Biomedical subjects

Yoshio Takeda

Publications and source records attributed to Yoshio Takeda.

At least 37 records · Page 2Linked to original sources

PubMed2003

Muscanone: a 3-O-(1", 8", 14"-trimethylhexadecanyl)naringenin from Commiphora wightii.

A new antifungal flavanone, muscanone (1), was isolated along with known naringenin (2) from Commiphora wightii (Arn.) Bhandari (Burseraceae) by directing the fractionation of an EtOH extract of the air-dried trunk of C. wightii with microbial sensitivity assay. The structures of 1 and 2 were determined from EIMS, HREIMS, DEPT, 1H-1H COSY, HSQC and HMBC spectral data. Muscanone (1) was identified as 3-O-(1", 8",14"-trimethylhexadecanyl)naringenin and was found to be active against Candida albicans. The isolation, structure elucidation, NMR spectral assignments, and bioactivities of 1 and 2 are reported.

Animals↗

PubMed2003

New icetexane and 20 norabietane diterpenes with trypanocidal activity from Dracocephalum komarovi.

Two new icetexane diterpenes, cyclocoulterone (1) and komaroviquinone (2), and a novel 20-norabietane diterpene, dracocephalone A (3), were isolated from Dracocephalum komarovi. Their structures were elucidated by extensive analyses of spectral data. Komaroviquinone (2) showed strong trypanocidal activity against epmastigotes of Trypanosoma cruzi, the causative agent of American trypanosomiasis, with a minimum lethal concentration of 0.4 micro M.

Animals↗

PubMed2003

Glochidionionosides A-D: megastigmane glucosides from leaves of Glochidion zeylanicum (Gaertn.) A. Juss.

Five megastigmane glucosides were isolated from the leaves of Glochidion zeylanicum. One of them was a known compound, blumenol C O-beta-D-glucopyranoside (1), and the structures of the four new compounds, glochidionionosides A-D (2-5), were mainly elucidated by spectroscopic methods, including a modified Mosher's method. The absolute configurations of the six-membered ring of glochidionionoside D (5) were deduced by beta-D-glucopyranosylation-induced shift trends in the (13)C-NMR spectra and confirmed by X-ray analysis as its p-bromobenzoate (5b), and the axis chirality of C-7 was determined to be R.

Cyclohexanones↗

PubMed2003

Cytotoxic screening of medicinal and edible plants in Okinawa, Japan, and identification of the main toxic constituent of Rhodea japonica (Omoto).

The cytotoxic activity of ethanol extracts from 53 parts of 36 species of medicinal and edible plants cultivated in Okinawa was measured by using K562 human leukemia cells by a flow cytometric method. Two extracts from Rhodea japonica and Hypericum chinense were cytotoxic at a concentration of 10 microg/ml. The main cytotoxic constituent of Rhodea japonica was isolated and identified to be rhodexin A, which has been isolated as a cardetonic agent of the plant. The IC(50) value for rhodexin A against the growth of K562 cells was 19 nM, this activity being much stronger than that of ouabain (IC(50), 60 nM).

Antineoplastic Agents↗

PubMed2002

Recovery mechanism of the antioxidant activity from carnosic acid quinone, an oxidized sage and rosemary antioxidant.

A solution of carnosic acid quinone, which is a radical chain-termination product having no antioxidant activity in the antioxidant reaction of carnosic acid, recovers potent antioxidant activity upon standing. The HPLC analysis of an aged solution of carnosic acid quinone revealed that several antioxidants are produced in the solution. From the time-course and quantitative analyses of the formation of the products and their structural analysis, an antioxidant mechanism from carnosic acid quinone is proposed that includes a redox reaction of carnosic acid quinone in addition to the isomerization to lactone derivatives. In the first stage of antioxidation, carnosic acid, the reduction product from carnosic acid quinone, contributes to the potent antioxidant activity of the solution. This proposed mechanism can explain one of the reasons for the strong antioxidant activity of the extract of the popular herbs sage and rosemary.

Abietanes↗

PubMed2002

Viral load is a significant prognostic factor for hepatitis B virus-associated hepatocellular carcinoma.

BACKGROUND: Hepatitis B virus (HBV) is closely linked to hepatocellular carcinoma (HCC). The objective of the current study was to identify the factors involved in the prognosis of patients with HBV-associated HCC using multivariate analysis. METHODS: The current study included 74 patients with HBV-associated HCC who were admitted to Nagasaki University Hospital, Nagasaki, Japan, between 1983-1998. Of these, 13 patients underwent surgical tumor resection; 43 patients received nonsurgical treatment with transcatheter arterial embolization, percutaneous ethanol injection, or both; and 18 patients were followed without any active treatment. The significance of the patient's age; gender; history of blood transfusion; alcohol use; serum levels of alanine aminotransferase, alpha-fetoprotein, and HBV-DNA; number and size of liver tumors; clinical stage; and histologic diagnosis of HCC as prognostic factors was evaluated using univariate and multivariate analyses. RESULTS: The 3-year, 5-year, and 10-year postdiagnosis cumulative survival rates were 36%, 21%, and 17%, respectively. Multivariate analysis identified the level of serum HBV-DNA and tumor size at diagnosis as independent and significant prognostic factors (P = 0.0022 and P = 0.0106, respectively). In addition, a low level of viremia was found to be associated with longer survival (P = 0.0057) even in patients who were negative for the hepatitis B e antigen. CONCLUSIONS: The results of the current study suggest that viral load is a useful prognostic marker for HBV-related HCC and that HCC patients with a less favorable course appear either to clear the virus poorly or to have a greater level of virus production.

Adult↗

PubMed2002

Structural identification of new curcumin dimers and their contribution to the antioxidant mechanism of curcumin.

As a part of the research project on the elucidation of the chain-breaking antioxidant mechanism of natural phenolics against the oxidation of food components, curcumin, a main turmeric pigment, was investigated. A relatively high concentration of curcumin gave three dimers as radical termination products in addition to the coupling products with curcumin and the lipid hydroperoxide. The structural analysis of these dimers and quantitative analysis of their production rates revealed that radical-radical termination mainly occurred at the 2-position of curcumin. The contribution of the pathway for production of these dimers to the antioxidant mechanism of curcumin was estimated from the concentration-dependent data of the antioxidant activity and formation rates of these termination products. The A-A termination (dimer formation) was estimated to contribute at least about 40% of the entire antioxidant process against ethyl linoleate oxidation.

Antioxidants↗

PubMed2002

Contribution of a combination of ponicidin and acyclovir/ganciclovir to the antitumor efficacy of the herpes simplex virus thymidine kinase gene therapy system.

We have previously reported that ponicidin (PND), isolated from Rabdosia ternifolia, potentiates the cell-killing activity of antiherpes prodrugs acyclovir (ACV) and ganciclovir (GCV) in human cancer cells expressing herpes simplex virus thymidine kinase (HSV-TK). To extend these in vitro results to in vivo situations, HSV-TK-expressing HeLa cells were injected into nude mice. The in vivo growth of TK(+) HeLa cells was significantly inhibited by coadministration of PND and ACV, or of PND and GCV, compared with single use of ACV or GCV in spite of lower doses of 1 or 0.25 mg/mouse, respectively. These results indicate that there is a good correlation between this in vivo efficacy and previously reported in vitro efficacy. Because of the insufficiency of incorporation of genes into tumors, bystander cell killing has attracted special interest. In the present study, we determined the ability of PND to potentiate the bystander effects of ACV and GCV in both in vitro and in vivo systems. In vitro combined use of PND with ACV or GCV rendered tumor cells more sensitive to the prodrugs, demonstrating a 1.8- to 97-fold or 2.8- to 26-fold reduction in IC(50) compared with ACV or GCV only, respectively, in 1 to 20% of HSV-TK(+) cells. In the in vivo experiments using nude mice injected with 3 or 10% HSV-TK(+) cells, tumor volume was lower in mice treated with a combination of PND and ACV/GCV than in those treated with ACV or GCV only. No toxicity of PND was seen in mice even at a dose 10-fold higher than that used in the in vivo experiments. These novel strategies could provide benefit to ablative cancer gene therapy by making it feasible to use toxic GCV at lower doses and relatively nontoxic ACV.

Acyclovir↗

PubMed2002

Monoacylglycerol from Punica granatum seed oil.

The seeds of Punica granatum, known as hap roman in the Arabian Peninsula, are commonly eaten as a dessert. As part of an ongoing project to find nonnutritional natural products which have health benefits, or that can be exploited to protect crops, the chloroform-soluble extract of the fermented seeds of P. granatum was found to be rich in 1-O-trans,cis,trans-9,11,13-octadecatrienoyl glycerol (1). The seed oil is not lethal to brine shrimp larvae. 1-O-isopentyl-3-O-octadec-2-enoyl glycerol (2) and the known cis-9-octadecenoic, octadecanoic, and eicosanoic acids were also detected in small amounts in the seed oil by LC and MS. The structure of 1 was determined from NMR and MS spectral data.

Fruit↗

PubMed2002

Flow cytometric estimation on cytotoxic activity of leaf extracts from seashore plants in subtropical Japan: isolation, quantification and cytotoxic action of (-)-deoxypodophyllotoxin.

The cytotoxic activity of methanol extracts of leaves collected from 39 seashore plants in Iriomote Island, subtropical Japan was examined on human leukaemia cells (K562 cells) using a flow cytometer with two fluorescent probes, ethidium bromide and annexin V-FITC. Five extracts (10 microg/mL) from Hernandia nymphaeaefolia, Cerbera manghas, Pongamia pinnata, Morus australis var. glabra and Thespesia populnea greatly inhibited the growth of K562 cells. When the concentration was decreased to 1 microg/mL, only one extract from H. nymphaeaefolia still inhibited the cell growth. A cytotoxic compound was isolated from the leaves by bioassay-guided fractionation and was identified as (-)-deoxypodophyllotoxin (DPT). The fresh leaves of H. nymphaeaefolia contained a remarkably high amount of DPT (0.21 +/- 0.07% of fresh leaf weight), being clarified by a quantitative HPLC analysis. DPT at 70-80 pM started to inhibit the growth of K562 cells in an all-or-none fashion and at 100 pM or more it produced complete inhibition in all cases. Therefore, the slope of the dose-response curve was very steep. DPT at 100 pM or more decreased the cell viability to 50%-60% and increased the number of cells undergoing apoptosis (annexin V-positive cells). The results indicate that DPT contributes to the cytotoxic action of the extract from the leaves of H. nymphaeaefolia on K562 cells.

Antineoplastic Agents, Phytogenic↗

PubMed2002

Coumarins and gamma-pyrone derivatives from Prangos pabularia: antibacterial activity and inhibition of cytokine release.

The n-hexane and ethyl acetate extracts of the stems and the ethyl acetate extracts of roots from Prangos pabularia afforded an gamma-pyrone derivative and furanocoumarin derivatives with three glucose and gamma-pyrone (pabularin A, B and C), along with 26 previously known compounds (18 coumarins, six terpenoids and two glycosides). Their structures were established on the basis of spectroscopic studies. Of these, 16 coumarin derivatives isolated from P. pabularia were tested for antibacterial activity and inhibition of cytokine release.

Anti-Bacterial Agents↗

PubMed2002

Benzoylphloroglucinol derivatives from Hypericum scabrum.

Nine new polyprenylated benzoylphloroglucinol derivatives, hyperibones A-I (1-9), were isolated from the aerial parts of the Uzbekistan medicinal plant Hypericum scabrum. Their structures were determined mainly on the basis of spectroscopic evidence (2D NMR and HRMS). Compounds 1, 2, and 4 showed mild in vitro antibacterial activity against methicillin-resistance Staphylococus aureus (MRSA) and methicillin-sensitive Staphylococus aureus (MSSA).

Anti-Bacterial Agents↗

PubMed2002

Polysulfide derivatives from Ferula foetida.

The ethyl acetate-soluble fraction from a methanol extract of Ferula foetida has afforded six new sulfide derivatives, (E)-3-methylsulfinyl-2-propenyl sec-butyl disulfide (foetisulfide A) (1), (Z)-3-methylsulfinyloxy-2-propenyl sec-butyl disulfide (foetisulfide B) (2), (E)-3-methylsulfinyloxy-2-propenyl sec-butyl disulfide (foetisulfide C) (3), bis(3-methylthio-2E-propenyl) disulfide (foetisulfide D) (4), 3,4,5-trimethyl-2-thiophenecarboxylic acid (foetithiophene A) (5), 3,4,5-trimethyl-2-(methylsulfinyloxymethyl)thiophene (foetithiophene B) (6), along with six known compounds. The structures of 1-6 were established on the basis of spectroscopic studies, with the elucidation of 5 confirmed by single-crystal X-ray crystallography.

Chromatography, High Pressure Liquid↗

PubMed2002

Tricalysiosides A-G: rearranged ent-kauranoid glycosides from the leaves of Tricalysia dubia.

Seven rearranged ent-kaurane glycosides, named tricalysiosides A-G (1-7), were isolated from the leaves of Tricalysia dubia collected on Okinawa Island. Their C-18 and 19 methyls were found to have rearranged to form an alpha,beta-unsaturated gamma-lactone ring, with other functional groups remotely located only on C-15, -16, and -17 of the five-membered ring. Information available from various kinds of two-dimensional NMR spectra was limited and insufficient to allow total characterization of the structures. Finally, using X-ray crystallographic analysis, the structure of tricalysioside A (1) was determined to be 4-nor-18-homo-ent-kauran-4(18)-en-15beta,16beta,17-triol-3beta,19-olide 16-O-beta-D-glucopyranoside (1). On the basis of the crystal structure of 1, the structures of the other tricalysiosides (2-7) were also established.

Chromatography↗

PubMed2002

Sesquiterpenes from Ferula penninervis.

The ethyl acetate soluble extract of the dried roots of Ferula penninervis gave 17 new sesquiterpenes [15 of the guaiane-type, ferupennins A-O (1-15), and two of the eudesmane-type, 1alpha-hydroxy-2-oxo-5alpha,7beta,11betaH-eudesm-3-en-6alpha,12-olide (16) and penninervin (17)] and nine known sesquiterpenes. The structures of the new compounds were elucidated on the basis of spectroscopic evidence and X-ray analysis. The absolute configuration of ferupennin A (1) was determined by a modified Mosher method.

Acetates↗

PubMed2002

An unusual sesquiterpene derivative from Ferula kuhistanica.

An unusual new sesquiterpene derivative, kuhistaferone (1), was isolated from the fruits of the Uzbekistan medicinal plant Ferula kuhistanica. The structure of 1 was established on the basis of spectroscopic evidence. Compound 1 showed moderate cytotoxicity against the human colon tumor cell line HCT116.

Anti-Bacterial Agents↗

PubMed2002

An iridoid glucoside dimer and a non-glycosidic iridoid from the leaves of Lasianthus wallichii.

A new iridoid glucoside dimer (1) and a non-glycosidic iridoid (2) was isolated together with the known compounds, asperuloside (3), paederoside (4), daphylloside (5), citroside A (6) and benzyl 6-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranoside (7), from the leaves of Lasianthus wallichii. The structures of the new compounds were elucidated by spectroscopic and chemical evidence.

Dimerization↗

PubMed2002

Turpinionosides A-E: megastigmane glucosides from leaves of Turpinia ternata Nakai.

From leaves of Turpenia ternata (Staphylaceae), one megastigmane and seven of its glucosides (1-8) were isolated. Megastigmane and two of the glucosides were found to be known compounds, namely, 3S,5R,6R,9S-tetrahydroxymegastigmane (1), corchoionoside C (2), and icariside B4 (3). The structures of compounds 4-8 (turpinionosides A-E, respectively) were elucidated by means of spectroscopic analyses, and then their absolute structures were determined by the modified Mosher's method to be (3S,5R,6S,9S)-3,6,9-trihydroxymegastigman-7-ene 3-O- and 9-O-beta-D-glucopyranosides (4, 5, respectively), (1S,3S,5R,6S,9R)-3,9,12-trihydroxymegastigmane 3-O-beta-D-glucopyranoside (6), (3S,4R,9R)-3,4,6-trihydroxymegastigman-5-ene 3-O-beta-D-glucopyranoside (7), and (2S,9R)-2,9-dihydroxymegastigman-5-en-4-one 2-O-beta-D-glucopyranoside (8).

Chromatography, Thin Layer↗