Comparative effects of food-derived polyphenols on the viability and apoptosis of a human hepatoma cell line (HepG2)     

Ramos S  Alía M  Bravo L  Goya L 《Journal of agricultural and food chemistry》2005,53(4):1271-1280

Consumption of fruits and vegetables, which are rich in polyphenols, has been associated with a reduced risk of chronic diseases such as cancer. Dietary polyphenols have antioxidant and antiproliferative properties that might explain their beneficial effect on cancer prevention. The aim of this study was to investigate the effects of different pure polyphenols [quercetin, chlorogenic acid, and (-)-epicatechin] and natural fruit extracts (strawberry and plum) on viability or apoptosis of human hepatoma HepG2 cells. The treatment of cells for 18 h with quercetin and fruit extracts reduced cell viability in a dose-dependent manner; however, chlorogenic acid and (-)-epicatechin had no prominent effects on the cell death rate. Similarly, quercetin and strawberry and plum extracts, rather than chlorogenic acid and (-)-epicatechin, induced apoptosis in HepG2 cells. Moreover, quercetin and fruit extracts arrested the G1 phase in the cell cycle progression prior to apoptosis. Quercetin and strawberry and plum extracts may induce apoptosis and contribute to a reduced cell viability in HepG2 cells.  相似文献   

In vitro determination of the indigestible fraction in foods: an alternative to dietary fiber analysis   总被引：3，自引：0，他引：3  

Saura-Calixto F  García-Alonso A  Goñi I  Bravo L 《Journal of agricultural and food chemistry》2000,48(8):3342-3347

Dietary fiber (DF) intakes in Western countries only accounts for about one-third of the substrates required for colonic bacterial cell turnover. There is a general trend among nutritionists to extend the DF concept to include all food constituents reaching the colon. In this line, a method to quantify the major nondigestible components in plant foods, namely, the indigestible fraction (IF), is presented. Analytical conditions for IF determination are close to physiological. Samples, analyzed as eaten, were successively incubated with pepsin and alpha-amylase; after centrifugation and dialysis, insoluble and soluble IFs were obtained. IF values include DF, resistant starch, resistant protein, and other associated compounds. IF contents determined in common foods (cereals, legumes, vegetables, and fruits) were higher than DF contents. Calculated IF intakes were close to the estimated amount of substrates reaching the colon. IF data could be more useful than DF data from a nutritional point of view; therefore, IF is proposed as an alternative to DF for food labeling and food composition tables.  相似文献   

On-site remediation of chromium-contaminated sediments by combination of sediment washing and stabilization with magnesium oxide/limestone mixtures     

Carlos?Wildt  Oriol?Gibert  José?Luis?CortinaEmail author  Giuliana?Coscera 《Journal of Soils and Sediments》2004,4(3):184-191

Goal, Scope and Background  The remediation of heavy-metalcontaminated soils and sediments is of significant value to industrial areas around the world. The spread of such pollutants can result in a potential risk of entering the groundwater system and being transported to potential receptors. Leaching techniques can be an effective treatment option for the metal removal from soils and sediments. This approach consists of washing or leaching the contaminated soil with an appropriate reagent and the subsequent treatment of the leaching in an above-ground installation (on-site treatment) where metals can be removed and concentrated into a smaller volume. Among the heavy metals, chromium is a commonly identified soil contaminant, particularly in sites with intensive economic activities including agriculture, industrial, mining and mineral,processing. Objective  The objective of this work was the evaluation and development of a leaching process for the remediation of soils and sediments polluted with chromium at laboratory scale. Chromium soil pollution was generated after the breakdown of a channel containing chromium wastes from a tannery plant. The pollution extension has been estimated to be on the order of thousands of tonnes of soil to be treated, with chromium contents ranging from 500 to 17,000 mg kg^-1 soil. Methods  The whole process investigated in this study integrates three stages; a) chromium leaching from a sediment using a diluted sulphuric acid solution, b) treatment of the leaching effluents with a magnesium oxide/limestone mixture for the precipitation of chromium hydroxide after acidity neutralisation, and c) polishing step to remove the eventual remaining chromium by adsorption onto natural zeolite. The amount of contaminated sediment treated ranged from 0.5 to 2 kg with chromium contents of between 2000 and 17,000 mg kg^-1. Results and Discussion  The paper describes results on the performance of the process and the optimisation of steps including influence of acid sulphuric concentration, chromium removal efficiency as well as alkaline reactive mixture proportions. Effluents from the leaching cells showed a significant decay on the chromium concentration with the increase of leaching runs and a high content of acidity (pH values close to 0.5). The treatment of these effluents in a second cell containing magnesium oxide/ limestone mixtures resulted in a high efficiency in neutralisation of acidity (pH values around 7) and chromium removal (concentrations below 5 mg 1^-1). The passage through a third compartment containing zeolite as an adsorbent decreased the chromium concentration below 0.5 mg 1^-1, Conclusions  From the results obtained on the chromium leaching and immobilisation with magnesium oxide/limestone mixture at a laboratory scale, it could be pointed out that: (a) diluted sulphuric acid solutions (3%) demonstrated a high efficiency on chromium removal from sandy polluted soils on the kilogram scale, (b) mixtures of magnesium oxide/limestone demonstrated a high capacity to neutralise the residual high acidity present on the effluents and to remove chromium by precipitation and (c) between the limestone and caustic magnesia mixtures, those containing more than 60% of caustic magnesia provide the higher efficiency. Recommendation and Outlook  Future work would be directed to the evaluation of the integrated process of leaching and chromium precipitation on column at a scale of 100 to 1000 kg.  相似文献   

7th International Conference on Mercury as a Global Pollutant     

Saulo?Rodrigues-FilhoEmail author  Luis?Gonzaga?Sobral 《Journal of Soils and Sediments》2004,4(3):197-200

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A multispectral vision system to evaluate enzymatic browning in fresh-cut apple slices     

Loredana Lunadei  Pamela Galleguillos  Beln Diezma  Lourdes Lle  Luis Ruiz-Garcia 《Postharvest Biology and Technology》2011,60(3):225-234

Increased regulation of chemical fumigants has forced the almond industry to seek alternatives for postharvest control of insect pests in raw almonds. This paper reports developments of non-chemical treatment for postharvest disinfestation of almonds using radio frequency (RF) energy. A pilot-scale 27 MHz RF unit was used to evaluate effects of a RF treatment protocol on quality attributes in treated in-shell and shelled almond samples. The RF treatment protocol used 0.75 kW RF power, a forced hot air at 63 °C, back and forth movements on the conveyor at 0.56 m/min, and single mixing, which all improved the final heating uniformity. RF treatments sharply reduced the heating time from 86 and 137 min for hot air heating to only 6.4 and 8.8 min for the center of 1.5 kg in-shell and 2.4 kg shelled almond samples to reach 63 °C, respectively. Almond quality was not affected by the RF treatments because peroxide values, fatty acid and kernel color of treated almonds were better than or similar to untreated controls after 20 d at 35 °C, simulating 2 years of storage at 4 °C. RF treatments did not significantly affect the kernel moisture content of both types of almonds but reduced the moisture content in the shell. RF treatments may hold great potential to replace chemical fumigation for disinfesting almonds.  相似文献   

A virus in a fungus in a plant: three-way symbiosis required for thermal tolerance   总被引：2，自引：0，他引：2  

Márquez LM  Redman RS  Rodriguez RJ  Roossinck MJ 《Science (New York, N.Y.)》2007,315(5811):513-515

A mutualistic association between a fungal endophyte and a tropical panic grass allows both organisms to grow at high soil temperatures. We characterized a virus from this fungus that is involved in the mutualistic interaction. Fungal isolates cured of the virus are unable to confer heat tolerance, but heat tolerance is restored after the virus is reintroduced. The virus-infected fungus confers heat tolerance not only to its native monocot host but also to a eudicot host, which suggests that the underlying mechanism involves pathways conserved between these two groups of plants.  相似文献   

Scientists and the Venezuelan crisis     

Jaffe K  Di Polo R  Cardier J  Rios R  Utrera R  Rodriguez M  Zoppi LB  Rojas AM  Ponte A  Scharifker B  Bemporad M;Board of Directors  Venezuelan Association for the Advancement of Science  Caracas 《Science (New York, N.Y.)》2003,299(5610):1184

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Virology. The SARS coronavirus: a postgenomic era     

Holmes KV  Enjuanes L 《Science (New York, N.Y.)》2003,300(5624):1377-1378

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A primer of acoustic analysis for landscape ecologists     

Luis J. Villanueva-Rivera  Bryan C. Pijanowski  Jarrod Doucette  Burak Pekin 《Landscape Ecology》2011,26(9):1233-1246

In this paper we present an introduction to the physical characteristics of sound, basic recording principles as well as several ways to analyze digital sound files using spectrogram analysis. This paper is designed to be a “primer” which we hope will encourage landscape ecologists to study soundscapes. This primer uses data from a long-term study that are analyzed using common software tools. The paper presents these analyses as exercises. Spectrogram analyses are presented here introducing indices familiar to ecologists (e.g., Shannon’s diversity, evenness, dominance) and GIS experts (patch analysis). A supplemental online tutorial provides detailed instructions with step by step directions for these exercises. We discuss specific terms when working with digital sound analysis, comment on the state of the art in acoustic analysis and present recommendations for future research.  相似文献   

Fermented vegetables containing benzoic and ascorbic acids as additives: benzene formation during storage and impact of additives on quality parameters     

Casado FJ  Sánchez AH  De Castro A  Rejano L  Beato VM  Montaño A 《Journal of agricultural and food chemistry》2011,59(6):2403-2409

Chemical and sensorial changes related to the use of benzoates and ascorbic acid as additives in packed fermented vegetables were investigated. For this, three selected vegetables (green olives, cucumbers, and caperberries) stored under different conditions (glass or plastic containers, ambient or refrigerated storage) were used. In all cases, benzoic acid remained unchanged (glass bottle) or decreased slightly (plastic pouch) at prolonged storage. Ascorbic acid was partially or totally degraded during storage, the degradation rate depending on the storage conditions and the vegetable matrix. Benzene levels higher than 10 μg/L were found in cucumbers and caperberries containing both additives, but only when packed in plastic pouches and after prolonged storage at room temperature. In these conditions, an appreciable browning of brine, related to AA degradation, was also found. The use of benzoate alone had a significant influence on vegetable color, but flavor was not significantly affected at the benzoate levels tested. On the basis of the present study, benzoates should be removed from fermented vegetable formulations containing ascorbic acid to eliminate possible benzene formation during long-term storage.  相似文献