Phloroglucinol Derivatives from Dryopteris crassirhizoma as Potent Xanthine Oxidase Inhibitors.

Dryopteris crassirhizoma rhizomes are used as a traditional medicine in Asia. The EtOAc extract of these roots has shown potent xanthine oxidase (XO) inhibitory activity. However, the main phloroglucinols in D. crassirhizoma rhizomes have not been analyzed. Thus, we investigated the major constituents responsible for this effect. Bioassay-guided purification isolated four compounds: flavaspidic acid AP (1), flavaspidic acid AB (2), flavaspidic acid PB (3), and flavaspidic acid BB (4). Among these, 1 showed the most potent inhibitory activity with a half-maximal inhibitory concentration (IC50) value of 6.3 µM, similar to that of allopurinol (IC50 = 5.7 µM) and better than that of oxypurinol (IC50 = 43.1 µM), which are XO inhibitors. A comparative activity screen indicated that the acetyl group at C3 and C3' is crucial for XO inhibition. For example, 1 showed nearly 4-fold higher efficacy than 4 (IC50 = 20.9 µM). Representative inhibitors (1-4) in the rhizomes of D. crassirhizoma showed reversible and noncompetitive inhibition toward XO. Furthermore, the potent inhibitors were shown to be present in high quantities in the rhizomes by a UPLC-QTOF-MS analysis. Therefore, the rhizomes of D. crassirhizoma could be used to develop nutraceuticals and medicines for the treatment of gout.

Antibacterial activity of Morinda citrifolia Linneo seeds against Methicillin-Resistant Staphylococcus spp.

In traditional medicine, Morinda citrifolia (Noni) is used to treat various ailments, including skin and respiratory-tract infections. In this work, a bio-directed study (seed extracts) with five bacteria was carried out against four clinical isolates of Methicillin-Resistant Staphylococcus (MRS) and Staphylococcus aureus ATCC 29213 strain to find molecules capable of inhibiting them. Three organic extracts were obtained by maceration of the noni seeds with ascending polarity solvents (n-hexane, dichloromethane and methanol) that were evaluated as antibacterial in the model of bioautography and broth microdilution techniques. The results showed that the methanolic extract was the most active against all bacteria (MIC = 16 mg/mL). The chromatographic fractionation performed on this extract allowed obtaining six fractions (EMF1-EMF6), of which F1, F2 and F5 exhibited activity against some of the bacteria. EMF1 fraction reached an MIC of 25 µg/mL against S. haemolyticus twice as much as the positive control, in which the chemical content is mainly composed of a mixture of γ-butyrolactones (1-2) and esterified fatty acids (3-9); chemical characterization of the nine compounds was carried out based on gas chromatography coupled to masses. EMF2 fraction, presented an MIC of 200 µg/mL against S. aureus 0198 and S. haemolyticus 562B, where a coumarin known as scopoletin (10) was isolated and active against S. aureus 0198 (MIC = 100 µg/mL). EMF5 fraction demonstrated an MIC of 200 µg/mL against S. aureus 0198, S. haemolyticus 562B and S. epidermidis 1042, in which a neolignan known as americanin A (11) was identified, showing activity against S. haemolyticus 562B and S. epidermidis 1042 (MIC = 100 µg/mL). The chemical characterization of isolated compounds 10 and 11 was performed by the analysis of 1H and 13C NMR. Therefore, the methanolic extract, identified and isolated compounds showed important antibacterial activity against the MRS, validating its use in traditional medicine.

Hyperjaponol H, A New Bioactive Filicinic Acid-Based Meroterpenoid from Hypericum japonicum Thunb. ex Murray.

Hyperjaponol H (1), a new filicinic acid-based meroterpenoid, with a 6/6/10 ring system trans-fused by hetero-Diels-Alder cycloaddition between a germacrane sesquiterpenoid and a filicinic acid moiety, was isolated from aerial parts of Hypericum japonicum. The elucidation of its structure and absolute configuration were accomplished by the analyses of extensive spectroscopic data and the comparison of Cotton effects of electron circular dichroism (ECD) with previously reported ones. The bioactivity assay showed that hyperjaponol H exhibited a moderate inhibitory efficacy on lytic Epstein-Barr virus (EBV) DNA replication in B95-8 cells.

Preseasonal prophylactic treatment with antihistamines suppresses IL-5 but not IL-33 mRNA expression in the nasal mucosa of patients with seasonal allergic rhinitis caused by Japanese cedar pollen.

CONCLUSIONS: These findings suggest that the down-regulation of interleukin (IL)-5 gene expression in collaboration with the suppression of histamine H(1) receptor (H1R) gene expression in the nasal mucosa provides the basis for better therapeutic effects of preseasonal prophylactic treatment with antihistamines in patients with seasonal allergic rhinitis caused by Japanese cedar pollen. OBJECTIVES: The effects of prophylactic administration of antihistamines on the expression of IL-5 and IL-33 mRNA in the nasal mucosa of the patients with pollinosis were investigated. METHODS: Eight patients had already visited the hospital before the peak pollen period and started preseasonal prophylactic treatment with antihistamines. Seventeen patients who first visited the hospital during the peak pollen period were designated as the no treatment group. After local anesthesia, nasal mucosa was obtained by scraping the inferior concha with a small spatula during the peak pollen period. RESULTS: During the peak pollen period, the expression of IL-5 mRNA, but not that of IL-33 mRNA, in the nasal mucosa of patients receiving preseasonal prophylactic treatment with antihistamines was significantly lower in comparison with that of patients without treatment. Moreover, there was a significant correlation between the expression of IL-5 mRNA and the nasal symptoms or the expression of H1R mRNA.

Toxicity of Rhododendron anthopogonoides essential oil and its constituent compounds towards Sitophilus zeamais.

The screening of several Chinese medicinal plants for insecticidal principles showed that essential oil of Rhododendron anthopogonoides flowering aerial parts possessed significant toxicity against maize weevils, Sitophilus zeamais. A total of 37 components were identified in the essential oil and the main constituents of the essential oil were 4-phenyl-2-butanone (27.22%), nerolidol (8.08%), 1,4-cineole (7.85%), caryophyllene (7.63%) and γ-elemene (6.10%), followed by α-farnesene (4.40%) and spathulenol (4.19%). Repeated bioactivity-directed chromatographic separation on silica gel columns led us to isolate three compounds, namely 4-phenyl-2-butanone, 1,4-cineole, and nerolidol. 4-Phenyl-2-butanone shows pronounced contact toxicity against S. zeamais (LD50 = 6.98 mg/adult) and was more toxic than either 1,4-cineole or nerolidol (LD50 = 50.86 mg/adult and 29.30 mg/adult, respectively) against the maize weevils, while the crude essential oil had a LD50 value of 11.67 mg/adult. 4-Phenyl-2-butanone and 1,4-cineole also possessed strong fumigant toxicity against the adults of S. zeamais (LC50 = 3.80 mg/L and 21.43 mg/L) while the crude essential oil had a LC50 value of 9.66 mg/L.

Insect antifeedant and growth regulating activities of salannobutyrolactone and desacetylsalannobutyrolactone.

Salannobutyrolactone and its deacetylderivative were tested for insect antifeedant and growth regulatory activities against the tobacco cutworm, Spodoptera litura. Salannobutyrolactone was the most effective antifeedant. Desacetylsalannobutyrolactone increased larval duration and larval mortality.

Involvement of CYP2J2 on the intestinal first-pass metabolism of antihistamine drug, astemizole.

Orally administered astemizole is well absorbed but undergoes an extensive first-pass metabolism to O-desmethylastemizole. Desmethylastemizole is formed in the human microsomal systems of the small intestine as well as the liver, which suggests the role of cytochromes P450 (P450s) in the first-pass metabolism of astemizole. Human P450s involved in the O-demethylation of astemizole have, however, not been identified, and the involvement of twelve known drug-metabolizing P450s were denied. During the course of the P450 identification study, higher activities of the astemizole O-demethylation in the rabbit small intestine than in the liver (about 3-fold) were found. These data suggest the possible involvement of CYP2J, since P450 included in this subfamily is dominantly expressed in the small intestine of rabbits. Therefore, CYP2J2 cDNA has been isolated from the human cDNA library and expressed in COS-1 cells. A clear activity of astemizole O-demethylation was detected in recombinant CYP2J2 with K(m) = 0.65 microM and V(max) = 1129 pmol/nmol P450/min. Expression of the immunoreactive protein with CYP2J2 antibody was detected in the small intestine and liver. Expression levels of the immunoreactive protein with the CYP2J2 antibody in the small intestine were well correlated with the activities of the astemizole O-demethylation (r = 0.901, n = 5, p < 0.05). The CYP2J2 substrates, arachidonic acid and ebastine, strongly inhibited the microsomal astemizole O-demethylation in the human small intestines and recombinant CYP2J2. These results indicate the involvement of CYP2J2 in the presystemic elimination of astemizole in the human small intestine.

Neuroimaging of histamine H1-receptor occupancy in human brain by positron emission tomography (PET): a comparative study of ebastine, a second-generation antihistamine, and (+)-chlorpheniramine, a classical antihistamine.

AIMS: Sedation induced by antihistamines is widely recognized to be caused by their penetration through the blood-brain-barrier and the consequent occupation of brain histamine H1-receptors. We previously studied the mechanism of sedation caused by antihistamines using positron emission tomography (PET). Recently, we revealed the nonsedative characteristic of ebastine, a second-generation antihistamine, with cognitive performance tests. In the present study, H1-receptor occupation by ebastine was examined in the human brain using PET. METHODS: Ebastine 10 mg and (+)-chlorpheniramine 2 or 6 mg were orally given to healthy male volunteers. PET scans with [11C]-doxepin, a potent H1-receptor antagonist, were conducted near tmax of respective drugs. Other volunteers in the control group also received PET scans. The binding potential of doxepin (BP = Bmax/Kd) for available brain H1-receptors was imaged on a voxel-by-voxel basis through graphical analysis. By setting regions of interest, the H1-receptor occupancy of drugs was calculated in several H1-receptor rich regions. RESULTS: Brain distribution of radioactivity after ebastine treatment was similar to that without any drugs. However, after the oral administration of 2 mg (+)-chlorpheniramine, the level was lower than after ebastine and nondrug treatments. Graphical analysis followed by statistical parametric mapping (SPM96) revealed that H1-receptor rich regions such as cortices, cingulate gyrus and thalamus were regions where the BPs after ebastine were significantly higher than after (+)-chlorpheniramine (2 mg). H1-receptor occupancies in cortex were approximately 10% by ebastine and > or = 50% by either dose of (+)-chlorpheniramine (95% confidence interval for difference in the mean receptor occupancies: 27%, 54% for 2 mg and 35%, 62% for 6 mg vs ebastine, respectively). Receptor occupancies increased with increasing plasma concentration of (+)-chlorpheniramine, but not with concentration of carebastine, an active metabolite of ebastine. CONCLUSIONS: Ebastine (10 mg orally) causes brain histamine H1-receptor occupation of approximately 10%, consistent with its lower incidence of sedative effect, whereas (+)-chlorpheniramine occupied about 50% of brain H1-receptors even at a low but sedative dose of 2 mg; occupancy of (+)-chlorpheniramine was correlated with plasma (+)-chlorpheniramine concentration.

Preclinical comparison of ebastine and other second generation H1-antihistamines.

The present study was performed to compare the properties of ebastine--the long duration of antiallergic effect and less penetration to the CNS--with those of other H1-antihistamines. Passive cutaneous anaphylactic reaction was induced and the dye leakage from the skin measured after oral administration of the various H1-antihistamines in guinea pigs. The H1-antihistamines examined inhibited passive cutaneous anaphylactic reactions, with ED50 values of 1.55-5.77 mg/kg administered orally. Evaluation at doses close to the ED50 values determined that the rank order of the various H1-antihistamines for the duration of antiallergic effects, calculated from the AUC, was as follows: ebastine>cetirizine> or =oxatomide=loratadine=epinastine. The inhibition of [3H]-mepyramine binding to the cortical membrane was examined ex vivo after oral administration of the drugs in rats. Ketotifen as a positive control of sedative antihistamine, oxatomide, cetirizine, ebastine and epinastine dose-dependently inhibited the [3H]-mepyramine binding to rat cortical membranes. However, ebastine and epinastine did not show 50% [3H]-mepyramine binding inhibition even at 100 mg/kg orally In conclusion, ebastine was shown to be a potent and long-lasting H1-antihistamine with less effect to the CNS. Consequently, in conjunction the two experimental models used in this study--passive cutaneous anaphylactic reaction in guinea pigs and ex vivo [3H]-mepyramine binding to rat cortical membrane--may be important to estimate the duration of antiallergic effects of drugs and to detect their sedative effects, which are important indicators in the development of new antiallergic drugs.

Comparative effects of nonsedating histamine H1 receptor antagonists, ebastine and terfenadine, on human Kv1.5 channels.

The effects of ebastine and terfenadine, long-acting nonsedating histamine H1 receptor antagonists, were studied on hKv1.5 channels using the whole-cell voltage-clamp configuration of the patch-clamp technique in Ltk- cells transfected with the gene encoding the hKv1.5 channel. Upon depolarization to +60 mV, terfenadine, 1 microM and 3 microM, inhibited the hKv1.5 current by 42.4 +/- 6.4% and 69.3 +/- 4.2% (P < 0.01). In contrast, at the same range of concentrations, ebastine-induced inhibition of this K+ current averaged 6.5 +/- 2.0% and 13.0 +/- 2.0 (P < 0.05). At the highest concentration tested (3 microM) neither terfenadine carboxylate nor carebastine significantly modified hKv1.5 current. All these results suggest that ebastine could represent a safer alternative to terfenadine in the clinical practice.

Use of the vasodilator sodium nitroprusside during local hyperthermia: effects on tumor temperature and tumor response in a rat tumor model.

PURPOSE: The effect of a decrease in the mean arterial blood pressure (MAP) induced by sodium nitroprusside (SNP) on the tumor temperature during hyperthermia (HT), and on the cytotoxic effect of HT, was studied in the BT4An tumor transplanted to the hind limb of BD IX rats. Experiments with two different anesthetics, pentobarbital and the midazolam/fentanyl/fluanisone combination (MFF), were performed to secure reliable conclusions. METHODS AND MATERIALS: In the tumor response experiments local waterbath HT at 44.0 degrees C was given for 60 min. Sodium nitroprusside was administered as a continuous intravenous infusion to lower the MAP to 60 or 80 mmHg during HT. In two other experiments the temperature at the base of the tumor during HT was measured before and during SNP infusion. In animals without tumor the temperature was measured subcutaneously on the foot during HT with or without SNP-induced hypotension. RESULTS: When SNP was given to lower the MAP to 60 mmHg during HT in MFF anesthetized animals, the median tumor growth time (TGT) was 70 days, compared to 14.5 days in the HT alone group. The corresponding figures were 127 and 12.1 days with pentobarbital anesthesia. In the HT + SNP group, more than 40% cure was observed in both experiments. No cures were seen in any of the other groups. Hyperthermia alone prolonged the TGT slightly, whereas SNP given alone had no effect, compared to controls. When the MAP was lowered to 80 mmHg by SNP infusion during HT (MFF anesthesia), the median TGT was 19.9 days, which was significantly longer than that in the HT alone group (10.9 days). In the MAP range from 60 to 120 mmHg, a nearly linear relationship between the MAP and the tumor temperature was found during HT in MFF anesthetized animals. With both anesthetics, the median temperature at the base of the tumor was about 0.8 degrees C higher during HT when the MAP was lowered to 60 mmHg by SNP. In animals without tumors, the temperature subcutaneously on the foot was 0.3 and 0.4 degrees C higher during SNP infusion in the MFF and pentobarbital group, respectively. CONCLUSION: We have developed a small animal model in inbred rats feasible for exploring the influence of a stable blood pressure reduction induced by SNP, on the effect of HT given alone or in combination with other treatment modalities to a transplantable tumor. The greatly increased cytotoxic effect of local waterbath HT in the present tumor response experiments is probably a consequence of increased tumor temperature during SNP infusion.

Anti-tumor promoting activity of Dryopteris phlorophenone derivatives.

As a part of screening studies for cancer chemopreventive agents (anti-tumor promoters) 33 Dryopteris phlorophenone derivatives have been evaluated. The compounds tested comprised of monomeric acylphloroglucinols (e.g. desaspidinol, aspidinol) as well as dimeric (e.g. aspidin, desaspidin), trimeric (e.g. filixic acids), and tetrameric (e.g. dryocrassin) phlorophenone, wherein hexacyclic rings are bound together by a methylene bridge. These compounds were examined for their in vitro anti-tumor promoting effect on Epstein-Barr virus antigen activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). The two dimeric compounds aspidin and desaspidin, which were found to be the most active among the tested phlorophenones, were also examined in vivo on two stage mouse skin carcinogenesis, and found to show significant inhibitory effect on 7,12-dimethylbenz[alpha]anthracene (DMBA)-TPA tumor promotion.

A preclinical overview of ebastine. Studies on the pharmacological properties of a novel histamine H1 receptor antagonist.

Ebastine is a novel histamine H1 receptor antagonist that combines potency with a rapid onset (fast absorption) and long duration (slow elimination) of action, at least partially mediated via the formation of an acid metabolite (carebastine) that is even more potent as an antihistamine. It shows clear selectivity for histamine H1 as opposed to H2 receptors, has moderate activity against other potential mediators of allergic phenomena such as leukotriene C4 and platelet-activating factor, and is clearly effective against anaphylactic reactions resulting from exposure of suitably sensitised tissues or animals to antigen. By contrast, ebastine has negligible activity against acetylcholine (no atropine-like adverse effects on secretions and visual accommodation) and only poorly penetrates the blood-brain barrier (no sedative adverse effects). Ebastine is without effects on the central nervous and cardiovascular systems, even after oral administration of high doses, and does not interact pharmacologically with a wide range of other drugs covering most areas of potential coadministration. Furthermore, ebastine showed no clinically relevant effects in a complete set of regulatory-required toxicity tests (including acute, chronic, reproductive, mutagenic and carcinogenic protocols) at doses giving blood concentrations representing high multiples of clinical exposure. In conclusion, ebastine has a preclinical profile indicative of an excellent therapeutic ratio of desired effects to undesired effects.

Calmodulin antagonists inhibit the mitochondrial pyruvate dehydrogenase complex.

Calmodulin antagonists, including phenothiazine, sulfonamide, butyrophenone, and imidazolium derivatives, were in vitro inhibitors of pea mitochondrial pyruvate dehydrogenase complex activity. Inhibition was observed both during direct assay of the partially purified complex and during assay of pyruvate oxidation by isolated, intact mitochondria. When tested against the purified complex, the sulfonamide compound N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7) was a competitive inhibitor with respect to coenzyme A and an uncompetitive inhibitor with respect to NAD and pyruvate. Inhibition of a process as crucial as mitochondrial respiration should serve to emphasize the care necessary in interpretation of whole-organism calmodulin antagonist studies.

Effects of antiglaucoma drugs on the blood flow in rabbit eyes.

Although it is essential that intraocular pressure (IOP) be reduced in glaucoma treatment, it is also vitally important to provide sufficient blood flow to eye tissues so that healthy visual field is maintained. It is possible for an agent to reduce IOP and blood supply to the eye. In that case, glaucoma appears to be under control since IOP has been reduced to within normal range, yet the disease is actually progressing, causing damage to the retina, optic nerve, and other tissues. The 85Sr-microsphere technique was used to study the effects of several antiglaucoma drugs on blood supply to various eye tissues. It was found that pilocarpine, L-timolol, D-timolol and haloperidol are good drugs to use in treating glaucoma because they do not reduce ocular blood flow. D-timolol is particularly good because it does not cause side effects through beta-adrenergic blockade or cholinergic stimulation. On the other hand, trifluperidol and moperone reduce IOP effectively, but also decrease blood supply.

Pergolide elevation of MHPG sulphate concentration in rat hypothalamus blocked by spiperone and mimicked by other dopamine agonists.

Pergolide increased the concentration of MHPG sulphate (3-methoxy-4-hydroxy-phenylethylene glycol sulphate) in rat hypothalamus, and the increase was prevented by pretreatment with spiperone, a dopamine antagonist. An increase in hypothalamic MHPG sulphate concentration similar to that caused by pergolide was found after injection of quinpirole, a 'partial ergoline' that is a selective D2 agonist not affecting alpha-adrenoceptors, and by (-)-N-propylnorapomorphine, a dopamine agonist not related to the ergolines. Although the increase in MHPG sulphate concentration produced by pergolide had earlier been assumed to result from blockage of alpha-adrenoceptors, the present data indicate that it is an effect produced by dopamine D2 receptor stimulation.

Effect of melperone, chlorpromazine, haloperidol, and diazepam on experimental anxiety in normal subjects.

An attempt was made to evaluate tranquilizing effects of three neuroleptic drugs (10 and 50 mg melperone, 1 mg haloperidol, and 50 mg chlorpromazine) and diazepam (10 mg) on experimental anxiety in normal subjects. This was done by studying the effects of the drugs on the anticipatory autonomic (skin conductance) response evoked during aversive classical conditioning. Diazepam, 50 mg melperone, and chlorpromazine completely abolished the anticipatory response, decreased the number of conditioned and unconditioned responses, and decreased skin conductance level. Treatment with 10 mg melperone and haloperidol had no effect on the conditioned and unconditioned responses.

Psychotropic drugs as potential antitumor agents: a selective screening study.

Compounds with known psychotropic properties were tested for activity in murine ip L1210 leukemia and B 16 melanoma in a protocol designed to obtain leads for new antitumor agents which might also possess central nervous system (CNS) antitumor properties. Barbiturates and hallucinogenic compounds were the only compound types deliberately excluded. Representatives from most of the other known CNS agent classes were included among the 297 psychotropic drugs evaluated. Sixteen of these agents were reproducibly active against the L1210 tumor system with T/C values of 125%. Phenothiazines such as fluphenazine and butyrophenones such as triperidol were prominent among the confirmed active structural types. Dopamine, a beta-phenethylamine neurotrasmitter, was active. While reproducible B16 melanoma activity was not observed among the psychotropic drugs, most of the L1210 confirmed active agents were effective against the ip P388 tumor model and also were active in vitro against KB cells. Ic L1210 activity was not observed among the few compounds chosen for testing in that tumor system. The yield of ip L1210 confirmed actives from this group of psychotropic agents was 18 times that which would have been expected from the random screening of compounds.