Metabolism and pharmacokinetics of paeoniflorin, a bioactive component from Peony roots

Paeoniflorin (PF, yield up to 5.8% of the dry weight) is the major and the most important component of peony roots. Recent studies demonstrate that PF improves the spatial and memory deficits in rodents and suggest possible utilization of this agent in the treatment of certain types of dementia. The understanding of the metabolism and pharmacokinetics of this agent may provide insights into the mechanism of its effects. Due to the poor absorption from intestine, PF is subjected to the metabolism to give three metabolites, by intestinal bacteria. Paeonimetabolin I (PM-I), the major intestinal bacterial metabolite of PF showed anticonvulsant action. And in the presence of thiol compounds, intestinal bacteria were found capable of transforming PF to more potent anticonvulsant thiopaeonimetabolin-I derivatives. The pharmacokinetics of PF and PM-I were investigated in rats by enzyme immunoassay (EIA), and were dose-dependent. PM-I was not detected in the rat plasma after intravenous (i.v.) administration of PF, and a significant difference in the plasma concentration of PM-I was observed between germ-free and conventional rats. After oral and i.v. administration of PM-I to rats, it was found at high concentrations in the plasmaこの論文は国立情報学研究所の学術雑誌公開支援事業により電子化されまし

Confirmation that Luobuma ameliorates the deterioration of antioxidant defense in senescence-accelerated mice

To determine whether Luobuma extract ameliorates the deterioration in antioxidant defense with aging, the effect of Luobuma extract was investigated in senescence-accelerated mice (SAM). In comparison with AKR/N Slc mice, a strain consistent with SAM but exhibiting normal aging, SAM treated with extract showed a lower glutathione (GSH) and glutathione/glutathione disulfide (GSH/GSSG) ratio in the liver and kidney, and increased levels of malondialdehyde (MDA), a lipid peroxidation product. Administration of Luobuma extract increased the GSH level and GSH/GSSG ratio, and suppressed MDA production. On the other hand, the reduced activities of hepatic superoxide dismutase (SOD), glutathione peroxidase and glutathione reductase participating in the glutathione redox cycle were increased significantly by administration of Luobuma extract. A significant increase in renal SOD activity was also observed. In addition, the increased level of MDA in hepatic tissue was reduced in SAM given Luobuma extract. These findings indicate that Luobuma extract helps to ameliorate oxidative stress in SAM. 羅布麻エキスが老化における酸化防御機構にいかなる影響を及ぼしているかについて,老化促進マウス(SAM)を用い検討した。SAMと同じ系統ではあるが,通常の老化過程を辿るAKR/N Slcマウスに比べ,SAMでは肝,腎組織中のグルタチオンレベルとグルタチオン/グルタチオンジスルフィド比は低下し,脂質過酸化物のマロンジアルデヒドは逆に増加していた。一方,羅布麻エキスを投与したSAMでは,これらパラメーターがいずれも改善し,グルタチオン酸化還元サイクルに関係している肝組織中のスーパーオキシドジスムターゼ,グルタチオンペルオキシダーゼ,グルタチオンレダクターゼ活性と腎組織中のスーパーオキシドジスムターゼ活性が有意に上昇していた。また肝組織中のマロンジアルデヒドも低下し,SAMで認められた酸化的ストレス状態を羅布麻エキスが緩和していた

Transformation of shikonin by a cell-free extract of Eubacterium sp. A-44, a human intestinal bacterium

For the purpose of investigating the metabolic processes of shikonin (1) by human intestinal bacteria, we prepared a sonicated bacterial cell suspension and a crude enzyme preparation from Eubacterium sp. A-44, one of the intestinal bacteria capable of transforming 1 to various metabolites. After anaerobic incubation with the suspension for 1 hr, most of 1 was transformed to prometaboshi-konin (2), and metaboshikonins I (3) and II (4). However, under aerobic conditions, the dimers, shikometabolins A (5) and B (6), were predominantly formed. In the presence of the crude enzyme preparation, formation of 2-4 was inhibited by oxygen, but markedly enhanced by the addition of NADH. On the other hand, formation of 5 and 6 was appreciably accelerated by the addition of NAD^+. In the absence of the crude enzyme preparation, NADH and/or NAD^+ showed no ability to transform 1 to the any metabolites, as in the case of a thermally inactivated preparation. Accordingly, the two different metabolic processes leading to compounds 2-4 and com-pounds 5 and 6 by Eubacterium sp. A-44 are concluded to be enzyme-dependent in the presence of NADH and NAD^+. ヒト腸内細菌による紫根成分shikoninの代謝過程を研究する目的でshikonin(1)を種々の代謝物に変換する腸内細菌Eubacterium sp.A-44の細胞破砕懸濁液及び粗酵素標品を調製した。この粗酵素標品とshikonin(1)を嫌気条件下で1時間インキュベーションすると,shikonin(1)のほとんどはprometaboshikonin(2)およびmetaboshikonin I(3),II(4)に変換された。しかしながら,好気条件下ではshikometabolin A(5),B(6)などの二量体が生成した。化合物2-4の生成は,酸素によって阻害され,NADHの添加により増強した。一方,化合物5,6の生成はNAD^+の添加により増加した。加熱処理した場合と同様,粗酵素標品を除去した場合は,NADH,NAD^+を添加してもshikoninの変換は起こらなかった。したがって,NADHやNAD^+の存在下での化合物2-4や化合物5,6への変換過程は酵素反応によって触媒されることを示している

Human intestinal Bacteroides spp. RHEIN-I and RHEIN-II capable of transforming rhein to rheinanthrone, induce rhein-dependent diarrhea in rats

Two rhein-metabolizing bacteria were isolated from human feces. The biochemical and morphological characteristics of both isolates were typical of Bacteroides spp. and named strains RHEIN-I and RHEIN-II, respectively. Rhein was effectively metabolized to rheinanthrone by both strains. In conventional male Wistar rats, diarrhea was not induced after oral administration of rhein at a dose of 100 mg/kg (fecal water content of 71 %), in spite of severe diarrhea with sennoside B at a dose of 40 mg/kg (increase of fecal water content to 89 %). Also in germ-free rats, rhein did not induce any diarrhea. Gnotobiote rats colonized with B. sp. strain RHEIN-I developed diarrhea (fecal water content increased to 85 %) 11 hr after the oral administration of rhein. These findings indicate that rhein-transforming bacteria are responsible for the laxative effect associated with the ingestion of rhein and rhein containing preparations. rhein, rheinanthrone, diarrhea, Bacteroides, gnotobiote. ヒト糞便から2種のrhein代謝細菌を単離した。これらは生化学的および形態学的特徴からBcteroidesに属する種と判断され,RHEIN-I,RHEIN-II株と仮称した。rheinは両菌株により完全にrheinanthroneに代謝された。通常の雄Wistarラットにおいてはrhein 100mg/kgの経口投与で下痢が生じなかったが(糞便の水分含量は71%),sennoside Bでは40mg/kgの用量で激しい下痢を生じた(水分含量89%)。又,無菌ラットではrheinは何ら下痢作用を示さなかった。ところが,Bacteroides sp. strain RHEIN-Iを消化管内に棲息させたラットではrhein経口投与の11時間後に下痢が生じた(糞便の水分含量は85%)。この結果は,これらrhein代謝菌がrheinやrheinを含む製剤を摂取した場合に生じる下痢作用に関与していることを示している

Effect of Luobuma leaves against oxidation of low-density lipoprotein : a cell culture assay

In a previous study, we observed an improvement in the atherosclerosis index, together with a decrease in blood cholesterol, in rats given Luobuma extract orally and fed a high-cholesterol diet. The present study was designed to examine the function of oxidized low-density lipoprotein (LDL) in atherosclerotic lesions, using cultured cells. When endothelial cells were cultured with LDL in the presence of Cu^, the release of thiobarbituric acid (TBA) -reactive substance and lactic dehydrogenase into the culture medium was increased, with a decrease in cell viability. However, when Luobuma extract was also present in the culture medium, changes in these parameters were more favorable. In another in vitro system using macrophages, the levels of TBA-reactive substance, total cholesterol and esterified cholesterol were all significantly lower in the presence of Luobuma extract than in its absence. There was also morphological evidence that foam cell formation through incorporation of oxidized LDL was suppressed. These findings indicate that Luobuma suppresses the progression of atherosclerosis, in which oxidized LDL is involved. 先に,高コレステロール食投与ラットに羅布麻エキスを経口投与した場合,高コレステロール血症の低下とともに動脈硬化指数の改善作用が認められたので,今回,粥状動脈硬化病変への酸化LDLの機能を細胞を用い検寸寸した。まず内皮細胞にLDLとCu^を添加して培養した場合,培地中へのチオバルビツール酸反応物質,総LDHの放出が増加して,細胞生存率の低下が観察された。しかし羅布麻エキス添加群ではこれらパラメータがいずれも改善し,またマクロファージを用いた系でもチオバルビツール酸反応物質,コレステロールエステル,コレステロールエステル/遊離コレステロール比がいずれも無添加群より有意に低下し,形態学的な変化も酸化LDLのとり込みに伴う泡沫化の形成を抑制する知見が得られた。このことから,羅布麻は酸化LDLが関与する動脈硬化の進展過程を抑制することが明らかとなった

Radical-scavenging activity of Wen-Pi-Tang and its component crude drugs : with special reference to the effects on nitric oxide, superoxide and peroxynitrite

In renal diseases, active oxygen and free radicals play various roles in the development and progression of the pathological condition. Our previous studies have provided evidence that the Oriental medical prescription Wen-Pi-Tang normalizes the kidney under conditions of increased oxidative stress. In the present study, we examined the antioxidant capacity of Wen-Pi-Tang and its component crude drugs in a nitric oxide, superoxide and peroxynitrite generation system. It was found that the radical-scavenging effect of Wen-Pi-Tang is dose-dependent, and that three of its component crude drugs, i.e., Rhei Rhizoma, Zingiberis Rhizoma and Glycyrrhizae Radix, play important roles in the antioxidant action.腎疾患において活性酸素,フリーラジカルはさまざまな形でその病態の成立,進展に関与しているが,漢方方剤温脾湯が酸化的ストレス状態にある腎を是正する作用をこれまで報告してきた。本研究では温脾湯と構成和漢薬の抗酸化能をNO,O^-_2並ぴにONOO^-発生系を用い検討し,温脾湯によるこれらラジカル消去作用は用量依存的に認められ,また構成和漢薬では大黄,乾姜,甘草が重要な役割を担っていることが明らかとなった

Protective effect of Sanguisorbae Radix against peroxynitrite-mediated renal injury

3-Nitrotyrosine, an oxidative product of protein that is produced via peroxynitrite (ONOO^-) nitration, was detected by HPLC analysis in plasma obtained from rats injected with lipopolysaccharide (LPS) and subjected to renal ischemia followed by reperfusion (LPS+ischemia-reperfusion), but not in rats subjected to sham-treatment. Rats pretreated with Sanguisorbae Radix extract orally for 30 days before LPS+ischemia-reperfusion, had lower 3-nitrotyrosine levels than rats without the pretreatment. Plasma levels of urea nitrogen and creatinine, indicators of renal dysfunction, were markedly lower in the animals pretreated with Sanguisorbae Radix extract than in those without the pretreatment. In addition, DNA fragmentation in renal tissues was significantly inhibited by administration of Sanguisorbae Radix prior to LPS+ischemia-reperfusion. These results suggest that Sanguisorbae Radix extract ameliorates oxidative damage caused by ONOO^-. パーオキシナイトライトは蛋白中のチロシンをニトロ化して3-ニトロチロシンを生成するが,この3-ニトロチロシンをHPLCで測定した結果,リポポリサッカライドと虚血-再灌流を施したラット血漿で検出され,偽処理した場合には検出されなかった。一方,リポポリサッカライドと虚血-再灌流を施す前に30日間地楡エキスを経口投与したラットでは,非投与群より低い3-ニトロチロシン値を示し,腎機能の指標の血漿尿素窒素,クレアチニンレベルも著しく低下していた。また腎組織中のDNA断片化も抑制され,地楡エキスがパーオキシナイトライトによる酸化的損傷を軽減することが推測された

Characterization of anti-herpes simplex virus type 1 activity of an alkaloid FK 3000 from Stephania cepharantha

A morphinane alkaloid FK 3000 (6,7-di-O-acetylsinococuline) from the root tubers of Stephania cepharantha showed antiviral activity against acyclovir (ACV)- and phosphonoacetic acid (PAA)-resistant herpes simplex virus type 1 (HSV-1), influenza virus, measles virus, and poliovirus. The anti-HSV action of FK 3000 was assessed in comparison with that of PAA that inhibits the activity of HSV DNA polymerase and HSV DNA synthesis. FK 3000 inhibited the growth of thymidine kinase-deficient and ACV and PAA-resistant HSV-1 strains, as well as wild type HSV strains in Vero cells. This compound, as well as PAA, interfered with the synthesis of late viral proteins but not early viral proteins. The analysis of HSV DNA synthesis by slot blot hybridization showed that FK 3000 inhibited the viral DNA synthesis in a dose-dependent manner. However, the viral RNA was partially synthesized in the presence of FK 3000 (even at a dose that HSV DNA synthesis was inhibited) and PAA, indicating that FK 3000, as well as PAA, allowed early viral RNA synthesis but not viral DNA synthesis. Since partially purified HSV DNA polymerase activity was not inhibited by FK 3000, this compound was suggested to inhibit HSV DNA synthesis by a mechanism different from that of PAA. Stephania cepharantha(タマザキツヅラフジ)から得たモルフィン骨格を有するアルカロイドFK3000はacyclovirやphosphonoacetic acid(PAA)抵抗性を有するHSV-1, influenza virs, measles virus, poho virsに対しても抗ウイルス作用を有していた。この抗HSV作用をHSV DNA polymeraseを阻害することによりHSV DNA合成を阻害することが知られているPAAとの比較から検討した。HSVに感染したVero細胞においてFK3000は,PAAと同様に後期ウイルス蛋白の合成を阻害したが初期ウイルス蛋白には影響しなかった。Slot blot hybridization法でHSV DNA合成を調べると,FK3000は濃度依存的にウイルスDNA合成を阻害することが判明した。しかし,ウイルスRNA合成はHSV DNA合成が阻害される濃度でもFK3000およびPAAによって部分的にのみ阻害された。このことはPAAと同様にFK3000はウイルスDNA合成は阻害するが初期ウイルスRNAの合成は許容することを示している。FK3000は粗精製したHSV-DNA polymerase活性を阻害しないことから,PAAと異なった機構でHSV DNA合成を阻害していることが示唆された

Endothelium-dependent vasodilator effect of tannin extract from Cinnamonomi Cortex on isolated rat aorta

Cinnamonomi Cortex (the bark of Cinnamomum cassia BLUME) is a crude drug that is widely used in spices and medical products. Although improvement of blood flow by this plant component has long been known, there have been no reports concerning the mechanism involved. We studied the vasodilator actions of this drug especially focusing on the role of endothelium in the isolated vascular bed. Tannin from Cinnamonomi Cortex (TCC) relaxed prostaglandin F_-precontracted ring preparations of rat aorta with intact endothelium. TCC did not cause relaxation of specimens without endothelium, and TCC-induced relaxation was inhibited by pretreatment with 10^M N^G-nitro-l-arginine methyl ester. Dimer, trimer, tetramer, and pentamer components of TCC also produced endothelium-dependent vasodilatation. Stronger relaxation was caused by higher molecular weight tannins, and endothelium-dependent vasodilation even appeared at low concentrations. In conclusion, we found that TCC exhibits an endothelium-dependent vasodilatation in the isolated rat aorta mainly via endothelium derived NO. NO mediated endothelium-dependent relaxation seems to be more potent for TCC with higher molecular weight than that with lower molecular weight. 桂皮の血流改善作用については古くから知られており,これに関連した報告はあるものの,その詳細な検討はなされていない。今回我々はマグヌス法を用いて,ラット胸部大動脈輪状標本における桂皮含有クンニンの血管作動性について検討した。桂皮含有タンニンは,プロスタグランディンF_(PGF_)の血管収縮に対し,内皮保存血管において濃度依存性に血管弛緩作用が認められた。しかし,内皮除去血管及ぴN^G-nitro-l-argininemethyl ester(L-NAME)前処置内皮保存血管においては,血管弛緩作用はほぼ消失した。以上より,桂皮含有タンニンの血管弛緩作用は内皮依存性であることが明らかとなった。桂皮含有タンニンをさらに二量体から五量体までのタンニン画分に分取し検討したところ,二量体以上の重合したタンニンにおいて血管弛緩作用が認められた。また,重合度が増すに従い血管弛緩作用はより低い濃度で発揮され,作用も増強されることが明らかとなった