Biomedical subjects

Hiroaki Kiyohara

Publications and source records attributed to Hiroaki Kiyohara.

14 recordsLinked to original sources

PubMed2006

Antimalarial activity of biflavonoids from Ochna integerrima.

During the screening of antimalarial substances, the 80% EtOH extract from the outer bark of Ochna integerrima Merr. (Ochnaceae) was shown to have a good anti-malarial activity (IC50 value: 6.5 microg/mL) whereas extracts from the inner barks of O.integerrima showed no antimalarial activity. Biflavanone (1), which had not been found previously from a natural plant source, was isolated as a potent antimalarial active ingredient (IC50 value: 80 ng/mL) from the extract of the outer barks. The stereoisomer of 1 ( = compound 2) was also isolated from this plant; however, its activity was significantly lower than that of 1.

Antimalarials↗

PubMed2006

Structures and structure-activity relationships of three mitogenic and complement fixing pectic arabinogalactans from the malian antiulcer plants Cochlospermum tinctorium A. Rich and Vernonia kotschyana Sch. Bip. ex Walp.

Structures of three pectic arabinogalactans, one from Vernonia kotschyana (Vk2a) and two from Cochlospermum tinctorium (Ct50A1 and Ct50A2), and their complement fixation and induction of B cell proliferation in vitro were compared. The polysaccharide Vk2a expressed potent biological activity in both assays compared with Ct50A1 and Ct50A2. Vk2a possessed a very high molecular weight (1150 +/- 20 kDa) compared with Ct50A1 and Ct50A2 which both showed a polydisperse nature with the highest molecular weight polymers in each fraction estimated at approximately 105 kDa (Ct1a) and 640 +/- 100 kDa (Ct2a), respectively. The HMW polymers showed complement fixation in the same range as the native fractions. The arabinogalactan II content was low in Vk2a (2%) compared with that in Ct50A1 (23%) and Ct50A2 (12%). The high molecular weight polymers were subjected to digestion with a beta-d-(1, 3)-galactanase-rich fraction from Driselase, oligomers were isolated by HPAEC, and their finer structures were determined by MALDI- and ES-qoToF-MS, linkage, and monosaccharide composition analyses. Vk2a consists of both a galacturonan core and a rhamnogalacturonan core rich in neutral side chains. The backbones of both Ct-polysaccharides consist mainly of RG-I regions with numerous neutral side chains dominated by galactosyl residues, whereas the homogalacturonan regions seem to be small. Differences in the chain lengths of the 6-linked galacto-oligosaccharides attached to the 3-linked galactan core could not be related to the differences in the potencies of the biological activities observed.

Amino Acids↗

PubMed2006

Suppression of Fas-mediated apoptosis of keratinocyte cells by chikusetsusaponins isolated from the roots of Panax japonicus.

Fas-mediated apoptotic cell death of a human keratinocyte cell line, HaCaT cells, and of a murine keratinocyte cell line, Pam212 cells, was suppressed by pre-treatment with a methanol extract from the roots of Panax japonicus C.A. Meyer. Activity-guided fractionation led to the isolation of chikusetsusaponins IV, IVa, V and polysciasaponin P5 as the active ingredients. Of these compounds, chikusetsusaponin IV, was most active when applied at a concentration of 12.5 microg/mL. The intracellular hallmark events of apoptosis such as DNA fragmentation and chromatin condensation were significantly reduced by the treatment with chikusetsusaponin IV. The apoptotic cell death of Jurkat cells was also suppressed by treatment with the active saponins. These results suggest that the use of chikusetsusaponins IV, IVa, V, polysciasaponin P5, or a crude extract of P. japonicus containing these saponins is expected to relieve cutaneous symptoms caused by excessive apoptotic cell death in the skin through the Fas/FasL pathway.

Animals↗

PubMed2005

Structure-immunomodulating activity relationships of a pectic arabinogalactan from Vernonia kotschyana Sch. Bip. ex Walp.

Structure and immunological characteristics of the pectic arabinogalactan Vk2a (previously reported as Vk100A2a) from the roots of Vernonia kotschyana Sch. Bip. ex Walp. were investigated after enzymatic digestion of the galacturonan moiety and the side chains of the rhamnogalacturonan structure of Vk2a. endo-alpha-D-(1-->4)-Polygalacturonase digestion released the high molecular weight 'hairy region' (Vk2a-HR) and oligogalacturonides. Vk2a-HR consisted of GalA (4-linked) and Rha (2- or 2,4-linked) in a 1:1 ratio, with 60% of Rha branched at C-4. The Rha located in the rhamnogalacturonan core was branched randomly by Gal units. Vk2a-HR was rich in neutral sugars such as Araf 5- (12.2%) and 3,5-substituted (12.8%) and terminally- (14.1%) linked and Gal 4- (13.0%), 3- (0.9%), 6- (2.2%) and 3,6- (1.1%) substituted. Arabinans with chain lengths up to 11 units were identified. Araf residues were attached to C-3 of alpha-L-(1-->5)-Araf chains and to C-4 of Gal residues. Single Gal units and chains of beta-D-(1-->6)-linked galacto di- to penta-saccharides were attached to a beta-D-(1-->3)-galactan core. All the enzyme resistant fractions expressed potent complement fixation and induction of B-cell mitogenic activity, and the present study indicates that there may be several and possibly structurally different active sites involved in the bioactivity of Vk2a. The bioactive sites may be located both in the more peripheral parts of the molecule but also in the inner core of the 'hairy region' or in larger enzyme-resistant chains.

Animals↗

PubMed2005

Structural and immunological studies of a pectin and a pectic arabinogalactan from Vernonia kotschyana Sch. Bip. ex Walp. (Asteraceae).

Two polysaccharides, a pectin (Vk100A2b) and a pectic arabinogalactan (Vk100A2a) with mean Mw 2 x 10(4) and 1.15 x 10(6)Da, respectively, were isolated from the dried powdered roots of Vernonia kotschyana Sch. Bip. ex Walp. by hot water extraction followed by fractionation on DEAE-Sepharose fast flow and Sephacryl S-400 HR. The pectin showed low-complement fixation activity and no influence on proliferation of B or T cells, while the pectic arabinogalactan showed a potent, dose-dependent complement fixation activity and a T cell independent induction of B-cell proliferation. Both polysaccharides induced chemotaxis of human macrophages, T cells and NK cells. exo-alpha-L-arabinofuranosidase and exo-beta-D-galactosidase digestion followed by component sugar and methylation analysis indicated that Vk100A2a consisted of a highly branched rhamnogalacturonan core with approximately 50% of the rhamnose 1,2,4-substituted, side chains rich in terminal-, 1,5-linked and 1,3,5-branched arabinose and terminal-, 1,4-, 1,6-linked and 1,3,6-branched galactose. The enzyme resistant part of Vk100A2a still showed strong complement fixating activity, suggesting that this activity may at least in part be expressed by carbohydrate structures present in the enzyme resistant, inner portion of the polymer.

Chemotaxis↗

PubMed2005

Medicinal use of Cochlospermum tinctorium in Mali Anti-ulcer-, radical scavenging- and immunomodulating activities of polymers in the aqueous extract of the roots.

Cochlospermum tinctorium A. Rich. (Cochlospermaceae) is a widely used medicinal plant in the West African country, Mali. An ethnopharmacological survey was conducted and 106 traditional practitioners interviewed. The roots were the part of the plant reported to be the most frequently used for medicinal purposes. The main indications were to treat jaundice (41), gastro intestinal diseases or ailments (28), malaria (12), schistosomiasis (10) and dysurea (6). A high-molecular weight water extract (25, 50 and 100 mg/kg, body weight) significantly inhibited HCl/ethanol-induced gastric lesions in mice. The extract showed DPPH-radical scavenging- and immunomodulating activities in vitro. The main components of the extract were identified as polysaccharides (59.3%) and polyphenols (9.3%). The polysaccharides were purified and characterised as highly complex pectic arabinogalactans type II. As parts of the polyphenol compounds gallotannins and ferulic acids were identified. This study shows that the polysaccharides are partly responsible for the bioactivities observed in vitro. Both polysaccharides and polyphenols may be responsible for the anti-ulcer activities observed.

Adjuvants, Immunologic↗

PubMed2004

Combination Effects of Herbs in a Multi-herbal Formula: Expression of Juzen-taiho-to's Immuno-modulatory Activity on the Intestinal Immune System.

Herbal formulas of traditional Japanese (Kampo), Chinese and Korean medicines usually comprise multiple herbs in a single formula. These medicines are expected to show their clinical effects by chemical, pharmacological and pharmaceutical combination effects of multi-herbs. However, little effort has been made so far to scientifically clarify the nature of such combination effects. Interestingly, for example, though a Kampo medicine Juzen-taiho-to (Shi-Quan-Da-Bu-Tang in Chinese) stimulates the immune functions of Peyer's patch cells, none of its single component herbs shows such activity. We thus examined the combination effect of herbs in the Juzen-taiho-to formula for the expression of its immuno-stimulating activity. Juzen-taiho-to, a composite formula of 10 herbs, has been generally considered to comprise two kinds of basic formula, each of which consists of four different herbs in addition to two others. The combinations of herbs based on these two basic formulas were evaluated for their stimulating activities on cytokine production from murine Peyer's patch cells both in vitro and ex vivo. Combined decoction of six among 10 herbs in Juzen-taiho-to is crucial for the expression of its stimulating activity on Peyer's patch cells. 3D-HPLC analysis of the ingredients in the fractions from the combined decoctions indicated that, in addition to quantitative changes of ingredients, alterations occur in their chemical composition by decoction of different herbs. The stimulating activity of Juzen-taiho-to on Peyer's patch cells results from the combination effect of its six essential component herbs. This combination effect is based on physicochemical interactions among the ingredients of the component herbs.

Journal Article↗

PubMed2004

Structure of oligosaccharide side chains of an intestinal immune system modulating arabinogalactan isolated from rhizomes of Atractylodes lancea DC.

An intestinal immune system modulating arabino-3,6-galactan (ALR-5IIa-1-1) has been found in rhizomes of Atractylodes lancea DC. [Planta Medica 1998, 64, 714-719; Carbohydr. Polyms. 2001, 46, 147-156], however other arabino-3,6-galactans from Larix and Acacia failed to express the modulating activity. Degradation of the galactosyl side chains in Araf-side chain-trimmed ALR-5IIa-1-1 (AF-ALR-5IIa-1-1) with an endo-beta-D-(1-->6)-galactanase remarkably decreased the activity of AF-ALR-5IIa-1-1. Structural analysis indicated that the major endo-beta-D-(1-->6)-galactanase-digestable side chains in ALR-5IIa-1-1 are composed of beta-D-(1-->6)-galactopyranosyl oligosaccharides having d.p. 1-8. Because degradation of the beta-D-(1-->3)-galactan backbone in AF-ALR-5IIa-1-1 also significantly reduced its activity, some of these galactosyl side chains attached to beta-D-(1-->3)-galactan backbone are suggested to be responsible for expression of the activity of ALR-5IIa-1-1.

Atractylodes↗

PubMed2004

Isolation, partial characterisation and immunomodulating activities of polysaccharides from Vernonia kotschyana Sch. Bip. ex Walp.

The roots from Vernonia kotschyana Sch. Bip. ex Walp. (Baccharoides adoensis var. kotschyana (Sch. Bip. ex Walp.) M.A. Isawumi, G.El-Ghazaly & B. Nordenstam) (Asteraceae) are used in Malian folk medicine for the treatment of gastritis, gastro duodenal ulcers, as an aid to ameliorate digestion and as a wound healing remedy. Since a common feature among these conditions is related to immune responses, immunomodulating activities of fractions isolated from both the 50 degrees C and the 100 degrees C water extracts from Vernonia kotschyana were investigated in this study. The active principles were identified as acidic polysaccharide fractions, containing pectic arabinogalactan type II structures, which showed both complement fixing ability and T-cell independent induction of B-cell proliferation in vitro. Some activity was also observed on macrophages. The present study may provide additional support for the popular use of this plant to improve intestinal health.

Animals↗

PubMed2004

In vitro antimalarial activity of biflavonoids from Wikstroemia indica.

In our investigation of in vitro antimalarial screening of medicinal herbal extracts, the n-BuOH extract from the root of Wikstroemia indica showed a potent inhibitory effect. Fractionation of the active extract led to the isolation of two biflavonoids, sikokianin B ( 1) and sikokianin C ( 2) with IC (50) values 0.54 microg/mL and 0.56 microg/mL, respectively, against the chloroquine-resistant strain of Plasmodium falciparum. This is the first report of the biological activity of 1 and 2. As the structure of l has remained unsettled, we confirmed the conformation by (1)H- and (13)C-NMR.

Animals↗

PubMed2004

A novel in vitro infection model of Helicobacter pylori using mucin-producing murine gastric surface mucous cells.

BACKGROUND: Helicobacter pylori is found within the gastric surface mucous gel layer and in the epithelial surface. Gastric cancer cells have been used in experimental H. pylori infection in vitro, although cancer cells have some abnormalities in cellular properties. The aim of this study was to develop an in vitro H. pylori infection model using normal gastric surface cells that produce gastric mucin. MATERIALS AND METHODS: Normal murine gastric surface mucous cells (GSM06) were cultured by the liquid interface method using a serum-free medium and a collagen gel containing a fibroblast cell line (L929) and infected with H. pylori. Infection by H. pylori was assessed by enumerating the colony-forming units (CFU) of H. pylori adhered to GSM06 cells and by transmission electron microscopy. The production of mucin was determined by a lectin binding assay, sugar analysis, and MUC5AC gene expression. RESULTS: GSM06 cells cultured under these conditions produced mucin containing N-acetylgalactosamine and MUC5AC as the core protein. Significantly higher numbers of H. pylori adhered to GSM06 cells under mucin-producing conditions than under nonproducing conditions. Microscopic observation showed a filamentous structure resembling a type IV secretion system apparatus formed between the surface of GSM06 cells and H. pylori. CONCLUSIONS: This study demonstrates a novel in vitro H. pylori infection model using mucin-producing murine GSM06 cells for early stages of infection.

Acetylgalactosamine↗

PubMed2003

Total synthesis and adjuvant activity of all stereoisomers of pinellic acid.

Pinellic acid is a novel and potentially useful oral adjuvant when used in conjunction with intranasal inoculation of influenza HA vaccines. All stereoisomers of pinellic acid have been synthesized via regioselective asymmetric dihydroxylation, regioselective inversion, and stereoselective reduction, and their adjuvant activities were characterized. Among this series of isomers, 9S, 12S, 13S compound has the most potent adjuvant activity. Structure-activity relationships are discussed.

Adjuvants, Immunologic↗

PubMed2002

Galactose-containing polysaccharides from Dictyostelium mucoroides as possible acceptor molecules for cell-type specific galactosyl transferase.

Dictyostelium discoideum has polysaccharides that accept galactose residues by the action of cell-type-specific galactosyl transferase. This paper describes partial purification of the major galactose-accepting polysaccharide that was isolated from the related strain, Dictyostelium mucoroides and proposes its plausible carbohydrate sequences. The most potent acceptor activity was observed in the neutral and Ricinus communis agglutinin (RCA-60) bound galactosaminoglycan, consisting of galactose (Gal) and galactosamine (GalN). However, the acceptor polysaccharides are highly heterogeneous in the reactivity with RCA-120 and in molecular mass. The peak fraction was analyzed by (1)H- and (13)C-NMR studies, methylation analysis, beta-D-galactosidase digestion, controlled Smith degradation and reducing terminal analysis. Based on these results, we tentatively propose the following novel type of the common carbohydrate sequences as the acceptor polysaccharides. [abstract - see text].

Animals↗

PubMed2002

Pinellic acid from the tuber of Pinellia ternata Breitenbach as an effective oral adjuvant for nasal influenza vaccine.

This study describes the isolation, purification, characterization, and adjuvant activity of an orally active adjuvant substance from the tuber of Pinellia ternata, as an active herbal component of the traditional Japanese herbal (Kampo) medicine, Sho-seiryu-to (SST, Chinese name: Xiao-Qing-Long-Tang), which has been reported to show oral adjuvant activity for nasally administered influenza HA vaccine [Int. J. Immunopharmacol. 16 (1994) 605]. The active compound was identified as 9S, 12S, 13S-trihydroxy-10E-octadecenoic acid using infrared spectra, proton magnetic resonance, mass spectrometry, and circular dichroism, and named pinellic acid. Oral administration of pinellic acid (1 microg) to BALB/c mice given primary and secondary intranasal inoculations of influenza HA vaccine (1 microg) enhanced antiviral IgA antibody (Ab) titers 5.2- and 2.5-fold in nasal and bronchoalveolar washes, respectively, and antiviral IgG Ab titers 3-fold in bronchoalveolar wash and serum. Intranasal administration of pinellic acid (1 microg) with influenza HA vaccine (1 microg) slightly enhanced antiviral IgG Ab titers in bronchoalveolar wash and serum but not antiviral IgA Ab titers in nasal and bronchoalveolar washes. Pinellic acid showed no hemolytic activity. The results of this study suggest that pinellic acid may provide a safe and potent oral adjuvant for nasal influenza HA vaccine.

Adjuvants, Immunologic↗