Gender-related differential effect of tachykinin NK2 receptor-mediated visceral hyperalgesia in guinea pig colon.

BACKGROUND AND PURPOSE: The tachykinin NK2 receptor antagonist ibodutant is under Phase III clinical investigation to treat female patients with irritable bowel syndrome. The aim of this study was to investigate the NK2 receptor-related gender specificity in a model of colitis. EXPERIMENTAL APPROACH: Colitis was induced by rectal instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS, 0.5 mL, 30 mg·mL(-1) in 30% ethanol) in female and male guinea pigs. Electromyographic recording of the responses to colorectal distension (CRD) was made 3 days later. Ibodutant (0.33 , 0.65, 1.9 and 6.5 mg·kg(-1) ) was given s.c., 30 min before CRD. Release of neurokinin A and substance P from isolated mucosal and smooth muscle tissues following treatment with KCl (80 mM) or capsaicin (10 µM) was measured by EIA. Plasma pharmacokinetics of ibodutant following a single s.c. administration (0.73 or 2.1 mg·kg(-1) ) were measured over 24 h. KEY RESULTS: Ibodutant did not affect abdominal contractions in control animals. After TNBS-induced colitis, ibodutant prevented the increased visceral hypersensitivity to CRD in females, at lower doses than in males. Ibodutant pharmacokinetics did not differ between females and males. Tachykinins release was greater in smooth muscle than in mucosal samples. Capsaicin-stimulated release of tachykinins from inflamed mucosal samples from females was significantly lower than in males. CONCLUSIONS AND IMPLICATIONS: Ibodutant prevented abdominal nociception in a model of visceral hypersensitivity in guinea pigs with a greater efficacy in females than in males. Our results highlight a gender-related difference in colonic visceral hypersensitivity and mucosal nerve activation.

Absorption and metabolism of bioactive molecules after oral consumption of cooked edible heads of Cynara scolymus L. (cultivar Violetto di Provenza) in human subjects: a pilot study.

The current growing interest for natural antioxidants has led to a renewed scientific attention for artichoke, due not only to its nutritional value, but, overall, to its polyphenolic content, showing strong antioxidant properties. The major constituents of artichoke extracts are hydroxycinnamic acids such as chlorogenic acid, dicaffeoylquinic acids caffeic acid and ferulic acid, and flavonoids such as luteolin and apigenin glycosides. In vitro studies, using cultured rat hepatocytes, have shown its hepatoprotective functions and in vivo studies have shown the inhibition of cholesterol biosynthesis in human subjects. Several studies have shown the effect on animal models of artichoke extracts, while information on human bioavailability and metabolism of hydroxycinnamates derivatives is still lacking. Results showed a plasma maximum concentration of 6.4 (SD 1.8) ng/ml for chlorogenic acid after 1 h and its disappearance within 2 h (P< 0.05). Peak plasma concentrations of 19.5 (SD 6.9) ng/ml for total caffeic acid were reached within 1 h, while ferulic acid plasma concentrations showed a biphasic profile with 6.4 (SD1.5) ng/ml and 8.4 (SD4.6) ng/ml within 1 h and after 8 h respectively. We observed a significant increase of dihydrocaffeic acid and dihydroferulic acid total levels after 8 h (P<0.05). No circulating plasma levels of luteolin and apigenin were present. Our study confirms the bioavailability of metabolites of hydroxycinnamic acids after ingestion of cooked edible Cynara scolymus L. (cultivar Violetto di Provenza).

Effect of domestic cooking on human bioavailability of naringenin, chlorogenic acid, lycopene and beta-carotene in cherry tomatoes.

BACKGROUND: Epidemiological data showed that tomato and tomato product (sauce, paste) consumption is associated with a protective effect against the development of some chronic-degenerative diseases. Tomato antioxidant bioactive molecules such as carotenoids and polyphenols could be responsible, at least in part, for the healthy effect observed. The bioavailability of these compounds is an essential requirement to sustain their in vivo role. While it is well known that many factors can influence the bioaccessibility of carotenoids from the food matrix, there is little information about the factors affecting phenolic compounds' bioaccessibility. AIM OF THE STUDY: This investigation was carried out to evaluate the effect of domestic cooking on the bioavailability in humans of antioxidant molecules after the administration of a test meal containing cherry tomatoes. METHODS: A cross-over design was conducted. Subjects (3 females and 2 males) consumed experimental meals containing fresh and cooked cherry tomatoes. Blood collection was performed at different time intervals (0, 2, 4, 6, 8 and 24 h). RESULTS: Carotenoid and phenol plasma concentrations were measured. Plasma levels of lycopene and beta-carotene were not significantly different with respect to the baseline after ingestion of both the test meals, while plasma concentrations of naringenin and chlorogenic acid increased significantly with respect to the baseline (P<0.05) after administration of cooked cherry tomatoes, but not after administration of fresh cherry tomatoes. CONCLUSIONS: The present study indicated that domestically cooked tomatoes significantly increase naringenin and chlorogenic acid plasma levels. Considering that both naringenin and chlorogenic acid are widely studied for their potential healthy properties, evidence of their bioavailability and of the factors influencing their bioaccessibility is an important tool to sustain the possibility that these polyphenols play a biological role in human physiology.

Flavonoids uptake and their effect on cell cycle of human colon adenocarcinoma cells (Caco2).

Green tea, mainly through its constituents epigallocatechin gallate, epigallocatechin, epicatechin gallate and epicatechin, has demonstrated anticarcinogenic activity in several animal models, including those for skin, lung and gastro-intestinal tract cancer, although less is known about colorectal cancer. Quercetin, the major flavonoid present in vegetables and fruit, exerts potential anticarcinogenic effects in animal models and cell cultures, but less is known about quercetin glucosides. The objectives of this study were to investigate (i) the antioxidant activity of the phenolic compounds epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside; (ii) the cytotoxicity of different concentrations of epicatechin, epigallocatechin gallate, and gallic acid; (iii) the cellular uptake of epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside and (iv) their effect on the cell cycle. Human colon adenocarcinoma cells were used as experimental model. The results of this study indicate that all dietary flavonoids studied (epicatechin, epigallocatechin gallate, gallic acid and quercetin-3-glucoside) show a significant antioxidant effect in a chemical model system, but only epigallocatechin gallate or gallic acid are able to interfere with the cell cycle in Caco2 cell lines. These data suggest that the antioxidant activity of flavonoids is not related to the inhibition of cellular growth. From a structural point of view, the galloyl moiety appears to be required for both the antioxidant and the antiproliferative effects.

Accumulation and interactions of beta-carotene and alpha-tocopherol in patients with adenomatous polyps.

OBJECTIVE: The aims of the present study were: (1) to determine whether short-term supplementation of beta-carotene (BC) or vitamin E (VE; alpha-tocopherol) would result in their respective accumulation in normal colonic mucosa and in adenomatous polyps; (2) to determine whether the intake of BC would interfere with the concentration of VE in these target tissues. DESIGN: Blood and colonic biopsy samples were taken before and after supplementation. SUBJECTS: Eighteen volunteers with colonic adenomatous polyps were enrolled into this study. INTERVENTIONS: The supplementation lasted for 43 days and patients were examined over the whole period. Subjects were randomised into four groups according to the four different supplementations: placebo, natural BC (25 000 IU/day), natural VE (400 IU/day), combination BC/VE. RESULTS: Initially we were aiming for recruitment of 20 patients in each group, however after 2 y of study (1997-1999), we terminated the study because of slow recruitment and analysed the data. In placebo subjects after supplementation, the plasma concentrations of BC and VE remained unchanged, however only two patients were recruited in this group and therefore we did not include this group in our final analysis. In BC group, the plasma BC concentrations increased significantly (P<0.001), while VE concentrations were unchanged. In VE group, VE concentrations increased (P<0.01) and BC did not change, and in BC/VE group both BC (P<0.001) and VE levels (P<0.01) increased significantly. After supplementation, the tissue concentration of BC in normal colonic mucosa in BC group increased significantly (P<0.01) while the VE concentration did not change. In VE group, the concentration of VE in normal colonic mucosa increased slightly but did not reach statistical significance. However, VE concentration increased significantly (P<0.05) in the polyps of this group. In BC/VE group, in which patients received the combination treatment, the BC concentration of normal colonic mucosa increased (P<0.05) but, surprisingly, the VE concentration decreased significantly (P<0.01). Interestingly in the polyps, although the BC concentration increased (P<0.01), the concentration of VE was reduced moderately but did not reach statistical significance. CONCLUSIONS: Supplementation of BC in doses used in this study may have significantly interfered with the VE concentration in the examined tissue and probably with its metabolic pathway.

High-performance liquid chromatography with coulometric electrode array detector for the determination of quercetin levels in cells of the immune system.

There is mounting evidence emphasizing the importance of intracellular antioxidant levels for maintenance of the immune function. The flavonoid quercetin, a natural antioxidant, has been shown to modulate enzymes involved in the regulation of the inflammatory response. However, up to now, there have been no studies describing quercetin levels in cells of the immune system. A gradient reversed-phase HPLC technique to identify and quantify intracellular levels of quercetin and its application in mice splenocytes are described. Mobile phases were a 0.01 M sodium phosphate monobasic solution adjusted to pH 2.8 with 85% orthophosphoric acid (buffer, Solvent A) and methanol (Solvent B) with a flow rate of 1 ml/min. An eight-channel coulometric electrode array detector was used. In vitro supplementation with increasing concentration of quercetin (25, 50, and 100 microM) raises intracellular quercetin levels in a dose-dependent manner. The method has the required features of specificity and sensitivity for monitoring quercetin uptake in cells of the immune system.

Identification and biochemical characterization of a novel nortriterpene inhibitor of the human lymphocyte voltage-gated potassium channel, Kv1.3.

A novel nortriterpene, termed correolide, purified from the tree Spachea correae, inhibits Kv1.3, a Shaker-type delayed rectifier potassium channel present in human T lymphocytes. Correolide inhibits 86Rb+ efflux through Kv1.3 channels expressed in CHO cells (IC50 86 nM; Hill coefficient 1) and displays a defined structure-activity relationship. Potency in this assay increases with preincubation time and with time after channel opening. Correolide displays marked selectivity against numerous receptors and voltage- and ligand-gated ion channels. Although correolide is most potent as a Kv1.3 inhibitor, it blocks all other members of the Kv1 family with 4-14-fold lower potency. C20-29-[3H]dihydrocorreolide (diTC) was prepared and shown to bind in a specific, saturable, and reversible fashion (Kd = 11 nM) to a single class of sites in membranes prepared from CHO/Kv1.3 cells. The molecular pharmacology and stoichiometry of this binding reaction suggest that one diTC site is present per Kv1.3 channel tetramer. This site is allosterically coupled to peptide and potassium binding sites in the pore of the channel. DiTC binding to human brain synaptic membranes identifies channels composed of other Kv1 family members. Correolide depolarizes human T cells to the same extent as peptidyl inhibitors of Kv1.3, suggesting that it is a candidate for development as an immunosuppressant. Correolide is the first potent, small molecule inhibitor of Kv1 series channels to be identified from a natural product source and will be useful as a probe for studying potassium channel structure and the physiological role of such channels in target tissues of interest.

Subunit composition of brain voltage-gated potassium channels determined by hongotoxin-1, a novel peptide derived from Centruroides limbatus venom.

Five novel peptidyl inhibitors of Shaker-type (Kv1) K+ channels have been purified to homogeneity from venom of the scorpion Centruroides limbatus. The complete primary amino acid sequence of the major component, hongotoxin-1 (HgTX1), has been determined and confirmed after expression of the peptide in Escherichia coli. HgTX1 inhibits 125I-margatoxin binding to rat brain membranes as well as depolarization-induced 86Rb+ flux through homotetrameric Kv1.1, Kv1. 2, and Kv1.3 channels stably transfected in HEK-293 cells, but it displays much lower affinity for Kv1.6 channels. A HgTX1 double mutant (HgTX1-A19Y/Y37F) was constructed to allow high specific activity iodination of the peptide. HgTX1-A19Y/Y37F and monoiodinated HgTX1-A19Y/Y37F are equally potent in inhibiting 125I-margatoxin binding to rat brain membranes as HgTX1 (IC50 values approximately 0.3 pM). 125I-HgTX1-A19Y/Y37F binds with subpicomolar affinities to membranes derived from HEK-293 cells expressing homotetrameric Kv1.1, Kv1.2, and Kv1.3 channels and to rat brain membranes (Kd values 0.1-0.25 pM, respectively) but with lower affinity to Kv1.6 channels (Kd 9.6 pM), and it does not interact with either Kv1.4 or Kv1.5 channels. Several subpopulations of native Kv1 subunit oligomers that contribute to the rat brain HgTX1 receptor have been deduced by immunoprecipitation experiments using antibodies specific for Kv1 subunits. HgTX1 represents a novel and useful tool with which to investigate subclasses of voltage-gated K+ channels and Kv1 subunit assembly in different tissues.

Blockade of the voltage-gated potassium channel Kv1.3 inhibits immune responses in vivo.

The voltage activated K+ channel (Kv1.3) has recently been identified as the molecule that sets the resting membrane potential of peripheral human T lymphoid cells. In vitro studies indicate that blockage of Kv1.3 inhibits T cell activation, suggesting that Kv1.3 may be a target for immunosuppression. However, despite the in vitro evidence, there has been no in vivo demonstration that blockade of Kv1.3 will attenuate an immune response. The difficulty is due to species differences, as the channel does not set the membrane potential in rodent peripheral T cells. In this study, we show that the channel is present on peripheral T cells of miniswine. Using the peptidyl Kv1.3 inhibitor, margatoxin, we demonstrate that Kv1.3 also regulates the resting membrane potential, and that blockade of Kv1.3 inhibits, in vivo, both a delayed-type hypersensitivity reaction and an Ab response to an allogeneic challenge. In addition, prolonged Kv1.3 blockade causes reduced thymic cellularity and inhibits the thymic development of T cell subsets. These results provide in vivo evidence that Kv1.3 is a novel target for immunomodulation.

Inhibition of stromelysin-1 (MMP-3) by P1'-biphenylylethyl carboxyalkyl dipeptides.

Carboxyalkyl peptides containing a biphenylylethyl group at the P1' position were found to be potent inhibitors of stromelysin-1 (MMP-3) and gelatinase A (MMP-2), in the range of 10-50 nM, but poor inhibitors of collagenase (MMP-1). Combination of a biphenylylethyl moiety at P1', a tert-butyl group at P2', and a methyl group at P3' produced orally bioavailable inhibitors as measured by an in vivo model of MMP-3 degradation of radiolabeled transferrin in the mouse pleural cavity. The X-ray structure of a complex of a P1-biphenyl inhibitor and the catalytic domain of MMP-3 is described. Inhibitors that contained halogenated biphenylylethyl residues at P1' proved to be superior in terms of enzyme potency and oral activity with 2(R)-[2-(4'-fluoro-4-biphenylyl)ethyl]-4(S)-n-butyl-1,5-pentane dioic acid 1-(alpha(S)-tert-butylglycine methylamide) amide (L-758,354, 26) having a Ki of 10 nM against MMP-3 and an ED50 of 11 mg/kg po in the mouse pleural cavity assay. This compound was evaluated in acute (MMP-3 and IL-1 beta injection in the rabbit) and chronic (rat adjuvant-induced arthritis and mouse collagen-induced arthritis) models of cartilage destruction but showed activity only in the MMP-3 injection model (ED50 = 6 mg/kg iv).

Margatoxin binds to a homomultimer of K(V)1.3 channels in Jurkat cells. Comparison with K(V)1.3 expressed in CHO cells.

Voltage-gated potassium (K(V)) channels play key roles in setting the resting potential and in the activation cascade of human peripheral T lymphocytes. Margatoxin (MgTX), a 39-amino acid peptide from Centruroides margaritatus, is a potent inhibitor of lymphocyte K(V) channels. The binding of monoiodotyrosinyl margatoxin ([125I]MgTX) to plasma membranes prepared from either Jurkat cells, a human leukemic T cell line, or CHO cells stably transfected with the Shaker-type voltage-gated K+ channel, K(V)1.3, has been used to investigate the properties of lymphocyte K(V) channels. These data were compared with [125I]MgTX binding to heterotetrameric K(V) channels in rat brain synaptic plasma membranes [Knaus, H. G., et al. (1995) Biochemistry 34, 13627-13634]. The affinity for [125I]MgTX is 100-200 fM in either Jurkat or CHO/K(V)1.3 membranes, and the receptor density is 20-120 fmol/mg in Jurkat membranes or 1000 fmol/mg in CHO/K(V)1.3 membranes. In contrast to rat brain, [125I]MgTX binding to Jurkat and CHO/K(V)1.3 membranes exhibits an absolute requirement for K+, with no potentiation of binding by Na+. K(V)1.3 was the only K(V)1 series channel present in either CHO/K(V)1.3 or Jurkat plasma membranes as determined by immunoprecipitation of [125I]MgTX binding or by Western blot analyses using sequence-specific antibodies prepared against members of the K(V)1 family. The relative potencies of a series of peptidyl K(V) channel inhibitors was essentially the same for inhibition of [125I]MgTX binding to Jurkat, CHO, or rat brain membranes and for blocking 86Rb+ efflux from the CHO/K(V)1.3 cells, except that alpha-dendrotoxin was more potent at blocking binding to rat brain membranes than in the other assays. The characteristics of [125I]MgTX binding, the antibody profiles, and the effects of the peptidyl K(V) inhibitors all indicate that the [125I]MgTX receptor in Jurkat lymphocytes is comprised of a homomultimer of K(V)1.3, unlike the heteromultimeric arrangement of the receptor in rat brain.

Structure-activity relationships of C1 and C6 side chains of zaragozic acid A derivatives.

Systematic modification of the C6 acyl side chain of zaragozic acid A, a potent squalene synthase inhibitor, was undertaken to improve its biological activity. Simplification of the C6 side chain to the octanoyl ester has deleterious effects; increasing the linear chain length improves the in vitro activity up to the tetradecanoyl ester. An omega-phenoxy group is a better activity enhancer than an omega-phenyl group. A number of C6 carbamates, ethers, and carbonates were prepared and found to have similar activity profiles as the C6 esters. In the preparation of C6 ethers, C4 and C4,6 bisethers were also isolated; their relative activity is: C6 > C4 > C4,6. These C6 long-chain derivatives are subnanomolar squalene synthase inhibitors; they are, however, only weakly active in inhibiting hepatic cholesterol synthesis in mice. The C6 short-chain derivatives are much less active in vitro, but they all have improved oral activity in mice. Modification of the C1 alkyl side chain of the n-butanoyl analogue (ED50 4.5 mg/kg) did not improve the po activity further. A number of these C6 long-chain derivatives are also potent antifungal agents in vitro.

Chemical synthesis and structure-function studies of margatoxin, a potent inhibitor of voltage-dependent potassium channel in human T lymphocytes.

The 39 amino acid peptide, margatoxin (MgTX), a potent inhibitor of the voltage-activated potassium channel (Kv 1.3) in human T lymphocytes, was synthesized by a solid phase technique. Formation of the disulfide bridges was rapid at pH 8.2. The final product was purified to homogeneity and was physically and biologically indistinguishable from the toxin prepared biosynthetically. The disulfide bridge pairing was similar to that found previously for the related toxin-charybdotoxin (3): from Cys7 to Cys29, from tested for inhibition of 125I margatoxin binding to voltage-activated potassium channels. The results indicate that the three C-terminal residues of MgTX are important for the efficient toxin binding to Kv1.3.

Development, synthesis, and biological evaluation of (-)-trans-(2S,5S)-2-[3-[(2-oxopropyl)sulfonyl]-4-n-propoxy-5-(3- hydroxypropoxy)-phenyl]-5-(3,4,5-trimethoxyphenyl)tetrahydrofuran, a potent orally active platelet-activating factor (PAF) antagonist and its water-soluble prodrug phosphate ester.

(-)-trans-(2S,5S)-2-[3-[(2-Oxopropyl)sulfonyl]-4-n-propoxy-5-(3- hydroxypropoxy)phenyl]-5-(3,4,5-trimethoxyphenyl)tetrahydrofuran (10) is one of the most potent platelet-activating factor (PAF) antagonists in vitro and in vivo developed to date. This diaryltetrahydrofuran derivative evolved from modifications of MK 0287 which has been evaluated in clinical studies for asthma. Two structural modifications of MK 0287 were made: (1) elaboration of the 3'-[(hydroxyethyl)sulfonyl] group to a beta-keto propylsulfonyl, and (2) replacement of the 5'-methyl ether by a 3-hydroxypropyl ether. Compound 10 potently and specifically inhibits the binding of [3H]-C18-PAF to human platelet membranes (Ki 1.85 nM) and PMN membranes (Ki 2.89 nM). In vivo, 10 inhibits PAF-induced plasma extravasation and elevated N-acetyl-beta-D-glucosaminidase (NAGA) levels in male rats with ED50 values of 60 micrograms/kg, po and 4 micrograms/kg, iv respectively, and inhibits PAF-induced bronchoconstriction in guinea pigs with an ED50 value of 15 micrograms/kg after intraduodenal administration. Compound 15, a water-soluble phosphate ester prodrug derivative of 10 is at least equipotent to 10 in the in vivo models. Compound 19S, the primary and major metabolite of 10 and 15, is equipotent in in vitro and in vivo models.

Metabolism of the platelet-activating factor antagonist (+/-)-trans-2-(3'-methoxy-5'-methylsulphonyl-4'-propoxyphenyl)-5-(3",4" ,5"- trimethoxyphenyl)tetrahydrofuran (L-659,989) in rhesus monkeys.

1. The plasma concentration, main route of metabolism and excretion of 3H-L-659,989 were studied in male and female rhesus monkeys by dosing either i.v. or orally at 10 mg/kg. 2. The percentage of the AUC for the plasma radioactivity concentration-time curve of oral vs i.v. dosed monkeys was 78% for males and 90% for females, indicating that the dose was well absorbed. 3. The bioavailability of the drug was low (less than or equal to 10%) for all monkeys, probably due to rapid first pass metabolism. The drug was metabolized-predominantly at the C-4'-propoxy side-chain. The two major plasma metabolites were identified as the 4'-2-(hydroxy)propoxy metabolite (3H-trans-4'-HP) and the 4'-hydroxy metabolite (3H-4'-hydroxy) which was isolated as a 2:1 mixture of (+/-)trans: (+/-)cis. 4. Approx. 80% of the radiolabelled dose was excreted equally in the urine and faeces in 96 h, with the largest percentage of the tritiated dose (31 +/- 4%) in the 0-24 h urine. 5. The major metabolites in the excreta were the (+/-)trans/(+/-)cis mixture of 3H-4'-hydroxy and the glucuronide conjugate of 3H-trans-4'-hydroxy. The glucuronide conjugate of 3H-trans-4'-hydroxy was excreted in the urine of i.v. and orally dosed monkeys and represented an average of 21% and 5.1% of the dose, respectively. 3H-4'-Hydroxy was excreted in both the urine and faeces, accounting for less than or equal to 0.1% and 7.4% of the dose in i.v. and orally dosed monkeys, respectively.

Biochemical and pharmacological characterization of L-659,989: an extremely potent, selective and competitive receptor antagonist of platelet-activating factor.

L-659,989 [trans-2-(3-methoxy-5-methylsulfonyl-4-propoxy-phenyl)-5-(3,4,5- trimethoxyphenyl)tetrahydrofuran] is a p.o. active and extremely potent, selective and competitive platelet-activating factor (PAF) receptor antagonist. It inhibited [3H]PAF binding to either rabbit platelet or rabbit polymorphonuclear leukocyte membranes with an equilibrium inhibition constant (Kl) of 1.1 nM; whereas in human platelet, human polymorphonuclear leukocyte or human lung membranes, L-659,989 was about 10 times less potent with a Kl of 14.3 nM. The structural specificity of L-659,989 was demonstrated by the low activity of its cisisomer which was about 100 to 200 times less potent, also the (-)-L-659,989 was found to be 20- to 30-fold more potent than (+)-L-659,989. In both [3H]PAF binding and PAF-induced platelet aggregation inhibition, L-659,989 was found to be a competitive inhibitor with an equilibrium dissociation constant (KB) of 1.5 and 1.7 nM, respectively, in rabbit platelets. Even up to 6 microM concentration, L-659,989 showed no inhibition on the aggregation of rabbit platelets in plasma induced by ADP, arachidonic acid, collagen or thrombin. In an in vivo model, it inhibited guinea pig bronchoconstriction induced by i.v. infusion of 75 ng/kg of PAF with ED50 values of 13 micrograms/kg i.v. and 0.5 mg/kg p.o.

(+/-)-trans-2-(3-Methoxy-5-methylsulfonyl-4-propoxyphenyl)-5-(3,4,5- trimethoxyphenyl)tetrahydrofuran (L-659,989), a novel, potent PAF receptor antagonist.

The title compound, L-659,989, is a highly potent, competitive, and selective antagonist of the binding of [3H]PAF to its receptors in platelet membranes from rabbits and humans. It exhibits equilibrium inhibition constants for PAF binding of 1.1 nM (rabbit) to 9.0 nM (human), values that are at least 1-2 orders of magnitude lower than those of other PAF antagonists tested. L-659,989 potently inhibits PAF-induced aggregation of rabbit platelets and degranulation of rat (ED50 4.5 nM) and human (ED50 10 nM) neutrophils. L-659,989 inhibits PAF-induced extravasation and lysosomal enzyme release in rats, and is active orally in female rats (ED50 0.2 mg/kg) with an extraordinary oral duration of action of 12 to 16 hours at 1.0 mg/kg p.o.

Inhibition of delayed hypersensitivity reactions by cinnamyl 1-thioglycosides.

Cinnamyl 1-thio-alpha-D-manno(and L-rhamno)pyranosides have good inhibitory effects in an antigen-specific T cell proliferation assay. The beta anomers are slightly less effective than the alpha anomers. The 6-substituted analogues of cinnamyl 1-thio-alpha-D-mannopyranoside such as 6-deoxy and 6-O-methyl derivatives also block macrophages in presenting the antigen to T cells. D-Mannose and L-rhamnose, when tested by themselves with no modifications, did not block at concentrations up to 1 mM. These cinnamyl 1-thioglycosides when given ip or po at 3-30 mg/kg to mice significantly inhibited the delayed type hypersensitivity reaction as measured by footpad swelling.

Structure-activity relationships of kadsurenone analogues.

Kadsurenone, a specific receptor antagonist of platelet-activating factor (PAF), and its analogues were prepared from derivatives of cinnamyl alcohol and (allyloxy)phenol. Racemic kadsurenone, resolvable by a Chiralpak column at low temperatures, has an IC50 value of 2 X 10(-7) M, which is about 50% of the activity of the natural product (IC50 = 1 X 10(-7) M). The structural specificity of kadsurenone was further demonstrated by the low PAF-receptor-blocking activities of denudatin B, mirandin A, desallylkadsurenone, and the 2-epimer of kadsurenone.

Targeting of synthetically glycosylated human placental glucocerebrosidase.

Human placental beta-glucocerebrosidase modified by covalent attachment of N2-(N2, N6-bis [3-(alpha-D-mannopyranosylthio)propionyl]-L- lysyl)-N6-[3-(alpha-D-mannopyranosylthio)propionyl]-L-lysine was administered to rats by intravenous injection. Comparison of enzyme distribution in isolated liver cell populations indicates an increase in enzyme-specific activity of 18-fold in nonparenchymal cells and only 1.5-fold to hepatocytes compared to uninjected control animals. This macrophage-specific delivery of an active lysosomal enzyme has potential for application in enzyme replacement trials.