Yuen Fan Wong

Anti-inflammatory and analgesic effect of plumbagin through inhibition of nuclear factor-κB activation.

Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) (PL) is a naturally occurring yellow pigment found in the plants of the Plumbaginaceae, Droseraceae, Ancistrocladaceae, and Dioncophyllaceae families. It has been reported that PL exhibits anticarcinogenic, anti-inflammatory, and analgesic activities. However, the mechanism underlying its anti-inflammatory action remains unknown. In the current study, we investigated and characterized the anti-inflammatory and analgesic effects of PL orally administrated in a range of dosages from 5 to 20 mg/kg. We also examined the role of nuclear factor κB (NF-κB) and proinflammatory cytokines and mediators in this effect. The results showed that PL significantly and dose-dependently suppressed the paw edema of rats induced by carrageenan and various proinflammatory mediators, including histamine, serotonin, bradykinin, and prostaglandin E2. PL reduced the number of writhing episodes of mice induced by the intraperitoneal injection of acetic acid, but it did not reduce the writhing episode numbers induced by MgSO4 in mice or prolong the tail-flick reaction time of rats to noxious thermal pain. Mechanistic studies showed that PL effectively decreased the production of the proinflammatory cytokines interleukin 1β, interleukin 6, and tumor necrosis factor α. It also inhibited the expression of the proinflammatory mediators inducible nitric-oxide synthase and cyclooxygenase 2, whereas it did not inhibit the expression of cyclooxygenase 1. Further studies demonstrated that PL suppressed inhibitor of κBα phosphorylation and degradation, thus inhibiting the phosphorylation of the p65 subunit of NF-κB. This study suggests that PL has a potential to be developed into an anti-inflammatory agent for treating inflammatory diseases.

Sinomenine ameliorates arthritis via MMPs, TIMPs, and cytokines in rats

Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disease that results in progressive joint destruction and substantial morbidity. The stem of the Chinese medicinal plant, Sinomenium acutum Rehder & Wilson (Family Menispermaceae), has been used to treat various rheumatic and arthritic diseases, of which the major bioactive component is sinomenine. We investigated the nature and molecular mechanisms of the anti-arthritic effect of sinomenine on collagen-induced arthritis in female Wistar rats. The results showed that sinomenine markedly suppressed the incidence and disease progression of established CIA, showing as dramatic reduction of paw swelling, ESR, and arthritic scores. Sinomenine suppressed the production of proinflammatory cytokines IL-1beta and IL-6 in serum, inhibited the protein expressions and activities of MMP-2 and MMP-9, and elevated the protein expressions and activities of TIMP-1 and TIMP-3 in rat paw tissues.

Ginseng protects rodent hearts from acute myocardial ischemia-reperfusion injury through GR/ER-activated RISK pathway in an endothelial NOS-dependent mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE Ginseng (Panax ginseng C.A. Meyer) is widely used in Asian communities for treating cardiovascular diseases. However, the mechanism by which it protects the myocardium in ischemia-reperfusion (I/R) injury remains unclear. In this study, we aim to investigate whether a standardized ginseng extract (RSE) protects rodent hearts against I/R injury and if glucocorticoid and/or estrogen receptor-mediated activation of Akt and Erk1/2 (the reperfusion injury salvage kinase pathway, RISK) and subsequent nitric oxide (NO) synthesis signaling are involved in this effect. MATERIALS AND METHODS Rats or gene-deleted mice were subjected to 30 min ischemia by occluding the left anterior descending coronary artery and 90 min reperfusion. Infarct size, serum level of creatine kinase (CK), lactate dehydrogenase (LDH), and NO, expression and phosphorylation of glucocorticoid receptor (GR), estrogen receptor (ER), phosphatidylinositol-3 kinase (PI3K), Akt, NO synthase (NOS), extracellular signal-regulated kinase (Erk) 1/2, p38, and c-Jun NH2 terminal kinases (JNK) were examined in rat or mice treated with or without RSE in the absence or presence of pharmacological inhibitors. RESULTS RSE significantly reduced infarct size in a dose-dependent manner and reduced the incidence of arrhythmia, increased serum NO production, reduced serum activities of creatine kinase and lactate dehydrogenase. The infarct size reduction effect of RSE was abolished by RU468 (an inhibitor of GR), tamoxifen (an inhibitor of ER), LY294002 (an inhibitor of PI3K), Akt inhibitor IV (an inhibitor of Akt protein kinase), U0126 (an inhibitor of Erk1/2) and NG-nitro-l-arginine methyl ester hydrochloride (an inhibitor of NOS), but not actinomycin D (an inhibitor of transcription process). RSE also significantly increased the activation of GR/ER, PI3K-Akt-eNOS cascades and Erk1/2 signaling in rat heart. However, RSE did not markedly reduce infarct size in endothelium NOS(-/-) mice. This differs from its effect in inducible NOS(-/-) and wild type mice, suggesting that endothelium NOS is required for the beneficial effect of RSE on the heart. CONCLUSION Our findings showed for the first time that RSE protects hearts subjected to acute I/R injury and the infarct size reduction effect of RSE is associated with GR and/or ER-mediated Akt and Erk1/2 activation in an endothelium NOS-dependent manner.

Pseudolaric acid B suppresses T lymphocyte activation through inhibition of NF-κB signaling pathway and p38 phosphorylation.

Pseudolaric acid B (PAB) is a major bioactive component of the medicinal plant Pseudolarix kaempferi. Traditional medicine practitioners in Asia have been using the roots of this plant to treat inflammatory and microbial skin diseases for centuries. In the current study, in vitro immunosuppressive effect of PAB and the underlying mechanisms have been investigated. The results showed that PAB dose‐dependently suppressed human T lymphocyte proliferation, IL‐2 production and CD25 expression induced by co‐stimulation of PMA plus ionomycin or of anti‐OKT‐3 plus anti‐CD28. Mechanistic studies showed that PAB significantly inhibited nuclear translocation of NF‐κB p65 and phosphorylation and degradation of IκB‐α evoked by co‐stimulation of PMA plus ionomycin. PAB could also suppress the phosphorylation of p38 in the MAPKs pathway. Based on these evidences, we conclude that PAB suppressed T lymphocyte activation through inhibition of NF‐κB and p38 signaling pathways; this would make PAB a strong candidate for further study as an anti‐inflammatory agent. J. Cell. Biochem. 108: 87–95, 2009.

Paeoniflorin reduced acute toxicity of aconitine in rats is associated with the pharmacokinetic alteration of aconitine

ETHNOPHARMACOLOGICAL RELEVANCE To investigate the influence of paeoniflorin (major bioactive component of Paeonia lactiflora Pall.) on the pharmacokinetic behavior of aconitine (major toxic and bioactive component of Aconitum carmichaeli Debx.) and potential detoxifying effect of paeoniflorin on the acute toxicity of aconitine, which may provide in depth understanding to the toxicity reduction effect of Paeonia lactiflora to Aconitum carmichaeli. MATERIALS AND METHODS Ultra high performance liquid chromatography coupled with triple quadrupole mass spectrometer (UHPLC-MS/MS) was employed to determine the plasma content of aconitine. Aconitine was administrated by oral to SD rats at the dosage of 200 μg/kg with or without paeoniflorin given by intraperitoneal injection at the dosage of 20 mg/kg. Plasma samples were collected for determination and analysis of pharmacokinetic parameters of aconitine. The LD(50) of aconitine and acute animal death induced by aconitine were examined when aconitine was given alone or jointly with paeoniflorin in ICR mice. RESULTS A sensitive, accurate, precise, reliable and repeatable UHPLC-MS/MS method was successfully established for determination of the plasma content of aconitine in 12.5 μL plasma sample. The lower limit of quantification of aconitine was 0.01 ng/mL. Compared with the SD rats that were orally administrated with aconitine alone, the rats received aconitine and co-administrated with paeoniflorin by peritoneal injection showed a remarkably lower C(max) (5.69 ng/mL vs 9.66 ng/mL, P<0.05) and delayed T(max) (70 min vs 46 min, P<0.05), as well as a trend of reduction in AUC(0-t) (1082.75 ng-min/mL vs 1650.27 ng-min/mL, P=0.395). The LD(50) values of aconitine coadministered with 120 or 240 mg/kg of paeoniflorin were obviously increased to 2.30 and 2.15 mg/kg against 1.80 mg/kg of aconitine by oral administration alone. Mice treated with paeoniflorin (240 mg/kg) and aconitine (1.8 mg/kg) together revealed a significant decreased death rate than that received aconitine treatment alone (15% vs 50%, P<0.05). CONCLUSIONS The acute oral toxicity of aconitine in rats was significantly reduced by paeoniflorin; this might result from the alterations of pharmacokinetic behavior of aconitine in the animals by coadministration of paeoniflorin.

An optimized high-performance liquid chromatography (HPLC) method for benzoylmesaconine determination in Radix Aconiti Lateralis Preparata ( Fuzi , aconite roots) and its products

BackgroundBenzoylmesaconine (BMA) is the main Aconitum alkaloid in Radix Aconiti Lateralis Preparata (Fuzi, aconite roots) with potent pharmacological activities, such as analgesia and anti-inflammation. The present study developed a simple and reliable method using BMA as a marker compound for the quality control of processed aconite roots and their products.MethodsAfter extraction, a high-performance liquid chromatography (HPLC) determination of BMA was conducted on a RP-C18 column by gradient elution with acetonitrile and aqueous phase, containing 0.1% phosphoric acid adjusted with triethylamine to pH 3.0.ResultsA distinct peak profile was obtained and separation of BMA was achieved. Method validation showed that the relative standard deviations (RSDs) of the precision of BMA in all intra-day and inter-day assays were less than 1.36%, and that the average recovery rate was 96.95%. Quantitative analysis of BMA showed that the content of BMA varied significantly in processed aconite roots and their products.ConclusionThis HPLC method using BMA as a marker compound is applicable to the quality control of processed aconite roots and their products.

Mutation of cysteine 46 in IKK-beta increases inflammatory responses

Activation of IκB kinase β (IKK-β) and nuclear factor (NF)-κB signaling contributes to cancer pathogenesis and inflammatory disease; therefore, the IKK-β−NF-κB signaling pathway is a potential therapeutic target. Current drug design strategies focus on blocking NF-κB signaling by binding to specific cysteine residues on IKK-β. However, mutations in IKK-β have been found in patients who may eventually develop drug resistance. For these patients, a new generation of IKK-β inhibitors are required to provide novel treatment options. We demonstrate in vitro that cysteine-46 (Cys-46) is an essential residue for IKK-β kinase activity. We then validate the role of Cys-46 in the pathogenesis of inflammation using delayed-type hypersensitivity (DTH) and an IKK-βC46A transgenic mouse model. We show that a novel IKK-β inhibitor, dihydromyricetin (DMY), has anti-inflammatory effects on WT DTH mice but not IKK-βC46A transgenic mice. These findings reveal the role of Cys-46 in the promotion of inflammatory responses, and suggest that Cys-46 is a novel drug-binding site for the inhibition of IKK-β.

The Predicted Proteomic Network Associated with the Antiarthritic Action of Qingfu Guanjieshu in Collagen-II-Induced Arthritis in Rats

Qingfu Guanjieshu (QFGJS) is an herbal preparation for treating rheumatoid arthritis (RA). Previous studies revealed that QFGJS significantly inhibited experimental arthritis and acute inflammation, accompanied by reduction of proinflammatory cytokines and elevation of anti-inflammatory cytokines. This study aims to identify the targeted proteins and predict the proteomic network associated with the drug action of QFGJS by using 2D gel and MALDI-TOF-MS/MS techniques. Thirty female Wistar rats were evenly grouped as normal and vehicle- and QFGJS-treated CIA rats. The antiarthritic effect of QFGJS was examined with a 19-day treatment course, and the knee synovial tissues of animals from each group were obtained for 2D gel and MALDI-TOF-MS/MS analysis. Results showed that QFGJS significantly ameliorated collagen II-induced arthritis when administrated at 2.8 g/kg body weight for 19 days. 2D gel image analysis revealed 89 differentially expressed proteins in the synovial tissues among the normal and vehicle- and QFGJS-treated CIA rats from over 1000 proteins of which 63 proteins were identified by MALDI-TOF-MS/MS analysis, and 32 proteins were included for classification of functions using Gene Ontology (GO) method. Finally, 14 proteins were analyzed using bioinformatics, and a predicted proteomic network related to the anti-arthritic effect of QFGJS was established, and Pgk1 plays a central role.