Stable carbon isotopic characterization of rice vinegar protein as an intrinsic reference for discriminating the authenticity of brewed rice vinegar.

Rice vinegar plays an important role in daily life. However, some unscrupulous manufacturers may deliberately add synthetic acetic acid in vinegar products to reduce fermentation time and save production costs. To protect the rights and health of consumers, vinegar authenticity must be controlled. The rice vinegar protein was used as an intrinsic reference and its stable carbon isotope ratio (δ13Cprotein) was analyzed by elemental analyzer-isotope ratio mass spectrometry. The stable carbon isotope ratio difference between the acetic acid and the rice vinegar protein (Δδ13Cacetic acid-protein) was calculated to evaluate vinegar authenticity. Sixteen rice vinegar samples were analyzed and a stable carbon isotopic pattern of rice vinegar was established by the 95% confidence interval for Δδ13Cacetic acid-protein (0.27‰-2.10‰). An acetic acid adulteration curve of Δδ13Cacetic acid-protein was also assumed according to the data from rice vinegar samples, and its validity was confirmed by rice vinegar deliberately blended with acetic acid at different ratios (25, 50, and 75%). The Δδ13Cacetic acid-protein values of the adulterated vinegars decreased with increasing amounts blended acetic acid, but the δ13Cprotein values did not, showing that rice vinegar protein could be used as an intrinsic reference for identifying the adulterated rice vinegar. The rice vinegar adulterated with acetic acid at higher than approximately 10% could be detected.

Development of the species-specific multiplex PCR and DNA sequencing methods for rapid authentication of Isatidis Folium and its adulterants.

Isatis indigotica Fort. (family Cruciferae), is an herb widely used in traditional herbal medicine and its dried leave was named "ISATIDIS FOLIUM". Baphicacanthus cusia (Ness) Bremek. and Polygonum tinctorium Ait. are commonly misused as ISATIDIS FOLIUM in Chinese Medicine pharmacy. For the purpose of being not misused, specific primers based on the sequence difference of chloroplast trnH-psbA intergenic spacer were designed and multiplex polymerase chain reaction method (multiplex PCR) was developed. In this study, 29 original herbal materials were analyzed and our results show that DNA size after multiplex PCR was able to distinguish variations between three herbs. DNA fragments of 464, 297, 170 base pairs (bps) were represented for I. indigotica and B. cusia and P. tinctorium, respectively. In conclusion, our investigations demonstrate that molecular identification method provides more accurate results for medicinal plants detection and good quality control of ISATIDIS FOLIUM.

Comprehensive detection of 120 additives in food using nontargeted MS data acquisition.

The compliance assessment on the labeling of food additives is a hard job, because there are nearly thousand legal food additives can be used in food, and countless illegal additives must also deal with. This study developed a non-targeted data acquisition screening method based on liquid chromatography high resolution mass spectrometry (HRMS) in which a precursor ion and two product ions of each analyte are able to be recorded. The high throughput screening method worked as foodomics that characterized and identified every food components as long as they were ionized in terms of theory. The data acquisition method called data independent acquisition (DIA) was achieved by a full scan form m/z 70-1050, and then followed wide window fragmentations of product ions recording. A full scan and the followed fragmentations generated 21 spectra in 2.6 s contributed about 6 data points for a typical 0.2-0.3 min width peak in HPLC. A detection database list of 120 additives included 79 colorants, 13 sweeteners, 12 preservatives and 7 antioxidants was established. Thirty-three commercial samples including beverages, candies, and sauces were surveyed for testing additives. Sweeteners (rebaudioside A) and flavoring agents (malic acid and fumaric acid) were found the most under declared additives. HPLC column often do not provide adequate retention for highly polar compounds such as organic acids (flavoring agents). In this study they were coeluted, but were able to be separated and determined by HRMS worked as the secondary separation tool. The surveillance results showed there is still room for food manufacturers to improve the connection between their product information and consumers.

Elucidation of two new corticosteroids, betamethasone dibutyrate and betamethasone tributyrate.

Corticosteroids were used normally as anti-inflammatory drugs. However, in some area certain corticosteroids might be illegally used as growth promoting agent in feed, and as prohibited doping substances in game and sport for human or/and animal performance-enhancing. Synthesized structural similar corticosteroids were popular in black market because they can pass routine drug screening. In this study two new artificial synthesized corticosteroids were found in claimed hydrolyzed wheat product. Liquid chromatography coupled with high resolution mass spectrometry (HRMS, Orbitrap) was applied to separate and elucidate the corticosteroids in the sample. Two unknown peaks with optical spectra similar to corticosteroids were first screened out at the beginning, and then their accurate molecular weight (M + H+) m/z 533.29059 and m/z 603.33289 were detected by HRMS. Element formulas of unknowns were calculated by the accurate mass and isotopes abundance. Structures were proposed by their fragment ions at high energy collision dissociation (HCD, 10 eV) and compared with candidate standard compounds. The two unknowns shared similar molecular skeleton with steroid core structure and presented man made fluorine element in their molecule. As the results, the unknowns in the sample were artificial synthesized, and the sample product was not a real food. The detected corticosteroids were also synthesized as reference compounds for conformation. Two new corticosteroids named betamethasone dibutyrate and betamethasone tributyrate were found and first time reported in this work. The legality of structural similar/modified corticosteroids were blurry and their safety were unverified. The confirmed identifications of two new found corticosteroids, and their mass spectra were provided in this paper for the reference of drug detection.

Simultaneous Analysis of the Stable Carbon Isotope Ratios of Acetoin and Acetic Acid by GC-C-IRMS for Adulteration Detection in Brewed Rice Vinegar Products.

In this study, we developed a method to simultaneously measure the stable carbon isotope ratio for acetic acid (δ 13Cacetic acid) and acetoin (δ13Cacetoin) in rice vinegar by gas chromatography-combustion-isotope ratio mass spectrometry. The method showed good precision and accuracy. With this method, data from 16 brewed rice vinegars and 10 acetic acid samples were used to evaluate the feasibility of adulteration detection. On the basis that all δ13Cacetoin values of brewed rice vinegars are nearly constant, a characteristic pattern of the stable carbon isotope in rice vinegar was built with the 95% confidence intervals for δ13Cacetic acid (-26.97 to -25.38‰), δ13Cacetoin (-28.14 to -27.09‰), and Δδ13C (0.61 to 2.27‰). An adulteration detection curve of Δδ13C was proposed based on the results of vinegar and acetic acid samples and confirmed by vinegar spiked with different amounts of acetic acid. This method could be useful in estimating the blending ratio of adulterated rice vinegar products. Products containing more than 10% of synthetic acetic acid could be possibly identified.

Isolation and identification of a novel sildenafil analogue adulterant in herbal products.

A novel sildenafil analogue found in herbal products by a routine drug-adulteration screening programme was isolated by column chromatography. On the basis of extensive 1D- and 2D-nuclear magnetic resonance (NMR) spectroscopy and mass spectral analysis, the structure of a new compound YJ-07 was established as 1-[4-ethoxy-3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl) benzenesulfonamide. It common name is aminosildenafil.

Identification of a new sildenafil analogue adulterant, desethylcarbodenafil, in a herbal supplement.

In a maca-containing herbal supplement claimed to remedy erectile dysfunction, a new sildenafil analogue was found using adulterant screening with TLC, GC-MS and LC-MS/MS. This compound was isolated by column chromatography and HPLC, and identified by extensive 1D- and 2D-NMR and mass spectral analyses. The structure of this new compound was established as 5-[2-ethoxy-5-(piperazine-1-carbonyl) phenyl]-1-methyl-3-propyl-1,6-dihydro-pyrazolo[4,3-d]pyrimidin-7-one, and was named desethylcarbodenafil.

Profound difference of metabolic pharmacokinetics between pure glycyrrhizin and glycyrrhizin in licorice decoction.

To investigate the difference of metabolic pharmacokinetics between pure glycyrrhizin (GZ) and GZ in licorice decoction, six New Zealand White rabbits were orally given pure GZ and licorice decoction containing equivalent content of GZ in a randomized crossover design. HPLC methods were used for the quantitation of GZ and glycyrrhetic acid (GA) in serum. The results indicated that the areas under curves (AUCs) of GZ and GA after administration of licorice decoction were significantly higher than those after pure GZ. This result was contradictory with that obtained in rats. To explore the mechanism of the pharmacokinetic difference, feces of rabbits, rats, pigs and humans were used to investigate the presystemic metabolism of pure GZ and GZ in licorice decoction. The results indicated that pure GZ was hydrolyzed to GA more rapidly and to a greater extent than that in licorice decoction by various feces. In addition, when pure GZ was fermented, the metabolic profiles of GA and 3-dehydroGA in rabbit feces were quite different from other feces. In conclusion, the bioavailabilities of GZ and GA are significantly better from licorice than from pure GZ in rabbits but the presystemic metabolism of pure GZ in rabbit is rather different from that in rat, pig and human.

Degradation of flavonoid aglycones by rabbit, rat and human fecal flora.

The degradation of thirteen flavonoid aglycones-wogonin, diosmetin, hesperetin, baicalein, morin, genistein, daidzein, quercetin, naringenin, luteolin, kaempferol, apigenin and neophellamuretin-were investigated in rabbit, rat and human fecal flora suspensions as well as in artificial intestinal juice, using high performance liquid chromatography. Separation were performed with a Cosmosil 5C(18)-AR II column by isocratic and gradient elution with 0.1% (v/v) phosphoric acid-acetonitrile as a mobile phase, and detected at 254 nm. The flow rate was 1.0 ml/min. 5,7-Dimethoxycoumarin was used as the internal standard. The result indicated that all flavonoid aglycones except baicalein, diosmetin and quercetin were quite stable in artificial intestinal juice, whereas all were degraded in rabbit, rat and human feces suspension. In rabbit feces, wogonin, diosmetin and hesperetin were less degraded, whereas neophellamuretin, apigenin, kaempferol, luteolin, and naringenin were the most extensively degraded. In rat feces, wogonin and diosmetin were least degraded, whereas kaempferol, quercetin, genistein, luteolin, naringenin and neophellamuretin were extensively degraded. As in human feces, wogonin, daidzein and diosmetin were less degraded, whereas morin, genistein, baicalein, and quercetin were extensively degraded. In conclusion, wogonin and diosmetin were among the less degraded ones for all three feces tested. The presence of a methoxy group on the A or B ring of the flavonoid seems to protect the structure from bacterial degradation.

A deglucosylated metabolite of paeoniflorin of the root of Paeonia lactiflora and its pharmacokinetics in rats.

Paeoniflorin is a bioactive monoterpene glucoside in Paeoniae Radix (PR), the roots of Paeonia lactiflora (Ranunculaceae). By oral administration to rats with the decoction of PR, the metabolism and pharmacokinetics of paeoniflorin were investigated in this study. A deglucosylated metabolite of paeoniflorin, paeoniflorgenin (PG), in serum was identified based on HPLC/MS and NMR spectral data. HPLC/UV methods were developed for determining PG in serum and feces suspension. A non-compartment model was used for the calculation of pharmacokinetic parameters. Moreover, the metabolism of paeoniflorin by various types of feces was investigated as well. The paeoniflorin levels in serum were below the detection limit throughout the study. The C (max), t (max), and AUC (0-t) of PG were 8.0 microg/mL, 10 min and 487.0 microg min/mL, respectively. Paeoniflorin was found to be hydrolyzed into PG through incubation with feces of rabbit, rat, pig or human. Similar profiles of PG were shown for various types of feces, except for rabbit. In conclusion, paeoniflorin was not absorbed per se, whereas its aglycone paeoniflorgenin was absorbable and circulating in the bloodstream. Rat and pig are appropriate models for investigating the metabolism and pharmacokinetics of paeoniflorin.