卷柏属7种药用植物的提取物对脂氧化酶的抑制作用

目的对卷柏属7种药用植物的28种提取物在体外对脂氧化酶的抑制活性进行了研究和比较.方法用带有酶动力学分析软件的紫外分光光度计,测定28种提取物对脂氧化酶的抑制活性,波长为234 nm、脂氧化酶浓度为1.08 mg·L-1,反应时间为2 min.结果卷柏属7种药用植物的醋酸乙酯提取物部位显示较强的活性,95%乙醇提取物部位显示出一定的抑制活性.结论醋酸乙酯提取物是卷柏属药用植物抑制脂氧化酶的主要活性部位,可进一步分离纯化得到活性化合物.     

Pharmacological mechanisms underlying the antinociceptive and tolerance effects of the 6,14-bridged oripavine compound 030418

Aim:

To investigate possible pharmacological mechanisms underlying the antinociceptive effect of and tolerance to N-methyl-7α-[(R)-1-hydroxy-1-methyl-3-(thien-3-yl)-propyl]-6,14-endo-ethanotetrahydronororipavine (030418), a derivative of thienorphine.

Methods:

The binding affinity and efficacy of 030418 were determined using receptor binding and guanosine 5′-O-(3-[³⁵S]thio)triphosphate ([³⁵S]GTPγS) assays in CHO-μ, CHO-κ, CHO-δ, and CHO-ORL1 cell membranes. The analgesic activity of and tolerance to 030418 were evaluated in thermal nociceptive tests in mice. The effects of 030418 on opioid receptors were further investigated using in vivo pharmacological antagonist blockade and in vitro tissue preparations.

Results:

The compound 030418 displayed high binding affinity to all subtypes of opioid receptors with K_i values in the nanomolar range. In [³⁵S]GTPγS binding assay, the maximal stimulation of 030418 to μ-, κ-, δ-receptors and the ORL1 receptor was 89%, 86%, 67% and 91%, respectively. In hot-plate test, the antinociceptive effect of 030418 was more potent and longer than morphine. The nonselective opioid receptor antagonist naloxone could completely block 030418-induced antinociception, while both the μ-opioid receptor antagonist β-FNA and the κ-opioid receptor antagonist nor-BNI attenuated 030418-induced antinociception. In contrast, the ORL1 receptor antagonist J-113397 enhanced the antinociceptive effect of 030418. Additionally, chronic treatment with 030418 resulted in a dramatic development of tolerance that could not be effectively prevented by J-113397. In guinea pig ileum preparation, the existing action of 030418 could be removed with difficulty after prolonged washing.

Conclusion:

The compound 030418 is a novel agonist of opioid receptors with high efficiency, long-lasting effect and liability to tolerance, which may be closely correlated with the methyl group at the N₁₇ position and the high hydrophobicity of the C₇-thiophene group in its chemical structure.     

玉郎伞提取物抗炎作用及机制研究

目的:研究玉郎伞(YLS)的抗炎作用及其可能的机制.方法:采用二甲苯致小鼠耳肿胀和角叉菜胶致小鼠足肿胀模型,考察YLS水提取物(TYLS,以生药计剂量分别为80,40 g·kg-1)及其总黄酮(FYLS,0.14,0.07 g·kg-1)的抗炎作用,连续灌胃给药7 d后测定小鼠耳肿胀度和炎症足前列腺素E2(PGE2)及一氧化氮(NO)的含量.采用去除双侧肾上腺小鼠足肿胀模型,观察TYLS(以生药计剂量分别为80,40 g·kg-1)及FYLS(0.14,0.07 g·kg-1)灌胃给药对二甲苯致小鼠耳肿胀的影响.正常大鼠灌胃TYLS(以生药计剂量分别为60,30 g·kg-1)及FYLS(0.1,0.05 g·kg-1)7 d后,测定大鼠肾上腺中维生素C和胆固醇含量及肾上腺重量.结果:TYLS及FYLS对二甲苯致小鼠耳肿胀、角叉菜胶致正常小鼠足肿胀均有显著的抑制作用,但对去肾上腺小鼠二甲苯所致耳肿胀无抑制作用(P0.05);可降低炎症渗出物中PGE2含量,但对NO含量无显著影响(P0.05);可降低正常大鼠肾上腺中维生素C和胆固醇的含量,对肾上腺指数无明显影响.结论:YLS具有明显抗炎作用,其作用可能与抑制PGE:产生,激动下丘脑-垂体一肾上腺轴有关,但对NO无显著抑制作用.     

Vascular mechanisms underlying the hypotensive effect of Rumex acetosa

Context: Rumex acetosa L. (Polygonaceae) is well known in traditional medicine for its therapeutic efficacy as an antihypertensive.

Objective: The study investigates antihypertensive potential of crude methanol extract (Ra.Cr) and fractions of Rumex acetosa in normotensive and hypertensive rat models and probes the underlying vascular mechanisms.

Materials and methods: Ra.Cr and its fractions were tested in vivo on normotensive and hypertensive Sprague-Dawley rats under anaesthesia for blood pressure lowering effect. In vitro experiments on rat and Oryctolagus cuniculus rabbit aortae were employed to probe the underlying vasorelaxant mechanism.

Results: In normotensive rats under anaesthesia, Ra.Cr caused fall in MAP (40?mmHg) at 50?mg/kg with % fall of 27.88?±?4.55. Among the fractions tested, aqueous fraction was more potent at the dose of 50?mg/kg with % fall of 45.63?±?2.84. In hypertensive rats under similar conditions, extract and fractions showed antihypertensive effect at same doses while aqueous fraction being more potent, exhibited 68.53?±?4.45% fall in MAP (70?mmHg). In isolated rat aortic rings precontracted with phenylephrine (PE), Ra.Cr and fractions induced endothelium-dependent vasorelaxation, which was partially blocked in presence of l-NAME, indomethacin and atropine. In isolated rabbit aortic rings pre-contracted with PE and K⁺-(80?mM), Ra.Cr induced vasorelaxation and shifted Ca²⁺ concentration–response curves to the right and suppressed PE peak formation, similar to verapamil, in Ca²⁺-free medium.

Discussion and conclusions: The data indicate that l-NAME and atropine-sensitive endothelial-derived NO and COX enzyme inhibitors and Ca²⁺ entry blocking-mediated vasodilator effect of the extract explain its antihypertensive potential.     

Investigation of the mechanisms underlying the gastroprotective effect of nicorandil

AIM: This study investigated possible mechanisms underlying the gastroprotective effect of nicorandil on experimentally-induced gastric lesions in rats. METHODS: Rats were randomly assigned to vehicle-, nicorandil (10 mg/kg)-, glibenclamide (6 mg/kg)-, nicorandil + glibenclamide- and cimetidine-pretreated groups, in addition to non-stressed control group, to demonstrate whether the K(ATP )channel opening contributed to nicorandil's gastroprotection. Lesions were induced by water immersion-restraint stress (WIRS) and ulcer indices were determined. Gastric juice parameters (pH, acid output, pepsin and mucin concentrations) were determined. Another set of rats was divided into control, saline-pretreated and nicorandil (10 mg/kg)-pretreated groups. Rats underwent WIRS and their stomachs were used for determination of gastric mucosal lipid peroxides, histamine, PGE(2), and total nitrites levels. RESULTS: Nicorandil displayed significant protection against gastric lesions formation, abolished by concomitant administration of glibenclamide. Nicorandil significantly reduced gastric acid and pepsin secretion, but upon coadministration with glibenclamide, these effects were blocked. Additionally, nicorandil significantly reduced gastric mucosal lipid peroxides and total nitrites, but did not affect PGE(2) and histamine levels. CONCLUSION: Results confirm a gastroprotective effect for nicorandil, the mechanism of which comprises K(ATP) channel opening, free radical scavenging, decrease of pepsin and acid secretion and prevention of the detrimental rise in nitric oxide during WIRS.     

红景天属植物的化学成分（英文）

景天科红景天属植物大概包括90个种,分布在高原地带。一些品种做成制剂可治疗多种疾病,如脑缺氧,心血管病,高原反应等。到现在为止,约180种化合物被分离鉴定,其中含有丰富的苷类,以及黄酮类、萜类、鞣质、甾醇等化合物。本综述主要总结了在过去的几十年中,从红景天属植物中分离出来的化学成分。特别强调的是,我们的课题小组正在对植物大花红景天进行化学成分及药理活性研究。     

Anti-cancer effect of toosendanin and its underlying mechanisms

Toosendanin (TSN) is a triterpenoid purified from the medicinal herb Melia toosendan Sieb. et Zucc and has been used as an insecticide for decades. Recent studies have attracted increasing interest of TSN due to its novel anti-cancer effect in diverse cancer models. The broad spectrum anti-cancer activity suggests that TSN inhibits multiple pathways/targets that are critical for cancer cell survival and proliferation. Our recent study indicated that TSN has anti-cancer effect in glioblastoma through induction of estrogen receptor β (ERβ) and p53. This review highlights the anti-cancer efficacy of TSN and provides proof-of-principle insight into the underlying mechanisms.     

Analysis of the mechanism underlying the peripheral antinociceptive action of sildenafil in the formalin test

The mechanism of the antinociceptive action of the phosphodiesterase 5 inhibitor, sildenafil, was assessed in the formalin test. Local peripheral ipsilateral, but not contralateral, administration of sildenafil (50-200 microg/paw) produced a dose-related antinociception during both phases of the formalin test. The local peripheral pretreatment with protein kinase G inhibitor peptide (PKG inhibitor, 0.01-1 microg/paw), charybdotoxin (large- and intermediate-conductance Ca2+-activated K+ channel blocker, 0.01-1 microg/paw), apamin (small-conductance Ca2+-activated K+ channel blocker, 0.1-2 microg/paw), tolbutamide (ATP-sensitive K+ channel blocker, 12.5-50 microg/paw), and tetraethylammonium (non-selective voltage-dependent K+ channel blocker, 12.5-50 microg/paw), but not 1H-(1,2,4)-oxadiazolo(4,2-a)quinoxalin-1-one (ODQ, inhibitor of guanylyl cyclase, 12.5-50 microg/paw) or saline, significantly diminished in a dose-dependent manner sildenafil-induced local peripheral antinociception. Given alone, local peripheral administration of inhibitors did not modify formalin-induced nociceptive behavior. Results suggest that sildenafil produces its local peripheral antinociceptive effect via activation of the cyclic GMP-PKG-K+ channel pathway.     

Anemia induced by repeated exposure to cyanobacterial extracts with explorations of underlying mechanisms

Hematological abnormalities or derangements have been demonstrated in patients suffering form microcystins (MCs) in hemodialysis unit in Caruaru, Brazil, 1996. While experimental study on hematological effect of microcystins has been rare and the underlying mechanisms are still puzzling. In the present study, microcystins were repeatedly intraperitoneally injected with a dose of 6 μg/kg/day in rabbits (Oryctolagus cuniculus) for 14 days, and the prolonged effects of extracted microcystins on hematotoxicology were investigated. Significant decreases were observed in the hematological indices red blood cell counts, hematocrit, hemoglobin, and platelet count, while an obvious anemia occurred in rabbits after 14-day exposure. Moreover, red blood cell volume distribution width, mean corpuscular volume, and mean corpuscular hemoglobin did not vary significantly, indicating that rabbits suffered from normocytic anemia. In bone marrow, on the 14th day after toxin exposure, the frequency of micronucleus increased significantly, and the viability of bone marrow cells decreased markedly compared with the control. Serum erythropoietin levels declined on the 7th and 14th day, which suggested that the ability to regulate differentiation and maturation of erythrocytes was impaired. These results indicate that repeated exposure of microcystins can result in normocyte anemia, and the bone marrow injures and the sharp decreases of erythropoietin levels were responsible for the anemia.     

Anti-inflammatory properties of extracts, fractions and lignans isolated from Phyllanthus amarus

This study assessed the anti-inflammatory effect of the extracts and purified lignans obtained from Phyllanthus amarus. Given orally, the hexane extract (HE), the lignan-rich fraction (LRF), or the lignans phyltetralin, nirtetralin, niranthin, but not hypophyllanthin or phyllanthin, inhibited carrageenan (Cg)-induced paw oedema and neutrophil influx. The HE, the LRF or nirtetralin also inhibited the increase of IL1-beta tissue levels induced by Cg. Furthermore, bradykinin (BK)-, platelet activating factor (PAF)- and endothelin-1 (ET-1)-induced paw oedema were significantly inhibited by the HE or LRF while histamine- and substance P-induced paw oedema were unaffected. Finally, nirtetralin or phyltetralin caused inhibition of paw oedema induced by PAF or ET-1. These results show that the HE, the LRF and the lignans niranthin, phyltetralin and nirtetralin exhibited marked anti-inflammatory properties and suggest that these lignans seem to be the main active principles responsible for the anti-inflammatory properties reported for the HE of P. amarus.     

The antinociceptive effect of amisulpride in mice is mediated through opioid mechanisms

Antinociceptive effects of various neuroleptics in animal acute pain-models have been described, mediated trough different pathways including the opioid system. In this study, we assessed the antinociceptive effects of the atypical neuroleptic drug amisulpride, which acts as a selective blocker of dopamine D2 and D3 receptors. Furthermore, at low doses amisulpride has a selective preference for presynaptic dopamine autoreceptors, while at high doses it manifests a preferential action at post-synaptic dopamine receptors. We found amisulpride to be a potent antinociceptor agent in the mouse tail-flick assay, with an ED50 of 36.6 mg/kg. This effect was antagonized by naloxone (P<0.05), indicating an involvement of opioid mechanisms as mediators of the antinociceptive effect of amisulpride. Beta-funaltrexamine (mu1- and mu2-opioid receptor antagonist), naloxonazine (selective mu1-opioid receptor antagonist), naltrindole (selective delta-opioid receptor antagonist), Nor-binaltorphamine (kappa1-opioid receptor antagonist) reversed amisulpride antinociception at the same dose that they antagonized morphine's antinociceptive effect (all P<0.005). We found that the sensitivity of amisulpride-induced antinociception is mediated through selective involvement of all three opioid receptor subtypes. Based on previous studies with risperidone, clozapine and olanzapine we tend to attribute this global interaction with the opioid system to amisulpride's action at the dopamine D2 receptor sites.     

Time course of the antipsychotic effect and the underlying behavioral mechanisms.

Antipsychotic drugs work for patients only when given repeatedly. The overall temporal pattern of symptom improvement is not clear. Some recent data question the traditional 'delayed-onset' hypothesis and suggest that the onset of antipsychotic response may be relatively early, and the improvement may grow with repeated treatment. The present study systematically examined the time course of the antipsychotic effect and the underlying behavioral mechanisms using a conditioned avoidance response (CAR) model. Rats repeatedly treated with either typical (haloperidol) or atypical (olanzapine, risperidone) antipsychotics, but not anxiolytics (chlordiazepoxide), show an early-onset, progressive across-session decline in avoidance responding, which re-emerges when the treatment is stopped. This effect is dose-dependent, transferable between antipsychotics, and cannot be attributed to simple sedation or motor side effects. Furthermore, we found that the pattern of this drug-induced decline depends on the number of exposures to the conditioned stimulus in the presence of the drug, and is best understood as the result of drug-induced attenuation of the reinforcing effectiveness of the conditioned stimulus. We also found that repeated drug exposure can create a drug interoceptive state that allows the attenuated reinforcing property of the stimulus to be maintained over time. Together, these data provide preclinical support for the newly postulated 'early-onset' hypothesis, and suggest that the repeated antipsychotic CAR model may be useful for understanding the neurochemical and behavioral mechanisms underlying the clinical effects of antipsychotics in patients with schizophrenia.     

The vasorelaxing effect of resveratrol on abdominal aorta from rats and its underlying mechanisms

Evidence has indicated that resveratrol (Res) produces vasorelaxation and may decrease the coronary heart disease mortality. However, several pathways involved in the mechanism of vasorelaxation are still unclear. This study was designed, therefore, to test the probable ion channels or receptors involved in the mechanism. The abdominal aortic rings from the male Sprague‐Dawley rats were perfused in the organ chambers filled with Kreb's solution, where the tension of each ring was measured. Treatment with L-NAME (a nitric oxide synthase inhibitor), glibenclamide and tetraethylammonium (TEA) significantly attenuated the vasorelaxing effect of Res. In lower concentration Res relaxed the ring in an endothelium-dependent manner, while in higher concentration the endothelium-independent manner could be observed. In calcium-free Kreb's solution, Res inhibited vasoconstriction induced by NE. With intracellular calcium depleted by thapsigargin, Res also inhibited vasoconstriction induced by Kreb's solution with high potassium via L-Ca^2 + channel. In a word, Res decreased both extracellular calcium influx and intracellular calcium release. These results suggest that: (1) Res may exert its relaxing effect on abdominal aorta by opening K⁺ channel to hyperpolarize vascular smooth muscle.(2) Res relaxes the abdominal aorta in both endothelium-dependent and endothelium-independent manners. (3) Finally, Res attenuates both extracellular calcium influx and intracellular calcium release, which results in vasorelaxation.     

5种鸢尾属药用植物甲醇提取物体外抗炎活性研究

目的研究5种鸢尾属药用植物(膜苞鸢尾、细叶鸢尾、蓝花喜盐鸢尾、粗根鸢尾、中亚鸢尾)根及根状茎甲醇提取物的体外抗炎活性。方法制备5种鸢尾属植物根及根状茎的甲醇提取物,并测定其总黄酮含量。采用脂多糖(LPS)刺激巨噬细胞RAW 264.7建立细胞炎症模型,观察5种鸢尾属植物提取物对NO、TNF-α、IL-6水平的影响。使用MTT测定细胞活力,Griess法测定NO的含量,ELISA法测定TNF-α及IL-6的含量。结果与模型组相比,5种提取物中,膜苞鸢尾及中亚鸢尾在12.5～100μg·mL~(-1),粗根鸢尾及蓝花喜盐鸢尾在25～100μg·mL~(-1),细叶鸢尾在50～100μg·mL~(-1)时,均能有效抑制巨噬细胞释放NO(P <0.05)。膜苞鸢尾、粗根鸢尾、中亚鸢尾、蓝花喜盐鸢尾在25～100μg·mL~(-1),细叶鸢尾在50～100μg·mL~(-1)时,均能有效抑制巨噬细胞释放TNF-α(P <0.05)。5种鸢尾在25～100μg·mL~(-1)时,均能有效抑制巨噬细胞释放IL-6(P <0.01)。组间对比表明,膜苞鸢尾在100μg·mL~(-1)时对NO和TNF-α的抑制作用最强,细叶鸢尾在25μg·mL~(-1)时对NO的抑制作用最弱,在100μg·mL~(-1)时对IL-6的抑制作用最弱(P <0.05)。结论 5种鸢尾属药用植物根及根状茎的甲醇提取物具有潜在的抗炎活性,本研究结果可为该属药用植物抗炎活性的研究提供参考。     

Pharmacological activity and chemical composition of callus culture extracts from selected species of Phyllanthus

This study was conducted in order to determine the chemical composition and the possible antinociceptive effects in mice of some species of Phyllanthus in vitro. The methanolic extracts obtained from callus cultures of P. fraternus, P. stipulatus and P. caroliniensis caused significant inhibition in to the late phase of the formalin test, whereas the extract from P. urinaria inhibited both neurogenic and inflammatory phases of the test. Conventional chromatographic methods (TLC, GC) permitted the detection of some steroids or triterpenes, including beta-sitosterol, glochidonol and glochidone, which seem be responsible for the antinociceptive effects of the callus extracts studied.     

Hepatoprotective effect of peony total glucosides and the underlying mechanisms in diabetic rats

Context: Total glucosides of peony (TGP), compounds extracted from the dried roots of Paeonia lactiflora Pall, have been reported to have anti-inflammatory and antioxidative activities. However, the protective effect of TGP on liver injury and the underlying mechanisms remains unknown in diabetic rats.

Objectives: Current study investigates prevention of liver injury by TGP in diabetic rats and its mechanism was related to the inhibition of endoplasmic reticulum stress (ERS).

Materials and methods: Fifty adult male rats were randomly divided into: Normal group, diabetic group, TGP (50, 100 and 200?mg/kg/day) treatment groups (n?=?10 per group). At the end of the 8th week, the liver was removed for biochemical and histological examinations.

Results: Compared with the diabetic group, administration of TGP at doses of 50, 100 and 200?mg/kg significantly prevented the increase of hepatic fibrosis score (ED₅₀ 139.4?mg/kg). Compared with diabetic group, TGP at doses of 50, 100 and 200?mg/kg showed an inhibition on the increased macrophage infiltration. MCP-1 and TNF-α mRNA and protein expression were significantly increased in diabetic group compared with normal group; TGP administration caused significant reduction of high levels of MCP-1 and TNF-α mRNA as well as protein levels. Also, TGP at all doses showed an inhibition on the increased GRP78 levels, p-Perk levels and p-Eif2α levels in liver from diabetic group.

Discussion and conclusions: Our results indicate that TGP has potential as a treatment for diabetic liver injury attenuating liver lipid accumulation and inflammation as well as ERS induced by diabetic condition.     

Neuronal and neurochemical mechanisms underlying the effect of a novel antiepileptic drug levetiracetam

Published data on the mechanisms involved in the action of levetiracetam (LVT, 2S-(oxo-1-pyrrolidinyl)butanoic acid amide), a widely used agent for the adjunctive therapy of partial epilepsy of different genesis, have been analyzed. A unique profile of the anticonvulsant action of LVT was already revealed at the screening stage: this agent was not effective in the traditional tests, but it demonstrated a pronounced protective effect in kindling models and in the experiments on mice sensitive to the audiogenic convulsions. Now it is commonly accepted that the LVT mode of action is different from that of the other known antiepileptic drugs. LVT was shown to have specific binding sites in the brain. It is believed that the synaptic vesicle protein SV2A is the binding site for LVT, and the main mechanism of its action involves the modulation of this protein functions, which probably accounts for the unique profile of the antiepileptic activity of LVT. The results of investigations of the neurochemical mechanisms of LVT action suggest that proteins involved in the vesicular exocytosis, in particular SV2, can be promising targets in the search for new effective agents for the treatment of CNS diseases.