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.

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.

Dietary ALA from Spinach Enhances Liver n-3 Fatty Acid Content to Greater Extent than Linseed Oil in Mice Fed Equivalent Amounts of ALA.

Although several works have reported absorption rate differences of n-3 polyunsaturated fatty acids (PUFA) bound to different lipid forms, such as ethyl ester, triacylglycerol (TAG), and phospholipids, no studies have investigated the effect of n-3 PUFA from glycolipids (GL). The present study compared the fatty acid contents of tissue and serum lipids from normal C57BL/6J mice fed two types of α-linolenic acid (ALA)-rich lipids, spinach lipid (SPL), and linseed oil (LO). ALA was primarily present as the GL form in SPL, while it existed as TAG in LO. Supplementation of both lipids increased ALA and its n-3 metabolites, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid, and decreased n-6 PUFA, linoleic acid and arachidonic acid, in the livers, small intestines, and sera of the treated mice compared with those of the control group. When the comparison between the SPL and LO diets containing the same amount of ALA was conducted, the EPA and DPA levels in the liver lipids from mice fed the SPL diet were significantly higher than those fed the LO diet. Additionally, the total contents of n-3 PUFA of lipids from the livers, small intestines, and sera of the SPL group were higher than those of the LO group.