Interdependent allosteric free fatty acid receptor 2 modulators synergistically induce functional selective activation and desensitization in neutrophils.

The non-activating allosteric modulator AZ1729, specific for free fatty acid receptor 2 (FFAR2), transfers the orthosteric FFAR2 agonists propionate and the P2Y2R specific agonist ATP into activating ligands that trigger an assembly of the neutrophil superoxide generating NADPH-oxidase. The homologous priming effect on the propionate response and the heterologous receptor cross-talk sensitized ATP response mediated by AZ1729 are functional characteristics shared with Cmp58, another non-activating allosteric FFAR2 modulator. In addition, AZ1729 also turned Cmp58 into a potent activator of the superoxide generating neutrophil NADPH-oxidase, and in agreement with the allosteric modulation concept, the effect was reciprocal in that Cmp58 turned AZ1729 into a potent activating allosteric agonist. The activation signals down-stream of FFAR2 when stimulated by the two interdependent allosteric modulators were biased in that, unlike for orthosteric agonists, the two complementary modulators together triggered an activation of the NADPH-oxidase, but not any transient rise in the cytosolic concentration of free calcium ions (Ca2+). Furthermore, following AZ1729/Cmp58 activation, the signaling by the desensitized FFAR2s was functionally selective in that the orthosteric agonist propionate could still induce a transient rise in intracellular Ca2+. The novel neutrophil activation and receptor down-stream signaling pattern mediated by the two cross-sensitizing allosteric FFAR2 modulators represent a new regulatory mechanism that controls receptor signaling.

Discovery of an Orally Bioavailable Pan αv Integrin Inhibitor for Idiopathic Pulmonary Fibrosis.

The heterodimeric transmembrane αv integrin receptors have recently emerged as potential targets for the treatment of idiopathic pulmonary fibrosis. Herein, we describe how subtle modifications of the central aromatic ring of a series of phenylbutyrate-based antagonists of the vitronectin receptors αvß3 and αvß5 significantly change the biological activities against αvß6 and αvß8. This resulted in the discovery of a pan αv antagonist (compound 39, 4-40 nM for the integrin receptors named above) possessing excellent oral pharmacokinetic properties in rats (with a clearance of 7.6 mL/(min kg) and a bioavailability of 97%).

Preclinical Pharmacokinetics Study of R- and S-Enantiomers of the Histone Deacetylase Inhibitor, AR-42 (NSC 731438), in Rodents.

AR-42, a new orally bioavailable, potent, hydroxamate-tethered phenylbutyrate class I/IIB histone deacetylase inhibitor currently is under evaluation in phase 1 and 2 clinical trials and has demonstrated activity in both hematologic and solid tumor malignancies. This report focuses on the preclinical characterization of the pharmacokinetics of AR-42 in mice and rats. A high-performance liquid chromatography-tandem mass spectrometry assay has been developed and applied to the pharmacokinetic study of the more active stereoisomer, S-AR-42, when administered via intravenous and oral routes in rodents, including plasma, bone marrow, and spleen pharmacokinetics (PK) in CD2F1 mice and plasma PK in F344 rats. Oral bioavailability was estimated to be 26 and 100% in mice and rats, respectively. R-AR-42 was also evaluated intravenously in rats and was shown to display different pharmacokinetics with a much shorter terminal half-life compared to that of S-AR-42. Renal clearance was a minor elimination pathway for parental S-AR-42. Oral administration of S-AR-42 to tumor-bearing mice demonstrated high uptake and exposure of the parent drug in the lymphoid tissues, spleen, and bone marrow. This is the first report of the pharmacokinetics of this novel agent, which is now in early phase clinical trials.

Protein tyrosine phosphatase 1B (PTP1B) inhibitory constituents from the aerial parts of Tradescantia spathacea Sw.

Inhibitors of protein tyrosine phosphatase 1B (PTP1B) are promising agents for the treatment of type 2 diabetes and obesity. The bioactivity-guided isolation led to the separation of two new compounds, (±)-tradescantin (13) and tradescantoside (16), along with fourteen known compounds (1-12, 14, and 15) from the aerial parts of Tradescantia spathacea Sw. (Commelinaceae). Their chemical structures were elucidated by spectroscopic methods as well as by comparing with those reported in the literature. The isolated compounds (1-16) were then examined for their inhibitory activity toward PTP1B. The results indicated that compounds 2, 6, 8, and 12 possessed potent inhibition with IC50 values of 7.82±0.79, 6.80±0.89, 4.55±0.92, and 6.38±0.14 µM, respectively. Kinetic study of compounds 2, 6, 8, 12, 13, and 16 was conducted and the structure-activity relationships of the isolated compounds (1-16) were also discussed herein. To the best of our knowledge, all the isolates were separated for the first time from this plant.

Carrier-linked mutual prodrugs of biphenylacetic acid as a promising alternative to bioprecursor fenbufen: design, kinetics, and pharmacological studies.

Novel mutual prodrugs of biphenylacetic acid were designed as a promising gastro-protective alternative to fenbufen. Biphenyacetic acid was covalently linked with two non-essential amino acids (D-phenylalanine and glycine) possessing wound healing, analgesic, and anti-inflammatory properties. The prodrugs exhibited good stability in stomach homogenates while hydrolytic release of biphenylacetic acid was observed in phosphate buffer, small intestinal homogenates, and 80% human plasma. In vivo behavior of prodrugs on oral administration to Wistar rats demonstrated 33-45% release of biphenylacetic acid in blood over a period of 24 h indicating passage of intact prodrugs to colon, colonic release of parent drug followed by its absorption through colonic mucosa into systemic circulation. Prodrugs were extensively evaluated for analgesic, anti-inflammatory, anti-arthritic, and ulcerogenic activities. Biochemical, haemetological, histopathological, and radiological studies were also performed. Conversion of bioprecusor fenbufen into mutual carrier-linked prodrugs proved to be promising alternative in terms of reduced ulcerogenic propensity, longer duration of analgesia, enhanced/prolonged anti-inflammatory activity, and superior anti-arthritic effect. These prodrugs could be developed further for chronotherapy of rheumatoid arthritis.

The in silico screening and X-ray structure analysis of the inhibitor complex of Plasmodium falciparum orotidine 5'-monophosphate decarboxylase.

Orotidine 5'-monophosphate decarboxylase from Plasmodium falciparum (PfOMPDC) catalyses the final step in the de novo synthesis of uridine 5'-monophosphate (UMP) from orotidine 5'-monophosphate (OMP). A defective PfOMPDC enzyme is lethal to the parasite. Novel in silico screening methods were performed to select 14 inhibitors against PfOMPDC, with a high hit rate of 9%. X-ray structure analysis of PfOMPDC in complex with one of the inhibitors, 4-(2-hydroxy-4-methoxyphenyl)-4-oxobutanoic acid, was carried out to at 2.1 Å resolution. The crystal structure revealed that the inhibitor molecule occupied a part of the active site that overlaps with the phosphate-binding region in the OMP- or UMP-bound complexes. Space occupied by the pyrimidine and ribose rings of OMP or UMP was not occupied by this inhibitor. The carboxyl group of the inhibitor caused a dramatic movement of the L1 and L2 loops that play a role in the recognition of the substrate and product molecules. Combining part of the inhibitor molecule with moieties of the pyrimidine and ribose rings of OMP and UMP represents a suitable avenue for further development of anti-malarial drugs.

Discovery and structural development of small molecules that enhance transport activity of bile salt export pump mutant associated with progressive familial intrahepatic cholestasis type 2.

Progressive familial intrahepatic cholestasis type 2 (PFIC2) is caused by hereditary mutations of bile salt export pump (BSEP), such as E297G BSEP, which is a folding-defective mutant that is unable to traffic beyond the endoplasmic reticulum (ER). 4-Phenylbutyric acid (4-PBA) enhances the cell surface expression and transport capacity of E297G BSEP, but has a relatively high dose (1mM or more) is required to show the effect. Here, we show that bile acids possibly act as pharmacological chaperones, promoting the proper folding and trafficking of E297G BSEP. We also describe the discovery and structural development of non-steroidal compounds with potent pharmacological chaperone activity for E297G BSEP.

Structure-activity relationship of small-sized HIV protease inhibitors containing allophenylnorstatine.

We designed and synthesized a new class of peptidomimetic human immunodeficiency virus (HIV) protease inhibitors containing a unique unnatural amino acid, allophenylnorstatine [Apns; (2S, 3S)-3-amino-2-hydroxy-4-phenylbutyric acid], with a hydroxymethylcarbonyl (HMC) isostere as the active moiety. A systematic evaluation of structure-activity relationships for HIV protease inhibition, anti-HIV activities, and pharmacokinetic profiles has led to the delineation of a set of structural charateristics that appear to afford an orally available HIV protease inhibitor. Optimum structures, exemplified by 21f (JE-2147), incorporated 3-hydroxy-2-methylbenzoyl groups as the P2 ligand, (R)-5,5-dimethyl-1,3-thiazolidine-4-carbonyl (Dmt) residue at the P1' site, and 2-methylbenzylcarboxamide group as the P2' ligand. The present study demonstrated that JE-2147 has potent antiviral activities in vitro and exhibits good oral bioavailability and plasma pharmacokinetic profiles in two species of laboratory animals.

[Separation and identification of thellungianin G from the root of Pimpinella thellungiana Wolff].

OBJECTIVE: To study the effective components in the root of Pimpinella thellungiana METHOD: Column chromatography with silica gel and ODS was employed for the isolation and purification of ingredients. Their structures were elucidated by spectral analysis. RESULT: Three compounds were obtained and identified as 2-(1',2'-epoxy)-4-methoxy pheryl-2-methyl-butyrate(I),4-(1'-propenyl) phenol(II) and 2-methyl butyric acid(III). CONCLUSION: Compound I is a new compound and named thellungianin G. Compounds II and III were separated from P. Thellungiana for the first time.