Low‐calorie Sweeteners and Other Sugar Substitutes: A Review of the Safety Issues

Sugar‐free or reduced‐sugar foods and beverages are very popular in the United States and other countries, and the sweeteners that make them possible are among the most conspicuous ingredients in the food supply. Extensive scientific research has demonstrated the safety of the 5 low‐calorie sweeteners currently approved for use in foods in the United States–acesulfame K, aspartame, neotame, saccharin, and sucralose. A controversial animal cancer study of aspartame conducted using unusual methodology is currently being reviewed by regulatory authorities in several countries. No other issues about the safety of these 5 sweeteners remain unresolved at the present time. Three other low‐calorie sweeteners currently used in some other countries–alitame, cyclamate, and steviol glycosides–are not approved as food ingredients in the United States. Steviol glycosides may be sold as a dietary supplement, but marketing this product as a food ingredient in the United States is illegal. A variety of polyols (sugar alcohols) and other bulk sweeteners are also accepted for use in the United States. The only significant health issue pertaining to polyols, most of which are incompletely digested, is the potential for gastrointestinal discomfort with excessive use. The availability of a variety of safe sweeteners is of benefit to consumers because it enables food manufacturers to formulate a variety of good‐tasting sweet foods and beverages that are safe for the teeth and lower in calorie content than sugar‐sweetened foods.     

Melanin and nicotine: A review of the literature.

The role of melanin in nicotine uptake and metabolism has received little attention. Because nicotine has been shown to accumulate in tissues containing melanin, exploring links between melanin and nicotine may provide additional clues to understanding smoking behavior and disease effects. To examine the scientific literature on the relationship between melanin and nicotine, we conducted a PubMed search. We also searched online archives of internal tobacco industry documents. We retrieved and reviewed 82 published research papers related to melanin and nicotine or melanin and metabolism of other drugs, and 150 relevant internal tobacco industry documents. The published literature suggests that nicotine may accumulate in human tissues containing melanin and this retention may increase melanin synthesis. Existing research on the relationship between melanin and nicotine lacks an adequate consideration of this relationship's potential impact, if any, on nicotine metabolism, level of nicotine dependence, and ability to quit smoking. Differential accumulation of nicotine in melanin-containing tissues could have implications for individuals with high levels of melanin.     

Status quo and future research challenges on organic food quality determination with focus on laboratory methods

Organic food quality determination needs multi‐dimensional evaluation tools. The main focus is on the authentication as an analytical verification of the certification process. New fingerprinting approaches such as ultra‐performance liquid chromatography–mass spectrometry, gas chromatography–mass spectrometry, direct analysis in real time–high‐resolution mass spectrometry as well as crystallization with and without the presence of additives seem to be promising methods in terms of time of analysis and detecting organic system‐related parameters. For further methodological development, a system approach is recommended, which also takes into account food structure aspects. Furthermore, the authentication of processed organic samples needs more consciousness, hence most of organic food is complex and processed. © 2013 Society of Chemical Industry     

Metabolites indicate hot spots of biodegradation and biogeochemical gradients in a high-resolution monitoring well

Anaerobic degradation processes play an important role in contaminated aquifers. To indicate active biodegradation processes signature metabolites can be used. In this study field samples from a high-resolution multilevel well in a tar oil-contaminated, anoxic aquifer were analyzed for metabolites by liquid chromatography-tandem mass spectrometry and time-of-flight mass spectrometry. In addition to already known specific degradation products of toluene, xylenes, and naphthalenes, the seldom reported degradation products benzothiophenemethylsuccinic acid (BTMS), benzofuranmethylsuccinic acid (BFMS), methylnaphthyl-2-methylsuccinic acid (MNMS), and acenaphthene-5-carboxylic acid (AC) could be identified (BFMS, AC) and tentatively identified (BTMS, MNMS). The occurrence of BTMS and BFMS clearly show that the fumarate addition pathway, known for toluene and methylnaphthalene, is also important for the anaerobic degradation of heterocyclic contaminants in aquifers. The molar concentration ratios of metabolites and their related parent compounds differ over a wide range which shows that there is no simple and consistent quantitative relation. However, generally higher ratios were found for the more recalcitrant compounds, which are putatively cometabolically degraded (e.g., 2-carboxybenzothiophene and acenaphthene-5-carboxylic acid), indicating an accumulation of these metabolites. Vertical concentration profiles of benzylsuccinic acid (BS) and methyl-benzylsuccinic acid (MBS) showed distinct peaks at the fringes of the toluene and xylene plume indicating hot spots of biodegradation activity and supporting the plume fringe concept. However, there are some compounds which show a different vertical distribution with the most prominent concentrations where also the precursor compounds peaked.     

Bicyclic substituted hydroxyphenylmethanone type inhibitors of 17 β-hydroxysteroid dehydrogenase Type 1 (17 β-HSD1): the role of the bicyclic moiety

An attractive target that has still to be explored for the treatment of estrogen‐dependent diseases, such as breast cancer and endometriosis, is the enzyme responsible for the last step in the biosynthesis of estradiol (E2): 17β‐hydroxysteroid dehydrogenase type 1 (17β‐HSD1). It catalyzes the reduction of the weakly active estrone (E1) into E2, which is the most potent estrogen in humans. Inhibition of 17β‐HSD1 lowers intracellular E2 concentrations and thus presents a therapeutic target for estrogen‐dependent pathologies. Recently, we reported a new class of highly active and selective 17β‐HSD1 inhibitors: bicyclic substituted hydroxyphenylmethanones. Here, further structural variations on the bicyclic moiety are described, especially focusing on the exchange of its hydroxy function. Twenty‐nine novel inhibitors were synthesized and evaluated for 17β‐HSD1 inhibition in a cell‐free and cellular assay, for selectivity toward 17βHSD2 and estrogen receptors (ER) alpha and beta, as well as for metabolic stability. The best compound exhibited IC₅₀ values of 12 nM (cell‐free assay) and 78 nM (cellular assay), high selectivity for 17β‐HSD1, and reasonable metabolic stability. A molecular docking study provided insight into the protein–ligand interactions of this compound with 17β‐HSD1.     

LipidomeDB Data Calculation Environment: Online Processing of Direct-Infusion Mass Spectral Data for Lipid Profiles

LipidomeDB Data Calculation Environment (DCE) is a web application to quantify complex lipids by processing data acquired after direct infusion of a lipid-containing biological extract, to which a cocktail of internal standards has been added, into an electrospray source of a triple quadrupole mass spectrometer. LipidomeDB DCE is located on the public Internet at . LipidomeDB DCE supports targeted analyses; analyte information can be entered, or pre-formulated lists of typical plant or animal polar lipid analytes can be selected. LipidomeDB DCE performs isotopic deconvolution and quantification in comparison to internal standard spectral peaks. Multiple precursor or neutral loss spectra from up to 35 samples may be processed simultaneously with data input as Excel files and output as tables viewable on the web and exportable in Excel. The pre-formulated compound lists and web access, used with direct-infusion mass spectrometry, provide a simple approach to lipidomic analysis, particularly for new users.     

Investigation of factors affecting the accumulation of vinyl chloride in polyvinyl chloride piping used in drinking water distribution systems

Plastic piping made of polyvinyl chloride (PVC), and chlorinated PVC (CPVC), is being increasingly used for drinking water distribution lines. Given the formulation of the material from vinyl chloride (VC), there has been concern that the VC (a confirmed human carcinogen) can leach from the plastic piping into drinking water. PVC/CPVC pipe reactors in the laboratory and tap samples collected from consumers homes (n = 15) revealed vinyl chloride accumulation in the tens of ng/L range after a few days and hundreds of ng/L after two years. While these levels did not exceed the EPA’s maximum contaminant level (MCL) of 2 μg/L, many readings that simulated stagnation times in homes (overnight) exceeded the MCL-Goal of 0 μg/L. Considerable differences in VC levels were seen across different manufacturers, while aging and biofilm effects were generally small. Preliminary evidence suggests that VC may accumulate not only via chemical leaching from the plastic piping, but also as a disinfection byproduct (DBP) via a chlorine-dependent reaction. This is supported from studies with CPVC pipe reactors where chlorinated reactors accumulated more VC than dechlorinated reactors, copper pipe reactors that accumulated VC in chlorinated reactors and not in dechlorinated reactors, and field samples where VC levels were the same before and after flushing the lines where PVC/CPVC fittings were contributing. Free chlorine residual tests suggest that VC may be formed as a secondary, rather than primary, DBP. Further research and additional studies need to be conducted in order to elucidate reaction mechanisms and tease apart relative contributions of VC accumulation from PVC/CPVC piping and chlorine-dependent reactions.     

Loss rates of urban biocides can exceed those of agricultural pesticides

Biocides and pesticides are used to control unwanted organisms in urban and agricultural areas. After application, they can be lost to surface waters and impair water quality. Several national consumption studies have shown that urban and agricultural use may be in the same range. It is difficult to judge whether this results in similar loadings of surface waters because there is a lack of sound, comparative studies addressing urban and agricultural losses simultaneously.The aim of this study is thus to relate the biocide and pesticide loads found in surface waters to their respective urban and agricultural usage (loss rates). To simultaneously assess the loss rates, we conducted a comprehensive field study in a catchment of mixed land use on the Swiss Plateau. The study area was divided into four sub-catchments with different degrees of urban and agricultural land use. In addition, we studied the only wastewater treatment plant, a combined sewer overflow and a storm sewer within the area. Rain events were sampled at high temporal resolution from March to November, 2007. Information on agricultural applications was gained from local farmers. For urban uses, consumption estimations were conducted based on statistical and product information.Despite substantially lower amounts used, the measured loads of urban biocides were in the same range as the most widely-used agricultural pesticides. The lower usage was compensated by urban loss rates that were up to ten times higher than agricultural ones (0.6 to 15% for urban, 0.4 to 0.9% for agricultural compounds). For most biocides and pesticides, the loads were controlled by rain events. Besides the rain-controlled losses, some urban-used biocides (e.g. diazinon) showed a continuous load independent of rain events and season. This study demonstrates that in catchments with mixed land use, mitigation strategies have to pay sufficient attention to the urban sources.