Chemical composition and antioxidant potential of essential oil and methanol extract from Tunisian and French fennel (Foeniculum vulgare Mill.) seeds.

This study was designed to examine the effect of provenance on the phytochemical and antioxidant properties of essential oil and methanolic extract from Tunisian and French fennel seeds (FFS). Analysis of the essential oil showed that although the same main compounds were found in Tunisian and FFS cultivars, some differences were present in their proportions allowing to classify them in two chemotypes. The first class was composed by trans-anethole (63.41%-78.26%) for Tunisian cultivars and the second one by estragole (44.72%-88.92%) for French cultivars. The phenolic composition of all fennel seed extracts was characterized by its richness in quinic acid, 4-O-caffeoylquinic acid, p-coumaric acid, and 4-O-caffeoylquinic acid. All fennel seed extracts showed a better antioxidant potential than their essential oils depending on the origin. Principal component analysis showed a dispersion of the cultivars on three groups depending on the chemotype diversity. PRACTICAL APPLICATIONS: Recently, much attention has been focused on fennel due to the nutritional and health-protective value of their seeds. Several studies have highlighted the importance of fennel seed extracts and essential oils as key ingredients rich in bioactive compounds serving in formulation of new functional food products. This investigation designed to examine the effect of provenance on phytochemical and antioxidant potentials of Tunisian and French fennel seed extracts and essential oils.

Brain specific delivery of pegylated indinavir submicron lipid emulsions.

The aim of this study was to develop stable parenteral pegylated indinavir submicron lipid emulsions (SLEs) for improving brain specific delivery. The O/W SLEs were prepared by homogenization and ultra sonication process. The sizes of oil globules varied from 241.5 to 296.4nm and zeta potential from -26.6 to -42.4mV. During in vitro drug release studies the cumulative amount of drug released within 12h from SLE-5, DSP2-3 and DPP5-3 was 71.8±0.76, 66.09±1.45 and 68.33±1.29, respectively. The total drug content and entrapment efficiencies were determined. The optimized formulations were stable for the effect of centrifugal stress, thermal stress, dilution stress and storage. In vivo pharmacokinetic and tissue distribution studies were performed in Swiss albino mice, the therapeutic availability (TA) of DSP2-3 was 3.59 times and 2.36 times in comparison to drug solution and SLE-5 respectively, where as DPP5-3 showed TA 2.8 and 1.84 times the drug solution and SLE-5, respectively. The brain to serum ratio of indinavir from DSP2-3 and DPP5-3 varied between 0.4 and 0.7 at all time points indicated the preferential accumulation of drug in brain. In conclusion, pegylated SLEs improved brain specific delivery of indinavir and will be useful in treating chronic HIV infection.

CH05-10, a novel indinavir analog, is a broad-spectrum antitumor agent that induces cell cycle arrest, apoptosis, endoplasmic reticulum stress and autophagy.

Indinavir, a human immunodeficiency virus (HIV) protease inhibitor, inhibits the growth of tumor cells in vivo but does not show any cytotoxicity against cancer cells in vitro. To optimize the anticancer activity of indinavir, two novel analogs, CH05-0 and CH05-10, were synthesized. CH05-10 was much more cytotoxic than indinavir and had similar cytotoxicity to nelfinavir, the one with the best anticancer activities among all HIV protease inhibitors examined. For 14 cell lines representing 10 different types of human malignancies, the 50% inhibitory concentration (IC(50)) values of CH05-10 are in the range of 4.64-38.87 µM. Further detailed studies using the lung cancer cell line A549 as the model system showed that the effect of CH05-10 on the A549 cell line is both time- and dose-dependent. The CH05-10 treatment not only induced cell cycle arrest at G(1) and caused caspase-dependent apoptosis, but also resulted in caspase-independent death via the induction of endoplasmic reticulum stress and unfolded protein response. These findings demonstrate that CH05-10, a novel indinavir analog, is a potent anticancer agent with pleiotropic effects.

An integrated method for metabolite detection and identification using a linear ion trap/Orbitrap mass spectrometer and multiple data processing techniques: application to indinavir metabolite detection.

A new strategy using a hybrid linear ion trap/Orbitrap mass spectrometer and multiple post-acquisition data mining techniques was evaluated and applied to the detection and characterization of in vitro metabolites of indinavir. Accurate-mass, full-scan MS and MS/MS data sets were acquired with a generic data-dependent method and processed with extracted-ion chromatography (EIC), mass-defect filter (MDF), product-ion filter (PIF), and neutral-loss filter (NLF) techniques. The high-resolution EIC process was shown to be highly effective in the detection of common metabolites with predicted molecular weights. The MDF process, which searched for metabolites based on the similarity of mass defects of metabolites to those of indinavir and its core substructures, was able to find uncommon metabolites not detected by the EIC processing. The high-resolution PIF and NLF processes selectively detected metabolites that underwent fragmentation pathways similar to those of indinavir or its known metabolites. As a result, a total of 15 metabolites including two new indinavir metabolites were detected and characterized in a rat liver S9 incubation sample. Overall, these data mining techniques, which employed distinct metabolite search mechanisms, were complementary and effective in detecting both common and uncommon metabolites. In summary, the results demonstrated that this analytical strategy enables the high-throughput acquisition of accurate-mass LC/MS data sets, comprehensive search of a variety of metabolites through the post-acquisition processes, and effective structural characterization based on elemental compositions of metabolite molecules and their product ions.

Orally bioavailable highly potent HIV protease inhibitors against PI-resistant virus.

Efforts directed to identifying potent HIV protease inhibitors (PI) have yielded a class of compounds that are not only very active against wild-type (NL4-3) HIV virus but also very potent against a panel of PI-resistant viral isolates. Chemistry and biology are described.

Investigation of oral bioavailability and brain distribution of the Ind(8)-Val conjugate of indinavir in rodents.

Protease inhibitors are successfully used for the treatment of acquired immune deficiency syndrome (AIDS) although their biopharmaceutical characteristics are not optimal. Prodrugs have therefore been synthesized to increase protease inhibitor bioavailability and brain distribution. Among several compounds tested, a valine derivative of indinavir (Ind(8)-Val) showed promising characteristics using an in-vitro Caco-2 cell model. The objective of this study was to further investigate this compound using in-situ and in-vivo approaches. The pharmacokinetics of indinavir (Ind) and Ind(8)-Val were investigated in rats after intravenous and oral administration. Free indinavir resulting from in-vivo hydrolysis of Ind(8)-Val could not be detected in the plasma of rats receiving Ind(8)-Val. Furthermore Ind(8)-Val bioavailability was only 32% on average compared with 76% for indinavir, and effective permeability coefficients determined with a single-pass intestinal perfusion method were close to 25x10(6)cms(-1) for the two compounds. Brain-to-plasma concentration ratios in the post equilibrium phase after intravenous administration to mice were 9.7+/-8.1% for indinavir and 2.5+/-2.7% for Ind(8)-Val. In conclusion, the promising biopharmaceutical characteristics of Ind(8)-Val suggested from previous in-vitro experiments with the Caco-2 cell model were not confirmed by in-situ and in-vivo experiments.

P1' oxadiazole protease inhibitors with excellent activity against native and protease inhibitor-resistant HIV-1.

HIV-1 protease inhibitors (PI's) bearing 1,3,4-oxadiazoles at the P1' position were prepared by a novel method involving the diastereoselective installation of a carboxylic acid and conversion to the P1' heterocycle. The compounds are picomolar inhibitors of native HIV-1 protease, with most of the compounds maintaining excellent antiviral activity against a panel of PI-resistant strains.

Interaction with indinavir to enhance systemic exposure of an investigational HIV protease inhibitor in rats, dogs and monkeys.

1. The use of a beneficial interaction between indinavir and compound A, a potent investigational HIV protease inhibitor to enhance systemic exposure of compound A, was investigated. 2. When administrated alone, compound A underwent extensive hepatic first-pass metabolism in rats and monkeys, resulting in low oral bioavailability. 3. In vitro studies with liver microsomes revealed that compound A metabolism was mediated exclusively by CYP3A enzymes in rats, dogs and monkeys. Indinavir, which also was metabolized predominantly by CYP3A enzymes, extensively inhibited compound A metabolism in microsomes, whereas compound A showed weak inhibitory potency on indinavir metabolism. 4. Consistent with in vitro observations, co-administration of the two compounds resulted in a 17-fold increase in oral AUC of compound A in rats owing to the inhibition of metabolism of compound A by indinavir, whereas compound A did not affect indinavir metabolism as indicated by the unchanged indinavir AUC. Similarly, the systemic exposure of compound A in dogs and monkeys was increased substantially following oral co-administration with indinavir by 7- and > 50-fold, respectively. 5. Enhancement in compound A systemic exposure by indinavir in humans, as predicted based on the in vivo animal and in vitro human liver microsomal data, was confirmed in subsequent clinical studies.

Combinatorial library of indinavir analogues: replacement for the aminoindanol at P2'.

A 1X22X41 combinatorial library or 902 compounds of indinavir analogues was synthesized on the solid support to identify a replacement for the aminoindanol moiety at P2'. 2,6-Dimethyl-4-hydroxy phenol was discovered to be a good replacement for aminoindanol.

Indinavir analogues with blocked metabolism sites as HIV protease inhibitors with improved pharmacological profiles and high potency against PI-resistant viral strains.

Indinavir analogues with blocked metabolism sites show highly improved pharmacokinetic profiles in animals. The cis-aminochromanol substituted analogues exhibited excellent potency against both the wild-type (NL4-3) virus and protease inhibitor-resistant HIV strains.

Synthesis and activity of novel HIV protease inhibitors with improved potency against multiple PI-resistant viral strains.

Substitution of the t-butylcarboxamide substituent in analogues of the HIV protease inhibitor (PI) Indinavir with a trifluoroethylamide moiety confers greater potency against both the wild-type (NL4-3) virus and PI-resistant HIV. The trifluoroethyl substituent also affords a slower clearance rate in vivo (dogs); however, this may be due to more potent inhibition of at least two P450 isoforms.

A combinatorial library of indinavir analogues and its in vitro and in vivo studies.

A combinatorial library of 300HIV protease inhibitors has been synthesized. The library was screened against recombinant wild-type and mutant HIV-1 protease enzymes. The pharmacokinetics of the library was evaluated by dosing in dogs. Compounds that are notably more potent than indinavir and have favorable pharmacokinetic properties were identified.

Asymmetric synthesis of chiral organofluorine compounds: use of nonracemic fluoroiodoacetic acid as a practical electrophile and its application to the synthesis of monofluoro hydroxyethylene dipeptide isosteres within a novel series of HIV protease inhibitors.

Two stereoselective routes to a series of diastereomeric inhibitors of HIV protease, monofluorinated analogues of the Merck HIV protease inhibitor indinavir, are described. The two routes feature stereoselective construction of the fluorinated core subunits by asymmetric alkylation reactions. The first-generation syntheses were based on the conjugate addition of the lithium enolate derived from pseudoephedrine alpha-fluoroacetamide to nitroalkene 12, a modestly diastereoselective transformation. A more practical second-generation synthetic route was developed that is based on a novel method for the asymmetric synthesis of organofluorine compounds, by enolate alkylation using optically active fluoroiodoacetic acid as the electrophile in combination with a chiral amide enolate. Resolution of fluoroiodoacetic acid with ephedrine provides either enantiomeric form of the electrophile in > or = 96% ee. Alkylation reactions with this stable and storable chiral fluorinated precursor are shown to proceed in a highly stereospecific manner. With the development of substrate-controlled syn- or anti-selective reductions of alpha-fluoro ketones 44 and 45 (diastereomeric ratios 12:1-84:1), efficient and stereoselective routes to each of the four targeted inhibitors were achieved. The optimized synthetic route to the most potent inhibitor (syn,syn-4, K(i) = 2.0 nM) proceeded in seven steps (87% average yield per step) from aminoindanol hydrocinnamide 40 and (S)-fluoroiodoacetic acid, and allowed for the preparation of more than 1 g of this compound. The inhibition of HIV-1 protease by each of the fluorinated inhibitors was evaluated in vitro, and the variation of potency as a function of inhibitor stereochemistry is discussed.

Combinatorial diversification of indinavir: in vivo mixture dosing of an HIV protease inhibitor library.

An efficient combination solution-phase/solid-phase route enabling the diversification of the P1', P2', and P3 subsites of indinavir has been established. The synthetic sequence can facilitate the rapid generation of HIV protease inhibitors possessing more favorable pharmacokinetic properties as well as enhanced potencies. Multiple compound dosing in vivo may also accelerate the identification of potential drug candidates.