Therapeutic potential of amniotic fluid stem cells to treat bilateral ovarian dystrophy in dairy cows in a subtropical region

Amniotic fluid is a rich source of multipotent mesenchymal stem cells (MSCs). Amniotic fluid stem cells (AFSCs) have become a new source of stem cells; they have low immunogenicity and are easily harvested. For this reason, they may be useful in clinical tissue engineering. Moreover, AFSCs have anti-inflammatory properties and can repair tissues. This study evaluated the utility of AFSC injection to treat bilateral ovarian dystrophy in Holstein-Friesian cows. Bovine AFSCs (BAFSCs) were collected at slaughter from Holstein-Friesian cows during the third or fourth month of pregnancy and cultured in vitro. The BAFSCs began to show a fibroblast-like morphology. They were positive for β-integrin, CD44, CD73, CD106 and Oct4 and negative for CD34 and CD45. After induction, the cells differentiated into mesodermal lineages. Bilateral ovarian dystrophy was confirmed by ultrasonography in 16 lactating cows. The subsequent experiment lasted 15 weeks. Serum was collected weekly to analyse progesterone concentrations, and weekly ultrasonography recorded ovarian changes. Each cow was equipped with an automatic heat detection system to facilitate oestrus observation and breeding records. The progesterone concentration of two cows in the treatment group (25%) significantly increased during weeks 10-15. On ultrasonography, the treatment group demonstrated mature follicles after BAFSCs injection, and foetuses were visualized approximately 40 days after artificial insemination (AI). Oestrus rates in the control and treatment groups were 0% (0/8) and 50% (4/8), respectively; pregnancy rates were 0% (0/8) and 25% (2/8), respectively. Calves were successfully delivered in both cases of pregnancy. These results show that BAFSCs can alleviate bovine ovarian dystrophy and restore fertility.

Tunable PEGylation of branch-type PEI/DNA polyplexes with a compromise of low cytotoxicity and high transgene expression: in vitro and in vivo gene delivery

Although PEGylated polyplexes for gene delivery are widespread, there is a need for an in-depth investigation of the role of the PEGylation degree on the delivery efficiency of the systems. For this, a low-toxicity series of polymers for gene delivery were designed via Michael addition of poly(ethylene glycol)methyl ether methacrylate (PEGMA) onto branched polyethylenimine PEI. The goal was to finely tune the PEGylation degree in order to determine the system offering the best compromise between low cytotoxicity and high transfection efficiency under both in vitro and in vivo conditions. From dynamic light scattering tests, zeta potential measurements and gel retardation assay, it was found that nanoparticle assembly of PEI-g-PEGMA and DNA exhibited stable complex formation when the PEGylation degree was below 2.9%. In addition, complexes formed from polymers with a PEGylation degree of at least 1.67% (from PEI-g-PEGMA-6 to PEI-g-PEGMA-18) all showed very low hemolysis activity. Transfection efficiencies of the prepared complexes were determined using the pEGFP-C3 vector and β-galactosidase. Complexes made of PEI-g-PEGMA-6 and PEI-g-PEGMA-10 at a polymer nitrogen/DNA phosphorus weight ratio (W_n/W_p) of 5 led to the best transfection efficiencies. Moreover, PEGylation ensured low cytotoxicity of the complexes in particular at high W_n/W_p ratios. In vivo tests in a mouse model confirmed the in vitro results obtained for PEI-g-PEGMA-6-based complexes, at all W_n/W_p ratios tested, but also showed that a high PEGylation degree (5.2% for PEI-g-PEGMA-18), though inefficient in vitro could still lead to successful delivery in vivo, due to a prolonged contact time between the complex and the cells, and to the change in the biological environment. Overall, provided a fine tuning of the grafting density of PEGMA onto PEI and the polymer nitrogen/DNA phosphorus weight ratio, our results prove that PEI-g-PEGMA polymers constitute an efficient platform for successful in vitro and in vivo gene delivery, and ensure low cytotoxicity and prolonged cell viability.

Novel Vitamin K analogs suppress seizures in zebrafish and mouse models of epilepsy

Epilepsy is a debilitating disease affecting 1-2% of the world's population. Despite this high prevalence, 30% of patients suffering from epilepsy are not successfully managed by current medication suggesting a critical need for new anti-epileptic drugs (AEDs). In an effort to discover new therapeutics for the management of epilepsy, we began our study by screening drugs that, like some currently used AEDs, inhibit histone deacetylases (HDACs) using a well-established larval zebrafish model. In this model, 7-day post fertilization (dpf) larvae are treated with the widely used seizure-inducing compound pentylenetetrazol (PTZ) which stimulates a rapid increase in swimming behavior previously determined to be a measurable manifestation of seizures. In our first screen, we tested a number of different HDAC inhibitors and found that one, 2-benzamido-1 4-naphthoquinone (NQN1), significantly decreased swim activity to levels equal to that of valproic acid, 2-n-propylpentanoic acid (VPA). We continued to screen structurally related compounds including Vitamin K3 (VK3) and a number of novel Vitamin K (VK) analogs. We found that VK3 was a robust inhibitor of the PTZ-induced swim activity, as were several of our novel compounds. Three of these compounds were subsequently tested on mouse seizure models at the National Institute of Neurological Disorders and Stroke (NINDS) Anticonvulsant Screening Program. Compound 2h reduced seizures particularly well in the minimal clonic seizure (6Hz) and corneal-kindled mouse models of epilepsy, with no observable toxicity. As VK3 affects mitochondrial function, we tested the effects of our compounds on mitochondrial respiration and ATP production in a mouse hippocampal cell line. We demonstrate that these compounds affect ATP metabolism and increase total cellular ATP. Our data indicate the potential utility of these and other VK analogs for the prevention of seizures and suggest the potential mechanism for this protection may lie in the ability of these compounds to affect energy production.

Increasing skeletal muscle fatty acid transport protein 1 (FATP1) targets fatty acids to oxidation and does not predispose mice to diet-induced insulin resistance

AIMS/HYPOTHESIS

We examined in skeletal muscle (1) whether fatty acid transport protein (FATP) 1 channels long-chain fatty acid (LCFA) to specific metabolic fates in rats; and (2) whether FATP1-mediated increases in LCFA uptake exacerbate the development of diet-induced insulin resistance in mice. We also examined whether FATP1 is altered in insulin-resistant obese Zucker rats.

METHODS

LCFA uptake, oxidation and triacylglycerol esterification rates were measured in control and Fatp1-transfected soleus muscles to determine FATP1-mediated lipid handling. The effects of FATP1 on insulin sensitivity and triacylglycerol accumulation were determined in high-fat diet-fed wild-type mice and in muscle-specific Fatp1 (also known as Slc27a1) overexpressing transgenic mice driven by the muscle creatine kinase (Mck [also known as Ckm]) promoter. We also examined the relationship between FATP1 and both fatty acid transport and metabolism in insulin-resistant obese Zucker rats.

RESULTS

Transient Fatp1 overexpression in soleus muscle increased (p < 0.05) palmitate transport (24%) and oxidation (35%), without altering triacylglycerol esterification or the intrinsic rate of palmitate oxidation in isolated mitochondria. In Mck/Fatp1 animals, Fatp1 mRNA and 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid uptake in skeletal muscle were upregulated (75%). However, insulin sensitivity and intramuscular triacylglycerol content did not differ between wild-type and Mck/Fatp1 mice following a 16 week high-fat diet. In insulin-resistant obese Zucker rats, LCFA transport and triacylglycerol accumulation were increased (85% and 24%, respectively), but this was not attributable to Fatp1 expression, as neither total cellular nor sarcolemmal FATP1 content were altered.

CONCLUSIONS/INTERPRETATION

Overexpression of Fatp1 in skeletal muscle increased the rate of LCFA transport and channelled these lipids to oxidation, not to intramuscular lipid accumulation. Therefore, skeletal muscle FATP1 overabundance does not predispose animals to diet-induced insulin resistance.

Six weeks' sebacic acid supplementation improves fasting plasma glucose, HbA1c and glucose tolerance in db/db mice

AIM

To investigate the impact of chronic ingestion of sebacic acid (SA), a 10-carbon medium-chain dicarboxylic acid, on glycaemic control in a mouse model of type 2 diabetes (T2D).

METHODS

Three groups of 15 db/db mice were fed for 6 weeks either a chow diet (Ctrl) or a chow diet supplemented with 1.5 or 15% (SA(1.5%) and SA(15%) , respectively) energy from SA. Fasting glycaemia was measured once a week and HbA1c before and after supplementation. An oral glucose tolerance test (OGTT) was performed at the end of the supplementation. Gene expression was determined by transcriptomic analysis on the liver of the Ctrl and SA(15%) groups.

RESULTS

After 42 days of supplementation, fasting glycaemia and HbA1c were ∼70 and 25% lower in the SA(15%) group compared with the other groups showing a beneficial effect of SA on hyperglycaemia. During OGTT, plasma glucose area under the curve was reduced after SA(15%) compared with the other groups. This effect was associated with a tendency for an improved insulin response. In the liver, Pck1 and FBP mRNA were statistically decreased in the SA(15%) compared with Ctrl suggesting a reduced hepatic glucose output induced by SA.

CONCLUSION

Dietary supplementation of SA largely improves glycaemic control in a mouse model of T2D. This beneficial effect may be due to (i) an improved glucose-induced insulin secretion and (ii) a reduced hepatic glucose output.

The Thermotoga maritima phenotype is impacted by syntrophic interaction with Methanococcus jannaschii in hyperthermophilic coculture

Significant growth phase-dependent differences were noted in the transcriptome of the hyperthermophilic bacterium Thermotoga maritima when it was cocultured with the hyperthermophilic archaeon Methanococcus jannaschii. For the mid-log-to-early-stationary-phase transition of a T. maritima monoculture, 24 genes (1.3% of the genome) were differentially expressed twofold or more. In contrast, methanogenic coculture gave rise to 292 genes differentially expressed in T. maritima at this level (15.5% of the genome) for the same growth phase transition. Interspecies H2 transfer resulted in three- to fivefold-higher T. maritima cell densities than in the monoculture, with concomitant formation of exopolysaccharide (EPS)-based cell aggregates. Differential expression of specific sigma factors and genes related to the ppGpp-dependent stringent response suggests involvement in the transition into stationary phase and aggregate formation. Cell aggregation was growth phase dependent, such that it was most prominent during mid-log phase and decayed as cells entered stationary phase. The reduction in cell aggregation was coincidental with down-regulation of genes encoding EPS-forming glycosyltranferases and up-regulation of genes encoding beta-specific glycosyl hydrolases; the latter were presumably involved in hydrolysis of beta-linked EPS to release cells from aggregates. Detachment of aggregates may facilitate colonization of new locations in natural environments where T. maritima coexists with other organisms. Taken together, these results demonstrate that syntrophic interactions can impact the transcriptome of heterotrophs in methanogenic coculture, and this factor should be considered in examining the microbial ecology in anaerobic environments.

PROP taster status and oral fatty acid perception

Recent studies with rat taste cells treated with polyunsaturated fatty acids suggest that fatty acids may play a role in dietary fat perception. In humans, sensitivity to the textural properties of fat is associated with the genetic ability to taste the bitter compound 6-N-2-propylthiouracil (PROP). However, it has not been shown that PROP tasters are more sensitive in discriminating fatty acids in a high-fat food. Our study with human subjects was designed to test the hypothesis that the ability to orally detect food-grade conjugated linoleic acid added to high-fat vanilla ice cream is associated with the ability to taste PROP. Eighty percent of the PROP tasters in this study, but only 17% of the PROP nontasters correctly discriminated the sample containing the added free fatty acid in a difference test versus unadulterated high-fat vanilla ice cream (Fisher's Exact Test, P=.05). Because most fatty foods contain minute amounts of free fatty acids, further studies with humans examining the contribution of fatty acids to fat perception seem warranted.

Activation and proliferation signals in primary human T lymphocytes inhibited by ergosterol peroxide isolated from Cordyceps cicadae

Effects of ergosterol peroxide (C28H44O3; Cpd 6A) from Cordyceps cicadae on phytohemagglutinin (PHA)-stimulated cell proliferation were studied in primary human T cells. The results showed that Cpd 6A suppressed T-cell proliferation for about 24 h after stimulation with PHA. Cell cycle analysis indicated that Cpd 6A arrested the cell cycle progression of activated T cells from the G1 transition to the S phase. To localize the point in the cell cycle where arrest occurred, a set of key regulatory events leading to the G1/S boundary, including the expression of cyclins D2, E, A1, and B1, interleukin (IL)-2, IL-4, interferon-gamma (IFN-gamma), and activating protein-1 (AP-1), was examined. Cpd 6A suppressed, in activated T lymphocytes, the production and mRNA expression of cyclin E, IL-2, IL-4, IL-10, and IFN-gamma in a dose-dependent manner. Expression of AP-1 proteins, consisting of c-Fos and c-Jun, in activated T lymphocytes was decreased by Cpd 6A. The kinetic study indicated that the inhibitory effects of Cpd 6A on IL-2 mRNA expressed in T cells might be related to blocking c-Fos protein synthesis. T-cell proliferation after Cpd 6A treatment was partially restored by addition of IL-2, IL-4, and IFN-gamma. These suppressant effects of Cpd 6A on T-cell proliferation, activated by PHA, appeared to be mediated, at least in part, through the inhibition of early gene transcripts, especially those of cyclin E, IFN-gamma, IL-2, and IL-4, and by arresting cell cycle progression in the cells.

The chelating treatment is not useful in human's intoxication with acute herbicidal organic arsenic

The clinical manifestations of acute organic arsenic intoxication in humans have seldom been described and the associated treatment has been thought to be the same as that of acute inorganic arsenic intoxication. We have studied a collection of patients from 1996 to 2001 who called the Poison Control Center of Kaohsiung Medical University Hospital asking for information regarding acute organic arsenic intoxication. The 17 patients ranged in age from 23 to 64 years old, with 5 females and 12 males. The cause of arsenic ingestion was attempted suicide. Abdominal pain and vomiting were the main symptoms. There were no differences in results between patients treated with and those treated without chelating agents. We therefore believe that the results of acute organic intoxication are not same as acute inorganic intoxication and it is unnecessary to use chelating agents in such conditions.

Isolation and characterization of an active compound from black soybean [Glycine max (L.) Merr.] and its effect on proliferation and differentiation of human leukemic U937 cells

Black soybean [Glycine max (L.) Merr.] has been used as a health food and herb in China for hundreds of years. In the present study, we purified a unique polysaccharide component from black soybean (PSBS) and found that it indirectly inhibits proliferation and induces differentiation of human leukemic U937 cells via activation of mononuclear cells (MNCs). We prepared conditioned media (MNC-CM) by incubating MNCs from human peripheral blood with or without PSBS (PSBS-MNC-CM and normal MNC-CM, respectively). Treatment of human leukemic U937 cells with PSBS-MNC-CM significantly inhibited proliferation of U937 cells, reducing their growth by 98.5%. Furthermore, PSBS-MNC-CM induced U937 cells to differentiate into mature monocytes/macrophages (83% by morphological examination and 90% by the nitroblue tetrazolium test). Neither PSBS alone nor normal MNC-CM had such effects. The molecular weight of PSBS was about 480 000 by gel filtration. Structural analysis of PSBS revealed that (1,6)-alpha-D-glucan might be its major active component. Our results suggest that the PSBS may inhibit proliferation and induce differentiation in human leukemic U937 cells by activating the immune response of MNCs.

Anti-inflammatory effects of the partially purified extract of radix Stephaniae tetrandrae: comparative studies of its active principles tetrandrine and fangchinoline on human polymorphonuclear leukocyte functions

We hypothesized that prevention of neutrophil from activation may underlie the myocardial protective effect of the specially processed extract of radix Stephaniae tetrandrae (SPRST). Inflammatory responses in isolated peripheral human neutrophils were studied in the presence or absence of SPRST. SPRST (1-10 microg/ml) concentration-dependently prevented N-formyl-methionyl-leucyl-phenylalanine (fMLP)- or leukotriene B(4) (LTB(4))-induced neutrophil adhesion and transmigration. Comparable results were also observed in neutrophils pretreated with fangchinoline (Fan) or tetrandrine (Tet), two active components in SPRST. It has been reported that neutrophil adhesion/transmigration is mainly Mac-1 (CD11b/CD18)-dependent and could be modulated by reactive oxygen species (ROS) production. SPRST, Tet, and Fan diminished fMLP- or LTB4-induced Mac-1 up-regulation and ROS production. SPRST, Fan, Tet, and verapamil impaired fMLP-induced rapid intracellular alkalization, an essential mechanism for neutrophil ROS production, and [Ca(2+)](i) increment, suggesting that a calcium dependent pathway might be involved. Direct G protein activation by AlF(4)(-) also triggered [Ca(2+)](i) increment and adhesion that could be abolished by pertussis toxin and were partially reversed by SPRST, Fan, and Tet. These results reveal that inhibition of neutrophil adhesion and transmigration may account for SPRST's myocardial protective effect. This effect of SPRST may be mediated by component(s) in addition to Tet and Fan because combination of 0.1 microg/ml of Tet and Fan did not mimic the effect of SPRST. We conclude that SPRST exerts anti-inflammatory effects by interfering with ROS production and Ca(2+) influx through G protein modulation to prevent Mac-1 up-regulation in neutrophil activation.

C. elegans CED-12 acts in the conserved crkII/DOCK180/Rac pathway to control cell migration and cell corpse engulfment

We have identified and characterized a novel C. elegans gene, ced-12, that functions in the conserved GTPase signaling pathway mediated by CED-2/Crkll, CED-5/DOCK180, and CED-10/Rac to control cell migration and phagocytosis of apoptotic cells. We provide evidence that ced-12 likely acts upstream of ced-10 during cell migration and phagocytosis and that CED-12 physically interacts with CED-5 and forms a ternary complex with CED-2 in vitro. We propose that the formation and localization of a CED-2-CED-5-CED-12 ternary complex to the plasma membrane activates CED-10, leading to the cytoskeletal reorganization that occurs in the polarized extension of cell surfaces in engulfing cells and migrating cells. We suggest that CED-12 counterparts in higher organisms regulate cytoskeleton dynamics, as CED-12 does in C. elegans.

Application of intrawell testing of RCRA groundwater monitoring data when no upgradient well exists

A statistical quality control approach to detect changes in groundwater quality from a regulated waste unit is described. The approach applies the combined Shewhart-CUSUM control chart methodology for intrawell comparison of analyte concentrations over time and does not require an upgradient well. A case study from the U.S. Department of Energy's Hanford Site is used for illustration purposes. This method is broadly applicable in groundwater monitoring programs where there is no clearly defined upgradient location, the groundwater flow rate is exceptionally slow, or where a high degree of spatial variability exists in parameter concentrations. This study also indicates that the use of the Data Quality Objectives (DQO) process can assist in designing an efficient and cost-effective groundwater monitoring plan to achieve the optimum goal of both low false positive and low false negative rates (high power).

Baicalein induces a dual growth arrest by modulating multiple cell cycle regulatory molecules

Baicalein, a flavonoid present in the root of Scutellaria baicalensis Georgi, has been reported to inhibit cell proliferation in several types of cells. In this study, the effect of baicalein on cell growth and the mechanism of growth modulation were examined in primary cultured rat heart endothelial cells. Here, we report that treatment with 100-microM baicalein caused an almost complete inhibition of cell proliferation after 5 days of incubation. Baicalein mediated G1 and G2 growth arrest accompanied by the down-regulation of cyclin D2, cyclin A, cyclin-dependent kinase 1 (Cdk1) and cyclin-dependent kinase 2 (Cdk2), and up-regulation of p15(Ink4B), p21(CIP1/Waf1), p53 and cyclin E. Evaluation of the kinase activity of cyclin-Cdk complexes showed that baicalein decreased Cdk1, Cdk2, cyclin D2 and cyclin A expression in endothelial cells, leading to markedly reduced Cdk/cyclin-associated kinase activities. These results suggest that baicalein inhibits the proliferation of rat heart endothelial cells via G1 and G2 arrest in association with the down-regulation of the expression and function of Cdk1, Cdk2, cyclin D2 and cyclin A proteins, and up-regulation of cyclin E, p15(Ink4B), p53 and p21(CIP1/Waf1).

Camptothecin suppresses nitric oxide biosynthesis in RAW 264.7 macrophages

Nitric oxide is an important cellular mediator that plays a role in tumor growth and angiogenesis. The present study was conducted to evaluate whether camptothecin (CPT), a topoisomerase I inhibitor, exhibits antitumor activity through regulation the inducible nitric oxide synthase (iNOS) biosynthesis pathway. Experiment was performed on RAW 264.7 cells, a transformed macrophage-like cell line, stimulated with lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma). Incubation of RAW264.7 cells with CPT (0.1 to 10 microM) inhibited the LPS/IFN-gamma-induced nitrite accumulation in a concentration-dependent manner with an IC50 value of 0.59+/-0.07 microM. Treatment of cells with concentrations of CPT (< or =3 microM) that are not growth inhibitory or cytotoxic strongly inhibited their ability to express iNOS mRNA and iNOS protein, however, without a direct regulatory effect on iNOS activity. Time course analysis also revealed that CPT acted in a fashion similar to the transcription inhibitor actinomycin-D. Thus, the suppressant effects of CPT on LPS/IFN-gamma-stimulated NO production seemed to be mediated probably through inhibition of iNOS gene transcription. From this observation we propose that inhibition of NO biosynthesis by CPT may underlie, at least in part, the efficacy of this antitumor agent.

Cytotoxic principles from Ventilago leiocarpa

Three new anthraquinones, islandicin 4-methyl ether (1), 1,2,6-trihydroxy-7,8-dimethoxy-3-methylanthraquinone (2), and 2-hydroxyemodin 1-methyl ether (3) as well as two known triterpenoids [taraxerol (4), lupeol (5)], six anthraquinones [chrysophanol (6), islandicin (8), parietin (9), emodin (10), catenarin (11), skyrin (15)], a 2,3-dihydroflavonol [(+)-aromadendrin (12)], two benzisochromanquinones [ventiloquinone K (13) and ventiloquinone I (14)], and stigmasterol (7) were isolated from Ventilago leiocarpa. The cytotoxicity of these compounds to various tumor cell lines was evaluated, and compound 15 significantly suppressed growth of HeLa, Vero, K562, Raji, Wish, and Calu-1 tumor cell lines. With the exception of K562 cells, the proliferation of other tumor cell lines was inhibited by compounds 3 and 10.

High-fat diet feeding elevates skeletal muscle uncoupling protein 3 levels but not its activity in rats

OBJECTIVE

The objective of this study is to test the impact of high-fat diet (HFD) feeding on skeletal muscle (SM) uncoupling protein 3 (UCP3) expression and its association with mitochondrial ion permeability and whole-body energy homeostasis.

RESEARCH METHODS AND PROCEDURES

Sprague-Dawley rats were fed ad libitum either a HFD (60% of energy from fat, n = 6) or a low-fat diet (12% of energy from fat, n = 6) for 4 weeks. Twenty-four-hour energy expenditure was measured by indirect calorimetry in the last week of the dietary treatment. Blood samples were collected for plasma leptin and free fatty acid assays, and mitochondria were isolated from hindlimb SM for subsequent determinations of UCP3 levels and mitochondrial ion permeability.

RESULTS

Plasma leptin levels were higher in rats fed the HFD despite the same body weight in two groups. The same dietary treatment also rendered a 2-fold increase in plasma free fatty acid and SM UCP3 protein levels (Western blot) compared with the group fed the low-fat diet. However, the elevated UCP3 protein levels did not correlate with mitochondrial swelling rates, a measure of mitochondrial chloride, and proton permeability, or with 24-hour energy expenditure.

DISCUSSION

The high correlation between the levels of plasma free fatty acid levels and SM UCP3 suggests that circulating free fatty acid may play an important role in UCP3 expression during the HFD feeding. However, the dissociation between the UCP3 protein levels and 24-hour energy expenditure as well as mitochondrial ion permeability suggests that mitochondrial proton leak mediated by muscle UCP3 may not be a major contributor in energy balance in HFD feeding, and other regulatory mechanisms independent of gene regulation may be responsible for the control of UCP3-mediated uncoupling activity.

Mice lacking the M3 muscarinic acetylcholine receptor are hypophagic and lean

Members of the muscarinic acetylcholine receptor family (M1-M5) have central roles in the regulation of many fundamental physiological functions. Identifying the specific receptor subtype(s) that mediate the diverse muscarinic actions of acetylcholine is of considerable therapeutic interest, but has proved difficult primarily because of a lack of subtype-selective ligands. Here we show that mice deficient in the M3 muscarinic receptor (M3R-/- mice) display a significant decrease in food intake, reduced body weight and peripheral fat deposits, and very low levels of serum leptin and insulin. Paradoxically, hypothalamic messenger RNA levels of melanin-concentrating hormone (MCH), which are normally upregulated in fasted animals leading to an increase in food intake, are significantly reduced in M3R-/- mice. Intra-cerebroventricular injection studies show that an agouti-related peptide analogue lacked orexigenic (appetite-stimulating) activity in M3R-/- mice. However, M3R-/- mice remained responsive to the orexigenic effects of MCH. Our data indicate that there may be a cholinergic pathway that involves M3-receptor-mediated facilitation of food intake at a site downstream of the hypothalamic leptin/melanocortin system and upstream of the MCH system.

Dehydroevodiamine attenuates beta-amyloid peptide-induced amnesia in mice

Dehydroevodiamine has been reported to have anticholinesterase activity and an anti-amnesic effect. This study examined the effects of dehydroevodiamine on scopolamine- and beta-amyloid peptide-(25--35)-induced amnesia in mice, using a step-through passive avoidance test. Similarly to the cholinesterase inhibitor, physostigmine (0.03--0.3 mg/kg, i.p.), dehydroevodiamine (0.75--12.0 mg/kg, i.p.) administered 30 min before the training trial, immediately after the training trial, and 30 min before the retention test significantly improved scopolamine- and beta-amyloid peptide-(25--35)-induced amnesia. In beta-amyloid peptide-(25--35)-induced amnesia, the rank order of anti-amnesic potency in these three administration schedules for dehydroevodiamine was different from that for physostigmine. Furthermore, dehydroevodiamine was more potent to improve beta-amyloid peptide-(25--35)-induced amnesia than scopolamine-induced amnesia when administered before the training trial. These results suggested that dehydroevodiamine may have an action other than that of an anticholinesterase and may be a novel and effective ligand for improvement of beta-amyloid type amnesia.

Regulation of cell proliferation, gene expression, production of cytokines, and cell cycle progression in primary human T lymphocytes by piperlactam S isolated from Piper kadsura

Effects of piperlactam S (C(17)H(13)NO(4); mol. wt. 295) isolated from Piper kadsura on phytohemagglutinin (PHA) stimulated cell proliferation were studied in primary culture of human T cells. The results showed that piperlactam S suppressed T cell proliferation at about 0 to 12 h after stimulation with PHA. Synthesis of total cellular proteins and RNA in activated cell cultures was also suppressed. The inhibitory action of piperlactam S was not through direct cytotoxicity. Cell cycle analysis indicated that piperlactam S arrested the cell cycle progression of activated T cells from the G(1) transition to the S phase. In an attempt to further localize the point in the cell cycle at which arrest occurred, a set of key regulatory events leading to the G(1)/S boundary, including gene expression of cytokines and c-Fos protein synthesis, was examined. Piperlactam S suppressed, in activated T lymphocytes, the production and mRNA expression of cytokines such as interleukin-2 (IL-2), IL-4, and interferon-gamma in a dose-dependent manner. In addition, Western blot analysis indicated that c-Fos protein expressed in activated T lymphocytes was decreased by piperlactam S. Results of kinetic study indicated that inhibitory effects of piperlactam S on IL-2 mRNA expressed in T cells might be related to blocking c-Fos protein synthesis. Thus, the suppressant effects of piperlactam S on proliferation of T cells activated by PHA seemed to be mediated, at least in part, through inhibition of early transcripts of T cells, especially those of important cytokines, IL-2, IL-4, and arresting cell cycle progression in the cells.

Lack of obesity and normal response to fasting and thyroid hormone in mice lacking uncoupling protein-3

Uncoupling protein-3 (UCP3) is a mitochondrial protein that can diminish the mitochondrial membrane potential. Levels of muscle Ucp3 mRNA are increased by thyroid hormone and fasting. Ucp3 has been proposed to influence metabolic efficiency and is a candidate obesity gene. We have produced a Ucp3 knockout mouse to test these hypotheses. The Ucp3 (-/-) mice had no detectable immunoreactive UCP3 by Western blotting. In mitochondria from the knockout mice, proton leak was greatly reduced in muscle, minimally reduced in brown fat, and not reduced at all in liver. These data suggest that UCP3 accounts for much of the proton leak in skeletal muscle. Despite the lack of UCP3, no consistent phenotypic abnormality was observed. The knockout mice were not obese and had normal serum insulin, triglyceride, and leptin levels, with a tendency toward reduced free fatty acids and glucose. Knockout mice showed a normal circadian rhythm in body temperature and motor activity and had normal body temperature responses to fasting, stress, thyroid hormone, and cold exposure. The base-line metabolic rate and respiratory exchange ratio were the same in knockout and control mice, as were the effects of fasting, a beta3-adrenergic agonist (CL316243), and thyroid hormone on these parameters. The phenotype of Ucp1/Ucp3 double knockout mice was indistinguishable from Ucp1 single knockout mice. These data suggest that Ucp3 is not a major determinant of metabolic rate but, rather, has other functions.

Anti-herpes simplex virus type-1 flavonoids and a new flavanone from the root of Limonium sinense

From the root of Limonium sinense (Girard) Ktze a new (2R,3S)-3,5,7,4'-tetrahydroxy-3',5'-dimethoxyflavanone was isolated and named isodihydrosyringetin (3), together with nine other known compounds, (-)-epigallocatechin 3-O-gallate (1), samarangenin B (2), myricetin (4), myricetin 3-O-alpha-rhamnopyranoside (5), quercetin 3-O-alpha-rhamnopyranoside (6), (-)-epigallocatechin (7), gallic acid (8), N-trans-caffeoyltyramine (9), and N-trans-feruloyltyramine (10). All of them were examined for their inhibitory effects on herpes simplex virus type-1 (HSV-1) replication in Vero cells. Both compounds 1 and 2 exhibited potent inhibitory activities in HSV-1 replication. Comparison of the IC50 values indicated that compounds 1 and 2 had higher inhibitory activities than the positive control acyclovir (38.6 +/- 2.6 vs. 55.4 +/- 5.3 microM, P < 0.001; 11.4 +/- 0.9 vs. 55.4 +/- 5.3 microM, P < 0.0005). Cytotoxicity was unlikely involved because no cell deaths were observable in the Vero cells following 5 day treatments with compound 1 or 2.

Flavonoids and phenolics from Limonium sinense

From the aerial part of Limonium sinense (Girard) Ktze, a new flavonol glycoside, myricetin 3-O-(2"-O-p-hydroxybenzoyl)-alpha-rhamnopyranoside has been isolated together with known flavonols, flavonol glycosides, flavonol glycoside gallates, flavones, flavanones, flavan-3-ols and gallic acid. The structural determinations of these compounds were based on spectral analyses.

Cytotoxic biflavonoids from Selaginella delicatula

Four new biflavonoids-robustaflavone 4'-methyl ether (1), robustaflavone 7,4'-dimethyl ether (2), 2",3" -dihydrorobustaflavone 7,4', -dimethyl ether (3), and 2",3" '-dihydrorobustaflavone 7,4', 7"-trimethyl ether (4)-as well as two known biflavonoids, robustaflavone and amentoflavone, and three caffeoylquinic acids, 3,5-di-O-caffeoylquinic acid, 3, 4-di-O-caffeoylquinic acid, and 4,5-di-O-caffeoylquinic acid, were isolated from Selaginella delicatula. The structures of the new compounds were established by spectroscopic analysis and chemical modification. The cytotoxic activity of these compounds on various tumor cell lines was evaluated, and both compounds 1 and 3 significantly suppressed the growth of Raji and Calu-1 tumor cell lines.

High-fat diet feeding reduces the diurnal variation of plasma leptin concentration in rats

To investigate the response of plasma leptin and its diurnal variation to graded levels of dietary fat intake, adult (486.8+/-10.8 g), male rats (N = 52) were fed diets containing 12%, 28%, 44%, and 60% fat for 4 weeks. The body weight gain and abdominal fat pad weight were higher (P < .05) in groups fed diets containing 44% and 60% fat compared with the two diets containing less fat. There were no significant differences in terms of body weight or fat pad weight between animals fed the two diets with higher fat content or between animals fed the two lower-fat diets. Twenty-four-hour energy expenditure was not different among the dietary fat groups. After 3 days on the experimental diets, plasma leptin increased (P < .03) in all dietary groups. The increases in leptin in animals fed 12% and 28% fat diets occurred primarily in the morning. In contrast, in groups fed the two diets containing higher fat content, leptin levels increased mainly in the afternoon. As a result, the daily variation in leptin increased (P < .05) in the two groups fed lower-fat diets, but decreased (P < .04) in animals fed the two higher-fat diets. These data demonstrate that short-term high-fat diet feeding abolished the diurnal fluctuation of plasma leptin levels, which may prevent proper leptin function and eventually contribute to the development of obesity.

Protein constituent contributes to the hypotensive and vasorelaxant activities of Cordyceps sinensis

Cordyceps sinensis is a herb medicine in China for the treatment of general debility after sickness and for persons of advanced age. In the present study, cordyceps sinensis was extract by phosphate buffer saline (PBS) and dialyzed overnight against PBS using a membrane cut off at 3,500 dalton molecular weight. The resulting macromolecule fraction (defined as CS) was assayed in anesthetized rats for hypotensive effects and in isolated aorta for vasorelaxant effects. Intravenous injection of CS (8,16, 24 and 32 mg/kg, respectively) suppressed significantly the mean arterial pressure (MAP) in a dose-dependent manner. 32 mg/kg of CS induces the maximal hypotensive response with a 58 +/- 4 mm Hg (from 107 +/- 6 to 49 +/- 3 mm Hg) change in MAP and a over 45 min action duration. In aortic rings precontracted with phenylephrine treatment with CS between 0.5 and 500 microg/ml induced dose dependent relaxation. Maximal vasorelaxant response evoked by 150 microg/ml CS was 68.9 +/- 7.3%. Furthermore, CS-induced vasorelaxation is mediated by the endothelium possibly by stimulating the release of the nitric oxide and endothelium-derived hyperpolarizing factor. In conclusion, the present study revealed that presence of a constituent in CS which reduces MAP by relaxing the vascular beds directly. However, the effect may be caused by a single active ingredient or by the combined action of many active agents found in the extract.

Measurement and pharmacokinetics of unbound 20(S)-camptothecin in rat blood and brain by microdialysis coupled to microbore liquid chromatography with fluorescence detection

To characterize the pharmacokinetics of protein-free camptothecin in blood and brain we implanted microdialysis probes into the jugular vein and striatum of rats for unbound drug sampling and determination. Camptothecin (2 or 5 mg/kg, i.v., n=6) was then administered from the femoral vein, and microdialysates were collected from blood and brain of both sites and assayed by a validated microbore scale high-performance liquid chromatographic method. The mobile phase consisted of methanol-100 mM monosodium phosphoric acid (35:65, v/v, pH 2.5) with a flow-rate 0.05 ml/min. The fluorescence response for camptothecin was observed at excitation and emission wavelengths of 360 and 440 nm, respectively. Pharmacokinetic parameters were calculated from the corrected data for dialysate concentrations of camptothecin versus time. The results suggest that the pharmacokinetics of unbound camptothecin in blood and brain can be fitted best to a two- and one-compartment model, respectively. Camptothecin rapidly entered the extracellular fluid of brain striatum at 10 min following camptothecin administration.

Flavonoid glycosides from viscum alniformosanae

Two new flavonoid glycosides, (2S)-5-hydroxy-7, 3'-dimethoxyflavanone-4'-O-beta-[apiosyl (1 --> 2)]glucoside (1) and rhamnazin-4'-O-beta-[apiosyl (1 --> 2)]glucoside (2) were isolated from Viscum alniformosanae. Structures were elucidated by NMR and mass spectroscopic analysis.

Determination of unbound 20(S)-camptothecin in rat bile by on-line microdialysis coupled to microbore liquid chromatography with fluorescence detection

To evaluate the biliary excretion of unbound camptothecin, a flow-through microdialysis probe was constructed for bile sampling. The shunt linear probe was connected from the bile duct, between the liver side to the duodenum to avoid obstruction of the bile duct or bile salt waste. For automatic analysis of microdialysate, an on-line injector was connected to a microbore high-performance liquid chromatographic column with fluorescence detection. Samples were eluted with a mobile phase containing methanol-100 mM monosodium phosphoric acid (35:65, v/v, pH 2.5, adjusted with orthophosphoric acid). The limit of quantification was 1 ng/ml for camptothecin. Following camptothecin administration (5 mg/kg, i.v.), it was found in the bile microdialysate. It was concluded that the in vivo microdialysis technique yields useful data on the biliary excretion of camptothecin. This method is suitable for additional pharmacokinetic studies in rat bile.

Immunomodulatory principles of Dichrocephala bicolor

From the ethanolic extract of Dichrocephala bicolor eight compounds-4,5-dicaffeoyl quinic acid (1); 3,4-dicaffeoyl quinic acid (2); 3,5-dicaffeoyl quinic acid (3); ethyl 4,5-dicaffeoyl quinate (4); methyl 3,5-dicaffeoyl quinate (5); 5-caffeoyl quinic acid (6); caffeic acid (7); and quercetin-3-O-rutinoside (8)-were isolated and identified. All of them were selected for immunopharmacological activity testing. Human mononuclear cells (HMNC) were used as target cells. Cell proliferation was determined by 3H-thymidine uptake. Compounds 2 and 6 potently enhanced HMNC proliferation and interferon-gamma production. Enhancement mechanisms may involve the increase of cytokines production.

Effects of methanol extract of Chansu on hypothalamic-pituitary-testis function in rats

Chansu, a galenical preparation of the dried white venom of Chinese Bufo bufo gargarizans, is one of the major components of Kyushin, a traditional Chinese medicine. Kyushin is reported to have a cardiotonic effect that has been suggested to be due to the action of bufadienolides such as bufalin and cinobufagin. Recently, we found that administration of bufalin in male rats diminished the luteinizing hormone (LH) response to gonadotropin-releasing hormone (GnRH) and the secretion of testosterone both in vivo and in vitro. These observations suggest that Chansu may possess hypogonadal effects in male rats. In the present study, the effects of the methanol extract of Chansu on hypothalamic-pituitary-testicular function in male rats were examined. Crude Chansu was extracted by methanol and purified by a Sep-Pak C18 column. No activity of bufalin, cinobufagin, estradiol, or digoxin in purified methanol extract was detected; all Chansu used in this study was the purified methanol extract. A single intravenous injection of Chansu resulted in a decrease of the basal (20% to 55%) and human chorionic gonadotropin (hCG)-induced (35% to 40%) levels of plasma testosterone and the GnRH-induced level of plasma LH (25% to 30%). Administration of Chansu in vitro decreased basal and hCG-stimulated testosterone production by 60% to 70% and 40% to 60%, respectively, as well as spontaneous and forskolin- or 3-isobutyl-1-methylxanthine (IBMX)-induced accumulation of adenosine 3',5'-cyclic monophosphate (cAMP) by 30% to 45% in rat testicular interstitial cells. Although LH release by rat anterior pituitary glands was diminished, GnRH release by the rat mediobasal hypothalamus was enhanced by administration of Chansu in vitro. These results suggest that the bufalin-free extracts of Chansu inhibit testosterone secretion in rats, in part, due to (1) a decreased production of testicular cAMP, (2) a decreased response of testosterone to gonadotropin, and (3) a reduction of the LH response to GnRH.

Cytotoxic constituents from the stems of Diospyros maritima

One novel coumaric acid ester of lupeol, dioslupecin A (1), three naphthoquinones, 8'-hydroxyisodiospyrin (2), isodiospyrin (3), and plumbagin (4), three triterpenes, lupeol, lupenone and taraxerone, and four sterols, beta-sitosterol, stigmasterol, stigmast-4-en-3-one and ergosta-4,6,8(14),22-tetraen-3-one were isolated from the n-hexane extract of the stems of Diospyros maritima Blume. The structural determination of 1 was based on 1D and 2D NMR spectra (including 1H-1H COSY, 1H-13C COSY, and HMBC). All compounds were evaluated for in vitro cytotoxicity in 4 cancer cell lines. Compound 2 showed similar cytotoxicity against hepatoma (HEPA-3B, ED50 = 1.72 micrograms/ml), nasopharynx carcinoma (KB, ED50 = 1.85 micrograms/ml), colon carcinoma (COLO-205, ED50 = 2.24 micrograms/ml) and cervical carcinoma (HELA, ED50 = 1.92 micrograms/ml). Compounds 3 and 4 exhibited strong cytotoxicity against HEPA-3B, KB, COLO-205 and HELA (ED50 = 0.25, 1.81, 0.13 and 0.27 micrograms/ml for 3; ED50 = 0.87, 3.27, 0.56 and 0.35 micrograms/ml for 4, respectively.

Determination of dicentrine in rat plasma by high-performance liquid chromatography and its application to pharmacokinetics

A simple high-performance liquid chromatographic method was developed to study the pharmacokinetics of dicentrine in rat plasma after 10 mg/kg intravenous administration. After addition of an internal standard (coumarin), plasma was deproteinized by acetonitrile for sample clean-up. The drugs were separated on a reversed-phase Nucleosil C18 column (250 x 4 mm I.D., particle size 5 microns) and detected by photodiode-array detection at a wavelength of 308 nm. Acetonitrile-water (35:65, v/v, pH 2.5-2.8, adjusted with orthophosphoric acid) was used as the mobile phase. A biphasic phenomenon with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration-time curve.

Determination of wogonin in rat plasma by liquid chromatography and its pharmacokinetic application

A high-performance liquid chromatographic method has been developed for the determination of wogonin in the rat plasma. After addition of an internal standard (clomipramine), plasma was deproteinized by acetonitrile and centrifuged for sample clean-up. The supernatant was separated by a reversed-phase column chromatography, identified by a photodiode-array detector, and quantified by ultraviolet detection at a wavelength of 275 nm. Acetonitrile-water-diethylamine (50:50:0.1, v/v/v, pH 3.0 adjusted by orthophosphoric acid) was used as the mobile phase. The method was applied to the pharmacokinetic study of wogonin in rats after a dose of mg/kg by intravenous administration. A biphasic phenomenon with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration time profile.

The vasorelaxing action of rutaecarpine: direct paradoxical effects on intracellular calcium concentration of vascular smooth muscle and endothelial cells

We have examined both the hypotensive effect and the mechanism of intracellular Ca++ regulation, underlying rutaecarpine (Rut)-induced vasodilatation. An i.v. bolus injection of Rut in anesthetized Sprague-Dawley rats produced a dose-dependent hypotensive effect. In isolated rat aorta rings, Rut (0.1-3 mu M) inhibited the phasic and tonic responses of norepinephrine- and phyenylephrine-induced contractions, respectively, mainly through an endothelium-dependent mechanism. However, the vasorelaxing effect of Rut (3 microM) persisted in denuded aorta, although to a much less extent than in intact tissue. As determined by the fura-2/AM (1-[2-(5-carboxyoxazol-2-yl)-6-aminobenzofuran-5-oxy]-2-(2'- amino-5'-methylphenoxy)-ethane-N,N,N,N-tetraacetic acid pentaacetoxymethyl ester) method, Rut (10 microM), in the presence of extracellular Ca++, suppressed the KCI-induced increment in the intracellular Ca++ concentration ([Ca++]i) of cultured vascular smooth muscle cells (VSMC). Rut (10 microM) also attenuated the norepinephrine-induced peak rise of [Ca++]i in VSMC placed in Ca++-free solution. On the other hand, Rut (1 and 10 microM) increased the level of [Ca++]i of cultured endothelial cells (EC) in the presence of extracellular Ca++. In conclusion, Rut acts on both VSMC and EC directly. In VSMC, it reduces [Ca++]i through the inhibition of Ca++ influx and Ca++ release from intracellular stores. In EC, Rut augments EC [Ca++]i by increasing Ca++ influx, possibly leading to nitric oxide release. The paradoxical regulation of Ca++ in both VSMC and EC acts simultaneously to cause vasorelaxation which could account, at least in part, for the hypotensive action. This is a most significant and a unique feature of this study.

Pharmacokinetics and brain distribution of magnolol in the rat after intravenous bolus injection

The pharmacokinetics of magnolol in rats was studied after 2, 5, or 10 mg/kg-1 intravenous bolus injection. Plasma concentration-time profiles of magnolol were fitted by a two-compartment open model. There were no significant differences in the elimination half-life, the total body clearance, steady-state volume of distribution, or mean residence time. The area under the plasma-time curve and area under the moment-time curve of magnolol appears to increase proportionally from a dose of 2 to 10 mg/kg-1. These results suggest that magnolol possess linear pharmacokinetics. Notwithstanding, brain concentration of magnolol showed no significant difference among various regions (cerebral cortex, olfactory bulb, hippocampus, striatum, cerebellum, brain stem and rest of brain) after 10 min of magnolol (5 mg/kg-1, i.v.) administration, the mean brain drug concentration was approximately fourfold that of magnolol in plasma.

High-performance liquid chromatographic determination of evodiamine in rat plasma: application to pharmacokinetic studies

A previously published simple and sensitive high-performance liquid chromatographic method for determination and identification of rutaecarpine in rat plasma was used for evodiamine determination. However, the ultraviolet detection was not 344 nm, but 227 nm. The method was applied to a pharmacokinetic study of evodiamine in rats after 2 mg/kg intravenous administration. A biphasic phenomenon with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration-time curve. Compartmental analysis yielded a two-compartment model.

Pharmacokinetics of paeonol after intravenous administration in rats

A simple high-performance liquid chromatography methodology was developed to study the pharmacokinetics of paeonol in the rat after intravenous (iv) bolus administration of various doses (2.5, 5, or 10 mg/kg). The pharmacokinetics of paeonol in rat plasma at each dose were well described by a two-compartment model. The area under the curve increased proportionally with dose and consequently total body clearance was independent of dose. There was no dose-related difference in the elimination half-life or volume of distribution. These results indicate that the pharmacokinetics of paeonol after iv administration are linear over the 2.5-10 mg/kg dose range.

Disposition of magnolol after intravenous bolus and infusion in rabbits

A simple and sensitive high-performance liquid chromatographic method was developed for the determination and identification of magnolol to study its pharmacokinetics in rabbits after a 5 mg/kg i.v. bolus and 76 micrograms/kg/min i.v. infusion. Plasma concentration time profiles were suited to a two-compartment open model. The elimination half-lives of magnolol were 14.56 and 15.71 min, and the total body clearances were 75.86 and 72.72 ml/min/kg for i.v. bolus and i.v. infusion, respectively. There were no significant differences in elimination half-life and total body clearance between i.v. bolus and i.v. infusion, which suggests that magnolol pharmacokinetics are linear.

The mechanism of the vasodilator effect of rutaecarpine, an alkaloid isolated from Evodia rutaecarpa

The mechanisms underlying the rutaecarpine-induced vasodilatation were studied using isolated rat mesenteric arterial ring segments. The results showed that rutaecarpine (0.1 microM to 0.1 mM) produced a dose-dependent vasorelaxing response in our preparations, which were precontracted with phenylephrine. This vasodilator effect was significantly attenuated by removal of the endothelium, treatment with L-NG-nitro-arginine, a nitric oxide synthase inhibitor, and methylene blue, a guanylyl cyclase inhibitor, but not by treatment with atropine, triprolidine and yohimbine. Rutaecarpine pretreatment (1 microM to 0.1 mM) reduced both the phasic (fast) and tonic (slow) phases of phenylephrine-induced contractions, suggesting that a reduction in intracellular calcium might be involved. It is thus concluded that while the vasorelaxing effect of rutaecarpine appeared to be endothelium-dependent and to involve nitric oxide and guanylyl cyclase, neither muscarinic receptors, histamine H1 receptors nor alpha 2-adrenoceptors are involved. Moreover, a direct effect on the vascular smooth muscle cell, possibly through a reduction in intracellular Ca2+, can not be excluded.

Pharmacokinetics of honokiol after intravenous administration in rats assessed using high-performance liquid chromatography

A simple and sensitive high-performance liquid chromatographic method for the identification and determination of honokiol in rat plasma has been developed. Up to 0.1 ml of plasma containing honokiol was deproteinized with acetonitrile, which contained an internal standard (paeonol). The supernatant was injected onto a reversed-phase C18 column using acetonitrile-water (70:30, v/v, adjusted to pH 2.5-2.8 with orthophosphoric acid) as the mobile phase and ultraviolet detection at 290 nm, followed by UV spectrum identification (between 220 and 380 nm) with a photodiode-array detector. The method was applied to pharmacokinetic studies of honokiol in rat following 5 or 10 mg/kg intravenous administration. A biphasic process consisting of a rapid distribution phase followed by a slower elimination phase was observed from the plasma concentration-time curves. Compartmental analysis yielded a two-compartment model.

High-performance liquid chromatographic determination of rutaecarpine in rat plasma: application to a pharmacokinetic study

A simple and sensitive high-performance liquid chromatographic method for determination and identification of rutaecarpine in rat plasma has been developed. Up to 0.1 ml of plasma containing rutaecarpine was deproteinized by acetonitrile, which contained an internal standard (paeonol). The supernatant was injected onto a reversed-phase column using a acetonitrile-water-orthophosphoric acid (85%) (60:40:0.1, v/v/v, pH 2.5-2.8) as the mobile phase and ultraviolet detection at 344 nm. It was applied to the pharmacokinetic study of rutaecarpine in rat after a 2 mg/kg intravenous administration. A biphasic process with a rapid distribution followed by a slower elimination phase was observed from the plasma concentration-time curve. Compartmental analysis yielded a two-compartment model.

The vasorelaxant effect of evodiamine in rat isolated mesenteric arteries: mode of action

The roles of the endothelium, Ca2+ and K+ fluxes in the evodiamine-induced attenuation of vascular contractile responses to vasoactive agents were examined. The results showed that: (1) in rat mesenteric artery rings, evodiamine elicited a concentration-dependent attenuation in the contractile response generated by phenylephrine. The inhibitory potency was greater for intact than for endothelium-denuded preparations. Thus, the vasodilator action of evodiamine appeared to be partially endothelium-interactive (dependent). (2) Evodiamine pretreatment had a greater inhibitory effect on the phenylephrine-induced tonic contraction (via Ca2+ influx) than on the phasic contraction (via Ca2+ release). In addition, evodiamine was more potent to inhibit the restoration by CaCl2 of contractile responses to phenylephrine than a potassium depolarizing solution in media that had been kept calcium-free. These results suggest that block of the Ca2+ influx through receptor-mediated Ca2+ channels may be the major mechanism underlying the vasodilator effect of evodiamine. (3) A K+ channel blocker, tetraethylammonium, almost completely abolished the vasodilatation induced by minoxidil (a known K+ channel opener) but not evodiamine. The possible involvement of K+ channel activation of the vasodilator effect produced by evodiamine was therefore excluded.