Protective effect of the ethanol extract of <Emphasis Type="Italic">Magnolia officinalis</Emphasis> and 4-<Emphasis Type="Italic">O</Emphasis>-methylhonokiol on scopolamine-induced memory impairment and the inhibition of acetylcholinesterase activity

Magnolol, honokiol, and obovatol are well-known bioactive constituents of the bark of Magnolia officinalis and have been used as traditional Chinese medicines for the treatment of neurosis, anxiety, and stroke. We recently isolated novel active compound (named 4-O-methylhonokiol) from the ethanol extract of Magnolia officinalis. The present study aimed to test two different doses of ethanol extracts of Magnolia officinalis (5 and 10 mg/kg/mouse, p.o., 1 week) and 4-O-methylhonokiol (0.75 and 1.5 mg/kg/mouse, p.o., 1 week) administered for 7 days on memory impairment induced by scopolamine (1 mg/kg body weight i.p.) in mice. Memory and learning were evaluated using the Morris water maze and the step-down avoidance test. Both the ethanol extract of Magnolia officinalis and 4-O-methylhonokiol prevented memory impairment induced by scopolamine in a dose-dependent manner. The ethanol extract of Magnolia officinalis and 4-O-methylhonokiol also dose-dependently attenuated the scopolamine-induced increase of acetylcholinesterase (AChE) activity in the cortex and hippocampus of mice, and inhibited AChE activity in vitro with IC₅₀ (12 nM). This study, therefore, suggests that the ethanol extract of Magnolia officinalis and its major ingredient, 4-O-methylhonokiol, may be useful for the prevention of the development or progression of AD.     

Generic systems for the enantioseparation of basic drugs in NACE using single-isomer anionic CDs

The enantioseparation of 10 basic drugs was evaluated in NACE systems using heptakis(2-O-methyl-3-O-acetyl-6-O-sulfo)-β-CD (HMAS-β-CD). For this purpose, a D-optimal design with 21 experimental points was applied. Four antifungal agents (econazole, isoconazole, miconazole, sulconazole), three local anesthetics (bupivacaine, mepivacaine and prilocaine), two sympathomimetics (salbutamol and terbutaline) and one β-blocker (carvedilol) were selected as basic model analytes. The influence on the enantiomeric resolution of anionic CD and BGE anion concentrations as well as the BGE anion nature was investigated. For all studied analytes, the enantiomeric resolution was shown to be significantly influenced by the CD concentration. Based on the observed results, a generic NACE system was recommended, namely 20 mM HMAS-β-CD and 10 mM ammonium camphorSO₃⁻ in methanol acidified with 0.75 M formic acid. Moreover, this NACE system was compared to previous conditions with heptakis(2,3-di-O-methyl-6-O-sulfo)-β-CD (HDMS-β-CD) or heptakis(2,3-di-O-acetyl-6-O-sulfo)-β-CD (HDAS-β-CD). Finally, two generic systems using either HDAS-β-CD or HMAS-β-CD were proposed and evaluated for the enantioseparation of ketamine and norketamine after incubation of ketamine in phenobarbital-induced male rat liver microsomes systems.     

Regioselective sulfonation of dopamine by SULT1A3 in vitro provides a molecular explanation for the preponderance of dopamine-3-O-sulfate in human blood circulation

SULT1A3 is an enzyme that catalyzes the sulfonation of many endogenous and exogenous phenols and catechols. The most important endogenous substrate is dopamine (DA), which is often used as a probe substrate for SULT1A3. We developed a new method for analyzing the SULT1A3 reaction products by high-performance liquid chromatography (HPLC) with electrochemical detection. The sulfonate donor 3′-phosphoadenosine-5′-phosphosulfate (PAPS), DA and the two dopamine sulfates, DA-3-O-sulfate and DA-4-O-sulfate, can be separated within 3 min. This enables quantitation of the sulfates without radioactive PAPS or the precipitation of unreacted PAPS. Both sulfates were synthesized as reference substances and characterized by ¹H and ¹³C nuclear magnetic resonance (NMR), mass spectrometry (MS) and tandem mass spectrometry (MS/MS). The purity of the dopamine sulfates was estimated by HPLC using a diode array detector. We determined the enzyme kinetic parameters for formation of DA-3-O-sulfate and DA-4-O-sulfate using purified recombinant human SULT1A3. The reactions followed Michaelis-Menten kinetics up to 50 μM DA concentration, and strong substrate inhibition was observed at higher concentrations. The apparent K_m values for sulfonation at both hydroxy groups were similar (2.21 ± 0.764 and 2.59 ± 1.06 μM for DA-4-O-sulfate and DA-3-O-sulfate, respectively), but the V_max was approximately six times higher for the formation of the 3-O-sulfate (344 ± 139 nmol/min/mg protein) than the 4-O-sulfate (45.4 ± 16.5 nmol/min/mg protein). These results are in accordance with the observation that DA-3-O-sulfate is more abundant in human blood than DA-4-O-sulfate and that in the crystal structure of SULT1A3 with dopamine bound to the active site, the 3-hydroxy group is aligned to form hydrogen bonds with catalytic residues of the enzyme.     

RANKL-induced osteoclastogenesis is suppressed by 4-<Emphasis Type="Italic">O</Emphasis>-methylhonokiol in bone marrow-derived macrophages

Magnolol, honokiol, and obovatol are well known bioactive constituents of the bark of Magnolia officinalis and have been reported to have beneficial effects in various diseases. We recently isolated a novel active compound, 4-O-methylhonokiol (4-O-MH) from the ethanol extract of M. officinalis, which was previously reported to have pharmacological effects including anti-inflammatory, anti-oxidative, and anti-aging activities. Here, we examined the pharmacological properties of 4-O-MH on osteoblast (bone-forming cells) and osteoclast (bone-resorbing cells) differentiation, and its underlying signaling pathways in primary cultured pre-osteoblasts and bone marrow macrophages. Our results showed that 4-O-MH did not affect cell viability in pre-osteoblasts and did not influence osteoblast differentiation and mineralized nodule formation, as assessed by alkaline phosphatase activity and Alizarin red staining. However, 4-O-MH significantly inhibited TRAP-positive multinuclear osteoclasts and F-actin ring formation during Receptor activator of NF-κB ligand (RANKL)-mediated osteoclastogenesis without cytotoxicity. In addition, 4-O-MH suppressed RANKL-induced critical factors (c-Fos, NF-ATc1, TRAP, and ITB3) for osteoclast differentiation and function. Furthermore, RANKL-mediated signaling, including ERK1/2, AKT, and NF-kB pathways was attenuated by 4-O-MH. Taken together, 4-O-MH has an inhibitory role in RANKL-mediated osteoclastogenesis but not osteoblast differentiation, and our findings also suggest that 4-O-MH is a potential therapeutic agent for bone-destructive diseases such as osteoporosis, alveolar bone resorption, and osteoarthritis.     

Diarylheptanoid 7-(3,4 dihydroxyphenyl)-5-hydroxy-1-phenyl-(1E)-1-heptene from Curcuma comosa Roxb. protects retinal pigment epithelial cells against oxidative stress-induced cell death

Chronic exposure to oxidative stress causes damage to retinal pigment epithelial cells which may lead to the development of age-related macular degeneration, the major cause of vision loss in humans. Anti-oxidants provide a natural defense against retinal cell damage. The present study was designed to evaluate the potential anti-oxidant activity and protective effect of two diarylheptanoids isolated from a medicinal herb Curcuma comosa; 7-(3,4 dihydroxyphenyl)-5-hydroxy-1-phenyl-(1E)-1-heptene (compound A), and 1,7-diphenyl-4(E),6(E)-heptadien-3-ol (compound B) against oxidative stress (H₂O₂)-induced human retinal pigment epithelial (APRE-19) cell death. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay indicated that the anti-oxidant activity (IC₅₀) of compound A was similar to that of vitamin C. Pre-treatment of ARPE-19 cells with 20 μM compound A for 4 h afforded greater protection against the insult from 500 μM H₂O₂, compared to a similar protection period for compound B. Compound A lowered H₂O₂-induced lipid peroxidation, malondialdehyde formation and intracellular reactive oxygen species. Furthermore, compound A ameliorated the H₂O₂-induced decrease in anti-oxidant enzyme activities and subsequent apoptotic cell death in ARPE-19 cells in a dose and time-dependent manner. These results suggest that compound A protects ARPE-19 cells against oxidative stress, in part, by enhancing several anti-oxidant defense mechanisms. Therefore, compound A may have therapeutic potential for diseases associated with oxidative stress, particularly degenerative retinal diseases.     

Hesperidin produces antinociceptive response and synergistic interaction with ketorolac in an arthritic gout-type pain in rats

Hesperidin occurs in greatest concentration in plants from the Rutaceae and Lamiaceae families. In human nutrition it contributes to the integrity of blood vessels and its deficiency in the diet has been linked to abnormal capillary leakiness as well as pain. In this study, the bioflavonoid hesperidin was identified as an active compound in an ethanol extract of the Rosmarinus officinalis aerial parts tested in the pain-induced functional impairment model in the rat (PIFIR) as an assay of inflammatory and chronic nociception similar to that observed in clinical gout. Hesperidin produced a dose-dependent and significant response with an ED₂₅ = 1666.72 mg/kg in comparison to an ED₂₅ = 302.90 mg/kg for the extract or an ED₂₅ = 0.47 mg/kg for the reference drug ketorolac in the PIFIR model. Although the antinociceptive response of R. officinalis was reverted in presence of the opioid antagonist naloxone (10 mg/kg, s.c.) and the 5HT_1A antagonist WAY100635 (0.12 mg/kg, s.c.), the hesperidin response was not modified by naloxone (10 mg/kg), WAY100635 (0.12 mg/kg), bicuculline (1 mg/kg, s.c.), flumazenil (10 mg/kg, i.p.) or caffeine (1 mg/kg, s.c.). Nevertheless, it was reduced in presence of capsazepine (10 or 20 mg/kg, s.c.) suggesting the participation of the TRPV1 receptor, which was reinforced when hesperidin significantly reduced the capsaicin-induced nociceptive response. A synergistic interaction was also observed when antinociceptive doses of hesperidin were combined with those of ketorolac producing 15 combinations mainly in additive and supra-additive responses. These results provide evidence for the antinociceptive activity of hesperidin and demonstrate synergistic response when combined with ketorolac, possibly by involvement of the TRPV1 receptor, suggesting their clinical potential in pain therapy.     

Effects of zearalenone and its derivatives on the innate immune response of swine

Zearalenone (ZEN) is an estrogenic mycotoxin produced by several fungi of Fusarium genera. As it can contaminate food and feed it is a risk factor from both public health and agricultural perspectives. In this in vitro study, we compared the effects of zearalenone (ZEN) and some of its derivatives: α-zearalenol (α-ZOL); β-zearalenol (β-ZOL) and zearalanone (ZAN) on several neutrophil functions: proliferation, cytokine synthesis and oxidative stress in a porcine PMN model. The concentrations of toxins necessary to inhibit viability, in a MTT test, by 50% were: 73.4 μM for ZEN; 59.0 μM for α-ZOL; 56.8 μM for β-ZOL and 53.1 μM for ZAN, with ZEN being less toxic than its derivatives. A significant increase of O₂⁻ synthesis compared to the control, as shown by NBT reduction, was observed at 1 μM concentration only for β-ZOL and ZAN, while at 10 μM, the ZEN derivatives (α-ZOL, β-ZOL, ZAN) induced a significant decrease of the IL-8 synthesis in swine PMNs with 49.2%, 45.6% and 45.1% respectively, compared to the control. Although, the precise mechanism of action of these toxins still remains unknown, the results of this study suggest that ZEN and its derivatives may have divergent effects on important parameters of swine innate immunity: cell proliferation, IL-8 and O₂⁻ synthesis. Also ZEN derivatives are more toxic than ZEN.     

Fermentation enhances the in vitro antioxidative effect of onion (Allium cepa) via an increase in quercetin content

Yellow onion (Allium cepa) extract showed enhanced antioxidative effects in 2,2-diphenyl-1-picrylhydrazyl (DPPH), Trolox equivalent antioxidant capacity (TEAC) and 5-(and-6)-chloromethyl-2′,7′-dichlorodihydrofluorescein diacetate and acetyl ester (CM-H₂DCFDA) assay after being treated with a crude enzyme extract from soybean paste fungi, Aspergillus kawachii. HPLC analysis showed two increased and two decreased peaks after enzyme treatment. The decreased peaks were identified as quercetin-3,4′-di-O-β-d-glucoside (1) and quercetin-4′-O-β-d-glucoside (2), and peaks that increased were quercetin-3-O-β-d-glucoside (3) and quercetin (4), respectively. It was expected that 3 and 4 were originated from the glucosidic cleavage of their glucosides, 1 and 2. Among the increased compounds, only quercetin (4) showed strong antioxidative activity in the DPPH assay. In addition, the protective effect against glutamate-induced neurotoxicity in HT22 cells was increased when treated with 25 μg/ml of fermented onion. The enhanced neuroprotective effect was also originated from the increased quercetin content. As a consequence, fermentation raised the quercetin content in onion, and subsequently increased the antioxidative and neuroprotective activities.     

Effects of standardized bilberry fruit extract (Mirtoselect®) on resolution of CCl4-induced liver fibrosis in mice

Bilberry (Vaccinium myrtillus L) has been traditionally used in the treatment of various liver disorders. The aim of this study was to investigate the effects of bilberry fruit extract (BE) on carbon tetrachloride (CCl₄)-induced hepatic fibrosis. Male Balb/C mice were treated with CCl₄ dissolved in olive oil (20% v/v, 2 ml/kg) intraperitoneally (i.p.), twice a week for 7 weeks. BE (1, 5, and 10 mg/kg) was given to mice for next 15 days, 72 h after the last dose of CCl₄. The CCl₄ administration increased oxidative stress as well as the expression of tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) in the liver. Furthermore, increased α-smooth muscle actin (α-SMA) expression and hydroxyproline levels indicated activation of hepatic stellate cells (HSCs) and enhanced collagen production. BE 10 mg/kg markedly attenuated oxidative stress, decreased TNF-α, TGF-β1, and α-SMA expression, and eliminated hepatic collagen deposits. These results indicate that BE, in a dose dependent manner, induces the resolution of liver fibrosis by decreasing oxidative stress and inactivating HSCs via down-regulation of fibrogenic cytokines, TGF-β1 and TNF-α.     

Amelioration of Cognitive Dysfunction in APP/PS1 Double Transgenic Mice by Long-Term Treatment of 4-O-Methylhonokiol

Alzheimer’s disease (AD) is the most common neurodegenerative disease without known ways to cure. A key neuropathologic manifestation of the disease is extracellular deposition of beta-amyloid peptide (Aβ). Specific mechanisms underlying the development of the disease have not yet been fully understood. In this study, we investigated effects of 4-O-methylhonokiol on memory dysfunction in APP/PS1 double transgenic mice. 4-O-methylhonokiol (1 mg/kg for 3 month) significantly reduced deficit in learning and memory of the transgenic mice, as determined by the Morris water maze test and step-through passive avoidance test. Our biochemical analysis suggested that 4-O-methylhonokiol ameliorated Aβ accumulation in the cortex and hippocampus via reduction in beta-site APP-cleaving enzyme 1 expression. In addition, 4-O-methylhonokiol attenuated lipid peroxidation and elevated glutathione peroxidase activity in the double transgenic mice brains. Thus, suppressive effects of 4-O-methylhonokiol on Aβ generation and oxidative stress in the brains of transgenic mice may be responsible for the enhancement in cognitive function. These results suggest that the natural compound has potential to intervene memory deficit and progressive neurodegeneration in AD patients.     

Aleurites moluccana and its main active ingredient, the flavonoid 2″-O-rhamnosylswertisin, have promising antinociceptive effects in experimental models of hypersensitivity in mice

This study investigated the antinociceptive effect of Aleurites moluccana dried extract (DE; 125 to 500 mg/kg, p.o.) and the isolated flavonoid 2″-O-rhamnosylswertisin (5 to 50.6 μmol/kg, p.o.) using different models of long-lasting inflammatory and neuropathic pain in mice. Attempts were made to analyse the mechanisms through which A. moluccana exerted its effects. A. moluccana DE inhibited complete Freund's adjuvant (CFA)-induced mechanical nociception. It was also evidenced by a reduction of sensitization in the contralateral hindpaw. The extract reversed the mechanical hypersensitivity of partial ligation of sciatic nerve (PLSN)-treated animals, similar to gabapentin. In PLSN model, the opioid, dopaminergic and oxidonitrergic pathways were involved in the A. moluccana DE antinociceptive effects. A single dose of 2″-O-rhamnosylswertisin inhibited the carrageenan- and CFA-induced mechanical nociception. Furthermore, the compound caused expressive antinociception in PLSN-mice, with inhibition value greater than obtained with gabapentin. Oral treatment with the extract or the isolated compound attenuated the neutrophil migration and IL-1β levels following carrageenan injection. Of note, A. moluccana DE did not interfere with thermal sensitivity in healthy mice. The absence of side effects, including interference in locomotor activity, motor performance in animals treated with the extract, showed excellent potential for the therapeutic use of this medicinal plant in treating persistent pain in humans.     

Antioxidant activity and protective effect of Turnera ulmifolia Linn. var. elegans against carbon tetrachloride-induced oxidative damage in rats

The present study aimed to determine whether the leaves of Turnera ulmifolia Linn. var. elegans extract exert significant antioxidant activity. The antioxidant activity of its hydroethanolic extract (HEETU) was evaluated by assessing (a) its radical scavenging ability in vitro, and (b) its in vivo effect on lipid peroxidation and antioxidant enzyme activities. The in vitro antioxidant assay (DPPH) clearly supported HEETU free radical scavenging potential. Moreover, glutathione content and antioxidant enzyme activities (glutathione peroxidase, superoxide dismutase and catalase) were significantly enhanced in CCl₄-treated rats due to oral HEETU-treatment (500 mg/kg b.w.) over 7 and 21 days. In addition, an improvement was observed in lipid peroxidation and serum biochemical parameters (aspartate aminotransferase and alanine aminotransferase), indicating a protective effect against CCl₄-induced liver injuries, confirmed by histopathological studies. The HEETU effect was comparable to the standard drug Legalon® (50 mg/kg b.w.) under the same experimental condition. Quantitative analysis of the HPLC extract revealed the presence of flavonoids, wich mediate the effects of antioxidant and oxidative stress. In conclusion, extract components exhibit antioxidant and hepatoprotective activities in vitro and in vivo.     

Antinociceptive activity of Annona diversifolia Saff. leaf extracts and palmitone as a bioactive compound

Annonas are consumed as fresh fruits, but are also widely used in folk medicine for treating pain and other ailments. Antinociceptive properties of the Annona diversifolia ethanol crude extract were tested using the pain-induced functional impairment model in rat (PIFIR) and the writhing test in mice. The ethanol extract caused a 25% recovery of limb function in rats; this response was significant and dose-dependent. Furthermore, this extract produced a similar antinociceptive response (ED₅₀ = 15.35 mg/kg) to that of the reference drug tramadol (ED₅₀ = 12.42 mg/kg) when evaluated in the writhing test in mice. Bio-guided fractionation yielded hexane and acetone active fractions from which the presence of palmitone and flavonoids was respectively detected. Palmitone produced an antinociceptive response with an ED₅₀ = 19.57 mg/kg in the writhing test. Antinociceptive responses from ethanol extract and tramadol were inhibited in the presence of either naloxone (1 mg/kg, s.c.)—an antagonist of endogenous opioids—or WAY100635 (0.8 mg/kg, s.c.)—a 5-HT_1A serotonin receptor antagonist. These results provide evidence that A. diversifolia possesses antinociceptive activity, giving support to their traditional use for treatment of spasmodic and arthritic pain. In addition, our results suggest the participation of endogenous opioids and 5-HT_1A receptors in this antinociceptive response.     

5-Hydroxymethylfurfural,an antioxidant agent from Alpinia oxyphylla Miq. improves cognitive impairment in Aβ1–42 mouse model of Alzheimer's disease

5-Hydroxymethylfurfural (5-HMF) is a main effective compound of Alpinia oxyphylla Miq. ethanol extract, which showed memory improvement activity against Alzheimer's disease in previous study. In order to identify a potential therapeutic agent, the neuroprotective effects of 5-HMF on impairment of cognition and memory function induced by intracerebroventricular (ICV) injection of Aβ_1–42 were investigated in vivo. The mice were treated with 5-HMF at dose of 15 μg/kg and 150 μg/kg (ICV) for five consecutive days after ICV-Aβ_1–42. The results showed that 5-HMF significantly ameliorated learning and memory impairment evaluated by the locomotor activity, Y-maze test, and Morris water maze test. Furthermore, 5-HMF significantly inhibited the β-secretase activity, decreased the content of Aβ_1–42 and malondialdehyde (MDA), and increased the antioxidative enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase (GPx). Results of hippocampus slices showed that neuronal were integrated and regularly arranged in the groups which were administered along with 5-HMF, indicating that 5-HMF could mitigate the degree of neuronal damage. The present study indicated that 5-HMF may serve as a potential therapeutic agent for the treatment of Alzheimer's disease.     

Simultaneous quantitation of levodopa and 3-O-methyldopa in human plasma by HPLC-ESI-MS/MS: application for a pharmacokinetic study with a levodopa/benserazide formulation

A sensitive and simple method was developed for the quantitation of levodopa and its metabolite 3-O-methyldopa, in human plasma, after oral administration of tablet formulations containing levodopa (200 mg) and benserazide (50 mg). The analytes were extracted by a protein precipitation procedure, using carbidopa as an internal standard. A mobile phase consisting of 0.2% formic acid and acetonitrile (94:6, v/v) was used and chromatographic separation was achieved using ACE C₁₈ column (50 mm × 4.6 mm i.d.; 5 μm particle size). Selected reaction monitoring was performed using the fragmentation transitions m/z 198 → m/z 107, m/z 212 → m/z 166 and m/z 227 → m/z 181 for levodopa, 3-O-methyldopa and carbidopa, respectively. Calibration curves were constructed over the range 50.0-6000.0 ng/mL for levodopa and 25.0-4000.0 ng/mL for 3-O-methyldopa. The method shown to be specific, precise, accurate and provided recovery rates higher than 85% for all analytes. No matrix effect was detected in the samples. The validated method was applied in a pharmacokinetic study with a levodopa/benserazide tablet formulation in healthy volunteers.     

A search for hepatoprotective activity of aqueous extract of Rhus coriaria L. against oxidative stress cytotoxicity

The protective effects of different concentrations of aqueous extract of Rhus coriaria L. fruit (75 and 100 μg/ml) and also gallic acid (100 μM) as one of its main components were examined against oxidative stress toxicity induced by cumene hydroperoxide (CHP) in isolated rat hepatocytes. Both extract concentrations and gallic acid (100 μM) significantly (P < 0.05) protected the hepatocyte against all oxidative stress markers including cell lysis, ROS generation, lipid peroxidation, glutathione depletion, mitochondrial membrane potential decrease, lysosomal membrane oxidative damage and cellular proteolysis. Aqueous extracts of Rhus coriaria L. (75 and 100 μg/ml) were more effective than gallic acid (100 μM) in protecting hepatocytes against CHP induced lipid peroxidation (P < 0.05). On the other hand gallic acid (100 μM) acted more effective than aqueous extracts of Rhus coriaria L. (75 and 100 μg/ml) at preventing hepatocyte membrane lysis (P < 0.05). In addition H₂O₂ scavenging effect of both extract concentrations (75 and 100 μg/ml) were determined in hepatocytes and compared with gallic acid (100 μM). Gallic acid (100 μM) was more effective than aqueous extracts of Rhus coriaria L. (75 and 100 μg/ml) at H₂O₂ scavenging activity (P < 0.05).     

A Comparison between Extract Products of Magnolia officinalis on Memory Impairment and Amyloidogenesis in a Transgenic Mouse Model of Alzheimer’s Disease

The components of Magnolia officinalis have well known to act anti-inflammatory, anti-oxidative and neuroprotective activities. These efficacies have been sold many products as nutritional supplement extracted from bark of Magnolia officinalis. Thus, to assess and compare neuroprotective effect in the nutritional supplement (Magnolia Extract^TM, Health Freedom Nutrition LLC, USA) and our ethanol extract of Magnolia officinalis (BioLand LTD, Korea), we investigated memorial improving and anti-Alzheimer’s disease effects of extract products of Magnolia officinalis in a transgenic AD mice model. Oral pretreatment of two extract products of Magnolia officinalis (10 mg/kg/day in 0.05% ethanol) into drinking water for 3 months ameliorated memorial dysfunction and prevented Aβ accumulation in the brain of Tg2576 mice. In addition, extract products of Magnolia officinalis also decreased expression of β-site APP cleaving enzyme 1 (BACE1), amyloid precursor protein (APP) and its product, C99. Although both two extract products of Magnolia officinalis could show preventive effect of memorial dysfunction and Aβ accumulation, our ethanol extract of Magnolia officinalis (BioLand LTD, Korea) could be more effective than Magnolia Extract^TM (Health Freedom Nutrition LLC, USA). Therefore, our results showed that extract products of Magnolia officinalis were effective for prevention and treatment of AD through memorial improving and anti-amyloidogenic effects via down-regulating β-secretase activity, and neuroprotective efficacy of Magnolia extracts could be differed by cultivating area and manufacturing methods.     

The effects of acute and repeated oroxylin A treatments on Abeta(25-35)-induced memory impairment in mice

Oroxylin A is a flavonoid that is found in the roots of Scutellaria baicalensis Georgi. The aim of this study was to characterize the effects of oroxylin A on the memory impairments and pathological changes induced by Aβ_25-35 peptide in mice. The ameliorating effect of oroxylin A on memory impairment was investigated using passive avoidance and Y-maze tasks and pathological changes were identified by immunostaining and western blotting. Aβ_25-35 peptide (5 nmol) was administered by intracerebroventricular injection. In the acute treatment study, a single dose of oroxylin A (5 mg/kg, p.o.) treated 1 h before behavioral tests was found to significantly reverse Aβ_25-35-induced cognitive impairments based on passive avoidance and Y-maze task findings (P < 0.05). Moreover, these acute effects of oroxylin A were blocked by diazepam (1 mg/kg, i.p.), a GABA_A/benzodiazepine binding site agonist (P < 0.05). On the other hand, our subchronic studies revealed that oroxylin A (1 or 5 mg/kg/day, p.o.) for 7 days ameliorated the memory impairment induced by Aβ_25-35 peptide. Moreover, Aβ_25-35-induced increases in GFAP (an astroglia marker) and OX-42 (a microglia marker), and increases in iNOS positive cells in the hippocampus were found to be attenuated by subchronic oroxylin A (1 or 5 mg/kg/day, i.p., P < 0.05). In addition, reductions in the immunoreactivity and protein level of ChAT (a cholinergic neuronal cell marker) in the CA3 hippocampal area induced by Aβ_25-35 peptide were also attenuated by oroxylin A. Furthermore, lipid peroxidation induced by Aβ_25-35 was also reduced by oroxylin A. These results suggest that the amelioration of Aβ_25-35 peptide-induced memory impairment by oroxylin A is mediated via the GABAergic neurotransmitter system after a single administration, or by reductions in Aβ_25-35 peptide-induced astrocyte and microglia activations, iNOS expression, lipid peroxidation, and increased cholinergic neurotransmission after subchronic administration.