Hiroe Kikuzaki's research while affiliated with University of Human Environment, Japan and other places

Publications (104)

Article
Oxidative stress causes the progression of diabetes and its complications; thus, maintaining the balance between reactive oxygen species produced by hyperglycemia and the antioxidant defense system is important. We herein examined the antioxidant potential of non-extractable fractions of dried persimmon (NEP) against oxidative stress in diabetic ra...
Article
Full-text available
Histamine, known as bioactive amine, is synthesized through histidine decarboxylase (HDC). HDC is the sole enzyme that catalyzes histamine production in the human body and thus HDC inhibitor is expected to control histamine-mediating biological activity by controlling histamine production. In the present study, active compound that inhibits HDC act...
Article
Vegetables are rich sources of nutrients such as fiber, minerals, vitamins, and antioxidants. Vegetables also contain various free-form amino acids, which improves their nutritional and palatable value. Cooking alters the content of free amino acids in vegetables, which affects their nutritional values. In this study, free amino acid levels were ev...
Article
Rugosin G, an ellagitannin trimer, was isolated from the water-soluble fraction of red rose petals, and its inhibitory activity against recombinant human histidine decarboxylase was investigated. Rugosin G showed potent inhibition compared to ellagitannin monomers and a dimer with macrocyclic structure (oenothein B), suggesting the potent inhibitio...
Article
Sugarcane extract (Saccharum officinarum extract: SOE), a byproduct containing polyphenols obtained through the process of making raw sugar from sugarcane, exhibited an effect on the discoloration of salmon that suggests SOE inhibits lipid oxidation, which inhibits discoloration of carotenoid as a result. Therefore, we considered an in vitro evalua...
Article
Objective Secretory sphingomyelinase (sSMase) is one of the key enzymes involved in oxidative stress-related diseases [Biol. Pharm. Bull, 2013]. The elevation of its activity resulted in an increase of ceramide that is the bioactive lipid inducing cellular apoptosis, proliferation, and differentiation. In this study, we searched for novel sSMase in...
Article
Strawberry fruit contains many constituents, some of which have the potential to inhibit histidine decarboxylase (HDC) activity. HDC converts l-histidine to histamine, which is associated with allergic and other biological reactions in the human body. The HDC inhibition levels were different and the component ratios varied by genotype in strawberry...
Article
Full-text available
Gracilaria species are red marine macroalgae that are found abundantly in Malaysia. Gracilaria changii from Morib, Selangor, G. manilaensis and Gracilaria sp. from Gelang Patah, Johor were used in this study. Five compounds were successfully isolated and identified as hexadecanoic acid (1), cholest-5-en-3-ol (2), 2-hydroxymyristic acid (3), cholest...
Article
Sphingomyelinases (SMases) are key enzymes involved in many diseases which are caused by oxidative stress, such as atherosclerosis, diabetes mellitus, nonalcoholic fatty liver disease, and Alzheimer’s disease. SMases hydrolyze sphingomyelin to generate ceramide, a well-known pro-apoptotic lipid. SMases are classified into five types based on pH opt...
Article
Filipendula ulmaria, also known as meadowsweet, is an herb; its extract was examined for the prevention of histamine production, primarily that caused by contaminated fish. The efficacy of meadowsweet was assessed using two parameters: inhibition of Morganella morganii histidine decarboxylase (HDC) and inhibition of histamine accumulation in macker...
Article
Full-text available
Gracilaria species are red marine macroalgae that are found abundantly in Malaysia. Gracilaria changii from Morib, Selangor, G. manilaensis and Gracilaria sp. from Gelang Patah, Johor were used in this study. Five compounds were successfully isolated and identified as hexadecanoic acid (1), cholest-5-en-3-ol (2), 2-hydroxymyristic acid (3), cholest...
Article
The inhibitory effects of 13 polymethoxyflavones (PMFs) obtained from Kaempferia parviflora extracts were evaluated on RBL-2H3 cell degranulation. These flavones suppressed antigen-induced degranulation in RBL-2H3 cells. 5-Hydroxy-3,7,4′,-trimethoxyflavone (KP02) and 5,3′-dihydroxy-3,7,4′,-trimethoxyflavone (KP10) showed potent inhibitory activitie...
Article
The chemical structures of 9 compounds isolated from the dried fruits of Prunus domestica L. were elucidated on the basis of NMR and MS analyses. Each isolated compound was determined to be scopolin (1), (3-O-cis-p-coumaroyl-beta-D-fructofuranosyl)-(2 -> 1)-alpha-D-glucopyranoside (2), 1S-(4-beta-D-glucopyranosyl- 3-methoxyphenyl)-2R-[4-(3-hydroxyp...
Article
Atherosclerosis is caused by many factors, one of which is oxidative stress. We recently demonstrated that systemic oxidative stress increased secretory sphingomyelinase (sSMase) activity and generated ceramides in the plasma of diabetic rats. In addition, we also showed that the total ceramide level in human plasma correlated with the level of oxi...
Article
Histidine decarboxylase (HDC) catalyses the formation of histamine, a bioactive amine. Agents that control HDC activity are beneficial for treating histamine-mediated symptoms, such as allergies and stomach ulceration. We searched for inhibitors of HDC from the ethyl acetate extract of the petal of Filipendula ulmaria, also called meadowsweet. Rugo...
Article
The kudzu root (Pueraria lobata) is used as an ingredient in kudzu-starch which is an important material for cooking as well as processed foods in Japan. On the other hand, this root is a kind of oriental crude drug and has been used for various medicinal purposes. In this chapter, chemical structures, and estrogenic and antimutagenic activities of...
Article
The chemical structures of six isoflavones (1–6) isolated from the kudzu root (Pueraria lobata) were elucidated on the basis of the NMR and MS analyses to be four isoflavone C-glycosides as 6″-O-α-d-glucopyranosylpuerarin (1), puerarin (2), 3′-methoxypuerarin (3), 6″-O-α-d-apiofranosylpuerarin (4), and two aglycons as biochanin A (5) and formononet...
Article
Constituents of the fruit of Amomum tsao-ko were investigated following a preliminary screening of the antioxidant activity of several extracts of the fruit of this plant that showed that the dichloromethane extract and the ethyl acetatesoluble and water-soluble fractions of the 70% aqueous acetone extract had higher activity than α-tocopherol and...
Article
As a preliminary study, we have found that honey from manuka (Leptospermum scoparium) in New Zealand inhibits myeloperoxidase (MPO) activity. In this study, using a chromatographic technique, we isolated two active compounds for MPO-inhibition from manuka honey. One is methyl syringate (MSYR), and the other was identified as a novel glycoside of MS...
Article
The dichloromethane extract and ethyl acetate soluble fraction of Kaempferia parviflora showed antimutagenicity and α-glucosidase inhibitory activity. 7-Methoxyflavones were the major constituents of both extracts and demonstrated antimutagenic activity. In particular, 5,7-dimethoxyflavone (IC50 = 0.40 nmol/plate), 5,3′-dihydroxy-3,7,4′-trimethoxyf...
Article
Histamine, a bioactive amine, is formed from histidine through histidine decarboxylase (HDC). The agent that controls histamine synthesis, i.e. activity of HDC, is beneficial for controlling histamine-related physiological actions, such as inflammation. In the present study, the ethyl acetate (EtOAc) extract of the berries of Pimenta dioica was inv...
Article
Three phenolic glycosides were isolated together with two known flavonol glycosides from the H2O-soluble fraction of rhizomes of Kaempferia parviflora. Their structures were determined to be rel-(5aS,10bS)-5a,10b-dihydro-1,3,5a,9-tetrahydroxy-8-methoxy-6H-benz[b]indeno[1,2-d]furan-6-one 5a-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-d-glucopyranoside]...
Article
The methylene chloride extract of Alpinia nutans was investigated for its antioxidant constituents. 5,6-Dehydrokawain (1), flavokawin-B (2), 1,7-diphenyl-5-hydroxy-6-hepten-3-one (3), (-)-pinocembrin (4) and a mixture of stigmasterol and ß-sitosterol were isolated. The antioxidant activity was measured on isolates 1–4 using ferric thiocyanate (FTC)...
Article
Three new phytoecdysteroids have been isolated from the seeds of Chenopodium quinoa and structurally identified as 20,26-dihydroxy, 28-methyl ecdysone, 20,26-dihydroxy, 24(28)-dehydro ecdysone, and 20-hydroxyecdysone 22-glycolate using serial chromatographic and spectroscopic methods. Both previously reported compounds and newly identified phytoecd...
Article
Four new phenolic glycosides, (2-hydroxy-3-methoxy-5-allyl)phenyl beta- d-(6-O-E-sinapoyl)glucopyranoside (1), (1' R,5' R)-5-(5-carboxymethyl-2-oxocyclopentyl)-3 Z-pentenyl beta-D-(6-O-galloyl)glucopyranoside (2), (S)-alpha-terpinyl [alpha-L-(2-O-galloyl)arabinofuranosyl]-(1-->6)-beta-D-glucopyranoside (3), and (R)-alpha-terpinyl [alpha-L-(2-O-gall...
Article
The antioxidant potency of various extracts and fractions from Chenopodium quinoa and Amaranthus sp. was evaluated using three established methods, specifically the DPPH scavenging activity, FRAP, and β-carotene bleaching assays. Satisfying results were obtained, which lead to expect the use of these seeds as health-promoting ingredients. The antio...
Article
Full-text available
The constituents of cape aloe were investigated after a preliminary screening of the growth-inhibiting effect on Ehrlich ascites tumor cells (EATC) of several extracts of this plant. Ten compounds were isolated from the dichloromethane (CH(2)Cl(2)) extract that showed the strongest activity, and their structures were elucidated as aloe-emodin (1),...
Article
Histidine decarboxylase (HDC) catalyzes histamine formation from histidine. Histamine is a bioactive amine acting as a neurotransmitter as well as a chemical mediator. Phenolic food components have been tested for their ability to inhibit recombinant human HDC. Epicatechin gallate (ECG) was found to be a potent inhibitor as it inhibited HDC activit...
Article
Four new terpenoids and a diarylheptanoid were isolated together with 16 known compounds from rhizomes of Zingiber ottensii. The structures of the new compounds were determined to be 1,10,10-trimethylbicyclo[7,4,0]tridecane-3,6-dione (1), (E)-14-hydroxy-15-norlabda-8(17),12-dien-16-al (2), (E)-labda-8(17),12,14-trien-15(16)-olide (3), (E)-14,15,16-...
Article
Capsaicinol is an ingredient of hot red pepper. In this study, we developed a novel method for capsaicinol synthesis and examined capsaicinol's physiological effects on capsaicin receptor (TRPV1)-related actions. Allylic oxidation of capsaicin by palladium acetate (Pd(OAc)(2)) resulted in the formation of (+/-)-capsaicinol acetate at a 7.2% yield i...
Article
Phytochemical studies on the rhizomes of Etlingera elatior have resulted in the isolation of 1,7-bis(4-hydroxyphenyl)-2,4,6-heptatrienone (1), demethoxycurcumin (2), 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one (3), 16-hydroxylabda-8(17),11,13-trien-15,16-olide (4), stigmast-4-en-3-one, stigmast-4-ene-3,6-dione, stigmast-4-en-6beta-ol-3-one, and...
Article
Full-text available
Phytochemical studies on rhizome of Etlingera elatior have resulted in the isolation of 1,7-bis(4-hydroxyphenyl)-2,4,6-heptatrienone (1), demethoxycurcumin (2), 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one (3), 16-hydroxylabda-8(17),11,13-trien-16,15-olide (4), stigmast-4-en-3-one (5), stigmast-4-ene-3,6-dione (6), stigmast-4-en-6b-ol-3-one (7),...
Article
Full-text available
The methanol extract of the dried ripe fruits of Alpinia rafflesiana was investigated for its DPPH free radical scavenger constituents. 2',3',4',6'-Tetrahydroxychalcone (7), which has never been isolated from natural sources was found to be most active as a DPPH free radical scavenger with the IC50 value of 55 microM. Other known compounds isolated...
Article
Full-text available
Isolation and structural elucidation of prune constituents were performed and total 10 compounds were determined by NMR and MS analyses. A novel compound was identified to be 2-(5-hydroxymethyl-2',5'-dioxo-2',3',4',5'-tetrahydro-1'H-1,3'-bipyrrole)carbaldehyde, and 7 phenolic compounds were isolated from prunes for the first time. In addition, anti...
Article
In the course of our study on the isolation and structure determination of constituents in tropical plants, we focused on Peucedanum japonicum Thunb., belonging to the family Umbelliferae. In this study, a new C(13) norisoprenoid glucoside, (3S)-O-beta-d-glucopyranosyl-6-[3-oxo-(2S)-butenylidenyl]-1,1,5-trimethylcyclohexan-(5R)-ol (1), and two new...
Article
Prunes contain large amounts of phenolics and show high antioxidant activity. The aim of this study is to clarify the contents of caffeoylquinic acid (CQA) isomers, and to estimate the contribution of these isomers to the antioxidant activity of prunes. Furthermore, structural elucidation and evaluation of antioxidant activity of prune components w...
Article
Four new abscisic acid related compounds (1-4), together with (+)-abscisic acid (5), (+)-beta-D-glucopyranosyl abscisate (6), (6S,9R)-roseoside (7), and two lignan glucosides ((+)-pinoresinol mono-beta-D-glucopyranoside (8) and 3-(beta-D-glucopyranosyloxymethyl)-2- (4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-7-methoxy-(2R,3S)-dihydrobenzofuran...
Article
Ginger (Zingiber officinale Roscoe) shows an antioxidant activity, and we have been engaging to determine the structures of more than 50 antioxidants isolated from the rhizomes of ginger. The isolated antioxidants are divided into two groups; gingerol related compounds and diarylheptanoids. In this study, structure-activity relationship of gingerol...
Article
The ethyl acetate-soluble part of allspice, berries of Pimenta dicica, showed strong antioxidant activity and radical-scavenging activity against 1,1diphenyl-2-picrylhydrazl (DPPH) radical. From the ethyl acetate-soluble part, two new compounds, 5-galloyloxy-3-4-dihydroxypentanoic acid and 5-(5-carboxmethyl-2-oxocyclopenty)3Z-penteny 6-O-galloy-bet...
Article
A new dimeric carbazole alkaloid, 8,10'-[3,3',11,11'-tetrahydro-9,9'-dihydroxy-3,3',5,8'-tetramethyl-3,3'-bis(4-methyl-3-pentenyl)]bipyrano[3,2-a]carbazole (12), was isolated from the CH(2)Cl(2) extract of Murraya koenigii together with six known carbazole alkaloids, koenimbine (6), O-methylmurrayamine A (7), O-methylmahanine (8), isomahanine (9),...
Article
We previously indicated that coumaperine isolated from pepper can protect against the initiation of rat hepatocarcinogenesis. In the present study, potential modifying effects of coumaperine on post-initiation promotion stage were examined, using a medium term rat liver bioassay (Ito test). F344 rats were given a single intraperitoneal injection of...
Article
Five flavonoids, including 3,7,4'-trimethoxy-5-hydroxyflavone (1), 3,4'-dimethoxy-5,7-dihydroxyflavone (2), 5,7,4'-trimethoxy-3-hydroxyflavone (3), 3,5,7,4'-tetramethoxyflavone (4), and 7,4'-dimethoxy-3,5-dihydroxyflavone (5), were isolated from the rhizome of Hedychium thyrsiforme and assayed for antioxidant and antitumor promoting activities. The...
Article
Seventeen compounds were isolated from the n-butanol soluble fraction of the leaves of Peucedanum japonicum Thunb. On the basis of MS and various NMR spectroscopic techniques, the structures of the isolated compounds were determined as isoquercitrin (1), rutin (2), 3-O-caffeoylquinic acid (3), 4-O-caffeoylquinic acid (4), 5-O-caffeoylquinic acid (5...
Article
Prunes are known to show high antioxidant activity on the basis of the oxygen radical absorbance capacity (ORAC), and their major antioxidant components are caffeoylquinic acid isomers. The aim of this study is to prove the contribution of caffeoylquinic acid isomers to the ORAC of prunes, and to investigate the existence of other antioxidant compo...
Article
One sphingolipid, 1-O-beta-D-glucopyranosyl-(2S,3R,4E,8Z)-2-[(2R)-2-hydroxyhexadecanoylamino]-4,8-octadecadiene-1,3-diol, and four other constituents, beta-sitosterol, daucosterol, uridine, and adenosine, have been isolated from the nuts of almond (Prunus amygdalus). Complete assignments of the proton and carbon chemical shifts for the sphingolipid...
Article
Ethanol extract of prune was separated into hexane-soluble and H(2)O-soluble fractions, and the H(2)O-soluble fraction was further separated into a methanol (MeOH) eluate and an H(2)O eluate by Diaion HP-20 column chromatography. The MeOH eluate exhibited the strongest antioxidant activity among the separated fractions evaluated by oxygen radical a...
Article
Two new flavonol-phenylbutadiene adducts, rel-5-hydroxy-7,4'-dimethoxy-2' 'S-(2,4,5-trimethoxy-E-styryl)tetrahydrofuro[4' 'R,5' 'R:2,3]flavanonol (1) and rel-5-hydroxy-7,4'-dimethoxy-3' 'S-(2,4,5-trimethoxy-E-styryl)tetrahydrofuro[4' 'R,5' 'R:2,3]flavanonol (2), were isolated from the leaves of Alpinia flabellata, along with three known compounds,...
Article
A new abietane diterpenoid, 12-O-methyl carnosol (2), was isolated from the leaves of sage (Salvia officinalis L.), together with 11 abietane diterpenoids, 3 apianane terpenoids, 1 anthraquinone, and 8 flavonoids. Antioxidant activity of these compounds along with 4 flavonoids isolated from thyme (Thymus vulgaris L.) was evaluated by the oil stabil...
Article
Antioxidant activity of 24 ferulic acid related compounds together with 6 gallic acid related compounds was evaluated using several different physical systems as well as their radical scavenging activity. The radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) decreased in the order caffeic acid > sinapic acid > ferulic acid > ferul...
Article
Full-text available
Two new garcinia acid derivatives, 2-(butoxycarbonylmethyl)-3-butoxycarbonyl-2-hydroxy-3-propanolide and 1',1"-dibutyl methyl hydroxycitrate, were isolated from the fruits of Garcinia atroviridis guided by TLC bioautography against the fungus Cladosporium herbarum. The structures of these compounds were established by spectral analysis. The former...
Article
Three apianane terpenoids, rel-(5S, 6S, 7S, 10R, 12S, 13R)-7-hydroxyapiana-8,14-diene-11,16-dion-(22,6)-olide, rel-(5S, 6S, 7R, 10R, 12S, 13R)-7-hydroxyapiana-8,14-diene-11,16-dion-(22,6)-olide and rel-(5S, 6S, 7S, 10R, 12R, 13S)-7-hydroxyapiana-8,14-diene-11,16-dion-(22,6)-olide were isolated from the leaves of Salvia officinalis, together with 15...
Chapter
Some species belonging to the Ginger family were assayed for antioxidant activity and their active components were characterized. From the rhizome of Zingiber officinale, the most common ginger, more than 50 compounds including gingerol-related compounds and diarylheptanoids were isolated. Their antioxidant assessment was performed by various assay...
Article
An investigation on the gum exudates of Commiphora myrrha has led to the isolation of six sesquiterpenoids. On the basis of spectroscopic data interpretation, they were determined as two new furanosesquiterpenoids, rel-1S,2S-epoxy-4R-furanogermacr-10(15)-en-6-one (1) and rel-2R-methyl-5S-acetoxy-4R-furanogermacr-1(10)Z-en-6-one (2), and four known...
Article
The antioxidative properties of the leaves extracts of Murraya koenigii using different solvents were evaluated based on the oil stability index (OSI) together with their radical scavenging ability against 1-1-diphenyl-2-picrylhydrazyl (DPPH). The methylene chloride (CH(2)Cl(2)) extract and the ethyl acetate (EtOAc) soluble fraction of the 70% acet...
Article
An investigation on the gum exudates of Commiphora myrrha has led to the isolation of six sesquiterpenoids. On the basis of spectroscopic data interpretation, they were determined as two new furanosesquiterpenoids, rel-1S,2S-epoxy-4R-furanogermacr-10(15)-en-6-one (1) and rel-2R-methyl-5S-acetoxy-4R-furanogermacr-1(10)Z-en-6-one (2), and four known...
Article
The antibacterial activity of compounds obtained from licorice was measured against upper airway respiratory tract bacteria such as Streptococcus pyogenes, Haemophilus influenzae and Moraxella catarrhalis. Among the tested compounds, licoricidin exhibited the highest activity against all tested microorganisms with an MIC of 12.5 microg/mL. Three co...
Article
Quinoa (Chenopodium quinoa) is a hardy and nutritious Latin American pseudo-cereal. Studies on the seeds led to the isolation of five ecdysteroids using column chromatography. Their structures were determined as ecdysterone, makisterone A, 24-epi-makisterone A, 24(28)-dehydromakisterone A, and 20,26-dihydroxyecdysone by spectroscopic methods. This...
Article
As a part of our studies on the constituents of plants belonging to the family Zingiberaceae,(1-5) we have focused on Alpinia flabellata Ridley, which is a rare species in Japan. The leaves of this plant have been used as a wrapping and flavoring material for foods on the islands of Iriomote and Ishigaki, Okinawa, which is the southernmost part of...
Article
Constituents of the fruits of greater cardamom (Amomum subulatum) were fractionated into three fractions, the dichloromethane extract, and the ethyl acetate-soluble and water-soluble fractions of the 70% aqueous acetone extract. The ethyl acetate-soluble fraction showed a high radical-scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH)...
Article
Three phenylbutanoid dimers, cis- and trans-1-(2,4,5-trimethoxy-E-styryl)-2-(2,4,5-trimethoxy-Z-styryl)cyclobutane and 1,2-bis(2,4,5-trimethoxy-Z-styryl)- cyclobutane, were isolated from the leaves of Alpinia flabellata Ridley, together with three known compounds (2,4,5-trimethoxybenzaldehyde, 2,4,5-trimethoxycinnamaldehyde and 3,5-dihydroxy-7,4'-d...
Article
A model substrate oil using methyl linoleate was established for the determination of the antioxidant activity by Oil Stability Index (OSI) method. OSI values for methyl linoleate with different concentrations (5–100%) in silicone oil were measured at different temperatures (70–120°C). As the temperature increased, the OSI value decreased in each c...
Article
Neochlorogenic acid (3-CQA) and cryptochlorogenic acid (4-CQA), isolated from prune (Prunus domestica L.), were identified by NMR and MS analyses. In addition, the quantity of chlorogenic acid isomers in prune were measured by HPLC. These isomers, 3-CQA, 4-CQA, and chlorogenic acid (5-CQA), were contained in the ratio 78.7:18. 4:3.9, respectively....
Article
Dichloromethane and methanol extracts of 13 Zingiberaceae species from the Alpinia, Costus and Zingiber genera were screened for antimicrobial and antioxidant activities. The antimicrobial activity of most of the extracts was antibacterial with only the methanol extract of Costus discolor showing very potent antifungal activity against only Aspergi...
Article
Three new glycosides were isolated from the fruits of noni (Morinda citrifolia). Their structures were determined to be 6-O-(beta-D-glucopyranosyl)-1-O-octanoyl-beta-D-glucopyranose (1), 6-O-(beta-D-glucopyranosyl)-1-O-hexanoyl-beta-D-glucopyranose (2), and 3-methylbut-3-enyl 6-O-beta-D-glucopyranosyl-beta-D-glucopyranoside (3) using MS and NMR met...
Article
This study was designed to investigate the chemopreventive action of three natural products, coumaperine, aurapten and an extract from rosemary, against the initiation stage of rat hepatocarcinogenesis. Coumaperine has been isolated from white pepper as a naturally occurring antioxidative agent, but its potential modifying effects on carcinogenesis...
Article
Three new galloylglucosides, (4S)-alpha-terpineol 8-O-beta-D-(6-O-galloyl)glucopyranoside (1); (4R)-alpha-terpineol 8-O-beta-D-(6-O-galloyl)glucopyranoside (2), and 3-(4-hydroxy-3-methoxyphenyl)propane-1,2-diol 2-O-beta-D-(6-O-galloyl)glucopyranoside (3), were isolated from the berries of Pimenta dioica together with three known compounds, gallic a...
Article
Six compounds, 1-O-(2,3, 4-trihydroxy-3-methyl)butyl-6-O-feruloyl-beta-D-glucopyranoside, ethyl beta-D-glucopyranosyl tuberonate, p-hydroxybenzoic acid, (-)-hydroxyjasmonic acid, caffeic acid, and 4-hydroxyacetophenone 4-O-[5-O-(3, 5-dimethoxy-4-hydroxybenzoyl)-beta-D-apiofrunosyl]-(1-->2)-beta-D- glu copyranoside, were isolated from the n-butanol-...
Article
A phenylpropanoid, threo-3-chloro-1-(4-hydroxy-3-methoxyphenyl)propane-1,2-diol, was isolated from the berries of Pimenta dioica together with five known compounds, eugenol, 4-hydroxy-3-methoxycinnamaldehyde, 3,4-dimethoxycinnamaldehyde, vanillin and 3-(4-hydroxy-3-methoxyphenyl)propane-1,2-diol. In addition, the stereochemistry of 3-(4-hydroxy-3-m...
Article
Two known glycosides and a novel trisaccharide fatty acid ester were isolated from the n-butanol-soluble fraction of the fruits of Morinda citrifolia (noni). Structure determination was carried out by spectral techniques such as MS, IR, NMR, and 2D-NMR. The novel trisaccharide fatty acid ester was elucidated as 2, 6-di-O-(beta-D-glucopyranosyl)-1-O...
Article
Studies on the roots of Cynanchum stauntoi led to the isolation of two C21-steroidal glycosides, formally named stauntosides A and B. Their structures were elucidated on the basis of spectroscopic evidence, especially that from analysis of 2D-NMR spectra. They were found to possess an unusual skeleton and were identified as stauntogenin 3-O-α-L-dig...
Article
The antioxidant activities of several extracts from Susabinori (Porphyra yezoensis) were measured by the ferric thiocyanate method and the thiobarbituric acid method. The methanol, acetone, ethyl acetate, and hexane extracts, and the chloroform-soluble and water-soluble fractions from the chloroform-methanol extract exhibited higher activities than...
Article
Four acetophenone glycosides were isolated from the butanol-soluble fraction of thyme extracts. Their structures were determined by spectral methods (MS, NMR, and 2D-NMR). Among them, two new compounds, 4-hydroxyacetophenone 4-O-[5-O-(3, 5-dimethoxy-4-hydroxybenzoyl)-beta-D-apiofuranosyl]-(1-->2)-beta-D -gl ucopyranoside (1) and 4-hydroxyacetopheno...
Article
The new bitter diterpenes, rabdosianone I (C 20H 24O 5) and II (C 22H 28O 6), were isolated from Isodon japonicus (Japanese name, enmeiso), and their structures were elucidated by spectroscopic methods. Electrophysiological experiments were performed to compare rabdosianone I with quinine. The taste responses of chorda tympani nerves to rabdosianon...
Article
Seven coumaric compounds analogous to aurapten were synthesized. Their spasmolytic activity against Ba2+, acetylcholine and histamine was evaluated to investigate their structure-activity relationship. The results of the bioassay demonstrated the important roles of the cis type of double bond at C-2' and the epoxide between c-6' and 7'.