and whether activation of Nrf2 by CySSPe involves modification of the Kelch-like ECH-associated protein-1 (Keap1) to manifest these effects. We found that CySSPe stabilized Nrf2 protein and facilitated nuclear translocation to induce expression of antioxidant enzymes, including NQO1, HO-1, and GCL. Moreover, CySSPe attenuated tert-butyl hydroperoxide-induced cytotoxicity and dose-dependently inhibited reactive oxygen species production. Silencing experiments using Nrf2-siRNA confirmed that CySSPe conferred protection against oxidative stress by activating Nrf2. CySSPe enhanced cellular pool of reduced glutathione (GSH) and improved GSH:GSSG ratio. Pretreatment of cells with l-buthionine-S,R-sulfoximine (BSO) confirmed that CySSPe increases de novo synthesis of GSH by upregulating expression of the GSH-synthesizing enzyme GCL. Treatment of cells with CySSPe elevated hydrogen sulfide (H2S) production. Inhibition of H2S-synthesizing enzymes, cystathionine-gamma-lyase (CSE) and cystathionine-beta-synthase (CBS), by pretreating cells with propargylglycine (PAG) and oxyaminoacetic acid (AOAA) revealed that H2S production was partially dependent on a CSE/CBS-catalyzed β-elimination reaction with CySSPe that likely produced 1-propenyl persulfide (RSSH). Depleting cells of their GSH pool by exposure to BSO and diethylmaleate attenuated H2S production, suggesting a GSH-dependent formation of H2S, likely via the reduction of RSSH by GSH. Finally, treatment of cells with CySSPe persulfidated Keap1, which may be the mechanism involved for the stabilization of Nrf2 by CySSPe. Taken together, our results showed that attenuation of oxidative stress by CySSPe is associated with its ability to produce H2S or RSSH, which persulfidates Keap1 and activates Nrf2 signaling. This study provides insights on the potential of CySSPe as an onion-derived dietary agent that modulates redox homeostasis and combats oxidative stress
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
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