lignans and clausenamide

Multi-target drugs, such as the cocktail therapy used for treating AIDS, often show stronger efficacy than single-target drugs in treating complicated diseases. This review will focus on clausenamide (clau), a small molecule compound originally isolated from the traditional Chinese herbal medicine, Clausenalansium. The finding of four chiral centers in clau molecules predicted the presence of 16 clau enantiomers, including (-)-clau and (+)-clau. All of the predicted enantiomers have been successfully synthesized via innovative chemical approaches, and pharmacological studies have demonstrated (-)-clau as a eutomer and (+)-clau as a distomer in improving cognitive function in both normal physiological and pathological conditions. Mechanistically, the nootropic effect of (-)-clau is mediated by its multi-target actions, which include mild elevation of intracellular Ca(2+) concentrations, modulation of the cholinergic system, regulation of synaptic plasticity, and activation of cellular and molecular signaling pathways involved in learning and memory. Furthermore, (-)-clau suppresses the pathogenesis of Alzheimer's disease by inhibiting multiple etiological processes: (1) beta amyloid protein-induced intracellular Ca(2+) overload and apoptosis and (2) tau hyperphosphorylation and neurodegeneration. In conclusion, the nature of the multi-target actions of (-)-clau substantiates it as a promising chiral drug candidate for enhancing human cognition in normal conditions and treating memory impairment in neurodegenerative diseases.

Topics: Animals; Dementia; Humans; Lactams; Lignans; Medicine, Chinese Traditional; Memory Disorders

Natural products have been used as medicinal agents for many years. In addition, these compounds have also served as the starting points for semisynthetic analogs with improved properties. This review focuses on recent advances in the pharmacological studies on natural products mainly performed and published in China. Emphasis will be placed on those compounds that show the greatest promise clinically such as huperzine A (9-amino-13-ethylidene-11-methyl-4-azatricyclo[7.3.1.0(3.8)]trideca-3(8),6,11-trien-5-one), s-(-)-3-n-butylphthalide (s-(-)-3-butyl-1(3H)-isobenzofuranone), (-)-clausenamide (3-hydroxy-4-phenyl-5a-hydroxybenzyl-N-methyl-gamma-lactam) and Ginkgo biloba extract and its active components.

Topics: Alkaloids; Animals; Benzofurans; Berberine; China; Cholinesterase Inhibitors; Diterpenes; Dopamine Agonists; Dopamine Antagonists; Drugs, Chinese Herbal; Epoxy Compounds; Ginkgo biloba; Humans; Immunosuppressive Agents; Lactams; Lignans; Neuroprotective Agents; Phenanthrenes; Rutaceae; Sesquiterpenes

The endoplasmic reticulum stress (ERS) and ERS-related neuronal apoptosis contribute to the cerebral ischemia/reperfusion (I/R) injury. (-)-Clausenamide has been reported to be nootropic and improve learning and memory in amnesia animal models. However, whether (-)-Clau could protect neurons from ischemic injury and the possible mechanism needed further study. The present study aimed to explore the effects of (-)-Clau on primary cortical neurons treated with oxygen-glucose deprivation/reoxygenation (OGD/R).. Rat primary cortical neurons were used to set up an injury model of OGD/R which imitated the clinical I/R injury. Cell viability and apoptosis were measured by CCK-8 assay, LDH detection and TUNEL staining, respectively. The activation of GRP78/eIF2α-ATF4-CHOP signaling pathway, one of the three branches of ERS, and cleaved caspase-3, the apoptotic marker, were assessed by western blotting.. OGD/R induced activation of GRP78/eIF2α-ATF4-CHOP signaling pathway. (-)-Clau significantly attenuated OGD/R-induced decrease in the cellular viability and the activation of GRP78, eIF2α, ATF4 and CHOP. To further confirm the effect of (-)-Clau on OGD/R-induced ERS activation, the ERS inducer Tunicamycin (TM) was applied. TM significantly abolished (-)-Clau's protective effect against ERS and neuronal apoptosis, indicating that the protective effect of (-)-Clau was dependent on inhibiting ERS.. The present work demonstrated for the first time that (-)-Clau could reverse the activation of GRP78/eIF2α-ATF4-CHOP branch, thus inhibited ERS and the subsequent apoptosis induced by OGD/R and promoted cell viability in vitro. (-)-Clau could serve as a promising therapeutic agent in the treatment for ischemic stroke in the future.. ATF4: activating transcription factor-4; ATF6: activating transcription factor-6; CHOP: transcriptional induction of CCAAT/enhancer binding protein homologous protein; (-)-Clau: 3-hydroxy-4-phenyl-5a-hydroxybenzylN-methyl-g-lactam; eIF2α: eukaryotic initiation factor 2α; ER: endoplasmic reticulum; ERS: endoplasmic reticulum stress; GRP78: 78-kDa glucose regulated protein; I/R: ischemia/reperfusion; IRE1: inositol requiring enzyme-1; JNK: c-Jun N-terminal kinase; OGD/R: oxygen-glucose deprivation/reoxygenation; PERK: double-stranded RNA-dependent protein kinase-like ER kinase; TM: Tunicamycin; UPR: unfolded protein response.

Topics: Animals; Apoptosis; Brain Ischemia; Cell Survival; Endoplasmic Reticulum Stress; Female; Lactams; Lignans; Male; Neurons; Neuroprotective Agents; Primary Cell Culture; Rats, Wistar; Reperfusion Injury; Signal Transduction

Drug-induced liver injury is the major cause of acute liver failure. However, the underlying mechanisms seem to be multifaceted and remain poorly understood, resulting in few effective therapies. Here, we report a novel mechanism that contributes to acetaminophen-induced hepatotoxicity through the induction of ferroptosis, a distinctive form of programmed cell death. We subsequently identified therapies protective against acetaminophen-induced liver damage and found that (+)-clausenamide ((+)-CLA), an active alkaloid isolated from the leaves of Clausena lansium (Lour.) Skeels, inhibited acetaminophen-induced hepatocyte ferroptosis both in vivo and in vitro. Consistently, (+)-CLA significantly alleviated acetaminophen-induced or erastin-induced hepatic pathological damages, hepatic dysfunctions and excessive production of lipid peroxidation both in cultured hepatic cell lines and mouse liver. Furthermore, treatment with (+)-CLA reduced the mRNA level of prostaglandin endoperoxide synthase 2 while it increased the protein level of glutathione peroxidase 4 in hepatocytes and mouse liver, confirming that the inhibition of ferroptosis contributes to the protective effect of (+)-CLA on drug-induced liver damage. We further revealed that (+)-CLA specifically reacted with the Cys-151 residue of Keap1, which blocked Nrf2 ubiquitylation and resulted in an increased Nrf2 stability, thereby leading to the activation of the Keap1-Nrf2 pathway to prevent drug-induced hepatocyte ferroptosis. Our studies illustrate the innovative mechanisms of acetaminophen-induced liver damage and present a novel intervention strategy to treat drug overdose by using (+)-CLA.

Topics: Animals; Chemical and Drug Induced Liver Injury; Ferroptosis; Hepatocytes; Lactams; Lignans; Liver; Liver Failure, Acute; Male; Mice, Inbred C57BL; Oxidative Stress; Protective Agents; Reactive Oxygen Species

The (-)- and (+)-clausenamide (CLA) enantiomers have different pharmacokinetic effects in animals, but their association with putative stereoselective regulation of P-glycoprotein (P-gp) remains unclear. Using three cells expressing P-gp-Caco-2, KBv and rat brain microvessel endothelial cells(RBMEC), this study investigated the association of CLA enantiomers with P-gp. The results showed that the rhodamine 123 (Rh123) accumulation, an indicator of P-gp activity, in Caco-2, KBv and RBMECs was increased by (-)CLA (1 or 5 μmol/L) at 8.2%-28.5%, but reduced by (+)CLA at 11.7%-25.9%, showing stereoselectivity in their regulation of P-gp activity. Following co-treatment of these cells with each CLA enantiomer and verapamil as a P-gp inhibitor, the (+)-isomer clearly antagonized the inhibitory effects of verapamil on P-gp efflux, whereas the (-)-isomer had slightly synergistic or additive effects. When higher concentrations (5 or 10 μmol/L) of CLA enantiomers were added, the stimulatory effects of the (+)-isomer were converted into inhibitory ones, leading to an enhanced intracellular uptake of Rh123 by 24.5%-58.2%; but (-)-isomer kept its inhibition to P-gp activity, causing 30.0%-63.0% increase in the Rh123 uptake. The biphasic effects of (+)CLA were confirmed by CLA uptake in the Caco-2 cells. (+)CLA at 1 μmol/L had significantly lower intracellular uptake than (-)CLA with a ratio[(-)/(+)] of 2.593, which was decreased to 2.167 and 1.893 after CLA concentrations increased to 2.5 and 5 μmol/L. Besides, in the non-induced KB cells, (+)CLA(5 μmol/L) upregulated P-gp expression at 54.5% relative to vehicle control, and decreased Rh123 accumulation by 28.2%, while (-)CLA(5 μmol/L) downregulated P-gp expression at 15.9% and increased Rh123 accumulation by 18.0%. These results suggested that (-)CLA could be a P-gp inhibitor and (+)CLA could be a modulator with concentration-dependent biphasic effects on P-gp activity, which may result in drug-drug interactions when combined with other P-gp substrate drugs.

Topics: Animals; Antiviral Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Brain; Caco-2 Cells; Cell Line; Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Antagonism; Drug Synergism; Drugs, Chinese Herbal; Endothelial Cells; Epithelial Cells; Gene Expression Regulation; Humans; Lactams; Lignans; Rats; Rhodamine 123; Stereoisomerism; Verapamil

The present study developed a CYP3A4-expressed Caco-2 monolayer model at which effects of the efflux-metabolism alliance on the transport and uptake of clausenamide (CLA) enantiomers as CYP3A4 substrates were investigated. The apparent permeability coefficients (Papp) of (-) and (+)CLA were higher in the absorptive direction than those in the secretory direction with efflux ratios (ER) of 0.709±0.411 and 0.867±0.250 (×10(-6)cm/s), respectively. Their bidirectional transports were significantly reduced by 75.6-87.5% after treatment with verapamil (a P-glycoprotein inhibitor) that increased the rate of metabolism by CYP3A4, whereas the CYP3A4 inhibitor ketoconazole treatment markedly enhanced the basolateral to apical flux of (-) and (+)CLA with ERs being 2.934±1.432 and 1.877±0.148(×10(-6)cm/s) respectively. These changes could be blocked by the duel CYP3A4/P-glycoprotein inhibitor cyclosporine A, consequently, Papp values for CLA enantiomers in both directions were significantly greater than those obtained by using verapamil or ketoconazole, and their ERs were similar to those following (-) or (+)-isomer treatment alone. Furthermore, the uptake of (-)CLA was more than that of (+)CLA in the transfected cells. Incubation with ketoconazole decreased the intracellular concentrations of the two enantiomers. This effect disappeared in the presence of a CYP3A4 inducer dexamethasone. These results indicated that CYP3A4 could influence P-gp efflux, transport and uptake of CLA enantiomers as CYP3A4 substrates and that a duel inhibition to CYP3A4/ P-glycoprotein could enhance their absorption and bioavailability, which provides new insight into the efflux-metabolism alliance and will benefit the clinical pharmacology of (-)CLA as a candidate drug for treatment of Alzheimer's disease.

Topics: Biological Transport; Caco-2 Cells; Cloning, Molecular; Cytochrome P-450 CYP3A; DNA, Complementary; Dose-Response Relationship, Drug; Gene Expression Regulation, Enzymologic; Humans; Lactams; Lignans; Molecular Structure; Transfection

Eight new clausenamides, including three γ-lactams (1-3), four δ-lactams (4-7), and an amide (8), and seven known lactams, including compounds 9-11, which were purified from natural sources for the first time, were characterized from the leaves of Clausena lansium. Their structures were elucidated using spectroscopic methods, and the absolute configurations were determined using electronic circular dichroism and single-crystal X-ray diffraction analyses with Cu Kα radiation. Compound 2 (50 μM) protected 22.24% of cortical neurons against Aβ25-35-induced cell death.

Topics: Amyloid beta-Peptides; Carbazoles; Clausena; Lactams; Lignans; Molecular Structure; Neuroprotective Agents; Nuclear Magnetic Resonance, Biomolecular; Peptide Fragments; Plant Leaves; Stereoisomerism; Vietnam

The synthesis and biological evaluation of 5-hydroxy clausenamide (CM₂), one of the major metabolites of clausenamide, and its stereoisomers have been carried out. The absolute configurations of (-)- and (+)-CM₂ were assigned as 3S,4S,5S,6S and 3R,4R,5R,6R respectively based on (1)H NMR spectroscopic investigation and their chemical correlation to (-)- and (+)-clausenamidone (3). Electrophysiological assay showed that compound (+)-CM₂ and its C₆ epimer (+)-8a had significant effects on synaptic transmission and thus induced the long-term potentiation of the dentate gyrus.

Topics: Animals; Dentate Gyrus; Drug Evaluation, Preclinical; Female; Lactams; Lignans; Long-Term Potentiation; Magnetic Resonance Spectroscopy; Male; Mass Spectrometry; Rats, Sprague-Dawley; Stereoisomerism; Synaptic Transmission

Stereoselective differences in pharmacokinetics between clausenamide (CLA) enantiomers have been found after intravenous and oral administration of each enantiomer to rats. The differences could be associated with excretion and first-pass metabolism of two enantiomers. The data from this study demonstrated that (-)CLA was mainly excreted in feces with 13.9% of dose, whereas (+)CLA in bile with 17.2%. A large portion of CLA enantiomers could be transformed into hydroxyl metabolites. In the in vitro metabolic system using rat liver microsomes, it was found that (-)CLA was cleared more than its antipode with peak height ratios [(+)/(-)] from 1.0 to 1.8 at the corresponding substrate concentrations from 0.25 to 2mM. Further study in rabbits showed that two enantiomers underwent an intermediate degree of first-pass metabolism. (-)CLA had lower concentrations and AUC0-8h in the portal vein and heart than those of (+)CLA with rates of hepatic extraction 64.7% for (-)-isomer and 50.8% for (+)-isomer, and intrinsic metabolic clearances of (-) and (+)CLA being 186.3 and 107.2 (l/h), respectively. The first-pass metabolism was involved in CYP3A enzymes in the gut and liver, and different levels of CYP3A1 expression induced by (-)CLA or (+)CLA. Immunohistochemical analyses revealed that (-)-isomer significantly increased the expression of CYP3A1, while (+)-isomer had no obvious effects on it. Taken together, the results provided new evidence that stereoselective pharmacokinetics of CLA enantiomers could be resulted from their stereoselective excretion, first-pass metabolism and induction to metabolizing enzymes, which might be important in understanding the clinic pharmacology of active eutomer, (-)CLA, for treatment of Alzheimer's disease.

Topics: Animals; Bile; Cytochrome P-450 CYP3A; Feces; Female; Lactams; Lignans; Liver; Microsomes, Liver; Myocardium; Rabbits; Rats; Rats, Wistar; Stereoisomerism

Highly enantioselective synthesis of α,β-epoxy esters was achieved via one-pot organocatalytic epoxidation and consequent oxidative esterification. Excellent enantioselectivities (up to 99% ee) and good yields were obtained for a variety of α,β-epoxy esters. The method was readily scaled. Furthermore the product was applied towards the synthesis of (-)-clausenamide with excellent enantioselectivities (>99% ee).

Topics: Azoles; Catalysis; Epoxy Compounds; Esters; Lactams; Lignans; Molecular Structure; Oxidation-Reduction; Stereoisomerism

To investigate the signal mechanism of (-)clausenamide ((-)-3-hydroxy-5-(hydroxy-phenyl-methyl)-1-methyl-4-phenyl-pyrrolidin-2-one, 1) and for understanding its effect on synaptic transmission, electrophysiological recording was done for basal synaptic transmission determination. Western blot analysis was employed to examine the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and cAMP responsive element-binding protein (CREB). Immunohistochemistry and tissue in situ hybridization were applied to detect the expression of Zif268. The results showed that (-)clausenamide (1) increased the population spike of hippocampal dentate gyrus. The phosphorylation of ERK1/2 in hippocampus and cortex was increased and reached the maximum at 5 min and 30 min, respectively. (-)Clausenamide (1) promoted the phosphorylation of CREB, the downstream protein of ERK1/2. The expression of Zif268 protein and mRNA increased in both hippocampal dentate gyrus and cortex. Therefore, (-)clausenamide (1) activated the ERK1/2-CREB pathway, which may provide an explanation for its effect on potentiating synaptic transmission and improving learning and memory.

Topics: Animals; Cyclic AMP Response Element-Binding Protein; Dentate Gyrus; Early Growth Response Protein 1; Hippocampus; Lactams; Lignans; Male; Mitogen-Activated Protein Kinase 3; Molecular Structure; Phosphorylation; Rats; Rats, Wistar; Stereoisomerism; Synaptic Transmission

Clausenamide is a chiral compound isolated from leaves of the traditional Chinese herb Clausena lansium (lour) Skeels. It has been shown that (-)clausenamide, but not (+)clausenamide, improved learning and memory in amnesia animal models. However, the precise mechanism of clausenamide's actions remains unknown. Here we used an electrophysiological approach to observe the effect of (-)clausenamide on facilitating field excitatory postsynaptic potential (f-EPSP) in the CA1 area of hippocampal slices from rats. The results showed that (-)clausenamide enhanced synaptic transmission at doses 0.1, 1 and 10 μM. The increase of f-EPSP induced by (-)clausenamide was completely inhibited by preincubation with nimodipine (L-voltage-dependent calcium channel blocker, 10 μM), but there was no change when nimodipine was added after (-)clausenamide application. However, ryanodine (ryanodine receptors blocker, 100 μM) attenuated the slope of f-EPSP before or after (-)clausenamide incubation. The data suggested that (-)clausenamide promoted calcium influx to trigger intracellular calcium release which was responsible for potentiating synaptic transmission. Intracellular calcium release induced by (-)clausenamide promoted the activation of CaMKIIα at concentrations of 0.1, 1 and 10 μM, and pretreatment with KN93 (CaMKIIα inhibitor, 10 μM) completely blocked the enhancement of synaptic transmission induced by (-)clausenamide. cAMP response element-binding protein (CREB) was activated by (-)clausenamide and inhibited by KN93 preincubation, but H89 (PKA inhibitor, 10 μM) had no effect, indicating that (-)clausenamide facilitated synaptic transmission by a PKA-independent pathway. Collectively, (-)clausenamide facilitated synaptic transmission by promoting calcium influx to trigger intracellular calcium release, subsequently activating CaMKIIα-CREB signal pathway.

Topics: Animals; Axons; CA1 Region, Hippocampal; Calcium; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Cyclic AMP Response Element-Binding Protein; Excitatory Postsynaptic Potentials; In Vitro Techniques; Lactams; Lignans; Male; Memory; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Phosphorylation; Rats; Rats, Wistar; Synapses; Synaptic Transmission

Effect of (+)-epi-clausenamide and (-)-epi-clausenamide on synaptic transmission in CA1 region of hippocampal slice was compared in this study. (+)-epi-Clausenamide showed more potency than (-)-clausenamide on either induction or maintenance of long term potentiation (LTP). Effect of (+)-epi-clausenamide on potentiating basic synaptic transmission was also superior to (-)-clausenamide. However, (-)-epi-clausenamide showed only slight effects on synaptic transmission, suggesting that the effect of (+)-epi-clausenamide and (-)-epi-clausenamide on synaptic transmission depended on their chirality. Calcium influx was not involved in (+)-epi-clausenamide facilitating synaptic transmission in this study. (+)-epi-Clausenamide might promote glutamate release through the activation of Synapsin I(Ser9) to activate the downstream effectors which play a key role in synaptic plasticity. Elucidating the mechanism of each optical isomer of clausenamide by electrophysiological methods provided basis for therapeutic strategies for neurological disorders.

Topics: Animals; Animals, Newborn; CA1 Region, Hippocampal; Cells, Cultured; Electric Stimulation; Excitatory Postsynaptic Potentials; In Vitro Techniques; Lactams; Lignans; Long-Term Potentiation; Male; Neurons; Rats; Rats, Wistar; Stereoisomerism; Synapses; Synaptic Transmission

The neurotoxicity of aggregated beta-amyloid (Abeta) has been implicated as a critical cause in the pathogenesis of Alzheimer's disease (AD). In the present study, we investigated the effect of (-)clausenamide ((-)Clau), an aqueous extract of leaves of Clausena lassium (lour) skeel, on the neurotoxicity of Abeta(25-35). The viability of differentiated PC12 cells was determined by MTT assay. Apoptosis was detected by flow cytometry. DCFH-DA was used for assessment of intracellular ROS generation, JC-1 and Rhodamine 123 for measurement of mitochondrial transmembrane potential (MMP). The intracellular calcium was determined with Fluo-3. The phosphorylation of p38 MAPK and the expression of Bcl-2, Bax, P53, Caspase 3 were examined by Western blot. The results showed that (-)Clau significantly elevated cell viability. Furthermore, (-)Clau arrested the apoptotic cascade by reversing overload of calcium, preventing ROS generation, moderated the dissipation of MMP and the misbalance of Bcl-2 and Bax, inhibiting the activation of p38 MAPK and the expression of P53 and cleaved Caspase 3. Our results suggested that (-)Clau may be a therapeutic agent for AD.

Topics: Amyloid beta-Peptides; Analysis of Variance; Animals; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Calcium; Caspase 3; Cell Differentiation; Lactams; Lignans; p38 Mitogen-Activated Protein Kinases; PC12 Cells; Phosphorylation; Proto-Oncogene Proteins c-bcl-2; Rats; Signal Transduction; Tumor Suppressor Protein p53

A practical synthesis of N-substituted Clausenamide analogues, including (-) and (+) CM1, Piracetam analogue 1 and Nefiracetam analogue 2, have been developed.

Topics: Animals; Lactams; Lignans; Long-Term Potentiation; Magnetic Resonance Spectroscopy; Nootropic Agents

Stereoselective differences in pharmacokinetics between clausenamide (CLA) enantiomers have been found after intravenous and oral administration of each enantiomer to rats. The differences could be associated with protein binding of CLA enantiomers. By equilibrium dialysis methods, the binding of CLA enantiomers to rat plasma protein was investigated. The results showed that mean percentages of (-) and (+)CLA in the bound form were 28.5% and 38.0%, respectively, indicating that the unbound fraction of (-)CLA was higher than that of (+)CLA, which provided an explanation for stereoselective pharmacokinetics of CLA enantiomers in rats. The results also showed that there were species differences in plasma protein binding of (-)-isomer between rats (28.5%) and rabbits (47.2%). Furthermore, effects of plasma protein binding on the distribution of CLA enantiomers to their possible target tissues were observed. The amount of (-)CLA in brain was greater than that of (+)CLA 15 min after administration of each enantiomer to rats. But the results were reverse at 4 h postdose. Further studies in distributional kinetics showed that (-)CLA had a more rapid absorption and distribution to hippocampus, cortex, and cerebellum than (+) CLA. (+)CLA had greater values for T(max), t(1/2) (beta), and AUC(0) (-->infinity), and smaller ones for CL/F and V(d)/F than its antipode. The data indicated that the distribution of (-) and (+)CLA in their target tissues was stereoselective. The stereoselective distribution might be involved in the metabolism and transport of two enantiomers in the central nerve system.

Topics: Animals; Blood Proteins; Brain; Kinetics; Lactams; Lignans; Protein Binding; Rabbits; Rats; Species Specificity; Stereoisomerism; Substrate Specificity; Tissue Distribution

Clausenamide, isolated from aqueous extract of dry leaves of Clausena lansium, a Chinese folk medicine, was found to have potent activity in enhancing LTP and show nootropic activity in animal tests. In order to discovery more potent stereoisomers and to analyze the relationship of structure-activity, the synthesis of 16 (8 pairs) optically pure stereoisomers of clausenamide with four chiral centers was achieved. The results of LTP assay showed that the nootropic activity of the stereoisomers of clausenamide is closely related to the configuration of stereoisomers.

Topics: Animals; Drugs, Chinese Herbal; Lactams; Lignans; Long-Term Potentiation; Plant Extracts; Plant Leaves; Stereoisomerism; Structure-Activity Relationship

The synthesis of both antipodes of N-methyl-N-[(Z)-styryl]-3-phenyloxirane-2-carboxamide (SB204900), clausenamide, neoclausenamide, homoclausenamide and zeta-clausenamide have been accomplished using (2S,3R)- and (2R,3S)-3-phenyloxirane-2-carboxamides as the starting materials, and SB204900 was found to be a common precursor to other N-heterocyclic clausena alkaloids. Mediated by Brønsted acids under different conditions, for example, SB204900 underwent efficient and diverse alkene-epoxide cyclization, enamide-epoxide cyclization and arene-epoxide cyclization reactions to produce the five-membered N-heterocyclic neoclausenamide, its 6-epimer, the six-membered N-heterocyclic homoclausenamide and the eight-membered N-heterocyclic zeta-clausenamide, respectively, in good to excellent yields. Regiospecific oxidation of neoclausenamide and its 6-epimer afforded neoclausenamidone. Enolization of neoclausenamidone in the presence of LiOH and the subsequent protonation under kinetic conditions at -78 degrees C led to the epimerization of neoclausenamidone into clausenamidone. Reduction of clausenamidone using NaBH(4) furnished clausenamide in high yield.

Topics: Alkaloids; Biomimetics; Clausena; Ethylene Oxide; Lactams; Lactones; Lignans; Pyridones; Stereoisomerism

Zetaclausenamide, which was isolated as a hepatoprotective agent from the leaves of medicinal plant Clausena lansium, was synthesized for the first time in six steps including Darzen's condensation, photoisomerization, and the final cyclization reactions.

Topics: Cyclization; Lactams; Light; Lignans; Models, Molecular; Molecular Structure; Rutaceae

Homoclausenamide was synthesized for the first time, and the intramolecular cyclization study of N-methyl-3-phenyl-N-(2-(E)-phenylethenyl)-trans(cis)-oxiranecarboxamide well demonstrated how the stereochemistry affects the cyclization paths.

Topics: Amides; Cyclization; Ethylene Oxide; Hydrogen; Lactams; Lignans; Methylation; Molecular Structure; Structure-Activity Relationship

This study is to investigate the protective effect of (-) clausenamide against the neurotoxicity of okadaic acid in SH-SY5Y cell line, and injection beta-amyloid peptide25-35 (Abeta25-35) to the cerebral ventricle in ovariectomy (OVX) rats. MTT assay, LDH assay, and Hoechst 33258 staining were used to detect the effect of (-) clausenamide on the toxicity of okadaic acid in SH-SY5Y cell line. The animal model was induced by ovariectomized and injection of Abeta25-35 in the cerebroventricle of rats. The effect of (-) clausenamide on learning and memory deficiency was observed by step-through test. Electron microscope, Nissl body staining, and HE staining were used to examine the morphological changes in hippocampus and cerebral cortex neurons. Pretreatment of (-) clausenamide and LiCl decreased the rate of cell death from MTT, LDH release, and apoptosis from Hoechst 33258 staining in SH-SY5Y cell line. The step-through tests showed (-) clausenamide could improve the ability of learning and memory. The Nissl body staining and HE staining experiments also showed the neuroprotective effects of (-) clausenamide on the neurons of hippocampus and cerebral cortex. (-) Clausenamide has the protective effects against the neurotoxicity induced by okadaic acid and Abeta25-35.

Topics: Amyloid beta-Peptides; Animals; Apoptosis; Cell Line, Tumor; Cell Survival; Cerebral Cortex; Clausena; Drugs, Chinese Herbal; Female; Hippocampus; Humans; L-Lactate Dehydrogenase; Lactams; Learning; Lignans; Memory Disorders; Neuroblastoma; Neurons; Neuroprotective Agents; Okadaic Acid; Ovariectomy; Peptide Fragments; Plants, Medicinal; Rats; Rats, Sprague-Dawley

To study the effects of nine synthetic clausenamide with different stereo structures on liver glutathione (GSH) biosynthesis and glutathione S-transferase (GST) activity in mice.. The nine test compounds were racemic mixtures and their ennatiomers of clausenamide, neoclausenamide and epineoclausenamide. Mice were administered clausenamide 250 mg/kg once daily for 3 consecutive days, ig, and were killed 24 h after the last dosing. The mouse liver cytosol GSH and GST were determined with related biochemical methods.. Nine clausenamides exhibited different effects on liver GSH and GST. Of nine clausenamides, only (+) and (+/-)clausenamide markedly increased liver cytosol GSH content. The mechanism of increasing liver GSH content of (+)clausenamide is mainly due to stimulating the key limiting enzyme gamma-glutamylcysteine synthetase (gamma-GCS) activity for GSH biosynthesis. The other test clausenamides had no such effect on liver GSH. All of the nine clausenamides induced a significant increase of GST activity.. The effects of clausenamide ennatiomers on liver GST and GSH varied with the alterations of their spatial structures. (+)Clausenamide stimulated liver GSH biosynthesis through enhancing gamma-GCS activity.

Topics: Animals; Cytosol; Glutamate-Cysteine Ligase; Glutathione; Glutathione Peroxidase; Glutathione Reductase; Glutathione Transferase; Lactams; Lignans; Liver; Male; Mice; Molecular Structure; Stereoisomerism; Structure-Activity Relationship

To study the excretion of (-)-clausenamide in rats.. The urine, feces and bile were collected at predetermined time points after (-)-clausenamide was orally administrated to 6 rats (30 mg x kg(-1)). The concentrations of (-)-clausenamide and its metabolite 6-OH-(-)-clausnamide were determined by HPLC-MS/MS method using glipzide as the internal reference, and the accumulative excretion amount of (-)-clausenamide and 6-OH-(-)-clausenamide was calculated in the urine, feces and bile, separately.. (-)-Clausenamide was recovered mostly (44%) from feces in 112 hours, 7.1% was found from urine in 120 hours and 0.013% was detected from bile in 24 hours. The accumulative excretions of 6-OH-(-)-clausenamide were 0.92% , 0.46% and 0.0003% of the administered dose from feces, urine and bile, respectively.. The major amount of (-)-clausenamide was recovered from feces after (-)-clausenamide was orally administrated to rats (30 mg kg(-1)).

Topics: Administration, Oral; Animals; Bile; Chromatography, High Pressure Liquid; Clausena; Feces; Female; Lactams; Lignans; Male; Mass Spectrometry; Neuroprotective Agents; Plant Leaves; Plants, Medicinal; Rats; Rats, Sprague-Dawley; Stereoisomerism

The effect of clausenamide on synaptic transmission in the dentate gyrus of rats in vivo and its possible mechanism of action were investigated in this study. Four of 16 enantiomers showed potentiating effects on basal synaptic transmission in anesthetized animals. By comparing one pair of enantiomers, (-)-clausenamide and (+)-clausenamide, we can report three primary findings: (1) (-)-clausenamide potentiated synaptic transmission in both anesthetized and freely moving animals while (+)-clausenamide showed no or little effect; (2) (-)-clausenamide increased the magnitude of long-term potentiation (LTP) induced by high-frequency stimulation (HFS) in anesthetized animals whereas (+)-clausenamide had no effect; (3) voltage-dependent calcium channels (VDCCs) calcineurin and calpain are involved in (-)-clausenamide-induced potentiation of synaptic transmission. Because hippocampal LTP is thought to reflect a cellular mechanism involved in learning and memory, our findings may provide the pharmacological basis for understanding the nootropic mechanisms of (-)-clausenamide, which is the first chiral nootropic agent developed in China.

Topics: Animals; Calcineurin; Calcium Channels; Calpain; Cerebral Cortex; Dentate Gyrus; Drug Delivery Systems; Drugs, Chinese Herbal; Electrophysiology; Hippocampus; Lactams; Lignans; Long-Term Potentiation; Male; Models, Chemical; Rats; Rats, Wistar; Stereoisomerism; Synaptic Transmission; Time Factors

To observe the effect and mechanism of clausenamide on the expression of Bcl-2 and apoptosis after focal cerebral ischemia/reperfusion in renovascular hypertensive rats.. Seventy-five renovascular hypertensive rats were randomly divided into three groups (25 in each group): clausenamide intervention group, single ischemia/reperfusion model group and sham-operated group. Focal cerebral ischemia was reproduced by ligature for 2 hours and loosening of the ligature in the rats. No arterial ligature was applied in sham-operated group. Computerized pathological image analyzer was used to determine the number of cells positive for Bcl-2 by immunohistochemical staining, and also the counts of apoptotic cells after TdT-mediated dUTP nick end labeling (TUNEL) staining respectively in coronal sections of brain after reperfusion (6, 12, 24, 48 and 72 hours).. (1) The expression of Bcl-2 protein was detected 6 hours after reperfusion, peaking at 24 hours, then declined gradually. The Bcl-2 protein positive cell counts at every time point in clausenamide intervention group were significantly higher than simple ischemia/reperfusion model group (all P<0.01). (2) The number of apoptotic cells was increased with reperfusion, reaching its peak at 72 hours. The apoptosis counts in clausenamide intervention group were significantly lower than single ischemia/reperfusion model group (all P<0.01). At all time points, except at 48 hours after reperfusion, as there was no significant difference (all P>0.05). No Bcl-2 positive cells and only 0-2 apoptotic cells could be discernible in brain sections from sham-operated animals or in the contralateral side of ischemia in animals of the other groups.. Expression of Bcl-2 protein is enhanced and apoptosis appears after focal cerebral ischemia/reperfusion in rat brain. Clausenamide can enhance the expression of Bcl-2 protein and inhibit apoptosis remarkably. Clausenamide may coordinate with Bcl-2 in inhibiting apoptosis. This may be the mechanism of protection of brain cells from ischemic damage of clausenamide treatment.

Topics: Animals; Apoptosis; Brain Ischemia; Disease Models, Animal; Hypertension; Lactams; Lignans; Male; Proto-Oncogene Proteins c-bcl-2; Random Allocation; Rats; Rats, Wistar; Reperfusion Injury

To establish a sensitive and accurate method to study the pharmacokinetics of (-)-clausenamide [(-)-clau] and its major metabolite 6-hydroxyl-clausenamide (6-OH-clau) in the plasma of the Beagle dog.. (-)-Clau was orally administered to six Beagle dogs at the dose of 30 mg x kg(-1), venous blood from front leg was sampled and plasma was separated for analysis. After extraction with ethyl acetate, the plasma samples were analyzed by HPLC/MS and the mobile phase was a mixture of methanol-water-acetic acid (60: 40: 0. 8) at the flow rate of 1.0 mL x min(-1). The API-ES positive ion SIM detection was carried out for the detection of both (-)-clau ([M + H] (+), m/z 298 ) and 6-OH-clau ([M + H - H2 O](+), m/z 296) with glipzide (glip) ([M + H](+), m/z 446) as internal standard. The pharmacokinetic parameters were calculated by 3P97 software.. There was good linear relationship ( r > 0. 999) between the SIM responses and the concentrations for (-)-clau and 6-OH-clau at the range from 1.0 to 200 ng x mL(-1) and 0.2 to 40.0 ng x mL(-1), respectively. The absolute recovery was greater than 85%. The plasma concentration-time curves of (-)-clau and 6-OH-clau were both best fitted to a two-compartment model. The C(max) of (-)-clau and 6-OH-clau were (21 +/- 10) ng x mL(-1) and (3.9 +/- 2.2) ng x mL(-1), T(max) were (0.8 +/- 0.5) h and (1.3 +/- 0.5) h, T 1/2 alpha were (0.9 +/- 0.6) hand (1.4 +/- 0.6) h, T 1/2 beta were (19 +/- 23) hand (13 +/- 12) h, AUC(0-24 h) were (69 +/- 14) h x ng x mL(-1) and (12 +/- 7) h x ng x mL(-1) respectively.. The established HPLC/MS method was sensitive and specific for the determination of (-)-clau. It was shown that the absorption and first phase elimination of (-)-clau were very quick in Beagle dogs, but the terminal elimination was very slow. The plasma concentration profile of its major metabolite 6-OH-clau was similar to (-)-clau and the AUC was relatively small in comparison with (-)-clau.

Topics: Administration, Oral; Animals; Area Under Curve; Chromatography, High Pressure Liquid; Dogs; Female; Lactams; Lignans; Male; Plant Leaves; Plants, Medicinal; Rutaceae; Spectrometry, Mass, Electrospray Ionization; Stereoisomerism

(-)clausenamide is a compound isolated from Clausena lansium (lour) Skeel with nootropic effects. At the present study, we investigated the clausenamide induced Ca2+ signaling in primary cultures of rat cortical neurons by using laser confocal microscopy. The mean amplitude of (-)clausenamide (1 microM) induced Ca2+ transient was similar in extracellular solution with or without calcium; and (-)clausenamide failed to trigger calcium transient after treatment with endoplasmic reticulum Ca2+ pumps inhibitor BHQ to exhaust intracellular Ca2+ stores. This result suggested that the primary source of (-)clausenamide induced Ca2+ transient was from internal stores. Application of IP3 receptor inhibitor MgCl2 and PLC-gamma inhibitor U73122 suppressed (-)clausenamide induced Ca2+ transient, suggesting that the major source of (-)clausenamide induced Ca2+ transient was from IP3 receptor pathway. We also found that mitochondria were involved in (-)clausenamide triggered Ca2+ transient. The distinctive spatial and temporal characteristic of (-)clausenamide induced Ca2+ transient may play an important role in its action.

Topics: Aniline Compounds; Animals; Calcium Signaling; Cells, Cultured; Cerebral Cortex; Enzyme Inhibitors; Female; Fluorescent Dyes; Inositol 1,4,5-Trisphosphate; Lactams; Lignans; Magnesium; Neurons; Pregnancy; Rats; Rats, Sprague-Dawley; Rutaceae; Stereoisomerism; Type C Phospholipases; Xanthenes

To identify which cytochrome P450 (CYP) isoform(s) are responsible for the metabolism of clausenamide (CLA) enantiomers in rats, effects of various CYP isoform inducers and inhibitors on the formation of CLA metabolites were investigated in liver microsomes. In incubations with rat liver microsomes, CLA enantiomers were mainly converted to 4-hydroxy, 5-hydroxy, and 7-hydroxy-metabolites. 4-OH-CLA was the major metabolite of (+)-3R, 4S, 5S, 6R-CLA [(+)-CLA], while 7-OH-CLA was the major one of (-)-3S, 4R, 5R, 6S-CLA [(-)-CLA]. In induction studies, enzymatic parameters were used to assess the role of different CYP forms in CLA hydroxylation reactions. A marked increase in the rate of metabolism of CLA enantiomers was observed in microsomes of dexamethasone treated rats, V(max)/K(m) values for 4-OH-(+)-CLA, 7-OH-, 5-OH-, and 4-OH-(-)-CLA were 5.3, 6.5, 3.0, and 5.9 times higher than those in control microsomes, respectively. Rifampicin treatment caused corresponding 1.7-, 2.6-, 3.1-, and 2.8-fold increases. Dex and Rif also increased in the amount of (+)-5- and (+)-7-OH-CLA that were not detectable in the control group. These results suggested that inducible CYP3A1 was involved in the hydroxylation of CLA enantiomers. In inhibition studies, ketoconazone (6.25 microM) completely inhibited the production of main metabolites of (-)-CLA (100%) and (+)-CLA (97%). Triacetyloleandomycin (12.5 microM) strongly inhibited the corresponding metabolites by 34-85%. These findings also indicated that institutive CYP3A2 shared a major role in the hydroxylation of CLA enantiomers with CYP3A1 in untreated rats. Together, the data suggested that CYP3A was the predominant isoform responsible for the metabolism of CLA enantiomers.

Topics: Animals; Aryl Hydrocarbon Hydroxylases; Chromatography, High Pressure Liquid; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Enzyme Induction; Enzyme Inhibitors; Female; In Vitro Techniques; Indicators and Reagents; Lactams; Lignans; Microsomes, Liver; Rats; Rats, Wistar; Stereoisomerism

The pharmacokinetics of clausenamide (CLA) enantiomers and their metabolites were investigated in Wistar rat. After intravenous and oral administration at a dose of 80 and 160 mg/kg each enantiomer, plasma concentrations of (-)- or (+)-CLA and its major metabolites were simultaneously determined by reverse-phase HPLC with UV detection. Notably, stereoselective differences in pharmacokinetics were found. The mean plasma levels of (+)-CLA were higher at almost all time points than those of (-)-CLA. (+)-CLA also exhibited greater t(max), C(max), t(1/2beta), AUC(0-12h), and AUC(0--> infinity) and smaller CL (or CL/F) and V(d) (or V(d)/F), than its antipode. The (+)/(-) isomer ratios for t(1/2beta), t(max), AUC(0-12 h), and AUC(0--> infinity), which ranged from 1.26 to 2.08. The ratio for CL (or CL/F) was about 0.5, and there were significant differences in these values between CLA enantiomers (P < 0.05), implying that the absorption, distribution, and elimination of (-)-CLA were more rapid than those of (+)-CLA. Similar findings for (-)-7-OH-CLA, the major metabolite of (-)-CLA, and (+)-4-OH-CLA, the major metabolite of (+)-CLA, can be also seen in rat plasma. The contributing factors for the differences in stereoselective pharmacokinetics of CLA enantiomers appeared to be involved in their different plasma protein binding, first-pass metabolism and interaction with CYP enzymes, especially with their metabolizing enzyme CYP 3A isoforms.

Topics: Administration, Oral; Algorithms; Animals; Area Under Curve; Biotransformation; Female; Half-Life; Injections, Intravenous; Lactams; Lignans; Magnetic Resonance Spectroscopy; Rats; Rats, Wistar; Stereoisomerism

The effects of (-)clausenamide (clau) on long-term potentiation (LTP) and neuronal DNA damage were investigated in a rat model of middle cerebral artery (MCA) occlusion. Four days after reperfusion, electrophysiology records revealed reduced LTP in the ipsilateral dentate gyrus of ischemic rats, while treatment with clau (10 mg kg-1 p.o. once daily) improved LTP impairment. The fractional increase of population spike amplitude 20-50 min after tetanus was significantly larger in ischemic rats treated with clau than vehicle treated animals. Terminal deoxynucleotidyltransferase mediated dUTP end labeling (TUNEL) assay revealed occurrence of apoptosis in the ipsilateral striatum. The numbers of TUNEL-positive particles were significantly reduced after treatment with clau compared with vehicle group (78.8 +/- 17.9 versus 105.8 +/- 27.2). Mitochondrial rhodamine 123 accumulation showed that clau treatment (55.0 +/- 8.5) elevated numbers of rhodamine 123-positive particles in the ipsilateral striatum compared with vehicle group (40.4 +/- 7.5) These results demonstrate that clau can improve LTP impairment in the ipsilateral dentate gyrus and enhance cell survival in the striatum compared to the vehicle-treated rats four days following ischemic damage and its protective effect on mitochondria may partially underlie its action.

Topics: Animals; Apoptosis; Drugs, Chinese Herbal; Infarction, Middle Cerebral Artery; Lactams; Lignans; Long-Term Potentiation; Male; Rats; Rats, Wistar

To establish culture procedures of neural stem cells from embryonic rat brain, determine their stem-cell characteristics and observe the effects of several compounds on their proliferation ability.. Firstly, a stem cell culture system was set up from embryonic rat cortex. The cells were identified as neural stem cells through immunocytochemistry, in which antibodies to neural stem cell specific protein and markers of mature neural cells were used. Then, by using MTT assay, the survival rate of neurospheres incubated with various concentrations of ginsenoside Rg1, (-)-clausenamide and salvianolic acid A were observed. Furthermore, the effect of these drugs was measured with 3[H] thymidine incorporation assay.. In this study, a culture model of neural stem cell was successfully set up. In this model, primary cells from E16-18 rat cortex were dissected out, and cultured as floating neurospheres. The results of immunocytochemistry showed that nestin was expressed by the majority of cells within the sphere. After growing for 8 days in differentiation medium, cells from a single neurosphere were shown to differentiate into 3 main kinds of neural cells: neurons, astrocytes and oligodendrocytes. MTT assay revealed that the three drugs all enhanced the survival rate of neural stem cells, but 3[H] thymidine incorporation assay suggested that only Rg1 significantly accelerated the proliferation rate.. One culture model of neural stem cell was set up successfully. Meanwhile, several drugs were found to increase the proliferation and/or survival rate of neural stem cells. It has been demonstrated that neural stem cells exist in adult mammalian brains. So, these drugs may become promising candidates for the therapy of neurodegenerative diseases; such as Alzheimer's disease and Parkinson's disease.

Topics: Animals; Caffeic Acids; Cell Differentiation; Cell Division; Cell Survival; Cells, Cultured; Cerebral Cortex; Drugs, Chinese Herbal; Embryo, Mammalian; Ginsenosides; Lactams; Lactates; Lignans; Rats; Rats, Wistar; Stem Cells

To investigate the enzyme kinetics of (-)3S,4R,5R,6S-clausenamide[(-)-Clau] and (+)-3R,4S,5S,6R-clausenamide[(+)-Clau] catalyzed by rat liver microsomes and compare their stereoselective differences.. An in vitro metabolic system was built by using rat liver microsomes and NADPH-generating system. Clau and its metabolites were determined simultaneously by a reversed-phase high performance liquid chromatography. The kinetic parameters, K(m), Vmax, and metabolic rate, Vmax/K(m), were calculated by Eadie-Hofstee plot.. In the metabolic system, (-)-Clau was found to be mainly metabolized to 7-hydroxy-, 5-hydoxy- and 4-hydroxy-Clau, and 7-hydroxylation was a preferential pathway which exhibited higher Vmax/K(m) value (0.135 microL.min-1.mg-1) than those of 5- and 4-hydroxylation (0.063 and 0.068 microL.min-1.mg-1, respectively). For (+)-Clau, it was mainly metabolized to 4-hydroxy-Clau, whereas 7-hydroxy- and 4-hydroxy-Clau were so small that they could not be detected systematically. 4-Hydroxylation of (+)-Clau showed highest Vmam/K(m) value (0.547 microL.min-1.mg-1) among all the metabolites tested, which was 8.0 times higher than that of 4-hydroxylation of its antipode.. The data indicated that there were obvious substrate stereoselective differences in the hydroxylation metabolism of (+)- and (-)-Clau, which provided an explanation of the difference of pharmacokinetic characteristics of Clau enantiomers in rats.

Topics: Animals; Drugs, Chinese Herbal; Female; Hydroxylation; Kinetics; Lactams; Lignans; Microsomes, Liver; NADP; Plants, Medicinal; Rats; Rats, Wistar; Rutaceae; Stereoisomerism

The effects of (-)clausenamide (clau) on spatial cognitive functions and hippocampal long-term potentiation (LTP) after transient focal cerebral ischemia in rats were investigated. Four weeks after middle cerebral artery occlusion, Morris water maze tasks demonstrated that 2 h of transient forebrain ischemia resulted in a significant decrease in spatial discrimination performance. The escape latency at 4 and 5 days of acquisition trial was lower in the ischemic rats than in sham-operated rats (33.8+/-6.7 sec and 26.8+/-5 sec versus 12.2+/-4.0 sec and 10.4+/-3.6 sec), chronic treatment with clau (10 mg kg(-1) p.o. once daily) significantly improved the impairment (12.4+/-4.1 sec and 15.2+/-3.1 sec). After Morris water maze, the changes in population spike (PS) amplitude were recorded as an index of LTP in the perforant path-dentate gyrus synapses. There was no difference in PS amplitude between the sham-operated and vehicle-treated animals, whereas the fractional increase of PS 20-50 min after tetanus was significantly larger in clau-treated group. Histopathological analysis revealed that clau could protect against neuron loss in the regions of cortex and striatum. In conclusion, these data indicate a beneficial effect of clau for synaptic plasticity and cognitive function impaired by transient focal cerebral ischemia.

Topics: Action Potentials; Animals; Brain; Brain Ischemia; Cognition Disorders; Drugs, Chinese Herbal; Infarction, Middle Cerebral Artery; Ischemic Attack, Transient; Lactams; Lignans; Male; Maze Learning; Nerve Degeneration; Neurons; Rats; Rats, Wistar; Recovery of Function; Reperfusion Injury; Treatment Outcome

To study the metabolic pathway of chiral clausenamide in the rat and understand its stereoselectivity.. The urine, feces and blood of rat were gathered after the drug was administered, the known metabolites were analyzed by HPLC-DAD and one unknown metabolite was elucidated by using LC-MS analysis. Metabolic stereoselectivity was determined by comparing the metabolic results of (+)- and (-)-clausenamide.. Six known metabolites were determined and one unknown metabolite was elucidated as N-demethylclausenamide. The metabolic stereoselectivity was shown distinctly.. Chiral clausenamide was mainly metabolized by hydroxylation in liver and the biotransformation exhibited pronounced substrate stereoselectivity.

Topics: Animals; Biotransformation; Chromatography, High Pressure Liquid; Drugs, Chinese Herbal; Lactams; Lignans; Male; Plant Leaves; Plants, Medicinal; Rats; Rats, Wistar; Rutaceae; Stereoisomerism

To investigate the mechanisms of l-clausenamide-induced long-term potentiation (LTP) in the dentate gyrus of anesthetized rats.. Extracellular recording technique was used to record the population spike (PS) in the dentate gyrus of anesthetized rats.. I.c.v. injection of naloxone 1 nmol, affecting neither the basal PS amplitude nor the LTP induced by tetanus, reduced the l-clausenamide-potentiated LTP only when it was administrated prior to clausenamide. Naloxone 1 nmol (i.c.v.), administrated 10 min before l-clausenamide, reduced the PS amplitude at 20 min, 55 min, and 90 min after i.c.v. injection of l-clausenamide 4 nmol from 138% +/- 10%, 170% +/- 10%, and 169% +/- 12% to 111% +/- 7%, 124% +/- 14%, and 123% +/- 11%, respectively. All P < 0.01 (n = 8). The same dose of naloxone (i.c.v.), delivered 10 min after l-clausenamide, did not affect the l-clausenamide-induced potentiation.. The activation of opioid receptors contributes to the induction of l-clausenamide-induced LTP of synaptic transmission in dentate gyrus of anesthetized rats.

Topics: Animals; Dentate Gyrus; Drugs, Chinese Herbal; Evoked Potentials; Lactams; Lignans; Long-Term Potentiation; Male; Naloxone; Narcotic Antagonists; Rats; Rats, Wistar; Synaptic Transmission

To study the antagonistic effect of selective neuronal nitric-oxide synthase (nNOS) inhibitor 7-nitroindazole on the long-term potentiation (LTP) induced by l-clausenamide (Cla) in rat hippocampus in vivo.. Population spike (PS) of evoked potentials was determined by extracellular recording technique in the hippocampal dentate gyrus (DG) of anesthetized rats.. 7-Nitroindazole 2 nmol icv blocked the induction of LTP elicited by high-frequency (100 Hz) stimulation or Cla 5 nmol icv (P < 0.01), and L-arginine 225 mg.kg-1 i.p. prevented the action of 7-nitroindazole (P < 0.01).. Nitric oxide produced by nNOS plays a role in the induction of Cla-induced LTP in hippocampus.

Topics: Animals; Dentate Gyrus; Drugs, Chinese Herbal; Evoked Potentials; Indazoles; Lactams; Lignans; Long-Term Potentiation; Male; Neuroprotective Agents; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Rats; Rats, Sprague-Dawley; Synaptic Transmission

To study the neurotrophic effects of (-) and (+)clausenamide on frontal cortex neurons in culture.. The activity of the choline acetyltransferase (ChAT) was determined by spectrophotometric method; protein content was assayed by Folin phenol method.. (-)Clausenamide increased the activity of ChAT and protein content in cultured neurons, as well as stimulated proliferation of neuronal cells, support survival and neurite outgrowth of neurons. The neurotrophic action of (-)clausenamide (0.001-10 mumol.L-1) was similar to that of nerve growth factor. The (+)clausenamide had no neurotrophic action, even at high concentrations (0.1-10 mumol.L-1), but neurons were damaged.. (-)Clausenamide stimulated central cholinergic neuron development.

Topics: Animals; Cells, Cultured; Choline O-Acetyltransferase; Drugs, Chinese Herbal; Fetus; Frontal Lobe; Lactams; Lignans; Microscopy, Phase-Contrast; Nerve Tissue Proteins; Neurons; Rats; Stereoisomerism

To study the action mechanism of a new cognition enhancer clausenamide and the effect of clausenamide on regional acetylcholine (ACh) levels, and to examine anisodine-induced ACh decrease in mice of memory deficits, and to compare the effect of (-)clausenamide on ACh with that of (+)clausenamide.. Animal amnesia model was induced by i.p. anisodine and brain ACh content was measured by high performance liquid chromatography with electrochemical detection.. Single administration of (-)clausenamide or (+)clausenamide (10, 20, 50 mg/kg, i.g.) had no effect on the ACh level in the frontal cortex, hippocampus and striatum. However, pretreatment with (-)clausenamide (10, 20, 50 mg/kg, i.g.) significantly ameliorated the reduction of ACh induced by anisodine (10 mg/kg, i.p.) in a dose-dependent manner. Physostigmine (0.2 mg/kg, s.c.), as a cholinesterase inhibitor significantly increased the ACh levels and reversed the anisodine-induced ACh decrease. In contrast, (+)clausenamide had no effect on ACh decrease in all examined brain regions. (-)Clausenamide ameliorated anisodine-induced memory deficits in step-through test in mice.. There is significant difference in the action of (-)clausenamide and (+)clausenamide. The protective action of (-)clausenamide against anisodine-induced amnesia is due to its ability to reverse the ACh reduction.

Topics: Acetylcholine; Amnesia; Animals; Brain; Chromatography, High Pressure Liquid; Drugs, Chinese Herbal; Lactams; Lignans; Mice; Random Allocation; Scopolamine Derivatives; Stereoisomerism

The metabolic transformation of (-)-clausenamide, isolated from the leaves of Clausena lansium (Lour.) Skeels, was studied in vitro with phenobarbital-induced rat liver microsomal incubate containing the NADPH-generating system. The constitution of the incubation system was optimized and a RP-HPLC-DAD method was developed for the on-line analysis of (-)-clausenamide and its metabolites. The major metabolites were isolated and purified by silica gel column chromatography, preparative TLC and HPLC and their structures were determined as 6-OH clausenamide (CM1) and 5-OH clausenamide (CM2) by 1HNMR and MS.

Topics: Animals; Drugs, Chinese Herbal; Lactams; Lignans; Male; Microsomes, Liver; Rats; Rats, Wistar; Rutaceae

The effect of a new cognition enhancer clausenamide on regional acetylcholine (ACh) levels and anisodine-induced ACh decrease were examined in mice of memory deficits. In the mean time, the effect of (-)clausenamide on ACh was compared with that of (+)clausenamide. Animal amnesia model was induced by i.p. anisodine, brain acetylcholine content was measured by high performance liquid chromatography with electrochemical detection. It was found that single administration of (-)clausenamide or (+)clausenamide(10, 20, 50 mg.kg-1, ig) showed no effect on the ACh level in the frontal cortex, hippocampus and striatum in normal condition. However, pretreatment with (-)clausenamide (10, 20, 50 mg.kg-1, ig) significantly ameliorated the reduction of ACh in these regions induced by anisodine (10 mg.kg-1, i.p.) in a dose-dependent manner. In the meantime, (-) clausenamide ameliorate anisodine-induced memory deficits in step-through test in mice. In contrast, (+)clausenamide showed no effect on these sides. The results indicate that there is significant difference between the actions of (-)clausenamide and (+)clausenamide; The protective action of (-)clausenamide against anisodine-induced amnesia is due to its ability to reverse ACh reduction.

Topics: Acetylcholine; Amnesia; Animals; Brain; Drugs, Chinese Herbal; Lactams; Lignans; Male; Mice; Rutaceae; Scopolamine Derivatives; Stereoisomerism

With the extracellular recording technique, the basal synaptic responses (population spike, PS) evoked by low frequency test stimulation in the dentate gyrus of anesthetized rats was recorded and the effects of (-) and (+) clausenamide(icv) on the PS and long-term potentiation (LTP) induced by tetanus (50 pulses at 200 Hz) were observed. The results showed that: (1) at a lower dose (1 nmol), (+) clausenamide showed no effect on either the basal PS or LTP, (-) clausenamide did not affect the basal PS but enhanced the magnitude of LTP. (2) At a higher dose (4 nmol), (-) clausenamide not only potentiated the basal PS but also dose-dependently augmented the magnitude of LTP. Meanwhile, (+) clausenamide did not affect the basal PS but attenuated the magnitude of LTP. These results suggest that the effects of clausenamide on the synaptic transmission in the dentate gyrus depend on its chirality. The potentiating effects of (-) clausenamide on synaptic transmission in hippocampus strongly support our previous behavioral and neurobiochemical studies on the nootropic action of (-) clausenamide.

Topics: Animals; Dentate Gyrus; Drugs, Chinese Herbal; Female; Lactams; Lignans; Long-Term Potentiation; Rats; Rats, Sprague-Dawley; Rutaceae; Stereoisomerism; Synaptic Transmission

Using radioligand binding assay, the effects of (-), (+) clausenamide on N-methyl-D-asparate(NMDA) receptor were studied in synaptic membrane, hippocampus and cerebral cortex in rats. The Bmax and KD values of NMDA receptor in mouse brain were measured with Scatchard plot method. Results showed that there was no specific binding of (-), (+) clausenamide to NMDA-receptor. However, higher Bmax values were observed in (-) clausenamide-treated rats than the control group, but no effect on KD value. (+) Clausenamide treatment showed no effect on Bmax and KD values. The findings suggest that the pharmacologic actions of clausenamide depends on its chirality. Up regulation of NMDA-receptor induced by (-) clausenamide is helpful to elucidate its nootropic mechanism.

Topics: Animals; Binding, Competitive; Cerebral Cortex; Dizocilpine Maleate; Hippocampus; Lactams; Lignans; Long-Term Potentiation; Male; Neuroprotective Agents; Rats; Receptors, N-Methyl-D-Aspartate; Stereoisomerism; Synaptic Membranes

Clausenamide is a compound isolated from Clausena lansium (lour) with the structure similar to piracetam. Pharmacological experiments showed that clausenamide po 100-200 mg/kg prolonged both the duration of gasping after decapitation and the survival time after sc NaNO2 225 mg/kg, clausenamide at the concentration of 10(-5) mol/L inhibited the contraction of basilar artery caused by 5-HT, PGF2 alpha and arachidonic acid, indicating that clausenamide is a cerebral protective agent. In addition, multiple doses clausenamide were shown to inhibit the liver lipid peroxidation caused by 50% alcohol and increase the GSH-peroxidase activity significantly in rat liver and brain cytosol.

Topics: Animals; Basilar Artery; Brain; Female; Glutathione Peroxidase; Hypoxia, Brain; Lactams; Lignans; Lipid Peroxidation; Liver; Male; Malondialdehyde; Mice; Microsomes, Liver; Rats; Vasoconstriction; Vasodilator Agents

Topics: Chemical Phenomena; Chemistry; Lactams; Lignans; Medicine, Chinese Traditional; Plants, Medicinal