Curcumin Alters Neural Plasticity and Viability of Intact Hippocampal Circuits and Attenuates Behavioral Despair and COX-2 Expression in Chronically Stressed Rats.

Curcumin is a major diarylheptanoid component of Curcuma longa with traditional usage for anxiety and depression. It has been known for the anti-inflammatory, antistress, and neurotropic effects. Here we examined curcumin effect in neural plasticity and cell viability. 60-channel multielectrode array was applied on organotypic hippocampal slice cultures (OHSCs) to monitor the effect of 10 µM curcumin in long-term depression (LTD) through low-frequency stimulation (LFS) to the Schaffer collaterals and commissural pathways. Cell viability was assayed by propidium iodide uptake test in OHSCs. In addition, the influence of oral curcumin administration on rat behavior was assessed with the forced swim test (FST). Finally, protein expression levels of brain-derived neurotrophic factor (BDNF) and cyclooxygenase-2 (COX-2) were measured by Western blot in chronically stressed rats. Our results demonstrated that 10 µM curcumin attenuated LTD and reduced cell death. It also recovered the behavior immobility of FST, rescued the attenuated BDNF expression, and inhibited the enhancement of COX-2 expression in stressed animals. These findings indicate that curcumin can enhance postsynaptic electrical reactivity and cell viability in intact neural circuits with antidepressant-like effects, possibly through the upregulation of BDNF and reduction of inflammatory factors in the brain.

Loganin enhances long-term potentiation and recovers scopolamine-induced learning and memory impairments.

Although the incidence rate of dementia is rapidly growing in the aged population, therapeutic and preventive reagents are still suboptimal. Various model systems are used for the development of such reagents in which scopolamine is one of the favorable pharmacological tools widely applied. Loganin is a major iridoid glycoside obtained from Corni fructus (Cornusofficinalis et Zucc) and demonstrated to have anti-inflammatory, anti-tumor and osteoporosis prevention effects. It has also been found to attenuate Aß-induced inflammatory reactions and ameliorate memory deficits induced by scopolamine. However, there has been limited information available on how loganin affects learning and memory both electrophysiologically and behaviorally. To assess its effect on learning and memory, we investigated the influence of acute loganin administration on long-term potentiation (LTP) using organotypic cultured hippocampal tissues. In addition, we measured the effects of loganin on the behavior performance related to avoidance memory, short-term spatial navigation memory and long-term spatial learning and memory in the passive avoidance, Y-maze, and Morris water maze learning paradigms, respectively. Loganin dose-dependently increased the total activity of fEPSP after high frequency stimulation and attenuated scopolamine-induced blockade of fEPSP in the hippocampal CA1 area. In accordance with these findings, loganin behaviorally attenuated scopolamine-induced shortening of step-through latency in the passive avoidance test, reduced the percent alternation in the Y-maze, and increased memory retention in the Morris water maze test. These results indicate that loganin can effectively block cholinergic muscarinic receptor blockade -induced deterioration of LTP and memory related behavioral performance. Based on these findings, loganin may aid in the prevention and treatment of Alzheimer's disease and learning and memory-deficit disorders in the future.

ESP-102, a Combined Herbal Extract of Angelica gigas, Saururus chinensis, and Schisandra chinensis, Changes Synaptic Plasticity and Attenuates Scopolamine-Induced Memory Impairment in Rat Hippocampus Tissue.

ESP-102, an extract from Angelica gigas, Saururus chinensis, and Schisandra chinensis, has been used as herbal medicine and dietary supplement in Korea. Despite the numerous bioactivities in vitro and in vivo studies, its effects on neuronal networks remain elusive. To address the neuronal effect, we examined synaptic plasticity in organotypic hippocampal slice culture with multielectrode array. Our results showed an increase in excitatory postsynaptic potential (EPSP), indicating the induction of long-term potentiation (LTP), in the presence of ESP-102. In addition, the neuroprotective effect of ESP-102 was also tested by application of scopolamine to the hippocampal slice. Interestingly, ESP-102 competitively antagonized the preventative LTP effect induced by scopolamine. The scopolamine-induced reduction in brain-derived neurotrophic factor (BDNF) and GluR-2 expression was also rescued by ESP-102. In terms of mode of action, ESP-102 appears to act on the presynaptic region independent of AMPA/NMDA receptors. Based on these findings, ESP-102 can be suggested as a novel herbal ingredient with memory enhancing as well as neuroprotective effects.

Acute rosmarinic acid treatment enhances long-term potentiation, BDNF and GluR-2 protein expression, and cell survival rate against scopolamine challenge in rat organotypic hippocampal slice cultures.

BACKGROUND: Rosmarinic acid (RA) is a polyphenolic ester of caffeic acid and is commonly found in the Nepetoideae subfamily of flowering mint plants. Because RA has previously exhibited antioxidant, neuroprotective, and antidepressant-like effects, we evaluated its influences on cellular functions in neuronal cultures. OBJECTIVE: To elucidate possible mechanisms of RA, we investigated the influences of acute RA administration on long-term potentiation (LTP), plasticity-related protein expression, and scopolamine-induced cell death in organotypic hippocampal slice cultures. METHODS: LTP analysis in organotypic hippocampal slice cultures (OHSCs) was carried out with various ion channel blockers, such as AP5 (10 µM), CNQX (10 µM), niflumic acid (100 µM), and scopolamine (300 µM) in response to RA (1, 10 or 100 µg/mL) treatment. Protein expression and cell death assays in the presence of scopolamine were examined to observe the effects of RA. For LTP analysis, baseline field excitatory postsynaptic potentials (fEPSPs) were recorded in CA1 by a 60-channel multielectrode array (MEA) every min for 40 min before 15 min of high-frequency stimulation (HFS) to the Schaffer collaterals and commissural pathways, followed by a successive 50 min of recording. For protein expression measurements, anti-BDNF and anti-GluR2 antibodies were used for Western blotting assays in whole-hippocampal tissue homogenate. Finally, for cell death assays, OHSCs were exposed to a culture medium containing propidium iodide (PI) for 24 or 48 h, followed by the assessment of cell death by fluorescent image analysis of PI uptake. RESULTS: and discussion: Our results indicate that RA treatment enhances fEPSPs following HFS in CA1 synapses at 1 and 10 µg/ml RA, an effect that was inhibited by CNQX and NFA but not by AP5. RA treatment also increases the expression of BDNF and GluR-2 proteins and prevents cell death of scopolamine-exposed OHSCs. Our results suggest the possibility that rosmarinic acid can enhance neural plasticity by modulating glutamatergic signaling pathways, as well as providing neuroprotection with reduced cholinergic activity.

Odisolane, a Novel Oxolane Derivative, and Antiangiogenic Constituents from the Fruits of Mulberry (Morus alba L.).

Mulberry, the fruit of Morus alba L., is known as an edible fruit and commonly used in Chinese medicines as a warming agent and as a sedative, tonic, laxative, odontalgic, expectorant, anthelmintic, and emetic. Systemic investigation of the chemical constituents of M. alba fruits led to the identification of a novel oxolane derivative, (R*)-2-((2S*,3R*)-tetrahydro-2-hydroxy-2-methylfuran-3-yl)propanoic acid (1), namely, odisolane, along with five known heterocyclic compounds (2-6). The structure of the new compound was elucidated on the basis of HR-MS, 1D and 2D NMR ((1)H-(1)H COSY, HSQC, HMBC, and NOESY) data analysis. Compound 1 has a novel skeleton that consists of 8 carbon units with an oxolane ring, which until now has never been identified in natural products. The isolated compounds were subjected to several activity tests to verify their biological function. Among them, compounds 1, 3, and 5 significantly inhibited cord formation in HUVECs. The action mechanism of compound 3, which had the strongest antiangiogenic activity, was mediated by decreasing VEGF, p-Akt, and p-ERK protein expression. These results suggest that compounds isolated from M. alba fruits might be beneficial in antiangiogenesis therapy for cancer treatment.

Dioscorea Extract (DA-9801) Modulates Markers of Peripheral Neuropathy in Type 2 Diabetic db/db Mice.

The purpose of this study was to investigate the therapeutic effects of DA-9801, an optimized extract of Dioscorea species, on diabetic peripheral neuropathy in a type 2 diabetic animal model. In this study, db/db mice were treated with DA-9801 (30 and 100 mg/kg, daily, p.o.) for 12 weeks. DA-9801 reduced the blood glucose levels and increased the withdrawal latencies in hot plate tests. Moreover, it prevented nerve damage based on increased nerve conduction velocity and ultrastructural changes. Decrease of nerve growth factor (NGF) may have a detrimental effect on diabetic neuropathy. We previously reported NGF regulatory properties of the Dioscorea genus. In this study, DA-9801 induced NGF production in rat primary astrocytes. In addition, it increased NGF levels in the sciatic nerve and the plasma of type 2 diabetic animals. DA-9801 also increased neurite outgrowth and mRNA expression of Tieg1/Klf10, an NGF target gene, in PC12 cells. These results demonstrated the attenuation of diabetic peripheral neuropathy by oral treatment with DA-9801 via NGF regulation. DA-9801 is currently being evaluated in a phase II clinical study.

Protective effects of Pogostemon cablin Bentham water extract on inflammatory cytokine expression in TNBS-induced colitis in rats.

In inflammatory bowel disease (IBD), colon epithelial cells express a variety of inflammatory mediators, including chemokines, which perpetuate inflammatory response. In the current study, we report that water extract of Pogostemon cablin Bentham aerial parts (PCW), which has traditionally been used for treatment of the common cold and infectious disease, suppressed colon inflammation. Treatment with PCW resulted in effective inhibition of tumor necrosis factor (TNF)-α-induced adhesion of monocytes to HT-29 human colonic epithelial cells. In a trinitrobenzene sulfonic acid (TNBS)-induced rat model of IBD, PCW suppressed clinical signs of colitis, including weight loss, colon tissue myeloperoxidase activity, a marker for inflammatory cell infiltration, and cyclooxygenase-2 expression in a dose-dependent manner. In addition, PCW suppressed TNBS-induced mRNA expression of IL-8, MCP-1, and IL-6 in rat colon. The nuclear level of NF-κB in TNBS-treated rat colon and NF-κB luciferase reporter gene activity in TNF-α-treated HT-29 cells were significantly inhibited by PCW. Taken together, the results of this study suggest that PCW suppressed colon inflammation via suppression of NF-κB-dependent expression of pro-inflammatory cytokines.

Anti-inflammatory and antiobesity effects of mulberry leaf and fruit extract on high fat diet-induced obesity.

The purpose of this study was to investigate the anti-inflammatory and antiobesity effect of combinational mulberry leaf extract (MLE) and mulberry fruit extract (MFE) in a high-fat (HF) diet-induced obese mice. Mice were fed a control diet or a HF diet for nine weeks. After obesity was induced, the mice were administered with single MLE at low dose (133 mg/kg/day, LMLE) and high dose (333 mg/kg/day, HMLE) or combinational MLE and MFE (MLFE) at low dose (133 mg MLE and 67 mg MFE/kg/day, LMLFE) and high dose (333 mg MLE and 167 mg MFE/kg/day, HMLFE) by stomach gavage for 12 weeks. The mulberry leaf and fruit extract treatment for 12 weeks did not show liver toxicity. The single MLE and combinational MLFE treatments significantly decreased plasma triglyceride, liver lipid peroxidation levels and adipocyte size and improved hepatic steatosis as compared with the HF group. The combinational MLFE treatment significantly decreased body weight gain, fasting plasma glucose and insulin, and homeostasis model assessment of insulin resistance. HMLFE treatment significantly improved glucose control during intraperitoneal glucose tolerance test compared with the HF group. Moreover, HMLFE treatment reduced protein levels of oxidative stress markers (manganese superoxide dismutase) and inflammatory markers (monocyte chemoattractant protein-1, inducible nitric oxide synthase, C-reactive protein, tumour necrosis factor-α and interleukin-1) in liver and adipose tissue. Taken together, combinational MLFE treatment has potential antiobesity and antidiabetic effects through modulation of obesity-induced inflammation and oxidative stress in HF diet-induced obesity.

Anti-neuroinflammatory diarylheptanoids from the rhizomes of Dioscorea nipponica.

In a continuing search for bioactive constituents from Dioscoreaceae medicinal plants, two new cyclic diarylheptanoids, diosniponol A (1) and B (2), together with 10 known compounds (3-12) were isolated from the rhizomes of Dioscorea nipponica. The structures of these new compounds were determined by spectroscopic analyses, including extensive two-dimensional nuclear magnetic resonance, high-resolution mass spectrometry, and optical rotation. All isolated compounds 1-12 were evaluated for their effects on nitric oxide (NO) production in murine microglia cell line BV-2. Compounds 8 and 11 showed potent inhibitory activities on NO production (IC50 13.36 and 14.36 µM, respectively) without cell toxicity in lipopolysaccharide-activated BV-2 cells.

5-HT(1A) receptor binding in the dorsal raphe nucleus is implicated in the anxiolytic-like effects of Cinnamomum cassia.

Previously we reported that the 50% EtOH extract of Cinnamomum cassia (C. cassia) possesses anxiolytic-like activity in the mouse elevated plus maze (EPM) test. This activity was blocked by the 5-HT(1A) receptor antagonist, WAY 100635. Therefore, in order to investigate the effect of C. cassia on 5-HT(1A) receptor binding, quantitative autoradiography of 5-HT(1A) receptors was carried out in brains of mice treated acutely and repeatedly with C. cassia. Binding of [(3)H]8-OH-DPAT to the 5-HT(1A) receptor was investigated in the mouse brain. After a single treatment of C. cassia (750 mg/kg, p.o.), [(3)H]8-OH-DPAT binding showed a significant increase in the dorsal raphe nucleus (DRN). After repeated treatment with C. cassia (100mg/kg, once a day for 5 days, p.o.), [(3)H]8-OH-DPAT binding showed no significant change in any brain region. Taken together, the anxiolytic-like effect of the 50% EtOH extract of C. cassia might be mediated by region specific change of 5-HT(1A) receptors in the dorsal raphe nucleus.

Effects of DA-9701, a novel prokinetic agent, on gastric accommodation in conscious dogs.

BACKGROUND AND AIM: DA-9701, a novel prokinetic agent formulated with Pharbitis Semen and Corydalis Tuber, has strong prokinetic effects, and enhances gastric compliance in conscious dogs. In this study, the effects of DA-9701 on gastric accommodation were studied in conscious dogs. METHODS: Beagle dogs with an implanted gastric cannula in the stomach were used in this study. After an overnight fast, the dogs received DA-9701 orally, or served as a positive control that received sumatriptan or a negative control before ingestion of a meal. The basal and postprandial gastric volumes were monitored at a constant operating pressure using an electronic barostat. To investigate the long-lasting effects on increased postprandial gastric volume, the area under the volume versus time curve (AUC) was calculated. RESULTS: DA-9701 significantly increased the basal gastric volume compared to the negative controls (P < 0.05); the effects were comparable to sumatriptan. DA-9701 and sumatriptan significantly increased gastric accommodation compared to the negative control (P < 0.05). In the negative control, the gastric volume reached the maximal volume 40 min after the meal, and then gradually decreased. However, with DA-9701, the increased gastric volume remained significantly elevated for 60 min postprandially (P < 0.05). DA-9701 significantly increased the value of AUC compared to the negative control; this was observed during both the early and late postprandial phases (P < 0.05). CONCLUSIONS: A novel prokinetic agent, DA-9701, improved gastric accommodation by increasing the postprandial gastric volume; these effects persisted for 60 min after a meal.

Tetrahydroberberine, an isoquinoline alkaloid isolated from corydalis tuber, enhances gastrointestinal motor function.

Because delayed gastric emptying and impaired gastric accommodation are regarded as pathophysiological mechanisms underlying functional dyspepsia (FD), prokinetics and fundic relaxants have been suggested as a new treatment for FD. We isolated tetrahydroberberine (THB), an isoquinoline alkaloid (5,8,13,13a-tetrahydro-9,10-dimethoxy-6H-benzo[g]-1,3-benzodioxolo[5,6-a]quinolizine) from Corydalis tuber, and found that it has micromolar affinity for dopamine D(2) (pK(i) = 6.08) and 5-HT(1A) (pK(i) = 5.38) receptors but moderate to no affinity for other relevant serotonin receptors (i.e., 5-HT(1B), 5-HT(1D), 5-HT(3), and 5-HT(4); pK(i) < 5.00). Oral administration of THB not only resulted in significantly accelerated gastric emptying of normal rats in a bell-shaped relationship, with a maximal efficacy at a dose of 30 µg/kg, but also restored the delayed gastric emptying caused by apomorphine, which might be mediated by an antidopaminergic effect. Data from electromyography indicated enhanced motor function of the upper gastrointestinal tract by THB, which occurred through strengthening contractility and shortening the contraction interval. Furthermore, in rats stressed by repeated restraint, a significantly higher shift in the pressure-volume curve by THB (10 µg/kg, p < 0.05), which was inhibited by [O-methyl-3H]-N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide trihydrochloride (WAY-100635), a 5-HT(1A) antagonist, and N(ω)-nitro-l-arginine methyl ester, a nitric-oxide synthase inhibitor but not a vasoactive intestinal peptide antagonist, was observed. Oral administration of THB resulted in a drastic increase of gastric accommodation in Beagle dogs. Area under the volume versus time curve was increased significantly by THB (30 µg/kg, p < 0.01) and comparable with that of sumatriptan (3 mg/kg), a potent fundic relaxant. Taken together, our data suggested that THB, with D(2) receptor antagonist and 5-HT(1A) receptor agonist properties, has significant potential as a therapeutic for treatment of FD.

Cytotoxic terpene hydroperoxides from the aerial parts of Aster spathulifolius.

Three new sesquiterpene hydroperoxides, 1-[3-(2-hydroperoxy-3-methylbut-3-en)-4-hydroxyphenyl]ethanone (2), 7beta-hydroperoxy-eudesma-11-en-4-ol (3), and 7alpha-hydroperoxymanool (4), together with three known compounds, germacrone (1), ent-germacra-4(15),5,10(14)-trien-1alpha-ol (5) and teucdiol A (6) were isolated from the aerial parts of Aster spathulifolius (Compositae). Their structures were characterized using chemical and spectroscopic methods. The isolated compounds were tested for their cytotoxicity against five human tumor cell lines in vitro using a SRB method. The two new compounds, 3 and 4, showed moderate cytotoxicity against human cancer cells with ED50 values ranging from 0.24 to 13.27 microg/mL.

Anti-platelet effects of bioactive compounds isolated from the bark of Rhus verniciflua Stokes.

It has previously been shown that EtOAc extracts of Rhus verniciflua Stokes (RVS) inhibit the platelet aggregation response. In this report, bioassay-guided fractionation using ADP-, arachidonic acid-, and collagen-induced human platelet aggregation by a whole blood aggregometer yielded the bioactive compounds isomaltol and pentagalloyl glucose from different highly effective fractions. In addition, column chromatography of fractions from RVS yielded another five compounds: butin, fisetin, sulfuretin, butein and 3,4',7,8-tetrahydroxyflavone. We investigated the effects of bioactive compounds from RVS fractions on several markers of platelet activation using receptor expression on platelet membranes, including glycoprotein IIb/IIIa (CD41), GPIIb/IIIa-like expression (PAC-1) and P-selectin (CD62), and intracelluar calcium mobilization responses by flow cytometry in healthy subjects. Dose-dependent inhibition of platelet aggregation and significantly decreased platelet activation were observed for the isomaltol- and pentagalloyl glucose-treated platelets, respectively. These results show that isomaltol and pentagalloyl glucose from the bark of Rhus verniciflua Stokes have potent anti-platelet activity and emphasize the need to further examine the mechanism of these active compounds for platelet modulation.

Labdane diterpenes from Aster spathulifolius and their cytotoxic effects on human cancer cell lines.

Three new labdane diterpenes (1-3), together with eight known diterpenoids, were isolated from a methanol extract of the aerial parts of Aster spathulifolius. The structures of 1-3 were determined as (13R)-labda-7,14-diene 13-O-beta-d-(4'-O-acetyl)fucopyranoside (1), (13R)-labda-7,14-diene 13-O-beta-d-(3'-O-acetyl)fucopyranoside (2), and (13R)-labda-14(15)-en-8,13-diol 13-O-beta-d-fucopyranoside (3), on the basis of spectroscopic and chemical methods. Compounds 1, 2, and four of the known compounds exhibited generally nonspecific cytotoxicity against human A549, SK-OV-3, SK-MEL-2, XF498, and HCT15 tumor cells.

Antidiabetic stilbene and anthraquinone derivatives from Rheum undulatum.

The antidiabetic-activity-guided fractionation and isolation of the 80% EtOH extracts obtained from cultivated Korean Rhubarb rhizomes (Rheum undulatum, Polygonaceae) led to the isolation and characterization of one stilbene, desoxyrhapontigenin (1) and two anthraquinones, emodin (2) and chrysophanol (3). Their structures were established by chemical and spectroscopic methods. Compounds 1, 2, and 3 inhibited postprandial hyperglycemia by 35.8, 29.5, 42.3%, respectively.

Antidiabetic coumarin and cyclitol compounds from Peucedanum japonicum.

The antidiabetic activity-guided fractionation and isolation of the 80% EtOH extracts from Peucedani Radix (Peucedanum japonicum, Umbelliferae) led to the isolation and characterization of a coumarin and a cyclitol as active principles, that is, peucedanol 7-O-beta-D-glucopyranoside (1) and myo-inositol (2). Their structures were identified by spectroscopic methods. Compound 1 showed 39% inhibition of postprandial hyperglycemia at 5.8 mg/kg dose, and compound 2 also significantly inhibited postprandial hyperglycemia by 34% (P<0.05).

A new sesquiterpene hydroperoxide from the aerial parts of Aster oharai.

Phytochemical works on the aerial parts of Aster oharai (Compositae) led to the isolation of a new sesquiterpene hydroperoxide, 7alpha-hydroperoxy-3,11-eudesmadiene (2) and seven known compounds, teucdiol B (1), alpha-spinasterol (3), oleanolic acid (4), alpha-spinasterol 3-O-beta-D-glucopyranoside (5), methyl 3,5-di-O-caffeoyl quinate (6), 3,5-di-O-caffeoylquinic acid (7), 3,4-di-O-caffeoylquinic acid (8). The chemical structures of 1-8 were established by chemical and spectroscopic methods. Compound 2 showed cytotoxicity against cultured human tumor cell lines in vitro, SK-OV-3 (ovarian), SK-MEL-2 (skin melanoma), and HCT15 (colon) with ED50 values ranging from 3.86-17.21 microg/mL.

Phospholipids from Bombycis corpus and their neurotrophic effects.

Three phospholipids (4-6) and three aromatic amines (1-3) were obtained from the methanol extract of Bombycis corpus. Based on spectral data, their structures have been elucidated as nicotiamide (1), cytidine (2), adenine (3), 1-O-(9Z-octadecenoyl)-2-O-(8Z,11Z-octadecadienoyl) sn-glycero-3-phosphorylcholine (4), 1,2-di-O-hexadecanoyl-sn-glycero-3-phosphorylcholine (5) and 1,2-di-O-9Z-octadecenoyl-sn-glycero-3-phosphorylcholine (6). We examined the effects of compounds on synthesis of NGF in cultured astrocytes. By RT-PCR analysis, expresison of NGF mRNA in astrocytes cultured in serum-starvation increased after the addition of phospholipid (10 microM). The NGF content in the culture medium was significantly increased by compound 5, compared with the control value. These results suggest that three phospholipid compounds isolated from the methanol extract of Bombycis corpus may exert neurotrophic effects by stimulation of NGF synthesis in astrocytes.