Inhibition of UDP‐Glucuronosyltransferase (UGT) Isoforms by Arctiin and Arctigenin

Arctiin is the major pharmacological ingredient of Fructus Arctii, and arctigenin is the metabolite of arctiin formed via the catalysis of human intestinal bacteria. The present study aims to investigate the inhibition profile of arctiin and arctigenin on important phase II drug‐metabolizing enzymes UDP‐glucuronosyltransferases (UGTs), indicating the possible herb–drug interaction. In vitro screening experiment showed that 100 μM of arctiin and arctigenin inhibited the activity of UGT1A3, 1A9, 2B7, and 2B15. Homology modeling‐based in silico docking of arctiin and arctigenin into the activity cavity of UGT2B15 showed that hydrogen bonds and hydrophobic interactions contributed to the strong binding free energy of arctiin (?8.14 kcal/mol) and arctigenin (?8.43 kcal/mol) with UGT2B15. Inhibition kinetics study showed that arctiin and arctigenin exerted competitive and noncompetitive inhibition toward UGT2B15, respectively. The inhibition kinetic parameters (K_i) were calculated to be 16.0 and 76.7 μM for the inhibition of UGT2B15 by arctiin and arctigenin, respectively. Based on the plasma concentration of arctiin and arctigenin after administration of 100 mg/kg of arctiin, the [I]/K_i values were calculated to be 0.3 and 0.007 for arctiin and arctigenin, respectively. Based on the inhibition evaluation standard ([I]/K_i < 0.1, low possibility; 0.1 < [I]/K_i < 1, medium possibility; [I]/K_i > 1, high possibility), arctiin might induce drug–drug interaction with medium possibility. Based on these results, clinical monitoring the utilization of Fructus Arctii is very important and necessary. Copyright © 2016 John Wiley & Sons, Ltd.     

Anti-inflammatory activity of arctigenin from Forsythiae Fructus

Oleaceae Forsythiae Fructus has been used for anti-inflammatory, diuretics, antidote, and antibacterials in traditional herbal medicine. Our previous screening of medicinal plants showed that methanol (MeOH) extract of Forsythiae Fructus had significant anti-inflammatory activity, but the active ingredients remain unclear. For isolation of active ingredient of MeOH extract of Forsythiae Fructus, it was partitioned with n-hexane and ethylacetate (EtOAc), and arctigenin was isolated from EtOAc fraction by column chromatography with anti-inflammatory activity-guided separation. Its activity was evaluated in the animal models of inflammation including myeloperoxidase (MPO) and eosinophil peroxidase (EPO) activities in the edematous tissues homogenate, and silica-induced reactive oxygen species (ROS) production in the RAW 264.7 cell line. It was shown that arctigenin (100 mg/kg) had significantly decreased not only carrageenan-induced paw edema 3 and 4h after injection of carrageenan, arachidonic acid (AA)-induced ear edema at a painting dose of 0.1-1.0mg/ear, and acetic acid-induced writhing response and acetic acid-induced capillary permeability accentuation at an oral dose of 25-100, and 100 mg/kg, respectively, but also MPO and EPO activities at a painting dose of 0.1-1.0mg/ear in the AA-induced edematous tissues homogenate as indicators of neutrophils and eosinophils recruitment into the inflamed tissue. Further, arctigenin (0.1-10 microM) also significantly inhibited the intracellular ROS production by silica. These results indicate that arctigenin is a bioactive agent of Forsythiae Fructus having significant anti-inflammatory action by inhibition of the exudation, and leukocytes recruitment into the inflamed tissues. The pharmacologic mechanism of action of arctigenin may be due to the inhibition of release/production of inflammatory mediators such as AA metabolites and free radicals.     

Pharmacology and immunological actions of a herbal medicine ASHMITM on allergic asthma

Allergic asthma is a chronic and progressive inflammatory disease for which there is no satisfactory treatment. Studies reported tolerability and efficacy of an anti‐asthma herbal medicine intervention (ASHMI) for asthma patients, developed from traditional Chinese medicine. To investigate the pharmacological actions of ASHMI on early‐ and late‐phase airway responses (EAR and LAR), Ovalbumin (OVA)‐sensitized mice received 6 weeks of ASHMI treatment beginning 24 h following the first intratracheal OVA challenge. EAR were determined 30 min following the fourth challenge and LAR 48 h following the last challenge. ASHMI effects on cytokine secretion, murine tracheal ring contraction and human bronchial smooth muscle cell prostaglandin (PG) production were also determined. ASHMI abolished EAR, which was associated with significantly reduced histamine, leukotriene C4, and OVA‐specific IgE levels, as well as LAR, which was associated with significantly reduced bronchoalveolar lavage fluid (BALF) eosinophils, decreased airway remodeling, and lower Th2 cytokine levels in BALF and splenocyte cultures. Furthermore, ASHMI inhibited contraction of murine tracheal rings and increased production of the potent smooth muscle relaxer PGI₂. ASHMI abrogation of allergic airway responses is associated with broad effects on asthma pathological mechanisms. Copyright © 2009 John Wiley & Sons, Ltd.     

Anti‐inflammatory activity of Rhodiola rosea – “a second‐generation adaptogen”

Rhodiola rosea (golden root), a unique phytoadaptogen grown in high‐altitude regions has gained attention for its various therapeutic properties. In India, this plant is found in the Himalayan belt and has not been completely explored for its beneficial health effects. The present study was undertaken to evaluate the anti‐inflammatory efficacy of the tincture extract of Rhodiola rosea roots (RTE). The anti‐inflammatory activity was determined through carrageenan‐induced paw oedema, formaldehyde‐induced arthritis and nystatin‐induced paw oedema in rat model. The tincture extract exhibited inhibitory effect against acute and subacute inflammation at a dose of 250 mg/kg body weight. Inhibition of nystatin‐induced oedema was also observed in a dose‐dependent manner. The in vitro inhibitory effects of the tincture extract from R. rosea roots was evaluated against the enzymes relating to inflammation. The enzymes include cyclooxygenase‐1 (COX‐1), cyclooxygenase‐2 (COX‐2) and Phospholipase A₂ (PLA₂). The extract showed varying inhibitory activities against these enzymes depending on the concentrations. A potent inhibition was observed against Cox‐2 and PLA₂. Inhibition of nystatin induced oedema and phospholipase A₂ suggested that membrane stabilization could be the most probable mechanism of action of RTE in anti‐inflammation. The findings in this study may provide the use of R. rosea root extract in the treatment of inflammatory conditions. Copyright © 2009 John Wiley & Sons, Ltd.     

虫草菌粉对致敏豚鼠肺功能和大鼠气道炎症反应的影响

目的 :探索人工发酵虫草菌粉防治支气管哮喘方面的新用途。方法 :测定肺功能和肺灌流液中嗜酸性粒细胞变化。结果 :虫草菌粉 5 g·kg^-1对致敏豚鼠抗原攻击引起的肺阻力增高和动态肺顺应性降低以及致敏大鼠肺灌流液中嗜酸性粒细胞增多都有明显抑制作用 (P<0 .05)。结论 :结果提示虫草菌粉可用于哮喘缓解期的治疗或与其它平喘药合用。     

Bioactivity-guided isolation of antiproliferative compounds from Centaurea arenaria

The antiproliferative effects of n-hexane, chloroform and aqueous methanol extracts prepared from the whole plant of Centaurea arenaria M.B. ex Willd. were investigated against cervix adenocarcinoma (HeLa), breast adenocarcinoma (MCF7) and skin epidermoid carcinoma (A431) cells, using the MTT assay. The chloroform extract displayed high tumour cell proliferation inhibitory activity (higher than 85% at 10 μg/mL concentration), and was therefore subjected to a bioassay-guided multistep separation procedure. Flavonoids (eupatilin, eupatorin, 3'-methyleupatorin, apigenin and isokaempferid), lignans (arctigenin, arctiin and matairesinol), the sesquiterpene cnicin, serotonin conjugates (moschamine and cis-moschamine), β-amyrin and β-sitosterin-β-D-glycopyranoside, identified by means of UV, MS and NMR spectroscopy, were obtained for the first time from this species. The isolated compounds were also evaluated for their tumour cell growth inhibitory activities on HeLa, MCF7 and A431 cells, and different types of secondary metabolites were found to be responsible for the antitumour effects of the extracts; in addition to moderately active compounds (isokaempferid and moschamine), especially apigenin, eupatorin, arctigenin, arctiin, matairesinol and cnicin exert marked antitumour effects against these cell lines.     

Antidepressant profile of Ptychopetalum olacoides Bentham (Marapuama) in mice

Depression has become of universal major importance, and it is therefore vital to expand the armamentarium for treating the condition. Lack of motivation and lassitude are major symptoms treated with the use of Marapuama (Ptychopetalum olacoides, PO) remedies by communities in the Brazilian Amazon. Considering the prominence of such symptoms in depression, the present study was designed to verify the effects of a standardized PO ethanol extract (POEE) on the forced swimming (FST) and tail suspension tests (TST). POEE i.p. (15–100 mg/kg) and oral (300 mg/kg) resulted in a significant and dose‐related anti‐immobility effect. We further examined the involvement of dopamine, noradrenaline and serotonin in these antidepressant‐like effects. POEE effects were prevented when catecholamine synthesis was inhibited by ‐α‐methyl‐ρ‐tyrosine (AMPT) (100 mg/kg, i.p.), while inhibition of serotonin synthesis with ρ‐chlorophenylalanine methyl ester hydrochloride (PCPA) (100 mg/kg, i.p.) was devoid of effect. The blockade of β‐adrenergic (propranolol 2 mg/kg, i.p.) and D₁ dopamine (SCH 23390 0.5 mg/kg, i.p.) receptors prevented POEE anti‐immobility effects; by contrast, blockade of D₂ dopamine (sulpiride 2 and 50 mg/kg, i.p.) receptors was ineffective. Consistent with traditional use, the results indicate that POEE possesses antidepressant‐like effects, possibly mediated by β‐adrenergic and D₁ dopamine receptors. Copyright © 2008 John Wiley & Sons, Ltd.     

Highly Oxygenated Sesquiterpene Lactones from Cousinia aitchisonii and their Cytotoxic Properties: Rhaserolide Induces Apoptosis in Human T Lymphocyte (Jurkat) Cells via the Activation of c‐Jun n‐terminal Kinase Phosphorylation

Infrared‐guided chromatographic fractionation of sesquiterpene lactones from the extracts of Cousinia aitchisonii and Cousinia concolor led to the isolation of five pure compounds. A new sesquiterpene lactone, namely, aitchisonolide, and two known sesquiterpene lactones (desoxyjanerin and rhaserolide) were isolated from C. aitchisonii and two known lignans (arctiin and arctigenin) from C. concolor. The structures of these compounds were elucidated by one‐dimensional and two‐dimensional nuclear magnetic resonance techniques, as well as high‐resolution mass spectrometry. The purified and characterized compounds were subjected to cytotoxicity assay. The sesquiterpene lactones desoxyjanerin and rhaserolide showed significant cytotoxic activities against five different cancer cell lines and the normal human embryonic kidney cell line. Rhaserolide was chosen to evaluate the possible mechanism of action. Western blot analysis revealed that rhaserolide could induce apoptosis in Jurkat cells via the activation of c‐Jun n ‐terminal kinase phosphorylation. Copyright © 2015 John Wiley & Sons, Ltd.     

Inhibitory effect of n-butylidenephthalide on neointimal hyperplasia in balloon injured rat carotid artery

This investigation was designed to determine the inhibitory effects and mechanisms of n‐butylidenephthalide (BP) from Angelica sinensis on smooth muscle cell (SMC) proliferation in vitro and in balloon injured rat carotid artery. Treatment of cultured rat aorta SMC‐derived A7r5 cells with 25–100 μg/mL BP significantly inhibited the proliferation and arrested the cell cycle in G₀/G₁ phase. BP induced the expression and migration of Nur77 from the nucleus to the cytoplasm. Among signal pathways, JNK and p38 MAPK were phosphorylated after BP treatment. In vivo, the neointimal area of common carotid artery 2 weeks after balloon injury reduced significantly in Sprague‐Dawley rats treated with 150–300 mg/kg BP compared with the control. The proliferative activity indicated by immunohistochemical detection of Ki‐67 positive cells in the neointima was significantly decreased in the 60–300 mg/kg BP treatment groups. The apoptotic activity indicated by cleaved caspase‐3 positive cells and Nur77 positive cells in the neointima was significantly increased in rats treated with 60–300 mg/kg BP. This study demonstrated BP inhibited neointimal hyperplasia in balloon injured rat carotid artery due to its dual effects of proliferative inhibition and apoptotic induction on SMCs. Up‐regulation of Nur77 gene may partly explain the antihyperplasia activity of BP on the neointima. Copyright © 2011 John Wiley & Sons, Ltd.     

Scutellarin inhibits cytochrome P450 isoenzyme 1A2 (CYP1A2) in rats

Scutellarin is the most important flavone glycoside in the herbal drug Erigeron breviscapus (Vant.) Hand.‐Mazz. It is used frequently in the clinic to treat ischemic vascular diseases in China. However, the direct relationship between scutellarin and cytochrome P450 (CYP450) is unclear. The present study investigated the in vitro and in vivo effects of scutellarin on cytochrome P450 1A2 (CYP 1A2) metabolism. According to in vitro experiments, scutellarin (10–250 µ m ) decreased the formation of 4‐acetamidophenol in a concentration‐dependent manner, with an IC₅₀ value of 108.20 ± 0.657 µ m . Furthermore, scutellarin exhibited a weak mixed‐type inhibition against the activity of CYP1A2 in rat liver microsomes, with a K_i value of 95.2 µ m . Whereas in whole animal studies, scutellarin treatment for 7 days (at 5, 15, 30 mg/kg, i.p.) decreased the clearance (CL), and increased the T_1/2 (at 15, 30 mg/kg, i.p.), it did not affect the V_d of phenacetin. Scutellarin treatment (at 5, 15, 30 mg/kg, i.p.) increased the AUC_0‐∞ by 14.3%, 67.3% and 159.2%, respectively. Scutellarin at 30 mg/kg also weakly inhibited CYP1A2 activity, in accordance with our in vitro study. Thus, the results indicate that CYP1A2 is inhibited directly, but weakly, by scutellarin in vivo, and provide useful information on the safe and effective use of scutellarin in clinical practice. Copyright © 2012 John Wiley & Sons, Ltd.     

Quercetin reduced the formation of N‐acetyl‐p‐benzoquinoneimine,a toxic metabolite of paracetamol in rats and isolated rat hepatocytes

N‐acetyl‐p‐benzoquinoneimine (NAPQI) is toxic metabolite of paracetamol formed primarily by cytochrome P4502E1 (CYP2E1) metabolic pathway when administered at therapeutic doses or overdose. The influence of quercetin (flavonoid) on the bioactivation of paracetamol to NAPQI was investigated using rat liver microsomes and rats in vivo. Paracetamol (80 mg/kg) was administered orally without or with silymarin (100 mg/kg), a known inhibitor of CYP2E1, CYP3A4 and quercetin (10 and 20 mg/kg) to rats for 15 consecutive days. Area under the plasma concentration–time curve (AUC_0‐∞) and the peakplasma concentration (C_max) of paracetamol were dose‐dependently increased with quercetin (10 and 20 mg/kg) compared to paracetamol control group (p < 0.001). On the other hand, the AUC_0‐∞ and C_max of NAPQI were decreased significantly with quercetin. The same results were observed with silymarin also. The elevated liver and kidney functional enzymes/compounds were significantly reduced by quercetin and silymarin compared to paracetamol control group. The formation of NAPQI was reduced in the incubation samples in presence of quercetin in experiment using isolated rat hepatocytes. The presentstudy results revealed that quercetin might be inhibited the CYP2E1‐mediated metabolism of paracetamol; thereby decreased the formation of NAPQI and protected the liver and kidney.     

Protective effects of neohesperidin and poncirin isolated from the fruits of Poncirus trifoliata on potential gastric disease

The effects of Poncirus trifoliata (P. trifoliata) (Ponciri Fructus, PF) extract and its constituents such as neohesperidin and poncirin on gastritis in rats and human gastric cancer cells were investigated. The PF 70% ethanol extracts (1 g) showed approximately 11.38% of acid‐neutralizing capacities and cytotoxicity (IC₅₀ = 85.39 µg/mL) against human AGS gastric cancer cells. In addition, neohesperidin exhibited antioxidant activity (IC₅₀ = 22.31 µg/mL) in the 1,1‐diphenyl‐2‐picryldydrazyl (DPPH) radical‐scavenging assay. Neohesperidin (50 mg/kg) and poncirin (100 mg/kg) significantly inhibited 55.0% and 60.0% of HCl/ethanol‐induced gastric lesions, respectively, and increased the mucus content. In pylorus ligated rats, neohesperidin (50 mg/kg) significantly decreased the volume of gastric secretion and gastric acid output, and increased the pH. From these results, it could be suggested that neohesperidin and poncirin isolated from PF may be useful for the treatment and/or protection of gastritis. Copyright © 2009 John Wiley & Sons, Ltd.     

Anti‐allergic effects of total bakkenolides from Petasites tricholobus in ovalbumin‐sensitized rats

The anti‐allergic effect of total bakkenolides from the rhizome of Petasites tricholobus (BAPT) was evaluated in an ovalbumin‐induced allergic rhinitis model in male Wistar rats. The major components of the bakkenolide fraction are bakkenolide‐D, bakkenolide‐B, bakkenolide‐IIIa and bakkenolide‐IVa, which account for 60.04% of the total. The rats were treated with 40 mg/kg, 20 mg/kg, 10 mg/kg or 5 mg/kg BAPT, and 0.942 mg/kg loratadine and 0.5% gum tragacanth were used as positive and negative controls, respectively. The frequency of nose rubbing and sneezing was observed, the number of eosinophils infiltrating into the nasal tissue was counted, and serum levels of IL‐4 and histamine were determined by ELISA. The results showed that BAPT had a beneficial effect on allergic rhinitis in ovalbumin‐sensitized Wistar rats, which was evidenced by a significant decrease in the frequency of sneezing, the number of eosinophils infiltrating into the nasal tissue, and the serum levels of IL‐4 and histamine. BAPT may therefore be a potential antiallergic drug. Copyright © 2010 John Wiley & Sons, Ltd.     

Amelioration of adjuvant induced arthritis by apocynin

The premise of the study was to investigate the antiarthritic potential of apocynin (APO) in Balb/c mice (in vivo). The experiment showed a dose‐dependent decrease in oedema and showed a suppression of proinflammatory cytokines such as TNF‐α and IL‐1β and mediators such as prostaglandin E₂ (PGE₂) and LTB₄. At oral doses of 0.5, 1.0, 2.0 and 4.0 mg/kg once daily during the course of the experiment, APO induced an inhibition of T cell mediated immune response causing suppression of CD4+ and CD8+ T cells and of intracellular interferon‐gamma (IFN‐γ) by flow cytometry in arthritic mice. In parallel there was a dose‐dependent inhibition in vascular permeability causing an inhibition in the migration of leucocytes and exudate volume at the site of the inflammatory reaction. These observations validate the immunoregulatory potential of apocynin. Copyright © 2009 John Wiley & Sons, Ltd.     

Effects of Piperine,Cinnamic Acid and Gallic Acid on Rosuvastatin Pharmacokinetics in Rats

The purpose of this study was to investigate the potential pharmacokinetic interactions with natural products (such as piperine (PIP), gallic acid (GA) and cinnamic acid (CA)) and rosuvastatin (RSV) (a specific breast cancer resistance protein, BCRP substrate) in rats. In Caco₂ cells, the polarized transport of RSV was effectively inhibited by PIP, CA and GA at concentration of 50 μM. After per oral (p.o.) coadministration of PIP, CA and GA (10 mg/kg) significantly increased intravenous exposure (AUC_last) of RSV (1 mg/kg) by 73.5%, 62.9% and 53.3% (p < 0.05), respectively than alone group (control). Compared with the control (alone) group, p.o. coadministration of PIP, CA and GA (10 mg/kg) significantly increased the oral exposure (AUC_last) of RSV (5 mg/kg) by 2.0‐fold, 1.83‐fold (p < 0.05) and 2.34 ‐fold (p < 0.05), respectively. Moreover, the cumulative biliary excretion of RSV (5 mg/kg, p.o.) was significantly decreased by 53.3, 33.4 and 39.2% at the end of 8 h after p.o. co‐administration of PIP, CA and GA (10 mg/kg), respectively. Taken together, these results indicate that the natural products such as PIP, CA and GA significantly inhibit RSV transport in to bile and increased the plasma exposure (AUC_last) of RSV. Copyright © 2012 John Wiley & Sons, Ltd.     

Screening of antiinflammatory medicinal plants used in traditional medicine against skin diseases

The antiinflammatory activity of twelve medicinal plants used against skin disorders were tested in different experimental models of topical inflammation and one in vitro inhibitory test against phospholipase A₂ (PLA₂) from Naja naja venom. Forsythia suspensa was the most active species on the arachidonic acid (AA) topical test. This last species together with Astragalus membranaceus and Ranunculus sceleratus were the most active on the 12-O-tetradecanoylphorbol-13-acetate (TPA) acute ear oedema test. Scrophularia auriculata was the most active on multiple topical applications of TPA and on the oxazolone-induced delayed type hypersensitivity (DTH). Santolina chamaecyparissus was the only species that inhibited PLA₂ in vitro. © 1998 John Wiley & Sons, Ltd.     

4‐Hydroxycinnamic acid suppresses airway inflammation and mucus hypersecretion in allergic asthma induced by ovalbumin challenge

In this study, we investigated whether 4‐hydroxycinnamic acid (HA) has a palliative effect on asthmatic inflammatory responses using a mouse model of ovalbumin (OVA)‐induced allergic asthma. The mice were divided into five groups, each consisting of seven females (normal control phosphate‐buffered saline); OVA (OVA sensitization/challenge); dexamethasone (DEX, OVA sensitization/challenge + dexamethasone 3 mg/kg); HA‐10 and HA‐20 OVA sensitization/challenge + HA 10 and 20 mg/kg, respectively). Mice treated with HA showed a reduction in airway hyperresponsiveness and in the number of inflammatory cells in bronchoalveolar lavage fluid (BALF) compared with asthmatic control. HA treatment also reduced the levels of interleukin (IL)‐5 and IL‐13 in BALF and of OVA‐specific immunoglobulin E in the serum compared with asthmatic control. HA treatment relieved airway inflammation and mucus overproduction caused by OVA exposure. Additionally, HA inhibited the increases in levels of nuclear factor kappa B, inducible nitric oxide synthase, and cyclooxygenase‐2 that normally occur after OVA exposure. HA treatment also reduced the activity and protein level of matrix metalloproteinase‐9. Taken together, HA effectively suppressed asthmatic airway inflammation and mucus production caused by OVA exposure. These findings indicate that HA has the potential to be used as a therapeutic agent for asthma.     

Effect of Curcumin Against Pentylenetetrazol‐Induced Seizure Threshold in Mice: Possible Involvement of Adenosine A1 Receptors

Curcumin, obtained from Curcuma longa, has been in use for manifold human disorders. The present study explores the effect of curcumin against pentylenetetrazol (PTZ) seizure threshold in mice. The possible involvement of adenosine receptor(s) mechanism was also investigated. Minimal dose of PTZ (i.v., mg/kg) needed to induce different phases of convulsions were recorded as an index of seizure threshold. Curcumin (20–120 mg/kg, p.o.) produced an increase in seizure threshold for convulsions induced by PTZ i.v. infusion. The anticonvulsant effect of curcumin (80 mg/kg) was prevented by 8‐phenyltheophylline (0.5 mg/kg, i.p., non‐selective adenosine receptor antagonist) and 8‐cyclopentyl‐1,3‐dipropylxanthine (5 mg/kg, i.p., adenosine A₁ receptor antagonist) but not by 8‐(3‐cholorostryl)caffeine (4 mg/kg, i.p., adenosine A_2A receptor antagonist). Further, 5′‐N‐ethylcarboxamidoadenosine (0.005 mg/kg, i.p., non‐selective A₁/A₂ receptor agonist), or N⁶‐cyclohexyladenosine (0.2 mg/kg, i.p., adenosine A₁ receptor agonist), was able to potentiate the anticonvulsant action of curcumin. In contrast, 5′‐(N‐cyclopropyl) carboxamidoadenosine (0.1 mg/kg, i.p., adenosine A_2A receptor agonist) failed to potentiate the effect of curcumin. This study demonstrated the anticonvulsant effect of curcumin against PTZ i.v. seizure threshold via a direct or indirect activation of adenosine A₁ but not A_2A receptors in mice. Thus, curcumin may prove to be an effective adjunct in treatment of convulsions. Copyright © 2013 John Wiley & Sons, Ltd.     

Suppression of inducible nitric oxide synthase expression by furfuran lignans from flower buds of Magnolia fargesii in BV‐2 microglial cells

Activated microglia produces diverse neurotoxic factors such as nitric oxide (NO) and tumor necrosis factor‐α that serve as apoptotic inducers resulting in various neurodegenerative diseases. The inhibition of microglia‐derived NO production by inducible nitric oxide synthase (iNOS) has been reported to be beneficial in retarding neurodegenerative disorders. Three active lignans have been isolated from the flower buds of Magnolia fargesii by the bioassay‐guided fractionation using lipopolysaccharide (LPS)‐activated BV‐2 microglial cell culture system. The structures of them were identified as kobusin (1), aschantin (2) and fargesin (3) by the analyses of spectroscopic data. They inhibited the production of NO by activated microglia. Their IC₅₀ values were 21.8 ± 3.7, 14.8 ± 2.5 and 10.4 ± 2.8 μg/mL, respectively. They suppressed LPS‐induced NF‐κB activation and the expression of iNOS protein and mRNA. Furthermore, they showed scavenging activity of neurotoxic peroxynitrite that can be produced by NO and superoxide anion. These results imply that lignans from Magnolia fargesii might be beneficial for the treatment of neuro‐inflammatory diseases through the inhibition of iNOS expression and peroxynitrite scavenging potential. Copyright © 2009 John Wiley & Sons, Ltd.     

Antithrombotic Effect of a Polysaccharide Fraction from Laminaria japonica from the South China Sea

Some in vitro studies have identified an antithrombotic effect of polysaccharides from Laminaria japonica, but this activity remains to be confirmed in vivo. In this study a polysaccharide fraction termed PLG was extracted from L. japonica in the Beibu Gulf in Guangxi, China, and its antithrombotic effects explored in rat models of carotid and venous thrombosis. Its anticoagulation and antiplatelet properties were assessed by measuring the prothrombin time (PT), activated partial thromboplastin time (APTT) and ADP‐induced platelet aggregation rate (Agg_max). Its effects on bleeding time were measured using the tail transection method. It was found that pretreatment with an intraperitoneal injection of PLG at 2.5 or 5.0 mg/kg significantly prolonged the occlusion time in the carotid thrombosis model, and a dose of 5.0 mg/kg reduced the thrombus weight in the venous thrombosis model. Pretreatment with PLG (5.0 mg/kg) increased the APTT and decreased the ADP‐induced platelet Agg_max. Neither dose of PLG significantly prolonged the bleeding time compared with the control group. In an in vitro anticoagulation assay using human plasma, PLG at 57.14, 28.57 and 28.57 μg/mL inhibited APTT and PT in a concentration‐dependent manner. The results show that PLG possesses antithrombotic activity in a rat model, and that it may prove to be clinically useful in humans. Copyright © 2011 John Wiley & Sons, Ltd.