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Recent reviews evidence that the naturally occurring compounds containing the chromone skeleton exhibit antiradical activities, providing protection against oxidative stress. The antioxidant activities of 13 new synthesized chromonyl-2,4-thiazolidinediones, chromonyl-2,4-imidazolidinediones and chromonyl-2-thioxoimidzolidine-4-ones were evaluated using in vitro antioxidant assays, including superoxide anion radical (), hydroxyl radical (), 2,2-diphenyl-1-picryl-hydrazyl free radical (DPPH•) scavenging capacity and total antioxidant capacity ferric ion reducing activity. Superoxide anion radical was produced using potassium superoxide/18-crown-6-ether dissolved in dimethylsulfoxide, and the Fenton-like reaction (Fe(II) + H2O2) was a generator of hydroxyl radicals. Chemiluminescence, spectrophotometry, electron paramagnetic resonance (EPR) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin trap were the measurement techniques. The results showed that the majority of the chromone derivatives tested showed a strong scavenging effect towards free radicals, similar to the chemiluminescence reaction with superoxide anion radical with a high activity, inhibition of the DMPO-OOH radical EPR signal (24–58%), the DMPO-OH radical EPR signal (4–75%) and DPPH radical EPR signal (6–100%) at 1 mmol/L. Several of the examined compounds exhibited the high reduction potentials. The results obtained show that the new synthesized chromone derivatives may directly scavenger reactive oxygen species and thus may play a protective role against oxidative damage. Copyright © 2014 John Wiley & Sons, Ltd.

Bisphenol A (BPA) is used in huge amounts for many plastic products and is a hormone (estrogen) disrupting agent. BPA as well as FFAs may be deleterious for the immune system. The aim was to identify Th2 cytokines and some of their signal transduction mechanisms in INS-1 cells, an insulin secreting cell line. Screening using a proteome profile indicated an increase of IL-1, IL-2, IL-4, IL-6, IL-10, IL-13 and IL-17 by BPA. Also FFAs (in combination with LPS) were positive. In detailed quantitative measurements, these results were confirmedly indicating a complex array of pro-and anti-inflammatory potential. The interaction of BPA with 17β-estradiol was non-additive with respect to IL-4 and IL-6 release and additive with respect to FFA interaction indicating same and different mechanisms of action, respecttively. As signal transduction PI3K (Wortmannin-sensitive) and STAT-3/6 (Tofacitinib-sensitive) are involved in various effects, INS-1 cells release several cytokines due to BPA and FFA attack which may be involved in disturbance of glucose homoeostasis and type 1 diabetes.

Cystic fibrosis is a life-threatening, wide spread genetic disease diagnosed in 1 to 3000 livebirths of the Caucasian population. Here a mouse model for this disease is described and optimized using the CFTR-channel selective inhibitor CFTR(inh 172). The target parameter was mucociliary clearance measured using microdialysis of the transported fluorescent dye rhodamine in the mouse trachea in situ. The impact of Ap4A (diadenosine tetraphosphate) as a potential drug was investigated. Its inhalation was effective at low concentrations; established compounds such as Salbutamol and UTP increased mucociliary clearance as well. Our data show a functioning model of cystic fibrosis and the effectiveness of the newly tested Ap4A.

The number of people with diabetes is expected to increase worldwide to 360 million within the next 15 years of which 90% will have type 2 diabetes (non-insulin-dependent diabetes mellitus). Established therapies mainly focus on the following principles: increase in plasma insulin, improving insulin sensitivity of tissues, reducing the rate of carbohydrate absorption and gluconeogenesis. The demand on compounds with new mechanisms of action is obvious. This articles summarizes new targets and compounds under development for pharmacotherapy of typ 2 diabetes; at present approx. 180 compounds are going to be developed worldwide.

Objectives Adenosine is known to induce a bronchospasm in asthma- and COPD patients. The role of A2B receptors was investigated with respect to several parameters of the respiratory tract: tonus of smooth muscle, ciliary beat frequency as measured by high-speed video camera connected to a microscope (both in rats) and mucociliary clearance (MCC; transport of a fluorescent dye using a microdialysis procedure) in mice. Key findings NECA (5′-N-ethylcarboxamidoadenosine) (a non-selective adenosine receptor agonist) was able to acutely induce a contraction, which was reversed to a relaxation after repeated dosing. This relaxation was completely abolished by PSB-1115, an A2B receptor antagonist. IL-13 (cytokine) was not involved mediating acute contractility effects. MCC was increased by BAY 60–6583 (A2B receptor agonist) and NECA (counteracted by the A2B receptor antagonist PSB-1115). Activation of A2B adenosine receptors by BAY 60–6583 induced an increase of the ciliary beat frequency, which could be reduced by administration of PSB-1115. Several cytokines were increased by NECA although only some are relevant because they are not blocked by A2B receptor antagonism. Conclusions The A2B receptors are involved in airway relaxation, MCC improvement and ciliary beat frequency. A2B receptor agonists may be of therapeutic value and should be developed.

Ethnopharmacological relevance Extracts from Thymus vulgaris L. and Thymus zygis L. are traditionally used for bronchitis, catarrhs of the respiratory tract and supportive treatment of pertussis. A potential spasmolytic effect is thought to be due to the presence of the monoterpenoid phenols thymol and carvacrol in the extract. Based on previous data the present investigation aimed to clarify if thymol-deprived thyme extracts (as been in use within German drug market) have antispasmodic activity. Additionally compounds responsible for this effect had to be identified. Materials and methods Thyme fluid extract was subsequently fractionated by FCPC, LPLC, and HPLC and compounds isolated were identified by spectroscopic methods. Bioassay testing was done by quantification of antispasmodic activity in the preconstricted rat smooth muscle trachea model against papaverin as positive control. Results Thymol-deprived spissum extract (SE) had good antispasmodic activity (−37%, related to the maximum contraction). Bioassay-guided fractionation indicated that rosmarinic acid and apigenin do not contribute to this effect. Luteolin contributed significantly to the antispasmodic activity (−9%). Conclusions Thyme extracts have antispasmodic activity, which is at least due to synergistic effects of phenolic volatile oil compounds and the flavone luteolin. Specifications of thyme-containing preparations should refer to this flavone in addition to focusing on the volatile phenols.

An extract was prepared from Egyptian stabilized rice bran and standardized to contain 2% γ-oryzanol in addition to its content of other bioactives, notably tocotrienol and policosanol. The standardized extract was found to have a concentration-dependent effect on insulin release in vitro, which, however, is not mediated by γ-tocotrienol in rice bran (detected by HPLC) as could have been expected. Policosanol and γ-oryzanol have insulinotropic effects. The in vitro data of rice bran directly translate into in vivo data of rats by using a glucose tolerance test (increase in plasma insulin). Tocotrienols are well known for their apoptotic effect on tumor cells; nevertheless, an attempt was made to study glucose uptake in HEP-G2 cells, which needs to induce an insulin-resistant state by TNF-α. The Egyptian rice bran extract has an antidiabetic effect. γ-Oryzanol, which is a possible precursor of the insulinotropic compound ferulic acid, is a candidate for this effect. Therefore, it is reasonable to assume that the prevalence of diabetes or at least a prediabetic (type 2) situation can be ameliorated by the investigated rice bran extract. The potential usefulness of the extract as a nutraceutical is currently undergoing more thorough investigations.

The huge increase in type 2 diabetes is a burden worldwide. Many marketed compounds do not address relevant aspects of the disease; they may already compensate for defects in insulin secretion and insulin action, but loss of secreting cells (β-cell destruction), hyperglucagonemia, gastric emptying, enzyme activation/inhibition in insulin-sensitive cells, substitution or antagonizing of physiological hormones and pathways, finally leading to secondary complications of diabetes, are not sufficiently addressed. In addition, side effects for established therapies such as hypoglycemias and weight gain have to be diminished. At present, nearly 1000 compounds have been described, and approximately 180 of these are going to be developed (already in clinical studies), some of them directly influencing enzyme activity, influencing pathophysiological pathways, and some using G-protein-coupled receptors. In addition, immunological approaches and antisense strategies are going to be developed. Many compounds are derived from physiological compounds (hormones) aiming at improving their kinetics and selectivity, and others are chemical compounds that were obtained by screening for a newly identified target in the physiological or pathophysiological machinery. In some areas, great progress is observed (e.g., incretin area); in others, no great progress is obvious (e.g., glucokinase activators), and other areas are not recommended for further research. For all scientific areas, conclusions with respect to their impact on diabetes are given. Potential targets for which no chemical compound has yet been identified as a ligand (agonist or antagonist) are also described.

The surface antigen CD14 plays an important role in innate immunity, serving as a pattern recognition receptor for lipopolysaccharides (LPS). The aim of this study was to investigate the proliferation, NFκB activation, and chemokine secretion of BEAS-2B cells, a human bronchial epithelial cell line, after LPS stimulation, and some details of inVolved signaling. The presence of CD14 was investigated by flow cytometry. Cell proliferation was measured with a [3H]-thymidine incorporation assay. sCD14, RANTES, and IL-8 concentrations in cell supernatants were measured by ELISA. BEAS-2B cells express CD14 on their surface and secrete soluble CD14 into the supernatant. Cells react on LPS with increased proliferation, activation of NFκB, and the secretion of the pro-inflammatory chemotactic cytokines IL-8 and RANTES, which proves the functionality of the CD14 receptor. Neither CD14 nor sCD14 are regulated by LPS. Specific inhibitors of various intracellular signaling pathways diminish the LPS-induced proliferation and IL-8 secretion: Thus MAP-Kinases p38 and JNK, tyrosine kinases, and PI3-kinase are involved in the signaling cascade from the LPS-CD14-complex on the cell surface to the increased cell proliferation and expression of IL-8; furthermore, ERK 1/2, IRAK 1/4, and the NFκB pathway are inVolved in the latter. The data show the existence and functionality of CD14 receptors on BEAS-2B cells and elucidate the signaling pathways inVolved. LPS is able to increase cell prolife-ration, various cytokines which are dependent on endogenous CD14. Three MAPK pathways, PI3 kinase and tyrosine kinase may be involved. Also CD14 is present/involved which was controversial.

A new series of flavonyl compounds (1–10) was prepared and tested for their in-sulinotropic activities in INS-1 cells. Compounds 2, 5 and 6 (at higher concentrations) and compounds 3 and 7–10 were able to increase insulin release in the presence of 5.6 mmol/l glucose at both concentrations used (1 and 10 μg/ml).

A series of chromonyl-2,4-thiazolidinediones (VIa-f) and chromonyl-2,4-imidazolidinediones (VIIa-f) was prepared by Knoevenagel reaction of substituted benzyl-2,4-thiazolidinediones (IVa-f) and substituted benzyl-2,4-imidazolidinediones (Va-f) with chromone-3-carboxaldehyde (I). The prepared compounds were tested for their insulinotropic activities in INS-1 cells. Compounds VIa, VIb, VId and VIIe (at lower concentration; 1 microg/ml) were able to increase insulin release in the presence of 5.6 mmol/l glucose; their effects were lower than that of glibenclamide (CAS 10238-21-8). The activity of the most potent compound (VId) was still 9% less than that of glibenclamide.

We report the synthesis and the in vitro insulin releasing and glucose uptake activity of the morpholino thiazolyl-2,4-thiazolidinediones (1-15). Compounds 5, 11-15 (at lower concentration; 0.001 mg/ml) were able to increase insulin release in the presence of 5.6 mmol/l glucose. The compounds, except derivative 3 show an increase of glucose uptake. Various compounds are interesting potential antidiabetic leads showing pancreatic and extrapancreatic effects.

Peppermint oil (Mentha × piperita L. (Lamiaceae) has been shown to exert potent antiemetic properties, but its mode of action has not yet been elucidated. Among its active constituents (-)-menthol is the most important. Three different in vitro models were used to investigate the effects on 5-HT(3) receptors (serotonin receptor subtype): [(14)C]guanidinium influx into N1E-115 cells which express 5-HT(3) receptors, isotonic contractions of the isolated rat ileum and equilibrium competition binding studies using a radioactively labelled 5-HT(3) receptor antagonist ([(3)H]GR65630) (3-(5-methyl-1H-imidazol-4-yl)-1-(1-methyl-1H-indol-3-yl)-1-propanone). Both peppermint oil and (-)-menthol inhibited [(14)C]guanidinium influx through 5-HT(3) receptor channels as well as contractions of the ileum induced by serotonin. Neither the peppermint oil nor (-)-menthol, however, was able to displace [(3)H]GR65630 from 5-HT(3) binding sites. It may be concluded that peppermint oil and (-)-menthol exert their antiemetic effect at least partly by acting on the 5-HT(3) receptor ion-channel complex, probably by binding to a modulatory site distinct from the serotonin binding site.

A series of chromonyl-2,4-thiazolidinediones/imidazolidinediones/2-thioxo-imidazolidine-4-ones (IIIa-i, IVa-i) was prepared by Knoevenagel reaction of 2,4-thiazolidinedione/2,4-imidazolidinedione/2-thioxo-imidazolidine-4- one (IIa-c) with 2/3-formyl chromone (Ia-b) and then alkylation with methyl/ethyl iodide. The prepared compounds were tested for their insulinotropic activities in INS-1 cells. Compounds iVb and iVc (at lower concentration, 1 mu g/mL) were able to increase insulin release in the presence of 5.6 mmol/L glucose." should be written as "Compounds IVb and IVc (at lower concentration, 1 mu g/mL) and also IIId and IIIg (at higher concentration) were able to increase insulin release in the presence of 5.6 mmol/L glucose. Compounds iVb and iVc (at lower concentration, 1 mu g/mL) were able to increase insulin release in the presence of 5.6 mmol/L glucose.

Known treatments of type 2 diabetes mellitus have limitations such as weight gain, and hypoglycaemias. A new perspective is the use of incretin hormones and incretin enhancers. Incretins are defined as being responsible for the higher insulin release after an oral glucose load compared to an intravenous glucose load. The delicate balance of glucose homeostasis, in which incretin hormones are involved, is disturbed in type 2 diabetes mellitus. The incretin GLP-1 helps to maintain glucose homeostasis through stimulation of insulin secretion and inhibition of glucagon release in a glucose-dependent manner. This is associated with reductions in body weight, and no risk of hypoglycaemias. When classical oral agents have failed to maintain adequate glycaemic control, incretin mimetics may be of particular value for obese patients and those who have little control over meal sizes. Exenatide was marketed as a GLP-1 analogue and longer acting incretin mimetics such as liraglutide, albiglutide and others have the same pharmacological profile. In addition to incretin mimetics incretin enhancers which inhibit/delay degradation of incretins were developed: so-called DPP-4 inhibitors such as sitagliptin and vildagliptin are approved in Europe. Their differences from incretin mimetics include: oral bioavailability, less side effects with overdose, no direct CNS effects (nausea and vomiting) and no effect on weight. In rodent models of diabetes, but not yet in humans, GLP-1 receptor agonists and DPP-4 inhibitors increase islet mass and preserve beta-cell function. Incretin mimetics and enhancers expand type 2 diabetes treatment, are still not first line therapy and it is discussed if they are to be prophylactically used.

A local paracrine angiotensin (ANG) system influences the insulin sensitivity and cell differentiation of adipose tissue. The limited view of a merely systemic renin-angiotensin-aldosterone-system with ANG II (1–8) as the main mediator of ANG-related effects may oversimplify the situation. The aim was to analyze the degradation of ANG by using capillary electrophoresis (CE) techniques. The supernatant of cultured 3T3-L1 adipocytes was used directly, and some data on degraded peptides were combined with a biological effect. The formation of several peptides such as ANG II (1–8), —III (2–8), —IV (3–8), and ANG (1–7) as degradation products is demonstrated; in addition low levels of ANG (3–7) are identified. The concentrations of the peptides ANG III (2–8) and ANG IV (3–8) (both are AT4 receptor agonists) are modified in the vicinity of adipose tissue cells by amino-terminal degradation which resulted in ANG (3–8), —(4–8) and —(5–8). ANG IV (3–8) and ANG II (1–8) were biologically highly effective in inhibiting IRAP (insulin regulated aminopeptidase, part of the AT4 receptor). It is observed that ANG (1–7) is the main degradation product derived from ANG I via ANG (1–9) and that ANG III (2–8) is one important regulated peptide for IRAP. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.

Aims of the study Eriobotrya japonica leaves had been used traditionally for the treatment of diabetes mellitus by immersing the dried leaves in a hot water drink. Few studies have shown the hypoglycemic effect of Eriobotrya japonica using crude alcoholic extract and isolated methanolic compounds. These studies proposed that the mechanism of action could be by stimulating the β-islets of Langerhans to secrete insulin, however with no scientific evidence. Methods Eriobotrya japonica water extract (EJWE) and the compounds derived from it: cinchonain Ib, procyanidin B-2, chlorogenic acid and epicatechin, were tested for their effects on insulin secretion from INS-1 cells and following oral administration in rats. Results The present study showed that EJWE increased significantly (p

Numerous compounds have been prepared in order to improve the pharmacological profile of insulinotropic activities. In the present paper, series of chromonyl-2,4-thiazolidinediones (Ia–e, IIa–e, and IIIa–e) were tested for their insulinotropic activities in INS-1 cells. Compounds IIb–d and IIId were very active even at a low concentration of 0.001 mg/ml. Compounds IIIa–c were active only at higher concentration (0.01 mg/ml). Increase of insulin release was observed in the presence of 5.6 mmol/l glucose.

Due to the lack of specific agonists and antagonists the role of adenosine receptor subtypes with respect to their effect on the insulin secretory system is not well investigated. The A1 receptor may be linked to different 2nd messenger systems, i.e. cAMP, K+- and 45Ca2+ channel activity. Partial A1 receptor agonists are going to be developed in order to improve diabetes (increase in insulin sensitivity, lowering of FFA and triglycerides). In this study newly synthesized selective A1 receptor agonists and antagonists were investigated thereby integrating three parameters, insulin release (RIA), 45Ca2+ uptake and 86Rb+ efflux (surrogate for K+ efflux) of INS-1 cells, an insulin secretory cell line. The presence of A1-receptors was demonstrated by Western blotting. The receptor nonselective adenosine analogue NECA (5-N-ethylcarboxyamidoadenosine) at high concentration (10 microM) had no effect on insulin release and 45Ca2+ uptake which could be interpreted as the sum of effects mediated by mutual antagonistic adenosine receptor subtypes. However, an inhibitory effect mediated by A1 receptor agonism was detected at 10 nM NECA and could be confirmed by adding the A1 receptor antagonist PSB-36 (1-butyl-8-(3-noradamantyl)-3-(3-hydroxy-propyl)xanthine). NECA inhibited 86Rb+ efflux which, however, did not fit with the simultaneous inhibition of insulin secretion. The selective A1 receptor agonist CHA (N6-cyclohexyladenosine) inhibited insulin release; the simultaneously increased Ca2+ uptake (nifedipine dependent) and inhibition of 86Rb+ efflux did not fit the insulin release data. The CHA effect (even the maximum effect at 50 microM) can be increased by 10 microM NECA indicating that CHA and NECA have nonspecific and physiologically non-relevant effects on 86Rb+ efflux in addition to their A1-receptor interaction. Since PSB-36 did not influence the NECA-induced inhibition of 86Rb+ efflux, the NECA effect is not mediated by potassium channel-linked A1 receptors. The nonselective adenosine receptor antagonist caffeine increased insulin release which was reversed by CHA as expected when hypothesizing that both act via A1 receptors in this case. In conclusion, stimulation of A1 receptors by receptor selective and nonselective compounds reduced insulin release which is not coupled to opening of potassium channels (86Rb+ efflux experiments) or inhibition of calcium channels (45Ca2+ uptake experiments). It may be expected that of all pleiotropic 2nd messengers, the cAMP system (not tested here) is predominant for A1 receptor effects and the channel systems (K+ and Ca2+) are of minor importance and do not contribute to insulin release though being coupled to the receptor in other tissues.

A local paracrine acting angiotensin (ANG) system of preadipocytes and mature adipocytes is involved in metabolic effects and tissue differentiation. The present study reports on the investigation of binding affinities for various angiotensin receptors including their relevance in 3T3-L1 adipocytes and preadipocytes and 3T3-442A preadipocytes. Competitive binding studies using both 125I-ANG II and its more stable analogue 125I-SARILE for investigating AT1/AT2 binding sites in 3T3-L1 preadipocytes reveal a biphasic competition curve with KDs at a low and high nanomolar range. By using the AT2 receptor selective ligand 125I-CGP4112A the presence of high affinity AT2 binding sites in preadipocytes was observed. High nonspecific binding and a low receptor number is characteristic for all these experiments. An AT4 binding site (binding site for ANG IV) exists in 3T3-L1 and F442A preadipocytes and adipocytes with a high nanomolar KD. This low binding affinity was confirmed by a biological assay, the IRAP assay (=insulin regulated aminopeptidase assay). IRAP is associated with the AT4 receptor, which is a binding site at the luminal part of membrane bound IRAP. The curves for competition binding and for inhibition of IRAP activity are superimposable with respect to angiotensin IV. In conclusion, AT1 and AT2 binding sites are present in preadipocytes. AT2 receptor binding affinities are shown in preadipocytes for the first time. The description of a non-AT1/AT2 binding site with low affinity remains speculative albeit of high interest because antidiabetic and obesity related effects of angiotensin peptides and sartanes as antagonists are observed at these high concentrations. Local concentrations of ANG II and their degradation products may be extremely high. The low amounts of AT1 and AT2 binding sites emphasize the relevance of other binding sites in adipose tissue development and metabolic effects. The AT4 binding site seems to be one of the predominant receptors in adipose cells. Other degraded, but still bioactive peptides like ANG III, IV and ANG(1-7), activating receptors not influenced by ANG II, could be of importance.

SPASMOLYTIC ACTIVITY OF THE CONSTITUENTS OF A HERBAL ANTIDIARRHEIC DRUGThe constituents of Diarrhoesan ® , apple pectin and chamomile flower fluid extract were tested alone and in combination for additive or antagonistic effects. As test system, the inhibition of the spasmodic effect of K + in isolated rat ileum was chosen. K+ induced a contraction in a concentration dependent manner between 3.2 and 32 mM KCl. The results obtained with the reference group (4 × 10 -5 M papaverine) confirm the sensitivity of the test system. Pectin (2.5 mg/ml) alone had no effect. The chamomile fluid extract (2.0 mg/ml) proved to be spasmolytic. In combination with pectin the effect of the chamomile extract (same concentrations used) was unchanged, except for the irrelevant high K + concentration of 32 mM. These findings show that the addition of pectin does not influence the spasmolytic effect of chamomile fluid extract.

A new series of flavonyl-2,4-thiazolidinediones (Va–c, VIa–c) was prepared by Knoevenagel reaction. The synthesized compounds were tested for their ability to inhibit rat kidney aldose reductase (AR) and for their insulinotropic activities in INS-1 cells. Compound Vb was able to increase insulin release in the presence of 5.6 mmol/l glucose. Compounds VIa–c displayed moderate to high AR inhibitory activity levels. Particularly, compound VIa showed the highest AR inhibitory activity (86.57%).

An ethanolic spissum extract of the aerial parts of Plantago lanceolata L. was examined for antispasmodic activity on isolated ileum and trachea of the guinea-pig. Isolated constituents were investigated as well. The P. lanceolata extract inhibited the contractions of the guinea-pig ileum that were induced by various agonists such as acetylcholine (ACh), histamine, potassium and barium ions. Additionally the trachea contractions induced by barium ions were inhibited. The compounds luteolin, acteoside, plantamajoside an catalpol peracetate but not catalpol, isoacteoside, lavandulifolioside and aucubin inhibited the ACh-induced contractions of the guinea-pig ileum. Luteolin and acteoside reduced the barium-induced contractions of the guinea-pig trachea. Two recently isolated compounds did not show antispasmodic activity: luteolin-3',7-diglucuronide and beta-hydroxy-acteoside.

UNLABELLED Thyme is a broncholytic und secretomotoric agent. Thus, our aim was to investigate the influence of a thyme extract on beta (2)-receptors in competition binding experiments and relaxation experiments on rat uteri and trachea. Furthermore, the influence of the extract on respiratory clearance was of interest. Binding experiments were performed using purified rat lung membranes with the beta(2)-receptor ligand [(125)I]-CYP {[(125)I]-(+/-)-Iodocyanopindolol}. The transport of the fluorescence dye rhodamin 123 concerning ciliary action in the tracheal area of a mouse was investigated using a microdialysis technique. The thyme extract reduces only slightly [(125)I]-CYP binding and amplifies the displacement of [(125)I]-CYP by propranolol (non-specific beta-receptor antagonist): the displacement curve in the concentration range representing beta (2)-receptors (nM) is shifted to the left. Thyme extract had relaxing effects on organs possessing beta (2)-receptors (uterus and trachea). The propranolol-induced antagonism to isoprenaline is reverted concentration-dependently by the extract. A duplication of the rate of ciliary clearance by the extract was observed. IN CONCLUSION 1) There is evidence for an influence of a thyme extract on beta (2)-receptors by both binding studies and biological effects: As can be derived from the shift of the propranolol displacement curve (nM), ingredients of the thyme extract slightly interact with beta (2)-receptors in rat lung tissue. This effect is indirect since no full range competition curve was reached. 2) An at least indirect interaction with beta (2)-receptors in rat uteri and trachea is revealed by a decreased antagonism of propranolol on the relaxing effect of isoprenaline by the plant extract. 3) An additional mechanism is presumed because at high extract concentrations isoprenaline-induced relaxation is complete, whereas the displacement of propranolol at beta (2)-receptors is only weak. 4) Thyme extract has an indirect (modulatory) effect on the beta (2)-receptor system. 5) Mucociliary clearance is improved in vivo. Its mechanism has still to be elucidated.

A contribution of the volatile oil from ginger rhizomes (Zingiber officinale Roscoe) on inhabiting the 5-HT3 receptor complex had been shown. In the present study a possible interaction of some compounds of the volatile oil with the 5-HT3 receptor system expressed in N1E-115 cells and with the serotoninergic system of the rat ileum was investigated. The volatile oil was obtained by steam distillation and fractionated using a silica gel column resulting in five fractions. Compounds of the fractions were identified by GC-MS. The influence of the volatile oil, its fractions and pure components on serotonin-induced [14C]guanidinium influx into N1E-115 cells was measured indicating the inhibitory interaction with the 5-HT3 receptor channel system. Most potent inhibitors of cation influx were the volatile oil, fraction 4, beta-pinene, terpinolene, alpha-copaene and alpha-phellandrene. The volatile oil and fractions 1 and 4 were not able to significantly influence either serotonin (10 microM)-induced maximum contraction of the rat ileum or the second phase of the biphasic contraction 2.5 min after serotonin addition. However, beta-pinene, terpinolene and alpha-phellandrene reduced both contractions. In conclusion, the volatile oil and distinct compounds such as terpinolene, beta-pinene and alpha-phellandrene interact with 5-HT3 receptor channel system and possess an antispasmodic effect at the rat ileum.

Adenosine and adenosine receptor antagonists are involved in glucose homoeostasis. The participating receptors are not known, mainly due to a lack of specific agonists and antagonists, but are reasonable targets for anti-diabetic therapy. The stable, albeit nonselective, adenosine analogue NECA (5′-N-ethylcarboxamidoadenosine) (10 μM) reduced glucose-stimulated insulin release from INS-1 cells. This was mimicked by A1-(CHA), A2A-(CGS-21680) and A3-receptor agonists (Cl-IB-MECA). Two newly synthesized A2B-receptor antagonists, PSB-53 and PSB-1115, counteracted the inhibitory effect of NECA. These in-vitro effects were mirrored by in-vivo data with respect to CHA, CGS and Cl-IB-MECA. Distinct concentrations of either PSB-53 or PSB-1115 reversed the decrease in plasma insulin induced by NECA. This was not mimicked by a corresponding change in blood glucose. The effect of PSB-1115 was also obvious in diabetic GotoKakizaki rats: plasma insulin was increased whereas blood glucose was unchanged. During most experiments the effects on blood glucose were not impressive probably because of the physiologically necessary homoeostasis. The adenosine levels were not different in normal Wistar rats and in diabetic GotoKakzaki rats. Altogether the A2B-receptor antagonists showed an anti-diabetic potential mainly by increasing plasma insulin levels under conditions when the adenosine tonus was elevated in-vivo and increased insulin release in-vitro.

Ginger (rhizomes of Zingiber officinale) has been shown to exert potent anti-emetic properties, but its mode of action has not yet been elucidated. Among its active constituents, [6]-, [8]- and [10]-gingerol as well as [6]-shogaol were shown in different in vivo studies to be at least partly responsible for the drug's anti-emetic properties. In an attempt to gain more insight into the mode of action of these compounds, three different in vitro models were used to investigate their effects on 5-HT(3) receptors (serotonin receptor subtype) in more detail: [(14)C]guanidinium influx into N1E-115 cells which express 5-HT(3) receptors, isotonic contractions of the isolated guinea-pig ileum and equilibrium competition binding studies using a radioactively labeled 5-HT(3) receptor antagonist ([(3)H]GR65630) (3-(5-methyl-1H-imidazol-4-yl)-1-(1-methyl-1H-indol-3-yl)-1-propanone). All four compounds inhibited the [(14)C]guanidinium influx through 5-HT(3) receptor channels as well as contractions of the guinea-pig ileum induced by SR57227A ((4-amino)-(6-chloro-2-pyridyl)l-piperidine hydrochloride), a highly selective 5-HT(3) receptor agonist. Both effects were concentration-dependent, with the following order of potency for both models: [6]-shogaolor =[8]-gingerol[10]-gingerolor =[6]-gingerol. All compounds showed also weak anticholinergic and antineurokininergic activities in the guinea-pig ileum (acetylcholine and substance P are mediators of the 5-HT(3) receptor effect). The vanilloid receptor did not seem to be involved derived from experiments using capsazepine. None of the tested ginger substances, however, was able to displace [(3)H]GR65630 from its binding site (5-HT(3) receptor) neither on intact N1E-115 cells nor on the purified membranes of HEK-293 cells over-expressing the h5-HT(3) receptor. It may be concluded that [6]-, [8]-, [10]-gingerol and [6]-shogaol exert their anti-emetic effect at least partly by acting on the 5-HT(3) receptor ion-channel complex, probably by binding to a modulatory site distinct from the serotonin binding site. This may include indirect effects via receptors in the signal cascade behind the 5-HT(3) receptor channel complex such as substance P receptors and muscarinic receptors; this needs further investigation since ginger is effective against motion sickness which is cured by some vanilloids and by anticholinergics such as scopolamine.

Rats were given Cinnamomum cassia bark or extracts from Cinnamomum cassia and zeylanicum to evaluate blood glucose and plasma insulin levels in rats under various conditions. The cassia extract was superior to the zeylanicum extract. The cassia extract was slightly more efficacious than the equivalent amount of Cassia bark. A decrease in blood glucose levels was observed in a glucose tolerance test (GTT), whereas it was not obvious in rats that were not challenged by a glucose load. The elevation in plasma insulin was direct since a stimulatory in vitro effect of insulin release from INS-1 cells (an insulin secreting cell line) was observed. Thus the cassia extract has a direct antidiabetic potency.

Diadenosine polyphosphates (Ap(x)A) are physiologically released and may be partly involved in the pathogenesis of diabetes mellitus. Ap(4)A (diadenosine tetraphosphate) leads to an increase in blood glucose while it decreases insulin levels in plasma. A possible link between Ap(x)A and diabetes mellitus-associated diseases such as insulin resistance and hyperlipidemia (plasma free fatty acids, cholesterol and its biosynthesis, triacylglycerols) has not been investigated yet. Parameters such as free fatty acid and cholesterol content in blood were determined enzymically. The biosynthesis of cholesterol and triacylglycerols was determined in HepG2 cells using the radioactive precursor [(14)C]-acetate and by using gas chromatography. Plasma free fatty acids were significantly decreased 5 and 10 min after an Ap(4)A bolus (0.75 mg kg(-1) b.w.) given to rats. Plasma cholesterol was reduced 5 and 60 min after Ap(4)A administration. LPDS (lipoprotein-deficient serum)-stimulated cholesterol biosynthesis in HepG2 cells was significantly reduced after 1 h incubation with Ap(4)A. Triacylglycerol (TAG) biosynthesis in HepG2 cells was not significantly influenced by Ap(4)A; there was just a tendency for a concentration-dependent decrease in TAG levels. In conclusion Ap(4)A as a diabetogenetic compound is not likely to be responsible for the development of insulin resistance or of hyperlipidemia. Parameters such as free fatty acids, cholesterol and triacylglycerols are not elevated by Ap(4)A, but are even decreased. Ap(4)A seems to be involved in the development of diabetes mellitus by increasing blood glucose and decreasing plasma insulin as shown earlier, but not in diabetes mellitus-associated diseases such as insulin resistance or hyperlipidemia.

UNLABELLED Specific binding sites for diadenosine polyphosphates (Ap (4)A, Ap (5)A, Ap (6)A) exist in VSMC (cultured vascular smooth muscle cells). These compounds may regulate VSMC growth and proliferation which is a key event in atherogenesis. Since diabetes is a known risk factor for atherosclerosis, the proliferation of VSMC from normoglycemic (control) and hyperglycemic (diabetic) rats were compared and the possibly involved receptors for diadenosine polyphosphates inducing this effect were investigated. Diabetes was induced by streptozotocin (66 mg/kg i.p.) and VSMC were prepared from rat aorta (primary culture). ( (3)H)thymidine incorporation was a measure of cell proliferation. For all diadenosine polyphosphates tested a stimulatory effect was observed as a bell-shaped concentration-response curve and a maximum effect at 10 micro M (physiological concentration). Ap (6)A has the most prominent effect (247.8 +/- 33.2 % increase over basal). In VSMC of diabetic rats the effects were even more prominent (Ap (5)A: 430.1 +/- 62.7 %). ATP (a degradation product of Ap (6)A) is able to increase the maximum effect of 10 micro M Ap (6)A. UTP (P2Y (2) agonist) exhibits a weaker proliferation. 1 micro M suramin (P2 receptor antagonist) shifts the concentration response curve of ATP and of Ap (6)A to the right. In contrast, 10 micro M PPADS (P2 X receptor antagonist) has no effect. There is no difference between VSMC of normal and diabetic rats in this respect. ADP, AMP, and adenosine exhibit a dual proliferative effect. The effect of either of these 3 compounds is much higher in VSMC of diabetic rats than of controls. 2MeSATP (P2Y (1) agonist) and alpha,beta-Methylen-ATP (P2X agonist) were not effective in VSMC of both normoglycemic and diabetic rats. IN CONCLUSION The proliferative effect of diadenosine polyphosphates and some degradation products is more pronounced in VSMC of diabetic than of normal rats. Ap (6)A acts maximally by itself and not by its degradation product ATP. Adenosine receptors or an unknown P2Y (ApxA) receptor may be involved in proliferative effects, but not P2X and P2Y (1) receptors irrespective of a diabetic situation.

In vitro testing of the extracts of medicinal plants collected from Islamabad and the Murree region on insulin secretagogue activity was carried out. Dried ethanol extracts of all plants (ZH1-ZH19) were dissolved in ethanol and DMSO, and tested at various concentrations (between 1 and 40 microg/mL) for insulin release from INS-1 cells in the presence of 5.5 mM glucose. Glibenclamide was used as a control. Promising insulin secretagogue activity in various plant extracts at 1, 10, 20 and 40 microg/mL was found, while in some cases a decrease in insulin secretion was also observed. Artemisia roxburghiana, Salvia coccinia and Monstera deliciosa showed insulin secretagogue activity at 1 microg/mL (p < 0.05) while Abies pindrow, Centaurea iberica and Euphorbia helioscopia were active at 10 microg/mL (p < 0.05). Extracts of Bauhinia variegata and Bergenia himalacia showed effects at 20 microg/mL (p < 0.05), and Taraxacum officinale and Viburnum foetens at 40 microg/mL (p < 0.05). Insulin secretagogue activity could not be detected in the extracts of Adhatoda vasica, Cassia fistula, Chrysanthemum leucanthemum, Morus alba, Plectranthus rugosus, Peganum harmala and Olea ferruginea. The results suggest that medicinal plants of Islamabad and the Murree region of Pakistan may be potential natural resources for antidiabetic compounds.

A new series of 3-benzyl(p-substituted benzyl)-5-[3'-(4H-4-oxo-1-benzopyran-2-yl)-benzylidene]-2,4-thiazolidinediones (8a-e) were synthesized. These products were prepared by Knoevenagel reaction from 3'-flavone carboxaldehyde and 3-substituted 2,4-thiazolidinediones. In vitro insulinotropic activity was determined for compounds 6a-e, 7a-e, 8b and 8c.

Both 9-cis-retinoic acid (9cRA) and all-trans-retinoic acid (ATRA) are active metabolites of vitamin A (retinol). There exists an interaction between retinoid receptors and peroxisome proliferator-activated receptors (PPARgamma). To define their functions in an insulin secreting system the effects of ATRA, 9cRA and the PPARgamma agonist rosiglitazone on cell proliferation, insulin release and glucose transporter (GLUT) 2 of INS-1 cells were tested. Retinoic acid receptor (RAR-alpha and -gamma) and retinoid X receptor (RXR-alpha and -beta) proteins are present (immunoblots). Both 9cRA and ATRA inhibit INS-1 cell proliferation ([3H]-thymidine assay) in a concentration dependent manner. Both 9cRA and ATRA increased insulin release, but only ATRA ralsed the GLUT 2 mRNA in a bell-shaped concentration response curve after 48 h. The insulinotropic effect of one compound is not significantly superimposed by the other indicating that the same binding sites are used by 9cRA and ATRA. The acute and chronic effects of the PPARgamma agonist rosiglitazone on insulin release were additionally determined since glitazones act as transcription factors together with RXR agonists. At high concentrations (100 microM) rosiglitazone inhibited glucose (8.3 mM) stimulated insulin secretion (acute experiment over 60 min). Insulin secretion, however, was increased during a 24 h treatment at a concentration of 10 microM and again inhibited at 100 microM. Changes in preproinsulin mRNA expression were not observed. Rosiglitazone (100 microM) increased GLUT 2 mRNA paralleled by an increase of GLUT 2 protein, but only after 24 h of treatment. This data indicate that RAR and RXR mediate insulin release. The changes in GLUT 2 have no direct impact on insulin release; the inhibition seen at high concentrations of either compound is possibly the result of the observed inhibition of cell proliferation. Effects of rosiglitazone on preproinsulin mRNA and GLUT 2 (mRNA and protein) do not play a role in modulating insulin secretion. With the presence of an RXR receptor agonist the effect of rosiglitazone on insulin release becomes stimulatory. Thus the effects of RAR-, RXR agonists and rosiglitazone depend on their concentrations, the duration of their presence and are due to specific interactions.

Some novel chiral sulfonyl hydantoin derivatives 2a-e and 3 a-e have been prepared. p-Toluenesulfonyl chloride on treatment with L-amino acids in presence of K2CO3/H2O yielded N-(p-toluensulfonyl-)amino acids 1a - e which were cyclized in presence of NH4-SCN Ac2O to afford 1-(p-toluenesulfonyl)-5-substituted-2-thiohydantoins 2a-e. These compounds were oxidized with HNO3 to yield 1-(p-toluenesulfonyl)-5-substituted hydantoins 3a-e. The enantiomeric ratios of 3a-e were determined by 1H NMR spectroscopy using Eu(hfc)3. The antidiabetic activity of 3a-d has been determined.

Cholecystokinin (CCK) is a gut hormone that regulates pancreatic endocrine functions via CCKA receptors. CCK4 (Trp-Met-Asp-Phe-NH2) has an insulinotropic effect, but is 1,000-fold less potent than CCK8 in rodents. The in vitro potencies with respect to binding, the biological effects and the selectivity of newly synthesized CCK4 analogs constructed by computer modelling experiments were investigated in vitro in rat pancreas and brain, INS-1 cells, and guinea pig ileum. Exchanging various amino acids, e.g. Met by either Pro or Nle, and modifying Phe by adding various substituents in different positions led to compounds which were more effective as insulin secretagogues than CCK4 itself and even show insulinotropic effects comparable with those of CCK8 (e.g. compounds M1 and M2 being substituted at Phe). Some compounds which possess electron withdrawing groups on the C-terminal Phe and possess a Pro instead of a Met were especially effective. The CCKA receptor antagonist L-364,718, but not by the CCKB receptor antagonist L-365,260, inhibited the insulinotropic effects. The synthetic CCK4 compounds were not selective for the endocrine pancreas: e.g. M1 and M2 had binding activity with respect to rat brain homogenates but no activity with respect to contraction of the guinea pig ileum. The data indicate that some of the newly synthesized CCK tetrapeptides exhibit a high affinity for the CCK receptor of β-cells and have an insulinotropic effect much higher than CCK4.

Gastrin-releasing peptide (GRP) receptors are present in pancreatic islets, though their regulation is unknown except for homologous desensitization. The modulation of binding of GRP to mouse pancreatic islets and INS-1 cells was studied. At 60 min (steady-state), total binding of [(125)I-Tyr(15)] GRP was 1.62 per cent of total radioactivity per 50 islets; non-specific binding (presence of 1 mM unlabelled GRP(1-27)) was 0.05 to 0.61 per cent of total radioactivity. A preincubation with 1000 nM cholecystokinin (CCK(8)) or with 1000 nM glucose-dependent insulinotropic peptide (GIP) augmented the number of GRP binding sites but not their affinity. [(125)I-Tyr(15)]GRP binding to INS-1 cells was saturable (90 min) and specific with respect to compounds that are not chemically related to GRP (e.g. calcitonin gene-regulated peptide-CGRP and atrial natriuretic peptide-ANP). Displacement studies showed one binding site with a K(d) of 0.39 nM and a B(max) of 13.2 fmoles mg(-1) protein. When the cells were pretreated for 24 h with 10 nM GIP or CCK(8), only GIP but not CCK(8) increased the B(max) of the GRP binding site. The affinity (K(d)) was not changed by either compound. This effect of GIP pretreatment was not affected by downregulating PKC by TPA (phorbol ester; long-term pretreatment). These data indicate that: (1) specific binding sites for GRP are present in mouse pancreatic islets and INS-1 cells; (2) the GRP binding is upregulated by GIP in both islets and INS-1 cells and additionally by CCK(8 ), albeit only in islets; and (3) PKC does not seem to be involved in the up-regulation process. Thus a positive interplay between both the incretins GIP and CCK(8) and the neurotransmitter GRP is obvious.

A new series of flavonyl-3'-sulphonylurea derivatives (1-7) was prepared by reaction of several isocyanates with flavone-3'-sulphonamide (III). The prepared compounds were tested for their insulinotropic activities in INS-1 cells. Compounds 1 and 4 were able to increase insulin release in the presence of 8.3 mM glucose at least at the higher concentrations used.

Structural modification of the GluN2B selective NMDA receptor antagonist ifenprodil led to the 3-benzazepine WMS-1410 with similar GluN2B affinity but higher receptor selectivity. Herein the in vitro and in vivo biotransformation of WMS-1410 is reported. Incubation of WMS-1410 with rat liver microsomes and different cofactors resulted in four hydroxylated phase I metabolites, two phase II metabolites and five combined phase I/II metabolites. With exception of catechol 4, these metabolites were also identified in the urine of a rat treated with WMS-1410. However the metabolites 7, 8 and 12 clearly show that the catechol metabolite 4 was also formed in vivo. As shown for ifenprodil the phenol of WMS-1410 represents the metabolically most reactive structural element. The biotransformation of WMS-1410 is considerably slower than the biotransformation of ifenprodil indicating a higher metabolic stability. From the viewpoint of metabolic stability the bioisosteric replacement of the phenol of WMS-1410 by a metabolically more stable moiety should be favourable.

Recent reviews evidence that the naturally occurring compounds containing the chromone skeleton exhibit antiradical activities, providing protection against oxidative stress. The antioxidant activities of 13 new synthesized chromonyl-2,4-thiazolidinediones, chromonyl-2,4-imidazolidinediones and chromonyl-2-thioxoimidzolidine-4-ones were evaluated using in vitro antioxidant assays, including superoxide anion radical (O2(-•)), hydroxyl radical (HO(•)), 2,2-diphenyl-1-picryl-hydrazyl free radical (DPPH(•)) scavenging capacity and total antioxidant capacity ferric ion reducing activity. Superoxide anion radical was produced using potassium superoxide/18-crown-6-ether dissolved in dimethylsulfoxide, and the Fenton-like reaction (Fe(II) + H2O2) was a generator of hydroxyl radicals. Chemiluminescence, spectrophotometry, electron paramagnetic resonance (EPR) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin trap were the measurement techniques. The results showed that the majority of the chromone derivatives tested showed a strong scavenging effect towards free radicals, similar to the chemiluminescence reaction with superoxide anion radical with a high activity, inhibition of the DMPO-OOH radical EPR signal (24-58%), the DMPO-OH radical EPR signal (4-75%) and DPPH radical EPR signal (6-100%) at 1 mmol/L. Several of the examined compounds exhibited the high reduction potentials. The results obtained show that the new synthesized chromone derivatives may directly scavenger reactive oxygen species and thus may play a protective role against oxidative damage.

The NMDA receptor antagonist ifenprodil is an important lead structure for developing new GluN2B selective NMDA receptor antagonists. Ifenprodil itself has a high affinity to the GluN2B subunit but a poor selectivity for the NMDA receptor. This aspect and the fast biotransformation are the major drawbacks of ifenprodil. In order to optimize the development of new and more selective GluN2B (NMDA) receptor antagonists, the identification of the main metabolic pathways of ifenprodil is necessary. Herein the in vitro and in vivo phase I and phase II metabolites of ifenprodil were generated and analyzed via LC-MS(n) experiments. In vitro experiments were carried out with rat liver microsomes and various co-factors to generate phase I and phase II metabolites. The application of ifenprodil to a rat and the analysis of its urine led to the identification of diverse formed in vivo metabolites. The phenol represents the metabolically most labile structural element since glucuronide 7 and 8 appeared as main metabolites.