Identification and evaluation of anti-inflammatory compounds from Kaempferia parviflora.

The rhizome of Kaempferia parviflora has been used in traditional Thai medicine. In this study, we identified and compared specific compounds from the hexane extract of K. parviflora with those from other Zingiberaceous plants by using gas chromatography-mass spectrometry. We identified 5,7-dimethoxyflavone (DMF), 5-hydroxy-3,7,3',4'-tetramethoxyflavone (TMF), estimated 3,5,7-trimethoxyflavone, 5-hydroxy-7,4'-dimethoxyflavone, 3,5,7,4'-tetramethoxyflavone, and investigated their anti-inflammatory effects in rat basophilic leukemia (RBL-2H3) cells stimulated with an IgE antigen or a calcium ionophore. We found that DMF and TMF more potently inhibited antigen-induced degranulation than did nobiletin, a well-known anti-inflammatory agent. In addition, compared to RBL-2H3 cells stimulated with a calcium ionophore, those treated with DMF and TMF showed more marked inhibition of the degranulation and the production and mRNA expression of inflammatory mediators. These results suggest that DMF and TMF inhibit an early step in the high-affinity IgE receptor signaling cascade rather than intracellular calcium release and protein kinase C activation.

Rapid and improved determination of furan in baby foods and infant formulas by headspace GC/MS.

Furan is a 5-membered ring compound with high volatility. The U.S. Food and Drug Administration (FDA) has recently published a report on the occurrence of furan in a large number of thermally processed foods. However, the FDA's analytical method, using standard curve addition, is not suitable for high-throughput routine laboratory operations. We developed a rapid and improved method for determination of furan in foods by headspace GC/MS. Quantification was achieved by using an internal standard of d4-furan and an external calibration curve of furan normalized against the internal standard. The incubation temperature for equilibration was set at 60 degrees C to avoid the formation of furan during analysis. The levels of furan in baby foods and infant formulas were determined with this method. Validation data showed good precision and accuracy. The LOD and LOQ were 0.2-0.5 ng/g and 0.5-2 ng/g for various food matrixes, respectively. The level of furan detected was in the range of 1.4 to 90 ng/g in baby foods and in the range of non-detectable to 36 ng/g in infant formulas.

Survey of 7 trichothecenes in corn-derived feed and feed ingredients.

Corn is a major ingredient of mixed feed, and it has been reported that corn may be contaminated with deoxynivalenol (DON). There is also a possibility of contamination with other trichothecenes. Recently, corn-derived products such as Distiller's Dried Grains with Solubles (DDGS), corn gluten feed and corn gluten meal have been introduced and used for mixed feed. However the actual occurrence of trichothecenes has not been sufficiently investigated. So, in this study, we analyzed DON and 6 other trichothecenes, i.e., 3-acetyl-deoxynivalenol (3AcDON), 15-acetyl-deoxynivalenol (15AcDON), T-2 toxin, HT-2 toxin, nivalenol, and fusarenon-X, in DDGS, corn gluten feed, corn gluten meal, and mixed feed containing corn-derived ingredients. The major trichothecenes identified in the samples tested were DON, 3AcDON and 15AcDON. In particular, DON, 3AcDON and 15AcDON were detected in most DDGS and corn gluten feed samples. Most samples of mixed feed contained DON and 15AcDON, but only one mixed feed sample contained 3AcDON. In contrast, corn gluten meal was contaminated with lower levels of these compounds than the other samples tested. Among 36 corn gluten meal samples, DON was detected in 24 and 15AcDON was detected in 20 samples. 3AcDON was not detected in any of the corn gluten meal samples.

Investigation of the suitability of immunochemical-based test kits for quantitative analysis of deoxynivalenol in corn-derived feed and feed ingredients.

We examined whether immunochemical-based test kits designed for quantitative analysis of deoxynivalenol (DON) screening in grain crops are applicable to corn processing by-products. Commercially available test kits (two types of immunochromatographic kits and three types of ELISA kits) were used to assay three types of corn processing by-products and mixed feed. The results obtained with some kits were significantly different from those of LC-MS analysis. Since the differences might be caused by insufficient extraction of DON from samples, the extraction time of all kits was set to be 20 minutes, based on a study of the dependence of the amount of DON extracted on the shaking time. Moreover, the extract of corn processing by-products was acidic, resulting in inhibition of the antigen-antibody reaction, so neutralization and centrifugation processes were introduced to prevent denaturation of antibody. After these modifications, the recovery for all kits in assays of corn gluten meal was within the range of 80-120%, and all kits showed acceptable accuracy. The relative standard deviation (RSD) of repeatability tests for all kits was less than 11.3% for analyses of both corn processing by-products and mixed feeds, indicating good precision. The above results showed that the kits studied were applicable to the quantitative assay of DON in corn processing by-products and mixed feed after modifications as described in this paper.

A method for the determination of acrylamide in a broad variety of processed foods by GC-MS using xanthydrol derivatization.

A novel GC-MS method was developed for the determination of acrylamide, which is applicable to a variety of processed foods, including potato snacks, corn snacks, biscuits, instant noodles, coffee, soy sauces and miso (fermented soy bean paste). The method involves the derivatization of acrylamide with xanthydrol instead of a bromine compound. Isotopically labelled acrylamide (d3-acrylamide) was used as the internal standard. The aqueous extract from samples was purified using Sep-Pak™ C18 and Sep-Pak™ AC-2 columns. For amino acid-rich samples, such as miso or soy sauce, an Extrelut™ column was used for purification or extraction. After reaction with xanthydrol, the resultant N-xanthyl acrylamide was determined by GC-MS. The method was validated for various food matrices and showed good linearity, precision and trueness. The limit of detection and limit of quantification ranged 0.5-5 and 5-20 µg kg⁻¹), respectively. The developed method was applied as an exploratory survey of acrylamide in Japanese foods and the method was shown to be applicable for all samples tested.

[Analysis of heterocyclic amines in food by liquid chromatography-tandem mass spectrometry].

A analytical method for simultaneous determination of 10 heterocyclic amines (HCAs) applicable to prepared foods on the market was studied. HCAs were extracted with acidic methanol, and then purified on a diatomaceous column and an ion-exchange column prior to LC-MS/MS. The method was validated within laboratory using three groups among the total diet samples (oils and fats, fish and shellfish, meat and eggs). The method showed good precision and trueness (as recovery) in duplicate analyses over 5 days, though there were some unsatisfactory results. Limits of detection (LOD) and quantification (LOQ) of the method were estimated from the deviation of the analytical results in samples spiked at a level of near 1 ng/g. In addition,13 groups of total diet samples, 27 items of retail food ready to eat and a few foods cooked in the laboratory were analyzed using this validated method. The results showed that the method is applicable to the foods tested in this study and provided information on the content of HCAs in some foods in Japan.

Monitoring of acrylamide concentrations in potato chips in Japan between 2006 and 2010.

Acrylamide levels in commercially available potato chips in Japan were monitored between August 2006 and June 2010 using the xanthydrol derivative gas chromatography-mass spectrometry (GC-MS) method. Seasonal and annual changes in acrylamide concentrations were determined. Nationwide bimonthly sampling of potato chips was carried out using a four-level design, and seasonal variations were detected in which the minimum acrylamide concentration was observed in August, and the maximum between February and June. Seasonal variations became less apparent after August 2008 as a result of annual effects and/or mitigation measures taken by the potato chip producers. Sampling uncertainties were separated into time-to-time, city-to-city, and lot-to-lot variation, and the largest variation was shown to be lot-to-lot including bag-to-bag.

Validation of an HPLC analytical method coupled to a multifunctional clean-up column for the determination of deoxynivalenol.

To evaluate a method using a multifunctional clean-up column coupled with high performance liquid chromatography as an official analytical method for the determination of deoxynivalenol in wheat used as food or feed, an inter-laboratory study was performed in 12 laboratories using four naturally contaminated wheat samples and one spiked sample. The relative standard deviations for repeatability (RSDr) and reproducibility (RSDR) of naturally contaminated wheat were in the range 5.8-11.3% and 12.0-20.7%, respectively. The HORRAT was less than 1.0 in each sample. From the spiking test, the recovery rate, RSDr, RSDR and HORRAT value were 100.0%, 11.2%, 10.3% and 0.5, respectively. The limit of quantification is 0.10 mg/kg from the range obtained in a linear calibration. Thus, it should be useful as a sensitive and validated analytical method for the determination of deoxynivalenol in wheat intended for use in food and feed.