玄参的脂溶性化学成分

目的：研究中药玄参(Scrophularia　ningpoensis　Hemsl.)脂溶性部位的化学成分。方法：利用溶剂提取和硅胶等色谱方法对玄参乙醚可溶部位进行分离纯化,通过化学和光谱方法鉴定结构。结果：共分得10个化合物,分别鉴定为3-O-乙酰基-2-O-阿魏酰基-α-L-鼠李糖(I),3-O-乙酰基-2-O-对羟基肉桂酰基-α-L-鼠李糖(II),肉桂酸(III),4-羟基-3-甲氧基苯甲酸(IV),对甲氧基肉桂酸(V),4-羟基-3-甲氧基肉桂酸(VI),5-羟甲基糠醛(VII),熊果酸(VIII),β-谷甾醇(IX),β-谷甾醇葡糖苷(X)。结论：化合物I,II为新化合物。化合物IV,V,VII,VIII为首次从该植物中分得。玄参脂溶性部位含有较多的酚性化合物。     

(9S)-12-亚甲基红霉素衍生物的合成及体外抗菌活性

目的合成新的具有抗菌活性的红霉素衍生物。方法以红霉素为原料，合成中间体2′-O,4″-O-二苯甲酰基-(9S)-9-O,11-O-异丙基-12-亚甲基红霉素与6,7-去氢-2′-O,4″-O-二苯甲酰基-(9S)-9-O,11-O-异丙基-12-亚甲基红霉素，进而合成相应(9S)-9-O,11-O-亚乙基-12-亚甲基衍生物。产物结构经¹³C NMR,FAB-MS确证。对所得化合物进行体外抗菌活性测定。结果制备11个红霉素衍生物，其中5个未见文献报道。化合物9和12进行了体外抗菌活性测定。结论化合物9和12表现出较弱的抗菌活性。     

中药大血藤的酚性化合物

目的对中药大血藤干燥藤茎的化学成分进行研究。方法采用现代色谱技术分离化合物，运用现代波谱技术(IR，MS，¹H NMR，¹³C NMR，²DNMR)对所得化合物的结构进行鉴定。结果从大血藤的藤茎中分得10个酚类化合物，分别鉴定为1-O-(香草酸)-6-(3″,5″-二-O-甲基-没食子酰基)-β-D-葡糖苷(I)、(-)-表儿茶素(II)、阿魏酸-对羟基苯乙醇酯(III)、3-O-咖啡酰奎宁酸(IV)、3-O-咖啡酰奎宁酸甲酯(V)、罗布麻宁(VI)、香草酸(VII)、原儿茶酸(VIII)、3,4-二羟基-苯乙醇(IX)、4-羟基-苯乙醇(X)。结论化合物I为新化合物，化合物III～VI和VIII～X为首次从该植物中分得。     

喙果黑面神化学成分研究

目的研究大戟科植物喙果黑面神(Breynia rostrata Merr.)的化学成分。方法利用硅胶、凝胶等色谱技术分离纯化化学成分,根据化合物的理化性质和光谱数据进行结构鉴定。结果从喙果黑面神的正丁醇萃取部分分离得到4个化合物,分别鉴定为6-O-甲基丙酰基-α-D-吡喃葡糖(6-O-methylpropanoyl-α-D-glucopyranose,1);4″-苯酚基-6-O-甲基丙酰基-β-D-吡喃葡糖苷(4″-phenolic-6-O-methylpropanoyl-β-D-glucopyranoside,2);1-O-没食子酰基-β-D-吡喃葡糖苷(1-O-galloyl-β-D-glucopyranoside,3);熊果苷(arbutin,4)。结论化合物1和2为新化合物,3和4均为首次从该种植物分离得到。     

高链孢霉属真菌YD-01菌丝体中化学成分的研究

通过对交链孢霉属真菌(Alternaria sp.)YD-01菌丝体的丙酮提取物进行化学成分研究，从中分离得到3个化合物，经波谱数据分析，鉴定其结构为2,3-二羟基喹啉-4-O-β-D-葡萄糖苷(1)、 3-甲基-吡咯并哌嗪-2,5-二酮(2)和柚皮素(3)，其中化合物1为新化合物。     

栾树种子的化学成分研究

目的：分离鉴定栾树(Koelreuteria paniculata Laxm.)种子的化学成分。 方法：分别用石油醚回流提取和95% EtOH浸提, 硅胶柱色谱分离, IR,MS,UV,¹HNMR,¹³CNMR等方法确定结构。 结果：分得8个化合物,分别为3/-O-十四烷酰基-1-腈基-2-甲基-1,2-丙烯(1), 3-O-二十碳-14,15-烯酰基-1-腈基-2-甲基-1,2-丙烯(2), 3-O-二十碳-14,15-烯酰基-4-O-十八烷酰基-1-腈基-2-氧代亚甲基-1,2-丙烯(3), 3-O-(6′-亚油酰基-葡萄糖)-β-谷甾醇(4), 1-O-β-D-葡萄糖-2-O-油酸-3-O-十六烷酸甘油酯（5), 1-O-十六烷酸甘油酯（6), 14,15-二十碳烯酸（7),三油酸甘油酯（8)。 结论：1～3为新化合物, 4～8系首次从该植物中分得, 并归属其波谱信号。     

银杏叶中的黄酮醇苷类成分

目的　对银杏（Ginkgo biloba L.）叶的化学成分进行分离、鉴定。方法　采用各种色谱技术进行分离,用IR,UV,MS,¹HNMR,¹³CNMR和2DNMR光谱技术确定化合物的结构。结果　分得8个黄酮醇苷类成分：槲皮素-3-O-β-D-葡糖苷（1）,山奈酚-3-O-β-D-葡糖苷（2）,芦丁（3）,山奈酚-3-O-β-D-芸香糖苷（4）,异鼠李素-3-O-β-D-芸香糖苷（5）,槲皮素-3-O-β-D-葡萄糖基(1-2)-α-L-鼠李糖苷（6）,山奈酚-3-O-β-D-葡萄糖基(1-2)-α-L-鼠李糖苷（7）,异鼠李素-3-O-β-D-葡萄糖基(1-2)-α-L-鼠李糖苷（8）。结论　化合物8为新化合物。     

红芽大戟化学成分研究

目的研究茜草科植物红芽大戟(Knoxia corymbosa Willd．)的化学成分。方法利用硅胶、聚酰胺等色谱技术分离纯化,根据化合物的理化性质和光谱数据进行鉴定。结果从红芽大戟的正丁醇萃取部分分离得到4个黄酮醇苷成分,分别鉴定为:槲皮素-7-O-α-L-阿拉伯糖-3-O-β-D-6″-乙酰基吡喃葡糖苷(quercetin-7- O-α-L-arabinosyl-3-O-β-D-6″-acetylglucopyranoside,1);山奈酚-7-O-α-L-阿拉伯糖-3-O-β-D-吡喃葡糖苷(kaempferol-7-O-α-L-arabinosyl-3-O-β-D-glucopyranoside,2);槲皮素-3-O-β-D-吡喃葡糖苷(quercetin-3-O-β-D-glucopyranoside,3); 槲皮素-3-O-β-D-6″-乙酰基吡喃葡糖苷(quercetin-3-O-β-D-6″-acetylglucopyranoside,4)。结论化合物1为新化合物,其余均为首次从该种植物分到。     

以OATP1B1/OATP1B3转运体为作用靶点的何首乌肝毒性成分筛选

目的 建立以有机阴离子转运多肽1B1（OATP1B1）和OATP1B3为作用靶点的何首乌肝毒性成分快速筛选方法。方法 使用Discovery Studio 2.5软件将何首乌主要单体成分（48个）与OATP1B1/OATP1B3蛋白进行分子对接,以OATP1B1和OATP1B3主要转运底物胆红素作为阳性对照,对目标化合物进行虚拟筛选;采用CCK-8法考察芦荟大黄素-8-O-β-D-葡萄糖苷（AEG）、大黄素-8-O-β-D-葡萄糖苷（EG）、大黄素甲醚-8-O-β-D-葡萄糖苷（PG）、2,3,5,4''-四羟基二苯乙烯-2-O-β-D-葡萄糖苷（TSG）处理24 h后对人源肝永生化肝细胞HepaRG的毒性强弱,并采用实时荧光定量PCR （qRT-PCR）技术测定4种化合物对HepaRG细胞的OATP1B1和OATP1B3 mRNA表达量的影响。结果 与OATP1B1对接结果显示,polygonumnolide B3、cis-emodin-physcionbianthrones、polygonumnolide B2、大黄素甲醚-8-β-D-（6''-O-乙酰基）-葡萄糖苷、trans-emodin-physcionbianthrones、大黄素-3-甲醚-8-O-β-D-葡萄糖苷、polygonumnolide B4、大黄酚-8-O-葡萄糖苷、EG、大黄素-1-O-β-D-葡萄糖苷、AEG、大黄酚-8-O-β-D-葡萄糖苷、大黄酸-8-O-葡萄糖苷高于胆红素打分值的80%,可被初步认定为潜在毒性成分;与OATP1B3对接结果显示,trans-emodin-physcionbianthrones、PG、polygonumnolide A4及虎杖苷高于胆红素打分值的80%,可被初步认定为潜在毒性成分。CCK-8实验进一步证实AEG、EG及PG均具肝细胞毒性作用,半数抑制浓度分别为16.10、49.43、69.44 μg·mL^-1,与分子对接结果一致。与对照组比较,AEG、EG均可显著下调OATP1B1的mRNA表达水平（P<0.05）;PG可显著下调OATP1B3的mRNA表达水平（P<0.05）。结论 以OATP1B1/OATP1B3分子对接技术为切入点,可有效预测何首乌潜在肝毒性成分,实现快速高效的高通量筛选,为中药安全性评价提供新思路。     

Inhibitors of catechol-O-methyltransferase sensitize mice to pain

BACKGROUND AND PURPOSE

Catechol-O-methyltransferase (COMT) inhibitors are used in Parkinson''s disease in which pain is an important symptom. COMT polymorphisms modulate pain and opioid analgesia in humans. In rats, COMT inhibitors have been shown to be pro-nociceptive in acute pain models, but also to attenuate allodynia and hyperalgesia in a model of diabetic neuropathy. Here, we have assessed the effects of acute and repeated administrations of COMT inhibitors on mechanical, thermal and carrageenan-induced nociception in male mice.

EXPERIMENTAL APPROACH

We used single and repeated administration of a peripherally restricted, short-acting (nitecapone) and also a centrally acting (3,5-dinitrocatechol, OR-486) COMT inhibitor. We also tested CGP 28014, an indirect inhibitor of COMT enzyme. Effects of OR-486 on thermal nociception were also studied in COMT deficient mice. Effects on spinal pathways were assessed in rats given intrathecal nitecapone.

KEY RESULTS

After single administration, both nitecapone and OR-486 reduced mechanical nociceptive thresholds and thermal nociceptive latencies (hot plate test) at 2 and 3 h, regardless of their brain penetration. These effects were still present after chronic treatment with COMT inhibitors for 5 days. Intraplantar injection of carrageenan reduced nociceptive latencies and both COMT inhibitors potentiated this reduction without modifying inflammation. CGP 28014 shortened paw flick latencies. OR-486 did not modify hot plate times in Comt gene deficient mice. Intrathecal nitecapone modified neither thermal nor mechanical nociception.

CONCLUSIONS AND IMPLICATIONS

Pro-nociceptive effects of COMT inhibitors were confirmed. The pro-nociceptive effects were primarily mediated via mechanisms acting outside the brain and spinal cord. COMT protein was required for these actions.     

Inhibition of human catechol-O-methyltransferase-mediated dopamine O-methylation by daphnetin and its Phase II metabolites

1.?Finding and developing inhibitors of catechol-O-methyltransferase (COMT) from natural products is highly recommended. Daphnetin, a naturally occurring catechol from the family thymelaeaceae, has a chemical structure similar to several potent COMT inhibitors reported previously. Here the potential of daphnetin and its Phase II metabolites as inhibitors of COMT was investigated with human liver cytosol (HLC).

2.?Daphnetin and its methylated metabolite (8-O-methyldaphnetin) were found to inhibit COMT-mediated dopamine O-methylation in a dose-dependent manner. The IC₅₀ values for daphnetin (0.51～0.53?μM) and 8-O-methyldaphnetin (22.5～24.3?μM) were little affected by changes in HLC concentrations. Further kinetic analysis showed the differences in inhibition type and parameters (K_i) between daphnetin (competitive, 0.37?μM) and 8-O-methyldaphnetin (noncompetitive, 25.7?μM). Other metabolites, including glucuronidated and sulfated species, showed negligible inhibition against COMT. By using in vitro–in vivo extrapolation (IV-IVE), a 24.3-fold increase in the exposure of the COMT substrates was predicted when they are co-administrated with daphnetin.

3.?With high COMT-inhibiting activity, daphnetin could serve as a lead compound for the design and development of new COMT inhibitors. Also, much attention should be paid to the clinical impact of combination of daphnetin and herbal preparations containing daphnetin with the drugs primarily cleared by COMT.     

General properties and clinical possibilities of new selective inhibitors of catechol O-methyltransferase

1. The structure of catechol O-methyltransferase (COMT) has been recently characterized and a series of new and selective COMT inhibitors developed.2. Entacapone, nitecapone and tolcapone are nitrocatechol-type potent COMT inhibitors in vitro (K_i in nanomolar range). They are also very selective for COMT and active in vivo even after oral administration. CGP 28014 is a pyridine derivative that is active only in vivo.3. In animal studies, these compounds inhibit effectively the O-methylation of l-dopa, thus improving its bioavailability and brain penetration and potentiating its behavioural effects.4. Entacapone and nitecapone have mainly a peripheral effect whereas tolcapone and CGP 28014 also inhibit O-methylation in the brain.5. In man, entacapone, nitecapone and tolcapone all inhibit dose dependently the COMT activity in erythrocytes. These COMT inhibitors also decrease the amount of COMT dependent metabolites of adrenaline and noradrenaline in plasma.6. In human volunteers, entacapone, tolcapone and CGP 28014 improve the bioavailability of l-dopa and inhibit the formation of 3-O-methyldopa.7. In the first clinical studies in patients with Parkinson's disease, both entacapone and tolcapone potentiate and prolong the therapeutic effect of l-dopa.     

Pharmacokinetic–pharmacodynamic interaction between BIA 3-202, a novel COMT inhibitor, and levodopa/benserazide

BIA 3-202 is a novel catechol-O-methyltransferase (COMT) inhibitor being developed for use as a levodopa-sparing agent in Parkinsons disease. This study investigated the effect of four single oral doses of BIA 3-202 (50 mg, 100 mg, 200 mg, and 400 mg) compared with placebo on plasma concentrations of levodopa and its metabolite 3-O-methyl-levodopa (3-OMD) and on inhibition of erythrocyte COMT in healthy subjects receiving 100 mg of levodopa and 25 mg of benserazide (Madopar 125). This was a single-centre, double-blind, placebo-controlled, randomised, crossover study with five single-dose treatment periods. The washout period between doses was 2 weeks. On each treatment period, a different dose of BIA 3-202 or placebo was administered concomitantly with Madopar 125. Tolerability was assessed by recording adverse events, vital signs, continuous electrocardiogram and clinical laboratory parameters. In the study, 18 subjects (12 male and 6 female) participated. The drug combination was well tolerated. All doses of BIA 3-202 significantly increased the area under the concentration–time curve (AUC) versus placebo, ranging from 39% (95% confidence intervals, 1.06–1.69) with 50 mg to 80% (95% confidence intervals, 1.42–2.22) with 400 mg. No significant change in mean maximum plasma concentrations (C_max) of levodopa was found. Mean C_max and AUC of 3-OMD significantly decreased for all doses tested. BIA 3-202 caused a rapid and reversible inhibition of S-COMT activity, ranging from 57% (50 mg) to 84% (400 mg). In conclusion, the novel COMT inhibitor BIA 3-202 was well tolerated and significantly increased the bioavailability of levodopa and reduced the formation of 3-OMD when administered with standard release levodopa/benserazide.     

Lack of increased oxidative stress in catechol-<Emphasis Type="Italic">O</Emphasis>-methyltransferase (COMT)-deficient mice

The effect of catechol-O-methyltransferase (COMT) deficiency on methamphetamine-induced hydroxyl radical production in the brain was assessed by the salicylate trapping method. Methamphetamine-induced hyperthermia was also studied. Furthermore, the effect of COMT deficiency on the activities of glutathione S-transferase, quinone reductase and liver mono-oxygenases was assessed with and without l-dopa challenge. Finally, two alternative pathways of l-dopa metabolism were evaluated. Methamphetamine increased 2,3-dihydroxybenzoic acid levels only slightly (n.s.) at the lowest dose level (2.5 mg/kg × 4 i.p.). This was accompanied by a simultaneous increase in salicylate levels so that the 2,3-dihydroxybenzoic acid/salicylate ratio decreased correspondingly. Most importantly, no COMT genotype-dependent changes were observed. However, hyperthermia was induced even at the lowest methamphetamine dose, the COMT-deficient mice being most sensitive. COMT deficiency did not significantly change the activities of liver glutathione S-transferase, quinone reductase or 7-ethoxyresorufin and 7-pentoxyresorufin O-dealkylation. In COMT-deficient female mice, l-dopa (30–80 mg/kg b.i.d. for 2 days) did not induce any significant changes in liver or brain glutathione S-transferase and quinone reductase activity or liver 7-ethoxyresorufin O-deethylation activity. The levels of l-dopa conjugates in urine were also negligible in COMT-deficient mice. Skin tyrosinase activity was increased in 7- to 8-day-old hairless COMT-deficient pups. The present results suggest that despite the increased hyperthermic response, COMT deficiency does not increase methamphetamine-induced hydroxyl radical production or change significantly the activity of certain enzymes involved in defense against reactive oxygen species. In conclusion, we found no evidence of increased oxidative stress in the liver or brain of adult mice lacking COMT activity.     

Inhibition of soluble catechol-O-methyltransferase and single-dose pharmacokinetics after oral and intravenous administration of entacapone

The inhibition of soluble catechol-O-methyltransferase (S-COMT) in red blood cells (RBCs) by entacapone, and the pharmacokinetics of entacapone after single oral (5–800 mg) and IV (25 mg) doses have been examined in an open study in 12 healthy young male volunteers.Oral entacapone dose-dependently decreased the activity of S-COMT in RBCs with a maximum inhibition of 82% after the highest dose (800 mg). The inhibition of S-COMT in RBCs was reversible and the activity recovered within 4–8 h.Entacapone showed linear pharmacokinetics over the dose range studied: C_max and AUC were correlated with the dose of the drug. Oral absorption of entacapone was fast, with a t_max ranging from 0.4 to 0.9 h, depending on the dose. Systemic availability of entacapone varied between 30 and 46%. Entacapone was rapidly eliminated by metabolism with a half-life of 0.27–0.30 h after oral doses of 5 to 50 mg. After doses from 100 to 800 mg the disposition was best described by two phases with a t_1/2 of 0.27–0.37 h and t_1/2 of 1.59–3.44 h.Over the dose range studied, the single oral and IV doses of entacapone were well tolerated. No haematological, biochemical or haemodynamic adverse effects were seen.The results show that entacapone is an orally effective and reversible COMT inhibitor in man and has simple, linear pharmacokinetics.     

Methylation and its role in the disposition of tanshinol,a cardiovascular carboxylic catechol from Salvia miltiorrhiza roots (Danshen)

Aim:

Tanshinol is an important catechol in the antianginal herb Salvia miltiorrhiza roots (Danshen). This study aimed to characterize tanshinol methylation.

Methods:

Metabolites of tanshinol were analyzed by liquid chromatography/mass spectrometry. Metabolism was assessed in vitro with rat and human enzymes. The major metabolites were synthesized for studying their interactions with drug metabolizing enzymes and transporters and their vasodilatory properties. Dose-related tanshinol methylation and its influences on tanshinol pharmacokinetics were also studied in rats.

Results:

Methylation, preferentially in the 3-hydroxyl group, was the major metabolic pathway of tanshinol. In rats, tanshinol also underwent considerable 3-O-sulfation, which appeared to be poor in human liver. These metabolites were mainly eliminated via renal excretion, which involved tubular secretion mainly by organic anion transporter (OAT) 1. The methylated metabolites had no vasodilatory activity. Entacapone-impaired methylation did not considerably increase systemic exposure to tanshinol in rats. The saturation of tanshinol methylation in rat liver could be predicted from the Michaelis constant of tanshinol for catechol-O-methyltransferase (COMT). Tanshinol had low affinity for human COMT and OATs; its methylated metabolites also had low affinity for the transporters. Tanshinol and its major human metabolite (3-O-methyltanshinol) exhibited negligible inhibitory activities against human cytochrome P450 enzymes, organic anion transporting polypeptides 1B1/1B3, multidrug resistance protein 1, multidrug resistance-associated protein 2, and breast cancer resistance protein.

Conclusion:

Tanshinol is mainly metabolized via methylation. Tanshinol and its major human metabolite have low potential for pharmacokinetic interactions with synthetic antianginal agents. This study will help define the risk of hyperhomocysteinemia related to tanshinol methylation.     

Sex-dependent compensated oxidative stress in the mouse liver upon deletion of catechol O-methyltransferase

Catechol-O-methyl transferase (COMT) methylates catechols, such as l-dopa and dopamine, and COMT deficient mice show dramatic shifts in the metabolite levels of catechols. Increase in catechol metabolite levels can, in principle, lead to oxidative stress but no indices of oxidative stress have been reported in COMT-knockout (KO) mice [Forsberg MM, Juvonen RO, Helisalmi P, Leppanen J, Gogos JA, Karayiorgou M, et al. Lack of increased oxidative stress in catechol-O-methyltransferase (COMT)-deficient mice. Naunyn Schmiedebergs Arch Pharmacol 2004;370:279-89.]. Here we perform a proteomic based analysis of the livers of COMT-KO mice in search for potential compensatory mechanisms developed to cope with the effects of disrupted catechol metabolism. We found sex specific changes in proteins connected to stress response. Our results show that alterations in protein levels contribute to the homeostatic regulation in the liver of COMT deficient mice.     

Determination of peripheral catecholO-methyltransferase (COMT) activityin vivo using [2-14C]-3′,4′-dihydroxyacetophenone

For the determination of peripheral COMT activity, we synthesized [2-¹⁴C]-3′,4′-dihydroxyacetophenone([¹⁴C]-DHAP), a model substrate closely related to catecholamines, which cannot be attacked by monoamine oxidase. After i.v.-injection of [¹⁴C]-DHAP in living animals, only 3′,4′-dihydroxy-acetophenone (3′,4′-DHAP) and 3′-methoxy-4′-hydroxyacetophenone (3′-MHAP) were detected in blood by thin layer radio chromatography. It could be speculated that 3′,4′-DHAP was primarilyO-methylated by COMT, followed by subsequent conjugations. The concentration of 3′,4′-DHAP, a substrate for COMT, in blood at 5 min after injection of [¹⁴C]-DHAP, were similar in all animals. The rate of 3′-MHAP formation can be therefore used as an indicator for peripheral COMT activity. The velocity of methylation in 15 min after i.v.-administration of [¹⁴C]-DHAP was 0.28 μg/ml·min. From these results, 3′,4′-DHAP was shown to be used as an appropriate substrate to determine the COMT activityin vivo.     

Antioxidative compounds from <Emphasis Type="Italic">Quercus salicina</Emphasis> Blume Stem

The chromatographic separation of MeOH extract from the Quercus salicina Blume Stem led to the isolation of five phenolic compounds. Using spectroscopic methods, the structures of these compounds were determined as D-threo-guaiacylglycerol 8-O-β-D-(6′-O-galloyl)glucopyranoside (1), 9-methoxy-D-threo-guaiacylglycerol 8-O-β-D-(6′-O-galloyl)glucopyranoside (2), 6″-O-galloyl salidroside (3), methyl gallate (4), quercetin (5). We measured radical scavenging activity with the DPPH method and the anti-lipid peroxidative efficacy on human LDL with TBARS assay, with the result that all these compounds exhibited the antioxidative activity.