18 research outputs found
Oxidation mechanism of black tea pigment theaflavin by peroxidase
A large number of black tea polyphenols remain uncharacterized because of the complexity of catechin oxidation reactions that occur during tea fermentation. In the course of our studies on black tea polyphenols, we examined the enzymatic degradation of theaflavins, which are black tea pigments having a benzotropolone chromophore. Oxidation of theaflavin with peroxidase afforded a new product named theacoumarin A together with known pigment theanaphthoquinone. The structure of the new compound was determined by spectroscopic examination and a production mechanism via theanaphthoquinone is proposed
Evaluation of olfactory impairment using a simple test kit āThe Odor Stick Identification test for the Japaneseā (OSIT-J) in neurodegenerative diseases
Purpose: Olfactory deficit has been studied in aging, amnestic mild cognitive impairment (aMCI), Alzheimerās disease (AD). Parkinson\u27s disease (PD), dementia with Lewy bodies (DLB) and idiopathic REM-sleep behavior disorder (iRBD). Our aim was to investigate the usefulness of a simple test kit āThe Odor Stick Identification test for the Japanese ā(OSIT-J) in clinical practice.Methods: A total of 240 patients were enrolled in this study, including 44 cognitively normal subjects (NS), 31 patients with aMCI, 70 patients with mild AD (AD-mild), 28 patients with DLB, 31 patients with PD and 36 patients with iRBD. The OSIT-J consists of 12 types of odor sticks. The subjects were asked to select an odor from a list of 4 odors that were rubbed on the medicine wraping paper for each odor stick. The maximum score was 12.Results: The mean odor identification (OI) score decreased in the order of aMCI, iRBD, AD-mild, PD and DLB (NS: aMCI, P<0.05, NS: AD-mild, DLB, PD and iRBD, P<0.001, aMCI: DLB, P<0.001, aMCI: PD, P<0.01 (Kruskal-Wallis, Dunnās test). The sensitivity and specificity in differentiating each disease from NS at a cutoff value of 8 was 96.8% and 79.5%, respectively, in PD, and 96.4% and 79.5% in DLB. An ageing effect was observed in NSs ( r=-0.453 (p<0.01)).Conclusions: Olfactory deficit is a non-specific phenomenon. However, it is important to be aware of the underlying diseases or future development of diseases. The OSIT-J, which is a simple test, is useful for detecting OI abnormalities in daily clinical practice
Lifestyle factors affecting gastroesophageal reflux disease symptoms: a cross-sectional study of healthy 19864 adults using FSSG scores
<p>Abstract</p> <p>Background</p> <p>Gastroesophageal reflux disease (GERD) is a very common disorder worldwide, comprised of reflux esophagitis (RE) and non-erosive reflux disease (NERD). As more than half of GERD patients are classified into the NERD group, precise evaluation of bothersome epigastric symptoms is essential. Nevertheless, compared with many reports targeting endoscopic reflux esophagitis, large-scale studies focusing on GERD symptoms have been very scarce.</p> <p>Methods</p> <p>To elucidate lifestyle factors affecting GERD symptoms, 19,864 healthy adults in Japan were analyzed. Sub-analyses of 371 proton pump inhibitor (PPI) users and 539 histamine H<sub>2</sub>-receptor antagonist (H<sub>2</sub>RA) users were also performed. Using the FSSG (Frequency Scale for the Symptoms of GERD) score as a response variable, 25 lifestyle-related factors were univariately evaluated by Student's <it>t</it>-test or Pearson's correlation coefficient, and were further analyzed with multiple linear regression modelling.</p> <p>Results</p> <p>Average FSSG scores were 4.8 Ā± 5.2 for total subjects, 9.0 Ā± 7.3 for PPI users, and 8.2 Ā± 6.6 for H<sub>2</sub>RA users. Among the total population, positively correlated factors and standardized coefficients (Ī²) for FSSG scores are inadequate sleep (Ī² = 0.158), digestive drug users (Ī² = 0.0972 for PPI, Ī² = 0.0903 for H<sub>2</sub>RA, and Ī² = 0.104 for others), increased body weight in adulthood (Ī² = 0.081), dinner just before bedtime (Ī² = 0.061), the habit of midnight snack (Ī² = 0.055), lower body mass index (Ī² = 0.054), NSAID users (Ī² = 0.051), female gender (Ī² = 0.048), lack of breakfast (Ī² = 0.045), lack of physical exercise (Ī² = 0.035), younger age (Ī² = 0.033), antihyperglycemic agents non-users (Ī² = 0.026), the habit of quick eating (Ī² = 0.025), alcohol drinking (Ī² = 0.025), history of gastrectomy (Ī² = 0.024), history of cardiovascular disease (Ī² = 0.020), and smoking (Ī² = 0.018). Positively correlated factors for PPI users are female gender (Ī² = 0.198), inadequate sleep (Ī² = 0.150), lack of breakfast (Ī² = 0.146), antihypertensive agent non-users (Ī² = 0.134), and dinner just before bedtime (Ī² = 0.129), whereas those for H<sub>2</sub>RA users are inadequate sleep (Ī² = 0.248), habit of midnight snack (Ī² = 0.160), anticoagulants non-users (Ī² = 0.106), and antihypertensive agents non-users (Ī² = 0.095).</p> <p>Conclusions</p> <p>Among many lifestyle-related factors correlated with GERD symptoms, poor quality of sleep and irregular dietary habits are strong risk factors for high FSSG scores. At present, usual dose of PPI or H<sub>2</sub>RA in Japan cannot fully relieve GERD symptoms.</p
Association of Tannins and Related Polyphenols with the Cyclic Peptide Gramicidin S
The association of 10 different tannins and related polyphenols with gramicidin S, a cyclic peptide having a rigid Ī²-turn structure, has been examined using 1H-NMR spectroscopy. In the presence of pentagalloylglucose and epigallocatechin-3-O-gallate, the proton signals due to proline and the adjacent phenylalanine moieties selectively shifted to up field, suggesting a regioselective association with the Ī²-turn structure. The association was also supported by the observation of intermolecular nuclear Overhauser effects between epigallocatechin-3-O-gallate and the peptide. In contrast, ellagitannins, biogenetically derived from pentagalloylglucose, showed small and non-selective chemical shift changes, suggesting that interaction with these tannins is relatively weak. The hydrophobicity of the tannin molecules and the steric hindrance of the interaction site are thought to be important in the association
Rapid Determination of Residues of 4 Tetracyclines in Meat by a Microbiological Screening, HPLC and LC/MS/MS
Structures of Epicatechin Gallate Trimer and Tetramer Produced by Enzymatic Oxidation
During black tea production, catechins and their galloyl esters are enzymatically oxidized to generate a complex mixture of black tea polyphenols. The role of galloyl ester groups in this process has yet to be determined. Enzymatic oxidation of epicatechin 3-O-gallate (1) yielded two new oxidation products, theaflavate C and bistheaflavate A, along with theaflavate A (2), a known dimer of 1 generated by coupling of the B-ring with the galloyl group. Theaflavate C is a trimer of 1 and possesses two benzotropolone moieties generated by the oxidative coupling of the galloyl groups with the catechol B-rings. Bistheaflavate A was found to be a tetramer produced by intermolecular coupling of two benzotropolone moieties of 2. From the structures of the products, it was deduced that oxidative coupling of galloyl groups resulted in extension of the molecular size of the products in catechin oxidation