著者

村岡 修 田邉 元三 森川 敏生 二宮 清文 松田 久司 吉川 雅之

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no.51, pp.1-6, 2009-09-01

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Salacinol and kotalanol are new class of potent glycosidase inhibitors, isolated by presenters from Ayruvedic traditional medicine Salacia reticulata, having the unique zwitter-ionic structure comprising of 1-deoxy-4-thio-D-arabinofranosyl cation and the sulfate anion in the alditol side chain. Elucidation of the stereostructure of kotalanol, which has long been unknown and very recently approved by Pinto and co-workers by the synthesis, by the independent manner involving the degradation of natural kotalanol is presented. In the detradation of 2, characteristic deprotective cyclization of heptitols to anhydroheptitols was found to occur to a large extent. Structural elucidation of salalprinol, one of the sulfonium analogs recently isolated from the same species, by the synthesis is also presented. Revisions of the structures of new constituents from Salacia species, neosalacinol and 13-membered cyclic sulfoxide, recently reported as constituents responsible for the α-glucosidase inhibitory activity by Minami and Osaki and co-workers, respectively, are presented. In relation to this study, synthetic route of de-O-sufonated salacinol, which was proved as potent as 1, has been developed. Finally, conditions for the quantitative analysis of 1, 2, and their de-O-sulfonates (3 and 4) by LC-MS for the qualitative evaluation of Salacia extracts is discussed.

著者

上江田 捷博 上村 大輔 平田 義正 高野 敏

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no.21, pp.245-252, 1978-08-22

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The isolation and structure elucidation of palytoxin, a potent coelenterate toxin, have been studied. Though palytoxin was not obtained as a crystalline form, the structures of λ233 and λ263 chromophores in palytoxin were determined. Oxidation of toxin with NaIO_4 was suitable for elucidation of these chromophores and the positive part to ninhydrin in palytoxin. On the other hand, in the course of our studies on toxin of Palythoa tuberculosa we have isolated four compounds (3), (4), (5), and (6) characterized by their absorption maxima at 310nm, 320nm, 332nm, and 360nm, respectively. Structures of these compounds and a 334nm UV-absorbing substance (7) isolated from Porphyra species were established.

著者

田中 正泰 針ヶ谷 弘子 鎌田 樹志 氏原 一哉 橋本 勝 橋本 貴美子 松田 冬彦 柳屋 光俊 白濱 晴久 奥野 智旦

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no.34, pp.110-117, 1992-09-10

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Ohwaraitake is Japanese name of a poisonous mushroom Gymnopilus spectabilis and means "a loud laugh mushroom". Accidental ingestion of it causes hallucinosis and abnormal behavior. A hallucinogenic mushroom contains usually psilocybin or its analogues but it is reported that any psilocybin or its congenor does not found in Japanese Ohwaraitake. The toxic symptoms suggest that any neuroexcitatory substance must be contained. The isolation was carried out monitoring depolarizing activity on the new born rat spinal cord. 1. Chromatographical fractionation and bisassay showed that the neuroexcitatory active compounds were gimnopilins (G) which were known as bitter principles of this fungus. Further fractionation revealed that G (1) was inactive and activities of G (2) increased from n=7 to n=5 and besides, G (2), which was newly isolated this time, was more active than G (2). 2. The structure of the new G was determined by the chemical degradation as formula 3. 3. The Chirality of hydroxymethylglutamic acid (HMGA) part was determined as S configuration by the acquisition of (R)-mevalonaloctone through LiBH4 reduction or G (1 and 2). 4. G (2) does not work as an ion carrier probably, since it does not particularly take metal ion from aqueous solution into an organic solvent. 5. Determination of the chirality of tert-alcohols in gymnoprenol (G'), that is, G without HMGA part, was attempted. Eight isomers of the model compounds corresponding to G' (m=2, n=4) were synthesized and were not discriminated by HPLC and NMR. Since two diastereoisomers of MTP-ethoxy-methoxy derivatives of G' (m=1, n=2) were distinguished by ^1H and ^<19>FNMR, these derivatives may be applicable to identification of the synthetic and the natural G'.

著者

原 修 中尾 一成 棚田 喜久 西尾 東 松原 淳 横川 文明 濱田 康正 塩入 孝之

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no.32, pp.617-624, 1990-09-25

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Calyculins having high cytotoxicity were isolated from the marine sponge Discordermia calyx in the Gulf of Sagami. Calyculin A (1), the major cytotoxic constituent, has 15 chiral centers, a spiroketal bearing phosphate, an oxazole ring, and a nitrile conjugated with all (E)-tetraene. However, its absolute stereostructure has remained uncovered. Interestingly, calyculin A (1) exhibits antitumor activity against Ehrlich and P-388 leukemia in mice. Its unique complex structure as well as its intriguing biological activity led us to investigate the total synthesis of 1, which will determine the absolute configuration of 1 as well. Retrosynthetic analysis has revealed that 1 would be constructed from four fragments A, B, C, and D, shown in Chart 1. Fragments A and B could be prepared by stereoselective reduction of tetronic acid derivatives 11 and 24, respectively. Fragments C and D were prepared from amino acids utilizing the methodology developed by us earlier.

著者

矢原 正治 金城 順英 下川 隆志 野原 稔弘 山原 條二 千坂 武司

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no.27, pp.726-733, 1985-09-07

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We have examined the constituents of three crude drugs showing an antihypercholesteremic activity. 1) Daemonorops draco --- D-7 was obtained as an active substance. It was further separated into two compounds (D-7-I,II) being the isomers each other and their substances were deduced to be the deoxy-proanthocyanidins by the spectral data. 2) Caesalpinia sappan --- Total nineteen compounds relating to brazilin were isolated and the chemical structures of fourteen compounds among them were discussed by the spectroscopic means. SO-k, g,e were the 3-benzyl-chroman-4-one derivatives; SO-i,b,c were shown to be the first examples of the 3-benzyl-chroman-4-ol derivatives and assumed to be the key-intermediates on the biogenetic route of brazilin; All of SO-j,p,SLC-b,c,d presented new novel framework-models among the naturally occurring compounds. SO-j was suggested to be produced from SO-i,b,c by oxidative coupling, SO-p was presumed to be derived from brazilin by oxidative fission. SLC-b,c,d were considered to be originated from brazilin. SLC-b was effective for antihypercholesteremia. 3) Dalbergia odorifera --- Five aromatic compounds, DO-I-V, were isolated from the active fraction and their structures were revealed to be the unique bi-isoflavanoids by the various spectral data.

著者

上原 忠夫 大沼 俊雄 鈴木 赳 加藤 忠弘 吉田 利男 高橋 勝宏

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no.22, pp.235-242, 1979-09-20

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From a higher boiling fraction (Bp>100℃/8 Torr) of peppermint oil (Mentha piperia L.) was isolated a white crystalline (mp 59-61℃, 300 mg from 80 g of the fraction) having a molecular formula of C_<15>H_<24>S. The structure of the crystalline was unequivocally determined by X-ray crystallographic analysis and we named it mintsulfide (1)(abbreviated as MS). Ultraviolet irradiation (Pyrex filter) of (-)-germacrene D (2)(abbreviated as GD), one of the major components of the oil, in the presence of sulfur powder afforded the mintsulfide (1), thus demonstrating the absolute configuration of MS. The mintsulfide was converted into the isomer (4). Both 1 and 4 were oxidized to give the products (5〜10), which showed the chemical shifts in the NMR spectra as summarized in table 1 and 2. Table 3 indicates the results of photochemical conversion of GD (2), giving MS (1) and/or β-bourbonene (3) under the various conditions. The evidence in table 3 suggests that activated sulfur (sulfur atom ?) is generated first under the Pyrex filtered irradiation. The activated sulfur reacts with GD, leading the formation of MS (1). This novel photoreaction is substrate specific since presence of caryophyllene (12) or β-bourbonene (3) affects no influence. The preliminary experiments revealed that myrcene (13) and tenmembered diene (14) also react with the photo-activated sulfur.

著者

アウン ニン・タンダ 二改 俊章 小森 由美子 野々垣 常正 高谷 芳明 丹羽 正武

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no.52, pp.607-612, 2010-09-01

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Monpanoki (Argusia (or Messerschmidia or Tournefortia) argentea (Boraginaceae)) is locally used in Okinawa in Japan as an antidote for poisoning from snakes venoms, Trimeresurus flavoviridis (habu). A methanolic extract of the plant significantly inhibited hemorrhage induced by crude venom of Trimeresurus flavoviridis. The extract was then separated according to antivenom activity by using silica gel (ODS) column to afford rosmarinic acid (RA) (1) as an active principle. RA (1) significantly inhibited the hemorrhagic effect of crude venoms of T. flavoviridis, Crotalus atrox, Gloydius blomhoffii, Bitis arietans as well as snake venom metalloproteinases, HT-b (C. atrox), bilitoxin 2 (Agkistrodon bilineatus), HF (B. arietans), and Acl-proteinase (Deinagkistrodon acutus). This is the first report of the antihemorrhage activity of RA (1) and RA (1) greatly contributes to the antihemorrhagic efficiency of this plant against crude snake venoms and hemorrhagic toxins. Furthermore, mechanistic evidence of RA's neutralization of the hemorrhagic effects of snake venom was invesitigated. Inhibitions against fibrinogen hydreolytic and collagen hydrolytic activities of T. flavoviridis venom were examined by SDS-PAGE. Histopathological study was done by using microscope afer administration of venom with or without RA. RA was found to markedly neutralize venom-induced hemorrhage, fibrinogenolysis, cytotoxicity and digestion of type IV collagen activity. Moreover, both hemorrhage and neutrophil infiltrations were inhibited by RA, although both were observed in pathology sections administered only T. flavoviridis venom. These results demonstrate that RA inhibited most of the hemorrhage effects of venom. These findings indicate that rosmarinic acid can be expected to provide therapeutic benefits in neutralization of snake venom accompanied by heat stability.

著者

川松 豊 杉原 弘貞 佐々木 希吉 森本 浩

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no.13, pp.99-106, 1969-09-01

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I. Synthesis of 2,3-dialkoxy-5-alkyl-1,4-benzoquinone a) 4a and 4b obtained from 1 were oxidized with organic peracids to give 2,3-dimethoxy-(5a) and 2,3-diethoxy-5-methyl-1,4-benzoquinone (5b). b) 9a and 9b obtained from 6 were oxidized in a similar manner to give 5a and 10. II. Synthesis of isoprenoid quinones The authors found two new condensation methods. a) Method using an N-sulfinylamine. A solution of hydroquinone (12), methyl N-sulfinylanthranilate (14) and phytol (13) in dioxane was heated and oxidized with ferric chloride to give 2,3-dimethoxy-5-methyl-6-phytyl-1,4-benzoquinone (15) as well as by-products 16 and 17. The structures of 16 and 17 were made clear and the reaction mechanism was discussed. The results are shown in Table 1. b) Method using a metal. A solution of 5a and X-CH_2-CH=C-CH_3-CH_2-R in petroleum ether was treated with slightly an excess amount of amalgamated zinc at the room temperature to give 18. The product 18 was obtained also from hydroquinone (12). The reaction mechanism and the results are shown in Table 2. III. Stereochemistry of isoprenoid quinones It has been so far known that the steric configuration of the side chain of naturally occurring isoprenoid quinones is all-trans, but synthesized isoprenoid quinones inevitably contain a small amount of the cis-isomer. Then, the authors separated these isomers by the column chromatography to confirm their yields and to compare their NMR spectra with each other. The relationship between the structures of the quinones and the biological activity is also mentioned.

著者

吉田 将人 大澤 宏祐 高木 基樹 広川 貴次 植草 義徳 加藤 晃一 新家 一男 夏目 徹 土井 隆行

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no.53, pp.241-245, 2011-09-02

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Thielocin B1 (1), isolated from the fermentation broth of Thielavia terricola RF-143 in 1995, consists of five multi-substituted benzene rings, which are connected with a 2,2', 6,6'-biaryl ether and four ester linkages. Recently, it was found that 1 strongly inhibits protein-protein interactions (PPIs) of PAC3 homodimer (IC_<50>= 0.02 μM) without inhibition of other PPIs such as PAC1/PAC2 or TCF/P-catenin. Since we are interested in the mode of action mechanisms of 1, we performed total synthesis of 1, and docking studies by NMR and in silico analyses. The key intermediate 2,2', 6,6'-biaryl ether 4 was synthesized from 7-membered lactone 6, which was prepared by oxidative lactonization of benzophenone 7, followed by chemoselective reduction of the lactone and removal of the resulting alcohol. The side wing 5 was synthesized from aldehyde 8 via formation of 3 and its coupling by esterification. Condensation of biaryl ether 4 and 5 was smoothly performed using trifluoroacetic anhydride to afford 21 in high yield. Formylation of 21 by treatment with dichloromethyl methyl ether and AgOTf, followed by Kraus oxidation provided acid 2. Coupling of the resulting acid 2 with phenol 3 afforded 22 in 70% yield. Finally, removal of the benzyl groups by-hydrogenation furnished thielocin B1 (1), whose spectral data were in good agreement with those of the natural product.

著者

岡部 光 宮原 由美 山内 辰郎

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no.24, pp.95-102, 1981-09-10

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An extensive survey for the triterpenoid constituents of Momordica charantia L. has been carried out in this laboratory, and so far, five glycosides (momordicosides A-E) of cucurbit-5-ene derivatives were isolated from the seeds, and their structures were determined. They are unique cucurbitacins being highly oxygenated only in the side chain and having no oxygen function at C_<11>. This study concerns the structure elucidation of two bitter glycosides, momordicosides K and L, and four non-bitter glycosides, momordicosides F_1, F_2, G and I isolated from the fruits. The structure of F_1 was proposed as 3-O-β-D-glucopyranoside of 5,19-epoxy-25-methoxy-5β-cucurbita-6,23-dien-3β-ol on the basis of PMR, CMR and CD spectral data and chemical conversion into a cucurbit-5-ene derivative. G is the corresponding β-D-allopyranoside. F_2 and I are the C_<25>-OH derivatives corresponding to G and F_1, respectively. K and L were determined as 7-O-β-D-glucopyranosides of 19-oxo-25-methoxy-cucurbita-5,23-diene-3β, 7β-diol and its C_<25>-OH derivative, respectively, on the basis of spectral data and chemical correlation with F_1-aglycone. F_1, F_2, G and I are the first cucurbitacins having 5β-cucurbitane nucleus found in nature, and K and L are noted as the new cucurbitacins having C_9-aldehyde and 7-O-β-D-glucopyranosyl groups. Among momordicosides, G and F_2 are the first triterpenoid glycosides having D-allose as a component sugar.

著者

志津里 芳一 山口 修 松永 公浩 玉木 和彦 山村 庄亮 寺田 幸正

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no.29, pp.333-340, 1987-07-25

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Two sex pheromones of the American cockroach, periplanone A and B, have been isolated by Persoons et al. The structure of the latter was proposed by the same authors, and then its stereostructure including the absolute configuration was unambiguously determined by its synthesis. Furthermore, the structure (1) of periplanone A has been proposed by Persoons et al., on the basis of its spectral data together with some chemical evidence, but the stereochemistry was not known. In order to elucidate the structure of periplanone A, the authors have synthesized two possible hydroazulenones (5 and 6) from germacrene-D by using biomimetic transannular reactions as a key step. However, the spectral data of synthetic compounds were entirely different from those of natural one. Therefore, the ^1H NMR and IR spectral data of periplanone A and its rearrangement product were reexamined, consequently, the structures of both compounds were found to be resembled each other. Clearly, the structure of periplanone A, which is quite labile as compared with the rearrangement product, seems to be represented by one of the possible decalones (I or II), while the latter must be depicted by III or IV. As shown in Table 1 and 2, the coupling constants based on the conformations I and III, obtained from molecular mechanics calculations, were compatible with the observed ones for periplanone A and rearrangement product, respectively. Thus, the stereostructure of periplanone A was elucidated as I.

著者

丹羽 正武 寺田 幸正 井口 正信 山村 庄亮

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no.23, pp.96-103, 1980-09-10

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From a biogenetic point of view, many sesquiterpenes are considered to be derived from germacrenes or germacrones as an important precurser, and their conformations have been discussed in connection with their transannular reactions as well as with thermal isomeizations. Thus, molecular mechanics calculations were successfully carried out to evaluate relative stabilities of each conformation of several germacrenes in their ground states and transition states. Particularly, molecular mechanics calculation was carried out successfully in the case of thermal reaction of acoragermacrone, and also attempted for the acid-catalyzed reaction of preisocalamendiol leading to the formation of isocalamendiol, although the result so far obtained was not necessarily satisfied. On the basis of the above results, acid and base-catalyzed reactions of epoxygermacrene-D were carried out to give many interesting compounds similar to oppositol, axisonitrile-1, periplanone-A, junenol and so on. Reaction process of these compounds is also presented.

著者

飯島 崇士 毛利 圭宏 提箸 正義 山田 大士 服部 恭尚 濱渦 康範 加茂 綱嗣 廣田 満 清田 洋正 真壁 秀文

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no.51, pp.289-294, 2009-09-01

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1. Synthesis of procyanidin B1-B4(1-4). Stereoselective synthesis of catechin and epocatechin under intermolecular condensation of equimolar amount of catechin derivatives catalyzed by Yb(OTf)_3. The coupled products were successfully converted to procyanidin B1 (1), B2 (2), B3 (3), and B4 (4), respectively. 2. synthetic of (-)-epicatechin 3-(3"-O-methylgallate) (13) and (+)-catechin 3-(3"-O-methylgallate) (14) A concise synthesis of (-)-epicatechin 3-(3"-O-methylgallate)(13, ECG3"Me), which is a minor constituent of tea, and (+)-catechin 3-(3"-O-methylgallate)(14, CG3"Me) via condensation of equimolar amount of catechin and gallate derivatives has been achieved. The anti-inflammatory effect of the synthetic compounds on TPA-induced inflammation of mouse ears was examined. Compounds 13 and 14 suppressed the TPA-induced inflammation of mouse ears by 50% and 43%, respectively, at a dose of 200μg. 3. Short step synthesis of resveratrol derivative. An efficient synthesis of trimethoxylated resveratrol (20) is presented using advanced Heck reaction promoted by Pd(dba)_2 in the presence of P(t-Bu)_3.

著者

工藤 雄大 此木 敬一 長 由扶子 安元 健 山下 まり

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no.53, pp.367-372, 2011-09-02

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Tetrodotoxin (TTX) is distributed in wide range of animals, marine puffer fish and terrestrial newts and frogs, for examples. We have isolated various TTX analogs from these animals, and attempted to obtain clues to biosynthetic pathway of TTX from the structures of these analogs. Here we isolated four new analogs of TTX from the Okinawan newt Cynops ensicauda popei, and determined their structures as 8-epi-5,6,11-trideoxyTTX, its 4,9-anhydro derivative, its 1-hydroxy derivative, and its 1-hydroxy-4,4a-anhydro derivative, by spectroscopic method. These analogs are not detected in puffer fish, instead, 5,6,11-trideoxyTTX is detected as a major analog in puffer fish eggs. 1-Hydroxy type analog might be specific to newts, since 1-hydroxy-5,11-dideoxyTTX was previously isolated from the other species of newt, Taricha granulosa, by other group. This is the first identification of 4,4a-anhydro type analog of TTX from the natural source.

著者

平田 義正 江口 昇次 下村 脩

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no.3, pp.83-93, 1959-10-17

著者

鈴木 智大 川口 卓巳 天野 裕子 小林 夕香 森田 達也 長井 薫 新井 信隆 河岸 洋和

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no.48, pp.325-330, 2006-09-15

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In autumn, 2004, 55 people got poisoned by eating an edible wild mushroom, Pleurocybella porrigens (Sugihiratake in Japanese) and 17 people among them died of acute encephalopathy. We found that mice died by injection of the wter-soluble extracts of the mushroom. We tried the isolation of the toxic principle(s) from the extracts. As a result, a lectin (PPL) and a glycoprotein were purified from the mushroom. PPL is a tetramer of identical subunits without S-S linkage. The lectin specifically bound N-acetylgalactosamine among monosacchrides tested. This lectin showed lethal toxicity against rats. In addition, a glycoprotein was isolated as a lethal toxin against mice and rats. The relation between these substances and acute encephalopathy is now being elucidated.

著者

丸山 雅雄 寺原 昭 中平 靖弘 Woods M. C. 板垣 又丕 高木 良子 中西 香爾

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no.10, pp.238-245, 1966-09-15

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From the root bark of Ginkgo biloba L. ("icho" in Japanese), a unique fossil tree which has remained unchanged for 1-2 million years, four bitter principles designated ginkgolides A, B, C and M (for "minor") (abbreviated to GA, GB, GC and GM) have been isolated. Early work was greatly hindered by purification problems and polymorphism, but the molecular formulae were finally settled by high resolution MS of GA dimethyl ether (Fig. 1). As shown in Fig. 2, a tert-Bu group is present; these are the first plant products to contain such a group. Establishing the number of lactone groups presented difficulty, but was achieved by titration according to Method B (Fig. 3). The partial structure comprising rings A/B was elucidated from the data summarized in Figs. 5 and 6. NMR analysis of the isolated 4 proton system E-H (Fig. 7) was simplified in GC because of an additional 2°-OH group. The bislactone system containing H_J was clarified (Figs. 8-10) by an NMR analysis of GA-triether utilizing extensively the techniques of solvent shifts and decoupling, and comparison with the triether-d_6 spectrum which resembles the GA spectrum (Fig. 13). An attempt to determine the number of lactone rings was made by measuring the M^+ and isotope peaks of GA dimethyl ether (Fig. 11), the lactone rings of which had been cleaved and recyclized in the presence of H_2O^<18> as depicted in Fig.13-Method B. However, the MS indicated that only two lactones had incorporated O^<18>; presumably, one of the lactones had been cleaved by O-alkyl fission and recyclized by expulsion of O^<18>H. Alkali fusion of GA gave two important bisnor products, but these are not discussed in the Abstract because of limitations of space. Part structures shown in Fig. 12 are proposed for the ginkgolides.

著者

松浦 正憲 加藤 優 犀川 陽子 乾 公正 橋本 貴美子 中田 雅也

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no.50, pp.415-420, 2008-09-01

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Accidental ingestion of a toadstool, Russula subnigricans causes lethal poisoning to human. In the 1950's, the first poisoning caused by this mushroom was reported. Since then there have been no reports about lethal poisoning for 50 years, which was enough to raise doubts about its existence. However, in these three years, 2005 to 2007, the poisoning accidents were continuously happened and four people died. Although chemical studies on this fungus were reported using mushrooms distributed in Miyagi prefecture, the isolated compounds, russuphelins, russupherol, and hydroxybaikiain, have no toxicity on mouse. Accordingly, we studied the isolation of the toxic constituent of R. subnigricans. One of the reasons that such a strong toxin has not been revealed until now is the incomplete classification of this mushroom, that is, there are many resemble species distributed in Japan. We collected three species in Kyoto, Miyagi, and Saitama prefectures. The aforementioned compounds were found only in the Miyagi species. All three species show toxicity on mouse by intraperitoneal injection of the water extract; however, only the Kyoto species exhibits toxicity by oral injection. Accordingly, we estimated that the Kyoto species is the genuine R. subnigricans. During the separation steps, we found that the toxicity was remarkably decreased after concentration to dryness; therefore, all manipulations were carefully performed. The water extract was successively separated through ODS column chromatography, ion exchange chromatography, and gel filtration to give an aqueous solution of the toxic compound. The toxic compound was revealed to be unstable under concentration to dryness (polymerization occurs) and volatile, which was turned out to be the cause of decrease in toxicity after evaporation. The unstable toxin was converted to a stable derivative using diphenyldiazomethane. Taking ^1H, ^<13>C NMR and MS spectral analyses of the toxic compound and its derivative into consideration, the structure of the toxic compound was determined to be cycloprop-2-ene carboxylic acid. This compound was found only in the Kyoto species.

著者

福井 祐子 岩下 孝 浅見 純生 野中 裕司 前田 満 橋本 文雄 木曽 良信

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雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

no.50, pp.475-480, 2008-09-01

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Oolong tea is a semi-fermented tea, which has been manufactured from leaves of Camellia sinensis (L) O. Kuntze, same as non-fermented Japanese or Chinese green teas. Major components of fresh tea leaves are caffeine and catechins such as epigallocatechin-3-O-gallete (EGCG). During the fermentation process, polyphenol oxidase (PPO) in tea leaves oxidizes the catechins into theasinensin and oolongtheanin. In addition, oolonghomobisflavans are known as condensation products of catechins by heat treatment. The aim of this study is to quantify these minor polymerized polyphenols by LC-MS/MS, and address their biological activities. Quantification of polyphenols by LC-MS/MS Theasinensin (TSN), oolongtheanin gallate (OTNG), and oolonghomobisflavan (OHBF) were synthesized from EGCG. Two new trimers and tetramers of oolonghomobisflavan were synthesized along the previous synthesis method of OHBF, and then their structures were determined by MS and NMR spectroscopy. Quantification of these compounds was performed by LC-MS/MS in the mode of multiple reaction monitoring (MRM). Compounds other than TSN-A were of small quantities in oolong tea leaves. Quantification of polymerized polyphenols was not performed with HPLC UV monitoring, but by LC-MS/MS method. Nine kinds of oolong teas in different fermentation levels were extracted and analyzed. The very small amount of trimers and tetramers of OHBF were included in "Black oolong tea", therefore, it was necessary to make concentrated solutions of these by column separation, and quantified the real amount by analyzing them. Biological activities of polymerized polyphenols Pancreatic lipase inhibitory activity of oolong tea polymerized polyphenols (OTPP) and some catechin dimmers have been already reported. In this study, new trimers and tetramers also exhibited strong inhibitory activity. Besides OTPP, the polymerized polyphenols, TSN, OTNG, and OHBF also have α-glucosidase inhibitory activity. These results suggest that oolong tea prevents the elevations of triglyceride in blood from meal fat, as well as inhibit the absorption of sugars derived from carbohydrates.

著者

竹内 純 甲斐 建次 片岡 太一 横山 峰幸 渡辺 修治

出版者

天然有機化合物討論会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

no.50, pp.439-444, 2008-09-01

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In the course of screening for endogenous flowering inducer, α-ketol of octadecadienoic acid (KODA, Figure1) was isolated from Lenma paucicostata. KODA showed the activity after reacting with norepinephrine (NE) under the basic conditions. Further investigations have revealed that FN1 is a major active compound, which is expected to be formed by cycloaddition between 12-olefin of KODA and α, β-unsaturated carbonyl of noradrenochrome, an oxygenated form of NE. However, the mechanism of flower-induction of FN has not been examined. In present study, we carried out the structure-activity relationship study of the fatty acid moiety of FN for flowering in L. paucicostata by using series of KODA analogs shown in Figure 2. Firstly, we synthesized nine fatty acid analogs, where single or combinative alterations have been made to the structural components of KODA and tested for their ability to induce flowering. With the exception of compounds 8, 10, 12, all these analogs proved to have a flowering activity after reacting with NE. Compound 4, in which 15-olefinic bond is saturated, displayed high activity of same magnitude as KODA. This suggested that olefinic bond at 15-position in KODA in not important for activity. Compounds 7 and 9 displayed a significant activity but less in magnitude as the parent KODA. This implied that 9-hydroxy group may not be involved in primary recognition of the target whereas the presence is favorable to show high activity. Compounds 5 and 6, in which their alkyl chains are shortened, displayed flowering activity at a concentration of more than 1μM. In addition to this, the biological result obtained with methyl ester 11 indicated that recognition of the aliphatic chain and terminal carboxy group in FNs is relatively obscure. On the other hand, compounds 8, 10, and, 12, changing of β, γ-unsaturated carbonyl moiety led to complete loss of activity in L. paucicostata. This result showed that cycloaddition of fatty acid with NE is inevitable process to induce flowering in L. paucicostata. Furthermore, to obtain clearly insight in the structural requirements of FN1 for flower inducing activity, we prepared FN derivatives from corresponding fatty acid analogs and evaluated their activity.