Anti-inflammatory effect and pharmacokinetics of dehydroandrographolide, an active component of Andrographis paniculata, on Poly(I:C)-induced acute lung injury.

Acute lung injury (ALI) is a common and critical respiratory disorder caused by various factors, with viral infection being the leading contributor. Dehydroandrographolide (DAP), a constituent of the Chinese herbal plant Andrographis paniculata, exhibits a range of activities including anti-inflammatory, in vitro antiviral and immune-enhancing effects. This study evaluated the anti-inflammatory effects and pharmacokinetics (PK) profile of DAP in ALI mice induced by intratracheal instillation of Poly(I:C) (PIC). The results showed that oral administration of DAP (10-40 mg/kg) effectively suppressed the increase in lung wet-dry weight ratio, total cells, total protein content, accumulation of immune cells, inflammatory cytokines and neutrophil elastase levels in bronchoalveolar lavage fluid of PIC-treated mice. DAP concentrations, determined by an LC-MS/MS method, in plasma after receiving DAP (20 mg/kg) were unchanged compared to those in normal mice. However, DAP concentrations and relative PK parameters in the lungs were significantly altered in PIC-treated mice, exhibiting a relatively higher maximum concentration, larger AUC, and longer elimination half-life than those in the lungs of normal mice. These results demonstrated that DAP could improve lung edema and inflammation in ALI mice, and suggested that lung injury might influence the PK properties of DAP, leading to increased lung distribution and residence. Our study provides evidence that DAP displays significant anti-inflammatory activity against viral lung injury and is more likely to distribute to damaged lung tissue.

Shen Yuan extract exerts a hypnotic effect via the tryptophan/5-hydroxytryptamine/melatonin pathway in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Sleep plays a critical role in several physiologic processes, and sleep disorders increase the risk of depression, dementia, stroke, cancer, and other diseases. Stress is one of the main causes of sleep disorders. Ginseng Radix et Rhizoma and Polygalae Radix have been reported to have effects of calming the mind and intensifying intelligence in Chinese Pharmacopoeia. Traditional Chinese medicine prescriptions composed of Ginseng Radix et Rhizoma and Polygalae Radix (Shen Yuan, SY) are commonly used to treat insomnia, depression, and other psychiatric disorders in clinical practice. Unfortunately, the underlying mechanisms of the SY extract's effect on sleep are still unknown. AIM OF THE STUDY: This study aimed to investigate the hypnotic effect of the SY extract in normal mice and mice with chronic restraint stress (CRS)-induced sleep disorders and elucidate the underlying mechanisms. MATERIALS AND METHODS: The SY extract (0.5 and 1.0 g/kg) was intragastrically administered to normal mice for 1, 14, and 28 days and to CRS-treated mice for 28 days. The open field test (OFT) and pentobarbital sodium-induced sleep test (PST) were used to evaluate the hypnotic effect of the SY extract. Liquid chromatography-tandem mass spectrometry and enzyme-linked immunosorbent assay were utilized to detect the levels of neurotransmitters and hormones. Molecular changes at the mRNA and protein levels were determined using real-time quantitative polymerase chain reaction and Western blot analysis to identify the mechanisms by which SY improves sleep disorders. RESULTS: The SY extract decreased sleep latency and increased sleep duration in normal mice. Similarly, the sleep duration of mice subjected to CRS was increased by administering SY. The SY extract increased the levels of tryptophan (Trp) and 5-hydroxytryptamine (5-HT) and the expression of tryptophan hydroxylase 2 (TPH2) in the cortex of normal mice. The SY extract increased the Trp level, transcription and expression of estrogen receptor beta and TPH2 in the cortex in mice with sleep disorders by decreasing the serum corticosterone level, which promoted the synthesis of 5-HT. Additionally, the SY extract enhanced the expression of arylalkylamine N-acetyltransferase, which increased the melatonin level and upregulated the expressions of melatonin receptor-2 (MT2) and Cryptochrome 1 (Cry1) in the hypothalamus of mice with sleep disorders. CONCLUSIONS: The SY extract exerted a hypnotic effect via the Trp/5-HT/melatonin pathway, which augmented the synthesis of 5-HT and melatonin and further increased the expressions of MT2 and Cry1.

Effect of Radix Polygalae extract on the colonic dysfunction in rats induced by chronic restraint stress.

ETHNOPHARMACOLOGICAL RELEVANCE: Radix Polygalae, a commonly used traditional Chinese herb, has conventionally functioned in tranquilization and sedation, where anti-inflammation may be the underlying mechanism. AIM OF THE STUDY: Chronic restraint stress (CRS), a risk factor for the etiology of intestinal disorders, was used in the present study to examine whether Radix Polygalae extract (RPE) could modulate colonic dysfunction in CRS rats. MATERIALS AND METHODS: Wistar rats were exposed to 28-day CRS (6 h daily), and RPE (135 mg/kg and 270 mg/kg) was intragastrically administered 1 h before CRS. Subsequently, the gut microbiota was determined using metagenomic sequencing. Colonic proinflammatory interleukin-1ß, -6, and -18 were assayed using qRT-PCR and ELISA. Tight junction proteins were quantified by qRT-PCR and western blotting (WB), and tryptophan metabolic enzymes and metabolites were determined using qRT-PCR and UFLC-QTRAP-5500/MS. Moreover, protein expression of colonic tight junction proteins, NF-κB-NLRP3 signaling involved in the underlying mechanism of RPE were detected by WB. RESULTS: RPE significantly decreased proinflammatory cytokines and reshaped the gut microbiota, especially the probiotics, including Lactobacillus and Bacteroides. Moreover, RPE could modulate the metabolite contents and enzyme expression associated with colonic tryptophan-kynurenine (TRP-KYN) metabolism and could increase tight junction protein expression in CRS rats. Furthermore, RPE inhibited the activation of NF-κB-NLRP3 signaling in the colon of CRS rats. CONCLUSION: RPE could modulate colonic inflammation, colonic microbiota, tight junction, TRP-KYN metabolism and NF-κB-NLRP3 signaling to reach a colonic balance of CRS rats. The present study helped us to better understand and appreciate the various beneficial effects of RPE.

Antidepressant-like effects of cajaninstilbene acid and its related mechanisms in mice.

Cajaninstilbene acid (CSA), a bioactive constituent isolated from pigeon pea leaves, exhibited neuroprotective activities in previous studies. The present study aims to evaluate the antidepressant effects of CSA by using behavioral despair models of tail suspension test (TST) and forced swimming test (FST), and a chronic unpredictable mild stress (CUMS) model. CSA (30 or 60 mg/kg), intragastrically administrated for 7 days, could significantly reduce the immobility time of mice in TST and FST. CSA treatment (15 or 30 mg/kg) significantly reversed the depressive-like behavioral changes of mice induced by 3 or 6 weeks CUMS that caused the decrease of sucrose preference, the increase of latency to feed in the novelty-suppressed feeding test, and the increase of immobility time in TST of mice. Furthermore, the related mechanisms of the effect were explored by accessing the metabolite levels of kynurenine pathway of tryptophan metabolism and the expression of some related proteins in cerebral cortex of CUMS mice. Our results showed that the kynurenine pathway was upregulated after CUMS, while the alteration could be significantly reversed by CSA. CSA also reversed the CUMS-induced decrease in the levels of BDNF, PSD-95, p-Akt/Akt and p-mTOR/mTOR. Therefore, the antidepressant-like effects of CSA might be achieved through regulating tryptophan metabolism, promoting BDNF and PSD-95 expression, and activating Akt/mTOR pathway in the cerebral cortex.

Antidepressant effects of dammarane sapogenins in chronic unpredictable mild stress-induced depressive mice.

Depression is a common, dysthymic, and psychiatric disorder, resulting in enormous social and economic burden. Dammarane sapogenins (DS), an active fraction from oriental ginseng, has shown antidepressant-like effects in chronic restraint rats and sleep interruption-induced mice, and the present study aimed to further confirm the antidepressant effects of DS in a model of chronic unpredictable mild stress (CUMS) and to explore the underlying mechanism. Oral administration of DS (20, 40, and 80 mg/kg) markedly improved depressant-like behaviors, increasing the sucrose intake in the sucrose preference test and reducing the latency in the novelty-suppressed feeding test, and decreasing the immobility time in both the tail suspension and forced swimming tests, compared with the CUMS mice. Biochemical analysis of brain tissue and serum showed that DS treatment restored the decreased hippocampal neurotransmitter concentrations of serotonin, dopamine, norepinephrine (noradrenaline), and gamma-aminobutyric acid, and decreased the elevated of serum hormone levels (corticotrophin releasing factor, adrenocorticotrophic hormone, and corticosterone) induced by CUMS. Our findings confirm that DS exerts an antidepressant-like effect in the CUMS model of depression in mice, and suggest it may be mediated by regulation of neurotransmitters and hypothalamic-pituitary-adrenal axis.

Pharmacokinetics of Cajaninstilbene Acid and Its Main Glucuronide Metabolite in Rats.

As a major active stilbene from the leaves of pigeon pea (Cajanus cajan), cajaninstilbene acid (CSA) exerts various pharmacological activities. The present study aimed to investigate the pharmacokinetics of CSA and one of its main metabolites (M1) to explore their fate in the body and provide a pharmacokinetic foundation for their in vivo biological activities and functional food or complementary medicine application. M1 was characterized as CSA-3-O-glucuronide using the multiple reaction monitoring-information-dependent acquisition-enhanced product ion technique. After oral and intravenous administration, plasma, urine, and bile were collected and analyzed to estimate pharmacokinetic properties of CSA and M1 and to explore the main excretion route. The oral bioavailability of CSA was estimated to be 44.36%. This study first reported that CSA is mainly metabolized to CSA-3-O-glucuronide via the first-pass effect to limit its oral bioavailability and excreted predominantly through the biliary route, while the enterohepatic circulation, extravascular distribution, and renal reabsorption characteristics of CSA might delay its elimination.

Plasma and brain pharmacokinetics of ganoderic acid A in rats determined by a developed UFLC-MS/MS method.

Ganoderic acid A (GAA), an active triterpenoid of the traditional Chinese herbal medicine Lingzhi, has been reported to exhibit antinociceptive, antioxidative, and anti-cancer activities. The present study aims to establish a sensitive and rapid UPLC-MS/MS method for studying the plasma and brain pharmacokinetics of GAA in rats. The analytes were separated on a C18 column eluted with a gradient mobile phase consisting of acetonitrile and 0.1% aqueous formic acid at 0.3mL/min. The eluate was monitored by a mass detector using an MRM (m/z, 515.3-285.1) model in negative electrospray ionization. The calibration curve showed good linearity (r2>0.99), with limits of detection and quantification of 0.25 and 2.00 nmol/L, respectively. The intra- and inter-day precision and accuracy were less than 9.99% and ranged from 97.45% to 114.62%, respectively. The extraction recovery from plasma was between 92.89% and 98.87%. GAA was found to be stable in treated samples at room temperature (22°C) for 12h and in plasma at -20°C for 7d. The developed method was successfully applied to a pharmacokinetic study of GAA in rats. GAA could be rapidly absorbed into the circulation (Tmax, 0.15h) and eliminated relatively slowly (t1/2, 2.46h) after orally dosing, and could also be detected in the brain lateral ventricle (Tmax, 0.25h and t1/2, 1.40h) after intravenously dosing. The absolute oral bioavailability and brain permeability of GAA were estimated to be 8.68% and 2.96%, respectively.

Effects of phenolic constituents of daylily flowers on corticosterone- and glutamate-treated PC12 cells.

BACKGROUND: Daylily flowers, the flower and bud parts of Hemerocallis citrina or H. fulva, are well known as Wang-You-Cao in Chinese, meaning forget-one's sadness plant. However, the major types of active constituents responsible for the neurological effects remain unclear. This study was to examine the protective effects of hydroalcoholic extract and fractions and to identify the active fractions. METHODS: The extract of daylily flowers was separated with AB-8 resin into different fractions containing non-phenolic compounds, phenolic acid derivatives and flavonoids as determined using UPLC-DAD chromatograms. The neuroprotective activity was measured by evaluating the cell viability and lactate dehydrogenase release using PC12 cell damage models induced by corticosterone and glutamate. The neurological mechanisms were explored by determining their effect on the levels of dopamine (DA), 5-hydroxy tryptamine (5-HT), γ-aminobutyric acid (GABA), noradrenaline (NE) and acetylcholine (ACh) in the cell culture medium measured using an LC-MS/MS method. RESULTS: Pretreatment of PC12 cells with the extract and phenolic fractions of daylily flowers at concentrations ranging from 0.63 to 5 mg raw material/mL significantly reversed corticosterone- and glutamate-induced neurotoxicity in a dose-dependent manner. The fractions containing phenolic acid derivatives (0.59% w/w in the flowers) and/or flavonoids (0.60% w/w) exerted similar dose-dependent neuroprotective effect whereas the fractions with non-phenolic compounds exhibited no activity. The presence of phenolic acid derivatives in the corticosterone- and glutamate-treated PC12 cells elevated the DA level in the cell culture medium whereas flavonoids resulted in increased ACH and 5-HT levels. CONCLUSION: Phenolic acid derivatives and flavonoids were likely the active constituents of daylily flowers and they conferred a similar extent of neuroprotection, but affected the release of neurotransmitters in a different manner.

Lotus leaf alkaloid fraction can strongly inhibit CYP2D6 isoenzyme activity.

ETHNOPHARMACOLOGICAL RELEVANCE: The Chinese herbal medicine He-Ye, the leaves of the lotus (Nelumbo nucifera) plant, is traditionally used in China for the treatment of sunstroke, thirst, diarrhea, and fever. Currently, the leaf is used not only as an herbal tea to reduce lipid level and control body weight, but also as a major ingredient in some lipid-lowering Chinese patented medicines. Our previous study demonstrated that the alkaloid fraction (AF) of the herb has a strong inhibitory effect on CYP2D6 isoenzyme activity in vitro. The present study aims to further verify this activity using the in vivo rat model and to explore the inhibitory mechanism on CYP2D6 using human liver microsomes (HLMs). MATERIALS AND METHODS: After a continuous 7-d oral dose of AF (50mg/kg) or a vehicle, Sprague Dawley rats received a single intravenous dose of dextromethorphan or metoprolol. Blood samples were collected at various time points, and the plasma concentrations of the relevant metabolites dextrorphan and hydroxymetoprolol were assayed by LC-MS/MS for evaluating the effect of AF on their pharmacokinetics and CYP2D6 activity. Dextromethorphan as a probe at different concentrations was incubated with HLMs in an incubation buffer system, in the presence or absence of AF at different concentrations. After incubation, the produced metabolite was assayed. RESULTS: After being pretreated with AF in rats, the plasma concentrations of dextrorphan and hydroxymetoprolol significantly decreased, with Cmax going from 79.44 to 29.96 and 151.18 to 83.39hng/mL (P<0.05), AUCall from 167.27 to 62.25 and 347.68 to 223.24hng/mL (P<0.05), and AUCinf from 183.39 to 84.76 and 350.59 to 234.57hng/mL (P<0.05), respectively, in comparison with those of untreated rats. The t1/2 of hydroxymetoprolol significantly increased from 1.14 to 1.99h (P<0.05). The in vitro incubation test showed that AF competitively inhibited the CYP2D6, with apparent Ki value of 0.64µg/mL. CONCLUSIONS: AF can strongly inhibit the activity of CYP2D6 enzyme, as confirmed by in vivo and in vitro models. Possible drug interactions may occur between AF and other medications metabolized by CYP2D6. Thus, caution should be paid when the lotus leaf and its preparations are concurrently administered with conventional medicines.

LC/MS-based metabolomics strategy to assess the amelioration effects of ginseng total saponins on memory deficiency induced by simulated microgravity.

Microgravity-induced memory deficiency seriously affects learning and memory ability of the astronaut during spaceflight, with few effective countermeasures. Panax ginseng C. A. Mey. has been used as a nootropic herb for thousands of years in Asian countries. Saponins are recognized as its major active components. Previous studies have shown that ginseng saponins offer protection against memory deficits caused by various factors. Nevertheless, the underlying mechanisms of their nootropic effects are still largely unknown. In this study, we evaluated the memory-improving effects of ginseng total saponins (GTS) on simulated microgravity hindlimb-unloaded rats using a metabolomics approach. After being exposed to a 7-days hindlimb unloading (HU), variations of plasmatic and hippocampal metabolic profiles of rats with and without GTS intervention were examined by a liquid chromatography-mass spectrometry (LC-MS) based untargeted metabolomics method. Subsequently, 8 hippocampal neurotransmitters were determined using a LC-MS/MS method. Finally, a LC-MS/MS based targeted metabolomics was performed to validate biomarkers found in the untargeted analysis. Besides, to support the metabolomics results, passive avoidance (PA) test, Nissl staining, and plasmatic corticosterone (CORT) levels determination were performed. The results showed that HU could lead to variations of 7 neurotransmitters and significantly different plasmatic and hippocampal metabolic profiles. GTS could restore most of the imbalanced neurotransmitters, especially glutamic acid and acetylcholine, and correct the levels of various disturbed learning and memory relevant biomarkers such as asparagine, phenylalanine, tyrosine, tryptophan, and choline. In addition, GTS could markedly ameliorate HU-induced memory deficiency, protect hippocampal neurons from damage, and down-regulate elevated CORT levels. In conclusion, GTS exhibits memory-improving effects mainly through regulating the metabolism of amino acids, neurotransmitters, choline, kynurenine, and sphingolipids. The findings of this study not only can deepen our understanding of the underlying molecular mechanisms of MG-induced memory disorders, but also provide scientific evidence for choosing ginseng as a countermeasure against MG-induced memory deficiency.

Anti-stress effects of ginseng total saponins on hindlimb-unloaded rats assessed by a metabolomics study.

ETHNOPHARMACOLOGICAL RELEVANCE: Ginseng, the roots and rhizomes of Panax ginseng C.A. Mey. (Araliaceae), is used as a tonic herb for thousands of years in Asian countries. Saponins are recognized as its major active ingredients and reportedly can ease disorders caused by various adverse stimuli. Nevertheless, it is unclear whether ginseng saponins have beneficial effects on stress caused by microgravity. AIM OF THE STUDY: This study aimed to assess the anti-stress effects and corresponding mechanisms of ginseng total saponins (GTSs) on simulated microgravity (SM) hindlimb-unloaded rats using a metabolomics method. MATERIALS AND METHODS: The stressed rats were induced by hindlimb unloading for 7 continuous days. Levels of plasma corticosterone (CORT) and weights of immune organs including the thymuses, spleens, and adrenal glands were determined. Urinary metabolic profiles of the rats under the simulated microgravity condition with and without GTSs intervention were compared using an ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-QTOF-MS) based metabolomics method. Multivariate statistical analysis including Principal Component Analysis (PCA) and Partial Least Squares project to latent structures-Discriminant Analysis (PLS-DA) were performed. RESULTS: Compared with control (66.22±10.40ng/mL), the plasma CORT level of the SM rats (82.67±13.64ng/mL) were significantly (p<0.05) elevated, and GTSs could restore this elevation to a lower level (77.75±14.35ng/mL). GTSs could also significantly alleviate the atrophy of the thymuses and the spleens, as well as the hypertrophy of the adrenal glands of the SM rats. Urinary metabolic profiling showed comprehensive metabolic variation among the three groups. A series of metabolic pathways including taurine and hypotaurine, purine and pyridine, and amino acid were affected. Eleven potential biomarkers such as taurine, adenine, and valine were identified. GTSs could correct the disturbed metabolic pathways and restore the variation of these potential markers. CONCLUSION: GTSs can exert anti-stress effects by reducing the secretion of plasma CORT, enhancing the immune function, and restoring an array of disturbed metabolic pathways and metabolites. The findings of this study provide crucial evidence of a link between metabolic imbalance and microgravity, and reveal a molecular basis for the anti-stress benefits of GTSs in the management of microgravity-related disorders.

Pharmacokinetic profiles of the five isoflavonoids from Pueraria lobata roots in the CSF and plasma of rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese medicine Radix Puerariae, the roots of Pueraria lobata (Wild.) Ohwi., has been widely used for the treatment of cardiovascular and cerebrovascular diseases in China for centuries. Isoflavonoids are believed the active components of this herb. AIM OF THIS STUDY: The present study aims to investigate the brain penetration and pharmacokinetics of five active isoflavonoids in the ventricular CSF and plasma of rats after intravenous administration of a Pueraria isoflavonoids (PIF) extract, to better understand the active components of this herb for neuro-activities. MATERIAL AND METHODS: Under anesthesia condition, SD rats (n=6) were successively suffered two surgeries for implanting cannulas at lateral ventricle and right jugular vein for brain microdialysis and blood collection, respectively. After recovery, the rats received intravenous dose of PIF at 80mg/kg and the concentrations of puerarin (PU), 3'-methoxypuerarin (MPU), 3'-hydroxypuerarin (HPU), daidzein (DA) and daidzein-8-C-apiosyl-(1-6)-glycoside (DAC) in the ventricular dialysate and plasma samples were determined using a ultra-fast liquid chromatography tandem mass spectrometry method. RESULTS: Complete concentration versus time profiles of the five components in plasma and four components except for HPU in ventricular CSF were obtained. After dosing, the average C0 values of PU, MPU, DA, DAC and HPU in plasma were estimated 6.53, 13.72, 1.54, 15.84 and 86.07µg/mL, and PU, MPU, DA and DAC were rapidly penetrated to the brain and reached to their Cmax of 521.52, 415.00, 74.34 and 380.03ng/mL in CSF at about 0.5-0.8h, respectively. The elimination t1/2 of PU, DA and DAC in CSF and plasma were no significant difference, while the t1/2 of MPU in ventricular CSF was longer than that in plasma which may attributable to the different physiological environment of central and peripheral compartments. The brain penetration index (AUCCSF/AUCplasma) was found to be about 9.29, 7.25, 11.96, and 4.21% for PU, MPU, DA, and DAC respectively. CONCLUSION: PU, MPU, DA, DAC can quickly penetrate to the brain through the blood brain barrier (BBB) and might be responsible for the neuro-pharmacological activities of P. lobata.

Metabolism profiles of nuciferine in rats using ultrafast liquid chromatography with tandem mass spectrometry.

Nuciferine (NF) is one of the main aporphine alkaloids existing in the traditional Chinese medicine Folium Nelumbinis (lotus leaves). Modern pharmacological studies have demonstrated that NF has a broad spectrum of bioactivities, such as anti-HIV and anti-hyperlipidemic effects, and has been recommended as a leading compound for new drug development. However, the metabolites and biotransformation pathway of NF in vivo have not yet been comprehensively investigated. The present study was performed to identify the metabolites of NF for exploring in vivo fates. Rat plasma and urine samples were collected after oral administration and prepared by liquid-liquid extraction with ethyl acetate. A method based on ultrafast liquid chromatography with tandem mass spectrometry was applied to identify the metabolites. Q1 (first quadrupole) full scan combined with a multiple reaction monitoring (MRM) survey scan were used for the detection of metabolites. MRM-information-dependent acquisition of enhanced product ions was used for the structural identification of detected metabolites. A total of 10 metabolites were identified, including phase I (demethylation, oxidation and dehydrogenation) and phase II (glucuronidation, sulfation and glutathione) biotransformation products. Demethylation is the main metabolic pathway of NF in the body. These results can help in improving understanding of the disposition and pharmacological mechanism of NF in the body. Copyright © 2016 John Wiley & Sons, Ltd.

An LC-MS/MS method for simultaneous determination of three Polygala saponin hydrolysates in rat plasma and its application to a pharmacokinetic study.

ETHNOPHARMACOLOGICAL RELEVANCE: Radix Polygala has a long history of use as a sedative in traditional Chinese medicine and its major ingredients are saponins, which are recognized effective in memory improvement but highly toxic to gastricintestinal mucosa. Polygala saponin hydrolysates (PSH), an alkaline hydrolysis product and also the intestinal metabolites of the saponins, exhibited stronger effects in improving memory of mice and had less toxicity than its original saponins. The present study aims to develop a sensitive LC-MS/MS method for simultaneously determining PSH three major active components, 3,4,5-trimethoxycinnamylic acid (TMCA), p-methoxycinnamylic acid (PMCA) and tenuifolin (TF), in rat plasma and apply the method to a pharmacokinetic study. MATERIALS AND METHODS: The acidic plasma (100µl) was treated by liquid-liquid extraction with ethyl acetate and reconstituted sample was analyzed on a C18 column eluted with acetonitrile-water (50:50) containing 0.2% formic acid at 0.4ml/min. The mass detection in negative electrospray ionization was used. The ion pairs for multiple reaction monitoring were set at m/z 237.0/103.0, 177.0/116.6 and 679.5/425.3 for TMCA, PMCA and TF, respectively. Their pharmacokinetic profiles were studied in rats after intravenous and oral dose of PSH at 20 and 100mg/kg, respectively. RESULTS: The calibration curves had good linearity (r(2)>0.99) for TMCA, PMCA and TF within the tested concentration ranges. The limits of detection and quantification were 1, 10, 0.5ng/ml and 10.0, 20.0, 1.0ng/ml, respectively. The intra-day and inter-day precisions were less than 18.9% and accuracies between 93.2% and 113.3%, and the extraction recovery ranged from 91.2% to 112.1% for all analytes. The pharmacokinetic study showed that TMCA, PMCA and TF could be rapidly absorbed into the circulation and reached their peak concentrations at about 9.1, 9.0 and 24.0min, respectively. TF had a lower oral bioavailability (2.0%) than TMCA (90.1%) and PMCA (96.5%), but it remained in the body much longer (t1/2, λz, 4.8h, oral dose) than TMCA (0.6h) and PMCA (0.9h). CONCLUSIONS: A sensitive LC-MS/MS method was developed and applied to a pharmacokinetic study of TMCA, PMCA and TF of PSH in rats. The three components are proved to be bio-available active components of PSH and might display their in vivo pharmacological activities at different levels and different time periods after oral administration.

Tenuifolin, a secondary saponin from hydrolysates of polygalasaponins, counteracts the neurotoxicity induced by Aß25-35 peptides in vitro and in vivo.

Alzheimer's disease (AD) is associated with damage to hippocampal neurons and declines in cognitive functions. The accumulation of amyloid peptides is regarded as a crucial event in the initiation of AD. The neurotoxicity induced by Aß25-35 peptides was used to screen for cytoprotective factors in vitro, and the cognitive deficits induced by the injection of Aß25-35 into the hippocampus were used to evaluate effect on learning and memory. Our previous study revealed that hydrolysate of polygalasaponins (HPS) clearly improve the cognitive deficits induced by the injection of Aß25-35 in mice, but the potential active constituent of HPS remains unclear. The purposes of this study were to separate and purify the secondary saponins of HPS, screen for neuroprotective effects of the constituents in vitro, and to evaluate the effect of cognition in vivo. Various chromatographic methods were used to separate and purify the HPS. The neuroprotective effects were examined in Aß25-35-damage-induced PC12 cells. The protective effect of tenuifolin on the cognitive impairments induced by Aß25-35 injection was assessed using the Morris water maze and step-through passive avoidance tests. Tenuifolin and fallaxsaponin A were isolated from the HPS. Tenuifolin possessed neuroprotective effects against Aß25-35-induced apoptosis in PC12 cells and significantly improved the cognitive deficits induced by the intrahippocampal injection of Aß25-35 in mice. Thus, tenuifolin is one of the active constituents of HPS against the neurotoxicity induced by Aß25-35 peptides in vitro and in vivo.

Antidepressant-like effects and mechanism of action of SYG in depression model in rats.

OBJECTIVES: The present study aimed to evaluate whether SYG, a Chinese herbal formula, could produce antidepressant-like effects in learned helplessness (LH) model and chronic mild stress (CMS) model in rats. The mechanism underlying the antidepressant-like action was investigated by exploring BDNF signaling way in the hippocampus. MATERIAL AND METHODS: SYG was administrated for 5 consecutive days (100 and 200 mg/kg/day, intragastrically) in the learned helplessness model; SYG was administered daily by gastric gavages during both the 5-week stress session and behavior tests periods in the chronic mild stress model (100 and 200 mg/kg). The serum corticosterone level was measured in the learned helplessness model. Levels of BDNF and Tyrosine-related kinase B (TrkB), were evaluated in the hippocampus of chronic mild stress model. RESULTS: A deficit in avoidance learning and higher corticosterone level were observed in learned helplessness rats. SYG significantly reduced this deficit and reversed the corticosterone alteration. CMS induced significant reduction of sucrose intake in the sucrose preference test, an increased latency to feed in the novelty-suppressed feeding test and an increased immobility time in the forced swim test as compared to the control. It was also found that BDNF and TrkB levels were decreased in CMS model. Chronic treatment of SYG significantly suppressed the behavioral changes and up-regulated the BDNF signal pathway in the hippocampus. CONCLUSION: Our results suggest that SYG alleviates depression induced by LH and CMS model. The antidepressant-like activity of SYG is likely mediated by activation the BDNF signal pathway in the hippocampus.

Identification and characterization of potent CYP2D6 inhibitors in lotus leaves.

ETHNOPHARMACOLOGICAL RELEVANCE: The herb of lotus (Nelumbo nucifera) leaves is a commonly used traditional Chinese herbal medicine that is utilized for the treatment of sunstroke, to assuage thirst, and to cure both diarrhea and fever in China. Modern pharmacological studies have demonstrated that the herb exhibits various pharmacological effects, such as anti-hyperlipidemia, anti-obesity, anti-oxidant, anti-HIV, anti-microbial, and anti-hypoglycemic activities. Currently, the herb is becoming more popular in China as a "tea drink" or as a main ingredient of some herbal formulations, which implies that the herb and/or its products are now more likely to be concurrently administered with conventional medicines for losing body weight and reducing blood lipids. However, its potential inhibitory effect on human cytochrome P450 (CYP) has not been systemically investigated to date. The present study was performed to assess the potential inhibitory effects of lotus leaf alcoholic extract (LAE), its major fractions, and its main compounds on five CYP isoenzymes (CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4) in vitro. MATERIAL AND METHODS: Five probe substrates were incubated with human liver microsomes in the presence or absence of the LAE, the alkaloid fraction (AF), the flavonoid fraction (FF), or the individual aporphine alkaloids, namely, nuciferine (NF), N-nornuciferine (N-NF), and 2-hydroxy-1-methoxyaporphine (HMA). After the incubation, the relative metabolites of the substrates were analyzed using LC-MS/MS. RESULTS: The results showed that the LAE strongly inhibited CYP2D6 with an IC50 value of 12.05µg/mL and weakly inhibited other isoenzymes. In addition, FF was found to weakly inhibit CYP2D6, whereas AF exerted a markedly higher inhibitory effect on CYP2D6 activity with an IC50 value of 0.96µg/mL. The three aporphine alkaloids isolated from the AF (NF, N-NF, and HMA) significantly inhibited CYP2D6 with IC50 values of 3.78, 3.76, and 3.15µM, respectively. Their Lineweaver-Burk plots and Dixon plots showed that NF, N-NF, and HMA competitively inhibited CYP2D6 activity with Ki values of 1.88, 2.34, and 1.56µM, respectively. CONCLUSION: The study revealed that the alkaloid compounds in lotus leaves exert a potent inhibitory effect on CYP2D6 isoenzyme. The possible drug interactions of the leaves and their preparations with conventional medicines should thus be taken into account.

Antidepressant-like effects and memory enhancement of a herbal formula in mice exposed to chronic mild stress.

Shen Yuan Gan (SYG) is a Chinese herbal prescription composed of total saponins of Panax ginseng and total oligosaccharide esters of Polygala tenuifolia (2:1). Our previous studies have demonstrated that SYG has antidepressant-like effects in various mouse models of behavioral depression. The present study aimed to test whether SYG affected chronic mild stress (CMS)-induced depression and cognitive impairment in mice. We found that a 5-week CMS schedule induced significant degradation of the coat state, decreased sucrose intake in the sucrose-preference test, and increased the latency to feed in the noveltysuppressed feeding test. All of these CMS-induced changes were ameliorated by SYG (100 and 200 mg/kg) and fluoxetine (10 mg/kg). In addition, SYG restored the decreased monoamine neurotransmitter concentrations (serotonin, dopamine, norepinephrine and acetylcholine) induced by CMS in the prefrontal cortex. Interestingly, SYG ameliorated CMS-induced cognitive impairment in the step-through test, and increased the acetylcholine level in the prefrontal cortex. These results suggest that SYG has an antidepressant-like action and enhances cognition by modulating the serotonin, dopamine, norepinephrine, and acetylcholine levels in the prefrontal cortex.

Neuroprotective effects of total saikosaponins of Bupleurum yinchowense on corticosterone-induced apoptosis in PC12 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: The root of Bupleurum yinchowense Shan et Y. Li, a well-known medicinal plant in China, was originally documented in the "Shennong's Herbal", which is the oldest Chinese materia medica monographs. It has the action of soothing liver and relieving constraint for improving symptoms of emotional instability such as depression, anxiety and phobia. The in vivo experiment of our previous study has showed an efficacy of Total Saikosaponins (TSS) from Bupleurum yinchowense in acute stress and chronic unpredictable mild stress models. Nevertheless, there are no studies on the cytoprotection and potential mechanisms of TSS on corticosterone-induced apoptosis in PC12 cells. The present study focuses on cytoprotection against corticosterone-induced neurotoxicity in PC12 cells and its underlying molecule mechanisms of the antidepressant-like effect of TSS. MATERIALS AND METHODS: The PC12 cells were treated with 250 µM corticosterone in the absence or presence of different concentrations of TSS for 24 h, then the cell viability, lactate dehydrogenase (LDH) release, Hoechst 33342 and propidium iodide (PI) double staining and the DNA fragmentation of the apoptotic PC12 cells were determined. The mitochondrial permeability transition pore (mPTP), mitochondrial membrane potential (MMP), intracellular Ca(2+) ([Ca(2+)]i) concentration and western blot analysis of caspase-3, glucose-regulated protein 78 (GRP78), growth arrest and DNA damage inducible proteins 153 (GADD-153), X-box DNA-binding protein-1 (XBP-1), Bax, Bcl-2 were investigated. RESULTS: Pretreatment of PC12 cells with TSS (3.125, 6.25, 12.5, 25 µg/ml) partly reversed corticosterone-induced neurotoxicity in a dose dependent manner. TSS (25 =g/ml) reversed the increase of dead cells in the Hoechst 33342 stain, the accumulation in LDH leakage and the number of TUNEL positive cells induced by corticosterone to PC12 cells. Moreover, the cytoprotection of TSS was proved to be associated with the homeostasis of intracellular Ca(2+), the stabilization of ER stress via the down-regulation of GRP78, GADD-153, XBP-1, and the restoration of mitochondrial function, which included mPTP, MMP and caspase-3 activity. Furthermore, TSS (25 µg/ml) markedly ameliorated up-regulation of Bax and down-regulation of Bcl-2 in corticosterone-induced PC12 cells. CONCLUSION: The result depicted that antidepressant-like effect of TSS in vivo may be associated with the cytoprotection of neuron, and the neuroprotective mechanisms were correlated with inhibiting the ER stress and the mitochondrial apoptotic pathways.

[Neuroprotective effect of longistyline A against corticosterone-induced neurotoxicity in PC12 cells].

This study is to investigate the protective effect of longistyline A against corticosterone-induced neurotoxicity in PC12 cells. While PC12 cells were exposed to 100 micromol x L(-1) corticosterone for 48 h, cell survival rate was reduced and lactate dehydrogenase (LDH) release increased. In parallel, corticosterone caused significant elevations of DNA fragmentation, [Ca2+]i and caspase-3 activity. However, when the PC12 cells were incubated with longistyline A (4.0, 8.0 and 16.0 micromol x L(-1)) in the presence of 100 micromol x L(-1) corticosterone for 48 h, the effects were evidently alleviated, but dose-dependent manner was not obvious. In summary, longistyline A could generate a neuroprotective effect against corticosterone-induced neurotoxicity in PC12 cells possibly by decreasing [Ca2+]i and caspase-3 activity.