We have previously found that picolinic acid and its related compounds can induce apoptosis in human promyelocytic leukemia (HL-60) cells, but not at <2 mM concentration. In the present study, we examined whether different esters of picolinic acid with alkyl groups and those with cholesterol can induce apoptosis. We found that the esters of picolinic acid with octyl, decyl, dodecyl, and hexadecyl groups induced apoptosis in HL-60 cells most effectively in a chain length-dependent manner. Particularly, dodecyl picolinate induced apoptosis even at over 0.01 mM concentration. On the other hand, cholesteryl picolinate did not induce apoptosis. In addition, we examined the effect of vitamin E as an antioxidant on apoptosis induced by picolinic acid or various esters of picolinic acid in HL-60 cells. We found that percent of sub-G1 peak was more effectively decreased by pre-treatment with vitamin E. Cumulatively, our results suggest that the apoptosis induced by esterification of the carboxyl group of picolinic acid with various alkyl groups is more effective.

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Few were known about presence of lower carbonyl compounds such as formaldehyde, acetaldehyde and acetone in air of household refrigerators. This study aimed to investigate the factors determining the levels of the gases in the air. Field measurements were carried out for 25 domestic refrigerators, which were actually employed for volunteers’ daily life, using a passive sampler. Air concentrations of lower carbonyl compounds were determined by DNPH-HPLC methodology. The results showed emission sources of acetaldehyde and acetone were suggested to exist inside the refrigerators, and distributions of their concentration levels did not depend on specifications and ways of use of the refrigerators. Then, emissions of lower carbonyl compounds from individual food samples were investigated using a model refrigerator. The results suggested steady and/ or unsteady emissions from stored foods determines air concentrations of acetaldehyde and acetone in air of the household refrigerator.

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A simultaneous quantitative analytical method for eight polyphenols, e.g. mangiferin (1), gallic acid (2), protpcatechuic acid (3), (+)-catechin (4), (–)-epicatechin (5), gallocatechin (6), (–)-epigallocatechin (7), and (–)-4'-O-methylepigallocatechin (8), as functional constituents in the roots and stems of the genus Salacia species (Hippocraceae) was developed. The content of caffeine (9), which showed similar chromatographic behavior under the analytical conditions, was also determined. The optimum conditions for separation and detection of these polyphenol constituents were achieved on an ODS column (3 μm particle size, 2.1 mm i.d. × 100 mm) with methanol / 0.1% aqueous formic acid solvent system as the mobile phase, associated with MS equipped with an electrospray ionization source. Totally 47 Salacia samples from the different origin including S. chinensis (2 roots and 28 stems), S. reticulata (6 roots and 3 stems), and S. oblonga (8 roots) were analyzed, and the results indicated that mangiferin (1) had a characteristic distributions due to the plant part [roots (1.95–40.5 mg/g from the dried material) > stems ( < 0.258 mg/g)]. Among the root part, the inner root bark was found to observe the richest content of mangiferin (1).

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In this study, we examined the effects of muscle glycogen and lactic acid contents on the meat quality of the Pacific mackerel Scomber japonicus. The fish samples were subjected to 30 min of forced exercise with a weight (40% of body weight) placed on the tail. The fish were then killed at 0, 6 and 24 hours after removing the weight (exercise-recovery groups). The glycogen content in the dorsal ordinary muscle markedly decreased after exercise, whereas it increased during rest. Conversely, increased lactic acid content in the dorsal ordinary muscle was observed after exercise, while its contents decreased to the same level as the control (without exercise) after 6 hours of rest. The decreasing rate of muscle pH in the meat of exercise-recovery groups which rested for 6 or 24 hours were smaller than those in the meat of the group without exercise during storage at 30˚C. The color L^* value was used as an indicator of whiteness of the dorsal ordinary muscle, and although it increased when meat of the control and the exerciserecovery groups rested for 0 hour were stored at 30˚C, that of the meat of the exercise-recovery group rested for 6 or 24 hours did not change during storage. Furthermore, increasing rate of K value of the meat of the exercise-recovery group which rested for 0 hour was significantly higher than those of the other groups. However, there was no significant difference in the K value of meat between the control and exercise-recovery groups which rested for 6 or 24 hours. These results suggest that low glycogen and lactic acid in the muscle prior to killing prevented the decrease in pH during storage, consequently suppressing the deterioration of the meat quality of the Pacific mackerel.

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Microscopy is the primary technique for identifying the origin plant of a starch sample but requires operators with highly proficient skills and experience, and is unsuitable for discriminating modified starches such as pregelatinized starches. The plant species from which the starch is isolated is reflected in the characteristic color of the iodine-starch reaction solution. However, visual observation is subjective and vague because color perception is organoleptic and color is expressed by ambiguous names such as “orange-red” and “deep blue”. Quality management using the color of samples is gaining wider acceptance in the field of natural products as well as industrial products because simple, easy to use, high-performance spectrophotometers are now widely used. In this study, the color of iodine-starch reaction solution of 31 kinds of starches and pregelatinized starches from maize, wheat, potato and rice were measured spectrophotometrically and the color was numerically described using the L^*a^*b^* color system. The characteristic (a^*, b^*) values grouped together on the color system according to the origin plant for each starch, suggesting that numerical information on the color reaction is useful for estimating the origins of starches.

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The inhibitory effect of Kaempferia parviflora (black ginger) constituents on nitric oxide (NO) production was examined. From the methanolic extract of K. parviflora rhizome, 16 flavones, 14 flavanones, 2 diarylheptanoids, 2 chalcones and a stilbene were isolated and their inhibitory activities toward NO production were examined. As a result, two methoxyflavones, 5,7,3’,4’-tetramethylluteolin and 5,7-dimethoxyflavone showed significant activities. Most of the flavanone constituents, except for 5,7,3’-trimethoxy-4’-hydroxyflavanone, showed lower activities. The most potent active constituent of Black ginger was the chalcone flavokavin B; its derivative, flavokavin A, also showed significant activity. The curcumin and its derivative, 1-(4-hydroxyphenyl)-7-phenyl-1,6-heptadiene-3,5-dione, showed significant activity. Only one stilbene was isolated, and it showed low activity.

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A screening method for deoxynivalenol (DON) residue in beer by use of a commercially available ELISA-kit was applied for its accuracy management for method validation. DON in beer sample was subjected to acetonitrile extraction and cleanup with a MycoSep #227 multifunctional column. Recovery experiments indicated that the trueness of the low concentration sample (10 ng/ mL) and that of the high concentration sample (100 ng/mL) were higher than 90%, respectively. The relative standard deviation (RSD) of repeatability and that of intermediate precision were less than 25%, respectively. In addition, the interlaboratory precision of seven laboratories was determined as an external quality control test with and without sample cleanup. The interlaboratory precision of the high concentration sample (100 ng/mL) showed an acceptable Z-score (less than 2.0 and greater than -2.0; |z| < 2) for all the seven laboratories, regardless of whether or not cleanup was performed. In addition, the gap between the added concentration and the average value (most probable value) was less than 20%. On the other hand, in the case of the low concentration sample (10 ng/mL) without cleanup, the Z-scores were “|z| < 2” for all the seven laboratories, but the residual variance was large and the deviation from the most probable value was increased. However, by performing cleanup pretreatment, DON concentrations down to 10 ng/mL could be measured by ELISA. Then, sixteen commercially available beer samples were subjected to DON determination using the present ELISA and a confirmation test using GC/MS. DON was detected in 9 beer samples (56.3%); the mean concentration was 14.3 ng/mL and the highest concentration was 54.8 ng/mL. The correlation coefficient (r) was high at 0.887. The results suggest that the ELISA-kit with the cleanup method is useful for a screening of low level DON in beer.

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In order to ensure the reliability of testing, measurement uncertainty arising from analysis can be useful scientific evidence. In this study, we analyzed food preservatives (sorbic acid [SOA], benzoic acid [BA], and dehydroacetic acid [DHA]) and sweetener additives (acesulfame potassium [Aces-K], and sodium saccharin [Sac-Na]) in many kinds of processed food by a simultaneous determination method with carrez extraction, and estimated measurement uncertainty with a top-down approach. The recoveries from 23 kinds of food fortified with sweetener additives at a level of 0.10 g/kg, and with food preservatives at 0.15 g/kg, were 82~98%. Repeatability was 0.9~3.1%, and the within-laboratory reproducibility was 4.2~6.8%. Considering expanded measurement uncertainty, the range of analytical values obtained in our laboratory will be limited as follows: Aces-K, 0.090~0.11 g/kg; Sac-Na, 0.082~0.11 g/kg; SOA, 0.12~0.16 g/kg; BA, 0.13~0.16 g/kg; and DHA, 0.11~0.14 g/kg.

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[in Japanese]

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