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Biomedical subjects

S Kadota

Publications and source records attributed to S Kadota.

At least 19 recordsLinked to original sources
PubMed2005

Hypoglycemic effects of the wood of Taxus yunnanensis on streptozotocin-induced diabetic rats and its active components.

Hypoglycemic effects of the H(2)O and MeOH extracts of the wood of Taxus yunnanensis were examined in streptozotocin (STZ)-induced diabetic rats. The H(2)O extract significantly lowered the fasting blood glucose level by 33.7% at a 100mg/kg dose on intraperitoneal administration. From the active H(2)O extract of the wood, three lignans, i.e., isotaxiresinol (1), secoisolariciresinol (2) and taxiresinol (3), were isolated as major components. These lignans were further tested for their hypoglycemic effects on the same experimental model. At a dose of 100mg/kg (i.p.), isotaxiresinol (1) reduced the fasting blood glucose level of diabetic rats by 34.5%, while secoisolariciresinol (2) and taxiresinol (3) reduced by 33.4% and 20.9%, respectively. The blood glucose lowering effects of 1 and 2 were stronger than the mixture of tolbutamide (200mg/kg) and buformin (1mg/kg) used as a positive control, which lowered fasting blood glucose level by 24.0%.

Animals↗
PubMed2005

In vivo anti-osteoporotic activity of isotaxiresinol, a lignan from wood of Taxus yunnanensis.

Isotaxiresinol, the main lignan isolated from the water extract of wood of Taxus yunnanensis, was investigated for its effect on bone loss, on serum biochemical markers for bone remodeling and on uterine tissue, using ovariectomized (OVX) rats as the model of postmenopausal osteoporosis. After oral administration of isotaxiresinol (50 and 100mg/kg/d) for 6 weeks, bone mineral content (BMC) and bone mineral density (BMD) in total and cortical bones were increased as compared to those of OVX control rats, and decreases of three bone strength indexes induced by OVX surgery were prevented. Serum biochemical markers for bone remodeling revealed that isotaxiresinol slightly increased bone formation and significantly inhibited bone resorption without side effect on uterine tissue. These results suggest that isotaxiresinol may be useful for treatment of postmenopausal osteoporosis, especially for prevention of bone fracture induced by estrogen deficiency.

Animals↗
PubMed2005

CYP3A4 and CYP2D6 inhibitory activities of Indonesian medicinal plants.

Thirty samples of Indonesian medicinal plants were analyzed for their capacity to inhibit in vitro metabolism by human cytochrome P450 3A4 (CYP3A4) and CYP2D6 with a radiometric assay. The MeOH-soluble fractions of 25 samples, prepared from water extracts, demonstrated inhibitory activity more than 50% on the metabolism mediated by CYP3A4, and 21 samples on the metabolism mediated by CYP2D6. Among the MeOH-soluble fractions, Piper nigrum leaf showed the highest inhibitory activity against CYP3A4 (91.7%), and Punica granatum against CYP2D6 (98.1%). The water extracts of which MeOH-soluble fraction showed inhibitory activity more than 70% were fractionated with EtOAc. From the EtOAc-soluble fractions, Curcuma heyneana (67.0%), Pi. cubeba (75.0%), Pi. nigrum fruit (84.0%), Pi. nigrum leaf (85.8%), and Zingiber aromaticum (75.3%) demonstrated inhibitory activity more than 50% on the metabolism mediated by CYP3A4, but only Pi. nigrum fruit (72.8%) and Pi. nigrum leaf (69.1%) showed strong inhibitory activity against CYP2D6. For samples that showed more than 70% inhibition, their IC(50) values were determined. The most potent inhibitory activity against CYP3A4 (IC(50) value of 25 microg/ml) was found for the extract of Pi. nigrum leaf, while that of Catharanthus roseus showed the most potent inhibitory effect against CYP2D6 (IC(50) value of 11 microg/ml). These results should indicate once more the possibility of potential medicinal plant-drug interactions.

Cytochrome P-450 CYP2D6↗
PubMed2005

Ischemic duodenitis.

Explore the source record for details and available documents.

Arteriosclerosis Obliterans↗
PubMed2001

Recent progress in pharmacological research of propolis.

Propolis is a resinous hive product collected by honeybees from various plant sources. It is a popular folk medicine possessing a broad spectrum of biological activities. It has also been used as a health drink in various Asian, European and American countries. Several groups of researchers have focused their attention on the biological activity of propolis and its active principles. Many scientific articles are published every year in different international journals related to the pharmacological properties of propolis. This review article compiles recent findings (since 1995) on the pharmacological properties of propolis focusing on its antihepatotoxic, antitumour, antioxidative, antimicrobial and antiinflammatory properties. The possible mechanism of action of propolis as well as the active compounds are discussed.

Anti-Infective Agents↗
PubMed2001

Screening of Chinese herbal drug extracts for inhibitory activity on nitric oxide production and identification of an active compound of Zanthoxylum bungeanum.

Sixty-eight water and methanol extracts from 34 Chinese herbal drugs, most of which are used for inflammatory diseases, were screened for their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated J774.1 macrophages and in LPS/interferon (IFN)-gamma-stimulated mouse peritoneal exudate macrophages. Among the extracts, methanol extracts of Myristica fragrans, Plantago asiatica, Rubia cordifolia, and Zanthoxylum bungeanum showed significant inhibition in J774.1 macrophages, while in mouse peritoneal exudate macrophages, water extracts of Ru. cordifolia and Scutellaria baicalensis and methanol extracts of Angelica megaphylla, My. fragrans, and Z. bungeanum inhibited the NO production. Among them, inhibition of water extract of Sc. baicalensis was found to be mainly due to direct scavenging of NO radicals, through an examination of its scavenging activity on PAPA NONOate-generated NO radicals, while water extract of Ru. cordifolia and methanol extracts of An. megaphylla, My. fragrans, P. asiatica, and Z. bungeanum showed inhibition on iNOS mRNA expression. At last, an inhibitory compound on iNOS mRNA expression was isolated from a methanol extract of Z. bungeanum and identified as 4-O-beta-D-glucopyranosyldihydroferulic acid by NMR spectral analyses and chemical synthesis.

Animals↗
PubMed2001

Triterpene saponins from Vietnamese ginseng (Panax vietnamensis) and their hepatocytoprotective activity.

The methanol extract of Vietnamese ginseng (Panax vietnamensis) was found to possess hepatocytoprotective effects on D-galactosamine (D-GalN)/tumor necrosis factor-alpha (TNF-alpha)-induced cell death in primary cultured mouse hepatocytes. Further chemical investigation of the extract afforded two new dammarane-type triterpene saponins, ginsenoside Rh(5) (1) and vina-ginsenoside R(25) (2), as well as eight known dammarane-type triterpene saponins, majonoside R(2) (3), pseudo-ginsenoside RT(4) (4), vina-ginsenosides R(1) (5), R(2) (6), and R(10) (7), ginsenosides Rg(1) (8), Rh(1) (9), and Rh(4) (10), and a known sapogenin protopanaxatriol oxide II (11). Their structures were elucidated on the basis of spectral analysis. In addition, by the using LC-electrospray ionization (ESI)-MS method, five known saponins, ginsenosides Rb(1), Rb(2), Rc, Rd, and Re (12--16), were also identified in the extract. Among the compounds isolated, majonoside R(2) (3), the main saponin in Vietnamese ginseng, showed strong protective activity against D-GalN/TNF-alpha-induced cell death in primary cultured mouse hepatocytes. This demonstrates that the hepatocytoprotective effect of Vietnamese ginseng is due to dammarane-type triterpene saponins that have an ocotillol-type side chain, a characteristic constituent of Vietnamese ginseng.

Animals↗
PubMed2001

Three new triterpenes from the seeds of Combretum quadrangulare and their hepatoprotective activity.

Three new triterpenes of the lupane type, 2alpha,6beta-dihydroxybetulinic acid (1) and 6beta-hydroxyhovenic acid (2), and an oleanane type, 6beta-hydroxyarjunic acid (3), together with several known compounds, have been isolated from the MeOH extract of the seeds of Combretum quadrangulare. The structures of these compounds were elucidated on the basis of spectroscopic analysis, and their hepatoprotective activities were tested for D-GalN/TNF-alpha-induced cell death in primary cultured mouse hepatocytes.

Asia↗
PubMed2001

Eleven novel diarylheptanoids and two unusual diarylheptanoid derivatives from the seeds of Alpinia blepharocalyx.

An EtOH extract of the seeds of Alpinia blepharocalyx afforded 11 novel diarylheptanoids, named deoxycalyxin A (1), epicalyxin F (2), calyxin K (3), epicalyxin K (4), calyxin I (5), epicalyxin I (6), calyxin J (7), epicalyxin J (8), and calyxin L (9), an epimeric mixture of calyxin M (10) and epicalyxin M (11), and two unusual diarylheptanoid derivatives, named neocalyxins A (12) and B (13), together with four known calyxins, calyxins A (14), F (15), E (16), and G (17). Structures were elucidated by spectroscopic techniques including 2D NMR spectroscopy. All compounds were examined for cytotoxicity toward murine colon 26-L5 carcinoma and human HT-1080 fibrosarcoma cells. Diarylheptanoids 2, 3, and 5 were cytotoxic against both cell lines, while 4 and 6-8 were cytotoxic against human fibrosarcoma cells.

Animals↗
PubMed2001

Blepharocalyxins C--E, three new dimeric diarylheptanoids, and related compounds from the seeds of Alpinia blepharocalyx.

Three novel diarylheptanoids, blepharocalyxins C--E (5--7), together with four new (1--4) and one known (8) diarylheptanoids bearing a tetrahydropyran ring were isolated from the residual fraction of an EtOH extract of the seeds of Alpinia blepharocalyx. The structures and the stereochemistry at the chiral centers of the new diarylheptanoids were elucidated by spectroscopic techniques including 2D NMR spectroscopy. Blepharocalyxins C--E (5--7) have a novel carbon framework and are dimeric diarylheptanoids consisting of two diarylheptanoid units. Blepharocalyxin D (6) showed potent antiproliferative activity against murine colon 26-L5 carcinoma cells (ED(50), 3.61 microM), while against human HT-1080 fibrosarcoma cells, blepharocalyxin E (7) showed potent activity (ED(50), 9.02 microM).

Animals↗
PubMed2001

Six new diarylheptanoids from the seeds of Alpinia blepharocalyx.

Chromatographic separation of part of an EtOH extract of the seeds of Alpinia blepharocalyx resulted in the isolation of six new (1-6) and two known (7, 8) diarylheptanoids together with 12 known compounds. The structures of the new compounds, including their absolute stereochemistry, were elucidated by spectroscopic and chemical methods as (3S,5S)- (1) and (3S,5R)-3-hydroxy-5-methoxy-1-(4-hydroxyphenyl)-7-phenyl-6E-heptene (2), (3S,5S)- (3) and (3S,5R)-3-hydroxy-5-ethoxy-1-(4-hydroxyphenyl)-7-phenyl-6E-heptene (4), (3S)-methoxy-1,7-bis(4-hydroxyphenyl)-6E-hepten-5-one (5), and 1,7-bis(4-hydroxyphenyl)hepta-4E,6E-dien-3-one (6). Among the isolated compounds, 5, (3S,5S)-3,5-dihydroxy-1,7-bis(4-hydroxyphenyl)heptane (8), 4'-hydroxy-5,6-dehydrokawain (14), and/or phloroglucinol (20) showed significant antiproliferative activity against murine colon 26-L5 carcinoma (ED(50): 5, 5.2 microM; 8, 12.8 microM; 14, 20.7 microM; 20, 26.4 microM) and human HT-1080 fibrosarcoma (ED(50): 5, 10.1 microM; 14, 20.1 microM; 20, 20.9 microM) cells.

Cell Division↗
PubMed2001

Five novel highly oxygenated diterpenes of Orthosiphon stamineus from Myanmar.

Five novel highly oxygenated diterpenes, orthosiphols K (1), L (2), M (3), and N (4) and norstaminone A (5), were isolated from the aerial part of Orthosiphon stamineus, together with three known diterpenes, orthosiphols A (6) and B (7) and neoorthosiphol A (8). Orthosiphol L (2) is an isopimarane-type diterpene with a hydroxyl group at C-12, which supports the biogenesis of staminane-type diterpenes, i.e., migration of a vinylic group from C-13 of isopimarane to C-12. Norstaminone A (5) has a staminane carbon framework and supports the biosynthetic pathway from staminols to norstaminols via staminolactones. All the isolated compounds showed mild to weak antiproliferative activities toward highly liver metastatic colon 26-L5 carcinoma and human HT-1080 fibrosarcoma cell lines.

Antineoplastic Agents, Phytogenic↗
PubMed2001

New spirostanol steroids and steroidal saponins from roots and rhizomes of Dracaena angustifolia and their antiproliferative activity.

The MeOH extract of Nam ginseng (roots and rhizomes of Dracaena angustifolia) afforded nine new compounds, including three spirostanol sapogenins, named namogenins A-C (1-3), four spirostanol saponins, named namonins A-D (4-7), a furostanol saponin, named namonin E (8), and a pregnan glycoside, named namonin F (9), along with another eight known steroidal saponins (10-17). Their structures were determined on the basis of spectral analyses and chemical methods. All compounds were tested for their antiproliferative activity against murine colon 26-L5 carcinoma, human HT-1080 fibrosarcoma, and B-16 BL6 melanoma cells. Compounds 4, 5, and 10 showed potent antiproliferative activity against HT-1080 fibrosarcoma cells, having IC(50) values of 0.2, 0.3, and 0.6 microM, respectively, comparable to that of doxorubicin.

Animals↗
PubMed2001

Studies on the hepatocyte protective activity and the structure-activity relationships of quinic acid and caffeic acid derivatives from the flower buds of Lonicera bournei.

13 quinic acid derivatives along with caffeic acid, methyl caffeate, myo-inositol, bis[5-formylfurfuryl] ether and 6,7-dihydroxycoumarin were isolated from the ethanol extract of the flower buds of Lonicera bournei Hemsl., among which 8 compounds were firstly obtained from this genus. The effects of different solvent soluble fractions of the ethanol extract and the pure compounds on heptocyte death induced by D-galactosamine (D-GalN)/tumor necrosis factor alpha (TNF-alpha) were studied, and the structure-activity relationships were also discussed.

Animals↗
PubMed2001

Phylogenetic analysis based on 18S rRNA gene and matK gene sequences of Panax vietnamensis and five related species.

Panax vietnamensis was discovered recently in Vietnam. Its bamboo-like rhizomes, called Vietnamese Ginseng, have attracted considerable attention because of their specific pharmacological activities. In order to define the taxonomic position of this new species and include it in the molecular authentication of Ginseng drugs, the 18S ribosomal RNA gene and matK gene sequences of P. vietnamensis were determined and compared with those of its related taxa, P. japonicus var. major and P. pseudo-ginseng subsp. himalaicus, besides previously reported P. ginseng, P. japonicus and P. quinquefolius. The 18S rRNA gene sequences were found to be 1809 bps in length. The sequence of P. vietnamensis was identical to that of P. quinquefolius, and presented one base substitution from those of both P. japonicus var. major and P. pseudo-ginseng subsp. himalaicus. The matK gene sequences of 6 taxa were found to be 1509 bps in length. The sequence of P. vietnamensis differed from those of P. japonicus var. major, P. pseudo-ginseng subsp. himalaicus, P. ginseng, P. japonicus and P. quinquefolius at 4, 5, 9, 9 and 10 nucleotide positions, respectively. The phylogenetic tree reconstructed by the combined 18S rRNA-matK gene analysis using the maximum parsimony method showed that P. vietnamensis was sympatric with other Panax species and had a close relationship with P. japonicus var. major and P. pseudo-ginseng subsp. himalaicus.

Amino Acid Sequence↗
PubMed2001

Hepatoprotective and anti-Helicobacter pylori activities of constituents from Brazilian propolis.

Propolis is a resinous hive product collected by honeybees from various plant sources. It is extensively used in food, beverage and in folk medicine for treating various ailments and reported to have broad spectrum of biological activities. The hepatoprotective activity of propolis and constituents from its MeOH extract belonging to various classes were tested on D-galactosamine (D-GalN)/tumor necrosis factor-alpha (TNF-alpha)-induced cell death in primary cultured mouse hepatocytes. The result indicated that hepatoprotective activity of alcoholic extract of tropical Brazilian propolis is mainly due to phenolic compounds including flavonoids. All the four isolated flavonoids possessed stronger inhibitory activity (IC50, < 25 microM) than silibinin (IC50, 39.6 microM) on TNF-alpha-induced cell death. The labdane-type diterpenes isolated from the MeOH extract also exhibited significant hepatoprotective activity in the same experimental model. Moreover, the labdane-type diterpenes and some of the prenylated phenolic compounds possessed antibacterial activity against Helicobacter pylori.

Animals↗
PubMed2001

Quinquenoside L9 from leaves and stems of Panax quinquefolium L.

During additional chemical investigation on the saponin composition of leaves and stems of Panax quinquefolium L, a new minor dammarane saponin, quinquenoside L9 (1) has been obtained. By means of physico-chemical evidences and spectral analysis, its structure was elucidated 6-O-[alpha-L-rhamnopyranosyl-(1-2)-beta-D-glucopyranosyl]-dammara-3beta, 6beta,12beta,20(S),24zeta,25-hexaol (1).

Chromatography, Gel↗