Publications by authors named "Jin Tatsuzaki"

Background/objectives: Extract (SIRTMAX) has been reported to alleviate obesity. However, few studies have investigated this topic and none have evaluated its potential among Koreans. Therefore, we aimed to evaluate the efficacy of extract in body fat reduction among Korean adults.

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Ethnopharmacological Relevance: Apocynum venetum L. has long been used to promote relaxation and alleviate anxiety. It has been prescribed to treat insomnia, reduce psychological stress, and support overall well-being.

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Pentosidine (PEN), an advanced glycation end product (AGE), is associated with various age-related diseases and schizophrenia. This study aimed to identify the natural compounds that inhibit PEN synthesis from glucuronic acid using an in vitro system. A screening of 93 natural compounds revealed 47 that reduced PEN synthesis by > 50 %, with eight inhibiting it by > 80 %.

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We examined ammonium glycyrrhizate listed in the monographs of the European Pharmacopoeia (EP) and United States Pharmacopoeia (USP) as well as in the reagents and solutions used in the general test of the Japanese Pharmacopoeia by performing HPLC on their sample standards or reference reagents under reported and modified conditions. Comparative experiments involving five authentic samples, namely, 18β-glycyrrhizin (1), 18α-glycyrrhizin (2), licorice-saponin G2 (3), licorice-saponin H2 (4), and galacturonic acid-replaced glycyrrhizin (the 4″-epimer of 18β-glycyrrhizin) (5), led us to propose the revision of the peak assignment of 18α-glycyrrhizin (2) and postscript a possible co-existence of galacturonic acid-replaced glycyrrhizin (5) as a hidden component in the EP and USP. We also proposed that the α-configuration used in the nomenclature of the glycosidic bond between aglycone and the sugar units of ammonium glycyrrhizate and impurities in the EP and USP should be revised to the β-configuration.

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18α-Glycyrrhizin is an epimer of 18β-glycyrrhizin, a major component of licorice (Glycyrrhiza sp.), which is widely used as a traditional medicine. Whether 18α-glycyrrhizin is a real natural product has been debated in the long history of glycyrrhizin chemistry because 18β-glycyrrhizin is epimerizable to a more thermodynamically stable 18α-glycyrrhizin under aqueous alkali conditions.

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Sirtuin 1 (SIRT1), an NAD-dependent deacetylase, is a crucial regulator that produces multiple physiological benefits, such as the prevention of cancer and age-related diseases. SIRT1 is activated by sirtuin-activating compounds (STACs). Here, we report that quercetin 3,5,7,3',4'-pentamethyl ether (KPMF-8), a natural STAC from Thai black ginger Kaempferia parviflora, interacts with SIRT1 directly and stimulates SIRT1 activity by enhancing the binding affinity of SIRT1 with Ac-p53 peptide, a native substrate peptide without a fluorogenic moiety.

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Natural flavonoids have powerful antioxidant activity and have been reported to show promising protective effects against cataracts. The plant Kaempferia parviflora (K. parviflora) is indigenous to southeast Asia, including Thailand, and typically contains polymethoxylated flavones.

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Among the five hydroxy (OH) groups of quercetin (3,5,7,3',4'-pentahydroxyflavone), the OH group at 5 position is the most resistant to methylation due to its strong intramolecular hydrogen bonding with the carbonyl group at 4 position. Thus, it is generally difficult to synthesize the pentamethyl ether efficiently by conventional methylation. Here, we describe a simple and effective per--methylation of quercetin with dimethyl sulfate in potassium (or sodium) hydroxide/dimethyl sulfoxide at room temperature for about 2 hours, affording quercetin pentamethyl ether (QPE) quantitatively as a single product.

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We report in this study novel biochemical activities of peanut skin extract (PEXT) on thrombocytopoiesis. Peanut skin, derived from Arachis hypogaea L., is a traditional Chinese medicine that is used to treat chronic hemorrhage.

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Background: A powdered ethanolic extract of root exhibits antimutagenic activity against -methyl--nitrosourea (MNU) based on the Ames assay with TA1535. The aim of this study was to identify the antimutagenic components of the powdered ethanolic extract of root.

Results: The powdered ethanolic extract of root was sequentially suspended in -hexane, carbon tetrachloride, dichloromethane, ethyl acetate, and ethanol, and each solvent soluble fraction and the residue were assayed for antimutagenic activity against MNU in TA1535.

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The effects of two food materials, γ-aminobutyric acid (GABA) produced by natural fermentation and Apocynum venetum leaf extract (AVLE), on the improvement of sleep were investigated in humans. The electroencephalogram (EEG) test revealed that oral administration of GABA (100 mg) and AVLE (50 mg) had beneficial effects on sleep. GABA shortened sleep latency by 5.

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Dehydrozingerone analogs and related compounds were screened as potential antitumor promoters by using the in vitro short-term 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced Epstein-Barr virus early antigen activation assay. Among the 40 synthesized compounds, the prenylated analogs 16 and 34-36 showed the most significant and promising activity (100% inhibition of activation at 1 x 10(3) mol ratio/TPA, and 82-80%, 37-35%, and 13-11% inhibition at 5 x 10(2), 1 x 10(2), and 1 x 10 mol ratio/TPA, respectively) in this screening. Their activity profiles were comparable to those of the reference standard curcumin.

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Esterification of glycyrrhetinic acid (GA) with dehydrozingerone (DZ) resulted in a novel cytotoxic GA-DZ conjugate. Based on this exciting finding, we conjugated eleven different DZ analogs with GA or other triterpenoids, including oleanoic acid (OA) or ursolic acid (UA). In an in vitro anti-cancer assay using nine different human tumor cell lines, most of the GA-DZ conjugates showed significant potency.

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Twenty-eight compounds related to dehydrozingerone (1), isoeugenol (3), and 2-hydroxychalcone (4) were synthesized and evaluated in vitro against human tumor cell replication. Except for isoeugenol analogues 27-35, most compounds exhibited moderate or strong cytotoxic activity against KB, KB-VCR (a multidrug-resistant derivative), and A549 cell lines. In particular, chalcone 15 showed significant cytotoxic activity against the A549 cell line with an IC50 value of 0.

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2-Phenyl-4-quinolone and 9-oxo-9,10-dihydroacridine derivatives were synthesized and screened as potential antitumor promoters by examining the ability of the compounds to inhibit Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. Interestingly, compounds 14, 15, and 17 showed similar inhibitory effects (89-92%, 66-69%, and 24-29% at 1000, 500, and 100 mol ratio to TPA, respectively) against EBV-EA with potencies comparable to those of glycyrrhetic acid, a known natural antitumor-promoter.

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