Iwao Toguchida
Kyoto Pharmaceutical University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Iwao Toguchida.
Life Sciences | 2000
Hisashi Matsuda; Tadashi Kagerura; Iwao Toguchida; Hiroki Ueda; Toshio Morikawa; Masayuki Yoshikawa
The methanolic extract from the leaves of Laurus nobilis (bay leaf, laurel) was found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse peritoneal macrophages. Through bioassay-guided separation, fourteen known sesquiterpenes were isolated from the active fraction and were examined for ability to inhibit the NO production. Seven sesquiterpene lactones (costunolide, dehydrocostus lactone, eremanthine, zaluzanin C, magnolialide, santamarine and spirafolide) potently inhibited LPS-induced NO production (IC50 = 1.2 approximately 3.8 microM). Other sesquiterpene constituents also showed the inhibitory activity (IC50 > or = 21 microM), but their inhibitory activities were less than those of sesquiterpene lactones. Alpha-methylene-gamma-butyrolactone also showed inhibitory activity (IC50 = 9.6 microM), while mokko lactone and watsonol A etc., reductants of the alpha-methylene-gamma-butyrolactone moiety by NaBH4 or DIBAL, and a 2-mercaptoethanol adduct of dehydrocostus lactone showed little activity (IC50 > or = 18 microM). These results indicated that the alpha-methylene-gamma-butyrolactone moiety is important for the activity. Furthermore, costunolide and dehydrocostus lactone inhibited inducible nitric oxide synthase (iNOS) induction in accordance with induction of heat shock protein 72 (HSP 72). These results suggested that, as one of their mechanisms of action, sesquiterpene lactones induce HSP 72 thereby preventing nuclear factor-kappaB activation followed by iNOS induction.
Bioorganic & Medicinal Chemistry | 2003
Hisashi Matsuda; Iwao Toguchida; Kiyofumi Ninomiya; Tadashi Kageura; Toshio Morikawa; Masayuki Yoshikawa
The methanolic extract of the roots of Saussurea lappa CLARKE, a Chinese medicinal herb Saussureae Radix, was found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse peritoneal macrophages. Among the constituents from the methanolic extract, two sesquiterpene lactones (costunolide and dehydrocostus lactone) and two amino acid-sesquiterpene conjugates (saussureamines A and B) potently inhibited LPS-induced NO production (IC(50)=1.2-2.8 microM). Saussureamines A and B in addition to costunolide and dehydrocostus lactone did not inhibit iNOS enzyme activity, but they inhibited both induction of inducible NO synthase and activation of nuclear factor-kappaB in accordance with induction of heat shock protein 72.
Bioorganic & Medicinal Chemistry | 2002
Hisashi Matsuda; Toshio Morikawa; Yasuko Sakamoto; Iwao Toguchida; Masayuki Yoshikawa
The methanolic extract from the rhizome of Hedychium coronarium was found to inhibit the increase in vascular permeability induced by acetic acid in mice and nitric oxide production in lipopolysaccharide-activated mouse peritoneal macrophages. From the methanolic extract, three new labdane-type diterpenes, hedychilactones A, B, and C, were isolated together with six known diterpenes. The structures of hedychilactones were elucidated on the basis of chemical and physicochemical evidence. The diterpene constituents showed inhibitory effects on the increase in vascular permeability, nitric oxide production, and inducible nitric oxide synthase induction.
Bioorganic & Medicinal Chemistry Letters | 1999
Hisashi Matsuda; Tadashi Kageura; Iwao Toguchida; Toshiyuki Murakami; Akinobu Kishi; Masayuki Yoshikawa
The methanolic extract from a Chinese herbal medicine, the rhizome of Alisma orientale, was found to exhibit inhibitory activity of nitric oxide (NO) production in lipopolysaccharide (LPS)activated macrophages. Novel triterpenes, alismaketones-B 23-acetate and -C 23-acetate, were isolated from the active extract together with eight sesquiterpenes and eighteen protostane-type triterpenes. The absolute stereostructures of new triterpenes were characterized on the basis of chemical and physicochemical evidence, which included the chemical correlations with known triterpenes. The guaiane-type sesquiterpenes (alismol, orientalols A and C) and protostane- and seco-protostane-types triterpenes (alisols C monoacetate, E-23-acetate, F, H, I, L-23-acetate, and M-23-acetate, alismaketones-B 23-acetate and -C 23-acetate, alismalactone 23-acetate, and 3-methylalismalactone 23-acetate) inhibited LPS-induced NO production (IC50 = 8.4-68 microM). Other triterpenes (alisols A, A monoacetate, B, B monoacetate, E, G, K-23-acetate, and N-23-acetate and 11-deoxyalisol B) also showed the potent inhibitory activity, but they showed cytotoxic effects more than 30 microM (MTT assay). In addition, alismol and alisol F were found to suppress iNOS induction.
Bioorganic & Medicinal Chemistry Letters | 1998
Hisashi Matsuda; Toshiyuki Murakami; Tadashi Kageura; Kiyofumi Ninomiya; Iwao Toguchida; Norihisa Nishida; Masayuki Yoshikawa
The methanolic extract from the roots of Angelica furcijuga KITAGAWA was found to exhibit protective effects on liver injury induced by D-galactosamine (D-GalN) and lipopolysaccharide (LPS). From the methanolic extract, seventeen coumarins, two phenylpropanoids, and two polyacetylenes were isolated and examined their in vitro and in vivo hepatoprotective effects and inhibitory activity of NO production in macrophages. A acylated khellactone, isoepoxypteryxin, showed protective activity against D-GalN-induced cytotoxicity in primary cultured rat hepatocytes. On the other hand, six acylated khellactones (hyuganins A, B, C, and D, anomalin, isopteryxin) and two polyacetylenes [(-)-falcarinol and falcarindiol] strongly inhibited NO production induced by LPS in cultured mouse peritoneal macrophages, and also other acylated khellactones (isoepoxypteryxin, pteryxin, and suksdorfin) and a coumarin glycosides (praeroside II) were found to show the activity. By comparison of the inhibitory activities for acylated khellactones with those for other coumarins, acyl groups were found to be essential to exerting potent activity.
Bioorganic & Medicinal Chemistry | 2002
Jing Tao; Toshio Morikawa; Iwao Toguchida; Shin Ando; Hisashi Matsuda; Masayuki Yoshikawa
Three new biphenyl type diarylheptanoid glycosides, myricanol 11-O-beta-D-glucopyranoside, myricanone 5-O-beta-D-glucopyranoside, and neomyricanone 5-O-beta-D-glucopyranoside, and a new taraxerane type triterpene, myricetrione, were isolated from the bark of Chinese Myrica rubra. Their structures were elucidated on the basis of chemical and physicochemical evidence. Biphenyl type diarylheptanoids, triterpene, and their polyphenols showed potent inhibitory effects on nitric oxide production in lipopolysaccharide-activated macrophages. Furthermore, diarylheptanoids, myricanol and myricanone, were found to inhibit induction of inducible nitric oxide synthase.
Bioorganic & Medicinal Chemistry Letters | 2001
Osamu Muraoka; Manabu Fujimoto; Genzoh Tanabe; Michinori Kubo; Toshie Minematsu; Hisashi Matsuda; Toshio Morikawa; Iwao Toguchida; Masayuki Yoshikawa
Novel 14-norcadinane-type sesquiterpenes, oxyphyllenodiols A and B, and 11,12,13-trinoreudesmane-type sesquiterpenes, oxyphyllenones A and B, were isolated from the methanolic extract of kernels of Alpinia oxyphylla. The absolute stereostructures of these norsesquiterpenes were determined on the basis of physicochemical and chemical evidence. In addition, oxyphyllenodiol A and oxyphyllenone A were found to inhibit the NO production in lipopolysaccharide-activated macrophages.
Heterocycles | 2002
Hisashi Matsuda; Toshio Morikawa; Yasuko Sakamoto; Iwao Toguchida; Masayuki Yoshikawa
Three new labdane-type diterpenes named hedychilactones A, B, and C were isolated from the methanolic extract of the fresh rhizome of Hedychium coronarium KOENG. Their structures were elucidated on the basis of chemical and physicochemical evidence, which included the application of the allylic benzoate rule. The methanolic extract and diterpene constituents were found to inhibit the increase of vascular permeability induced by acetic acid in mice and nitric oxide production in lipopolysaccharide-activated mouse peritoneal macrophages.
Chemical & Pharmaceutical Bulletin | 2002
Hisashi Matsuda; Toshio Morikawa; Iwao Toguchida; Masayuki Yoshikawa
Bioorganic & Medicinal Chemistry | 2003
Hisashi Matsuda; Toshio Morikawa; Shin Ando; Iwao Toguchida; Masayuki Yoshikawa