[Determination of Allyl Isothiocyanate in Mustard and Horseradish Extracts by Single Reference GC and HPLC Based on Relative Molar Sensitivities].

The main component of the Mustard and Horseradish extracts, which are used as natural food additives in Japan, is allyl isothiocyanate (AITC). The determination of AITC using GC-FID is the official method employed in the quality control assessments for these products. In this method, a commercially available AITC reagent is used as a calibrant. However, 1H-quantitative NMR (qNMR) analysis revealed that the AITC reagents contain impurity. Therefore, we examined the GC-FID and HPLC-refractive index detector (LC-RID) method based on relative molar sensitivities (RMSs) to high-purity single reference (SR). The RMSs of AITC/SR under the GC-FID and LC-RID conditions were accurately determined using qNMR. The AITC in two types of food additives was quantified using qNMR, SR GC-FID, and SR LC-RID methods. Both SR GC-FID and SR LC-RID showed good agreement within 2% with the AITC content determined by direct qNMR.

Determination of Mogroside V in Luohanguo Extract for Daily Quality Control Operation Using Relative Molar Sensitivity to Single-Reference Caffeine.

Mogroside V is one of the characteristic and effective components of luohanguo extract, a food additive used as a sweetener in Japan as per Japan's Standards and Specifications for Food Additives (JSFA; 9th ed.). JSFA stipulates that the quantitative determination for mogroside V content in luohanguo extract applies HPLC using analytical standard mogroside V. However, no mogroside V reagents with proven purities are commercially available. Therefore the current JSFA determination method is not particularly suited for daily quality control operations involving luohanguo extract. In this study, we applied an alternative quantitative method using a single reference with relative molar sensitivity (RMS). It was possible to calculate the accurate RMS by an offline combination of 1H-quantitative NMR spectroscopy (1H-qNMR) and an HPLC/variable-wavelength detector (VWD). Using the RMS of mogroside V to a commercial certified reference material grade caffeine, the mogroside V contents in luohanguo extracts could be determined using HPLC/VWD without analytical standard mogroside V. There was no significant difference between the mogroside V contents in luohanguo extracts determined using the method employing single-reference caffeine with the RMS and using the JSFA method. The absolute calibration curve for the latter was prepared using an analytical standard mogroside V whose purity was determined by 1H-qNMR. These results demonstrate that our proposed method using a single reference with RMS is suitable for quantitative determination of mogroside V in luohanguo extract and can be used as an alternative method to the current assay method in JSFA.

Quantification of tea-derived catechins without the requirement for respective calibration curves by single reference liquid chromatography based on relative molar sensitivity.

BACKGROUND: Many studies report the monitoring of catechins in tea samples by chromatographic techniques. Unfortunately, only a small number of screening assays for catechins exist as a result of the complexity of authentic standards for the respective calibration curves. In the present study, a single reference (SR) exhaustive assay for the simultaneous quantification of tea-derived catechins by liquid chromatography (LC) with photodiode array and fluorescence detectors based on relative molar sensitivity (RMS) was developed as a screening assay of common tea samples without respective calibration curves using authentic standards. RESULTS: Three original SR standards were proposed based on flavonoid structures, evaluated by quantitative 1 H-NMR based on an indirect standard (1,4-bis(trimethylsilyl) benzene-d4 ) and successfully separated in a LC chromatogram. In tea samples with these added SR calculated based on RMS, the concentrations of eight tea-derived catechins could be measured with a relative SD of < 8.5% by a single LC run. CONCLUSION: This LC screening assay based on RMS allows reliable quantification without the requirement for respective calibration curves using authentic standards. © 2020 Society of Chemical Industry.

Determination of perillaldehyde in perilla herbs using relative molar sensitivity to single-reference diphenyl sulfone.

Perillaldehyde (PRL) is one of the essential oil components derived from perilla plants (Perilla frutescens Britton) and is a characteristic compound of the traditional medicine "perilla herb ()" listed in the The Japanese Pharmacopoeia, 17th edition (JP17). HPLC using an analytical standard of PRL has been used to quantitatively determine the PRL content in perilla herb. However, PRL reagents have been reported to decompose easily. In this study, we utilized an alternative quantitative method using on a single reference with relative molar sensitivity (RMS) based on the results of experiments performed in two laboratories. It was possible to calculate the exact RMS using an offline combination of 1H-quantitative NMR spectroscopy (1H-qNMR) and an HPLC/photodiode array (PDA) detector (or an HPLC/variable-wavelength detector [VWD]). Using the RMS of PRL to the single-reference compound diphenyl sulfone (DFS), which is an inexpensive and stable compound, the PRL content in the perilla herb could be determined using HPLC/PDA or HPLC/VWD without the need for the analytical standard of PRL. There was no significant difference between the PRL contents of perilla herb determined using the method employing the single-reference DFS with RMS and using the JP17 assay, the calibration curve of which was generated using the analytical standard of PRL with adjusted purity measured by 1H-qNMR. These results demonstrate that our proposed method using a single reference with RMS is suitable for quantitative assays of perilla herb and can be an alternative method for the current assay method defined in the JP17.

Determination and purification of sesamin and sesamolin in sesame seed oil unsaponified matter using reversed-phase liquid chromatography coupled with photodiode array and tandem mass spectrometry and high-speed countercurrent chromatography.

In Asian countries, sesame seed oil unsaponified matter is used as a natural food additive due to its associated antioxidant effects. We determined and purified the primary lignans sesamin and sesamolin in sesame seed oil unsaponified matter using reversed-phase liquid chromatography coupled with photodiode array and tandem mass spectrometry and high-speed countercurrent chromatography. Calibration curves showed good correlation coefficients (r2 > 0.999, range 0.08 and/or 0.15 to 5 µg/mL) with a limit of detection (at 290 nm) of 0.02 µg/mL for sesamin and 0.04 µg/mL for sesamolin. Sesame seed oil unsaponified matter contained 2.82% sesamin and 2.54% sesamolin, respectively. Direct qualitative analysis of sesamin and sesamolin was achieved using quadrupole mass spectrometry with positive-mode electrospray ionization. Pure (>99%) sesamin and sesamolin standards were obtained using high-speed countercurrent chromatographic purification (hexane/ethyl acetate/methanol/water; 7:3:7:3). An effective method for determining and purifying sesamin and sesamolin from sesame seed oil unsaponified matter was developed by combining these separation techniques for standardized food additives.

Analytical methods for SiO2 and other inorganic oxides in titanium dioxide or certain silicates for food additive specifications.

An analytical method has been developed for the detection of SiO(2) and other oxides in titanium dioxide and certain silicates used in food additives using inductively coupled plasma (ICP) atomic emission spectrometry without hydrofluoric acid. SiO(2) and other oxides in titanium dioxide or certain silicates were resolved by alkali fusion with KOH and boric acid and then dissolved in dilute hydrochloric acid as a test solution for ICP. The recovery of SiO(2) and Al(2)O(3) added at 0.1 and 1.0%, respectively, in TiO(2) was 88-104%; coefficient of variation was <4%. The limit of determination of SiO(2) and Al(2)O(3) was about 0.08%, and the accuracy of the ICP method was better than that of the Joint FAO/WHO Expert Committee on Food Additives (JECFA) test method. The recovery of SiO(2) and other oxides in silicates was 95-107% with a coefficient of variation of <4%. Using energy dispersive X-ray fluorescence spectrometry (EDX) with fundamental parameter determination, the content of SiO(2) and other oxide in titanium dioxide and silicate showed good agreement with the ICP results. ICP with alkali fusion proved suitable as a test method for SiO(2), Al(2)O(3) and other oxides in titanium dioxide and certain silicates, and EDX proves useful for screening such impurities in titanium dioxide and componential analysis of certain silicates.

[Examination of original plant of Jamaica quassia extract, a natural bittering agent, based on composition of the constituents].

Jamaica quassia extract is a natural bittering agent used as a food additive in Japan. The main constituents of the extract have already been reported to be quassin and neoquassin. In this study, the differences in composition of the constituents among four Jamaican quassia extract products were analyzed by LC/MS. The results showed that the four products have similar compositions of their minor constituents, as well as their main constituents. We isolated four of the minor constituents that were commonly included in the four products, and identified them as 11-dihydro-12-norneoquassin, canthin-6-one, 4-methoxy-1-vinyl-beta-carboline and 4,9-dimethoxy-1-vinyl-beta-carboline. The List of Existing Food Additives in Japan mentions that Jamaica quassia (Picrasma excelsa) is the original plant from which Jamaica quassia extract is produced. However, we presume that Jamaica quassia extract may actually be made from appropriate plants other than Picrasma excelsa, since P. excelsa is listed as an endangered species by the International Union for Conservation of Nature and Natural Resources. We prepared hot water extracts from two other species of plants, Quassia amara (American quassia, Surinam quassia) and P. quassioides ('Nigaki' in Japanese), and investigated their constituents by LC/MS. The results showed that the compositions of the constituents in the Jamaica quassia extract products resembled those in the extract derived from Q. amara. These findings suggest that Jamaica quassia extract products are probably made from Q. amara.

[Survey of synthetic disinfectants in grapefruit seed extract and its compounded products].

Grapefruit seed extract (GSE), derived from the seeds of grapefruit (Citrus paradisi MCAF.), is listed as a natural food additive in Japan. Products containing GSE are used as disinfectants made from only natural sources, especially after Japanese researchers found that GSE prevents the growth of norovirus. On the other hand, recent overseas studies indicated that synthetic disinfectants, such as benzalkonium and benzethonium chlorides, were present in some commercial GSE products. To confirm the quality of commercial GSE products available in Japanese markets, we carried out comprehensive research to identify the major constituents of commercial GSE products which are used as food additives (13 products from 6 manufacturers), dietary supplements (5 products from 4 manufacturers), cosmetic materials (16 products from 10 manufacturers) and disinfectant or deodorant sprays (7 products from 7 manufacturers). By means of NMR and LC/MS analysis, synthetic disinfectants such as benzethonium or benzalkonium salts were detected in most of the commercial GSE products.

[A case report of a patient whose sputum culture of multidrug-resistant Pseudomonas aeruginosa (MDRP) disappeared after administration of green tea by gastric tube].

It costs a lot of burden to take care of MDRP carriers at home as well as preventing MDRP transmission to caregivers. It is reported that epigallocatechin gallate (EGCG), the most abundant chemical contained in tea catechin, is chemically similar to trimethoprim (TMP) and inhibits S. maltophilia growth by antifolate acitivity. In this report, we present a case of a patient, whose sputum culture of MDRP disappeared after a green tea administration by gastric tube. We thought that catechin escaped from a drug efflux mechanism(s) of MDRP and could act on its growth.

Neocrocin A: a novel crocetin glycoside with a unique system for binding sugars isolated from gardenia yellow.

A novel crocetin glycosyl ester, neocrocin A (2), was isolated from gardenia yellow. The structure of 2 was elucidated as that of an all-trans-crocetin beta-D-gentiobiosyl beta-D-glucopyranosyl-(1-->6)-D-2-deoxy-glucopyranos-2-yl diester based on chemical and spectral data. The findings provide evidence that the binding system of crocetin glycosides is not limited to the anomeric position.

[Analysis of constituents in Jamaica quassia extract, a natural bittering agent].

Jamaica quassia extract, a natural bittering agent, is described as "a substance extracted from bark of Jamaica quassia (Quassia excelsa Sw.)" in the List of Existing Food Additives in Japan. The constituents in Jamaica quassia extract product were investigated as a part of an ongoing study to evaluate its quality and safety as a food additive. The main constituents of the extract were identified as quassin and two isomers of neoquassin by using LC/MS. The main constituent, quassin, was isolated and the structure was determined by spectral means. The quantification of their main constituents was performed by HPLC using quassin as a standard, and the concentrations of quassin and total of neoquassin isomers were 21.4% and 55.5%. In addition, it was confirmed that Jamaica quassia extract was different from quassia extract, which is extracted from bark of Picrasma quassioides Benn. belonging to the same family as Q. excelsa, by comparing their HPLC profiles.

Analysis of rubusoside and related compounds in tenryocha extract sweetener.

The main and minor constituents of tenryocha extract product, a natural sweetener, were investigated as a part of an ongoing study to evaluate its quality and safety as a food additive. Four constituents, namely rubusoside, steviolmonoside, panicloside IV, and ent-16 alpha, 17-dihydroxykauran-19-oic acid, were isolated. The concentration of rubusoside, the main sweet constituent, was 8.65% in the tenryocha extract product. In addition, it was confirmed that the origin of the extract was the leaves of Rubus suavissimus S. Lee (Rosaseae), as determined by comparing TLC and HPLC profiles of the product and hot-water extract prepared from the leaves of R. suavissimus.