Lavender and coriander essential oils and their main component linalool exert a protective effect against amyloid-ß neurotoxicity.

Alzheimer's disease (AD) is a neurodegenerative disorder leading to cognitive deficits and cognitive decline. Since no cure or preventing therapy is currently available to counteract AD, natural-derived compounds are investigated to find new potential neuroprotective agents for its treatment. In the present study, we tested the neuroprotective effect of lavender and coriander essential oils (EOs) and their main active constituent linalool, against the neurotoxicity elicited by Aß1-42 oligomers, a key molecular factor in the neurodegeneration of AD. Importantly, our findings on neuronally differentiated PC12 cells exposed to Aß1-42 oligomers are in accordance with previous in vivo studies reporting the neuroprotective potential of lavender and coriander EOs and linalool. We found that lavender and coriander EOs at the concentration of 10 µg/mL as well as linalool at the same concentration were able to improve viability and to reduce nuclear morphological abnormalities in cells treated with Aß1-42 oligomers for 24 hours. Lavender and coriander EOs and linalool also showed to counteract the increase of intracellular reactive oxygen species production and the activation of the pro-apoptotic enzyme caspase-3 induced by Aß1-42 oligomers. Our findings provide further evidence that these EOs and their main constituent linalool could be natural agents of therapeutic interest against Aß1-42 -induced neurotoxicity.

Synthesis and pharmacological evaluation of functionalized isoindolinones on GABA-activated chloride currents in rat cerebellum granule cells in culture.

A focused N-substituted 3-(2-piperazin-1-yl-2-oxoethyl)-2-(pyridin-2-yl)iso-indolin-1-ones small library was synthesized for modulation of GABA-A receptor function and compared to Zopiclone for the ability to increase GABA-activated chloride currents. All compounds were tested for their effects on GABA-activated chloride currents in rat cerebellar granule cells by use of the whole-cell patch clamp technique. Electrophysiological studies on cultured cerebellar granule cells revealed 3-[2-(4-methylpiperazin-1-yl)-2-oxoethyl]-2-(5-nitropyridin-2-yl)iso-indolin-1-one (Id) as a partial agonist displaying 34% increase of the 10µM GABA evoked peak chloride currents, antagonized by flumazenil. Moreover, a second group of compounds, with bulky functional groups at N-4 position of piperazine, have shown inverse agonist effects. The simple synthetic procedure and the possibility of modulating the efficacy of this class of ligands through additional structural modifications pave the way for further development of new molecules as a novel class of compounds able to interfere with benzodiazepine receptors.

Bifunctional phase-transfer catalysis in the asymmetric synthesis of biologically active isoindolinones.

New bifunctional chiral ammonium salts were investigated in an asymmetric cascade synthesis of a key building block for a variety of biologically relevant isoindolinones. With this chiral compound in hand, the development of further transformations allowed for the synthesis of diverse derivatives of high pharmaceutical value, such as the Belliotti (S)-PD172938 and arylated analogues with hypnotic sedative activity, obtained in good overall total yield (50%) and high enantiomeric purity (95% ee). The synthetic routes developed herein are particularly convenient in comparison with the current methods available in literature and are particularly promising for large scale applications.

In vitro antiviral and immunomodulatory activity of arbidol and structurally related derivatives in herpes simplex virus type 1-infected human keratinocytes (HaCat).

Arbidol (ARB) is an antiviral drug that has broad-spectrum activity against a number of viral infections. To date, there are no specific data regarding its effects against a herpesvirus. Here, the in vitro antiviral effect of ARB and structurally related derivatives were evaluated in HaCat cells on different steps of herpes simplex virus type 1 replication: adsorption, entry and post-entry. The simplified pyrrolidine analogue, 9a2, showed the best antiviral activity in vitro by reducing the plaque numbers by about 50% instead of 42% obtained with ARB at the same concentration. Furthermore, we have reported that all tested compounds evaluated for their immunomodulatory activity showed the ability to reduce the viral proteins VP16 and ICP27 and to modify the virus-induced cytokine expression, allowing the host cell a more efficient antiviral response.

Further studies on ethyl 5-hydroxy-indole-3-carboxylate scaffold: design, synthesis and evaluation of 2-phenylthiomethyl-indole derivatives as efficient inhibitors of human 5-lipoxygenase.

5-Lipoxygenase (5-LO), an enzyme that catalyzes the initial steps in the biosynthesis of pro-inflammatory leukotrienes, is an attractive drug target for the pharmacotherapy of inflammatory and allergic diseases. Here, we present the design, synthesis and biological evaluation of novel series of ethyl 5-hydroxyindole-3-carboxylate derivatives that efficiently inhibit human 5-LO. SAR analysis revealed that the potency of compounds is closely related to the positioning of the substituents at the phenylthiomethyl ring. The introduction of methyl or chlorine groups in ortho- and ortho/para-position of thiophenol represent the most favorable modifications. Among all tested compounds, ethyl 5-hydroxy-2-(mesitylthiomethyl)-1-methyl-1H-indole-3-carboxylate (19) is the most potent derivative which blocks 5-LO activity in cell-free assays with IC50 = 0.7 µM, and suppressed 5-LO product synthesis in polymorphonuclear leukocytes with IC50 = 0.23 µM.

Multi-component, regio-selective aldol addition of ß-ketoesters to aldehydes: scope and applications.

Simple and effective multi-component one-pot aldol addition/protection reactions of ß-ketoesters to a series of aldehydes in the presence Me(3)SiCl and i-Pr(2)EtN have been described. The analysis of the scope of the reaction revealed a dramatic dependence of the reactivity on the substrates used. Thus the effect of a catalytic amount of DMF and different reaction conditions was widely investigated. Further transformations of the aldol adducts were particularly useful to give valuable diols and compounds with quaternary stereocenters, while X-ray structural analysis gave also important stereochemical information about this challenging reaction.

2,3-Dihydro-1,2-Diphenyl-substituted 4H-Pyridinone derivatives as new anti Flaviviridae inhibitors.

With the aim of identifying novel lead compounds active against emergent human infectious diseases, a series of 2,3-dihydro-4H-pyridinone derivatives has been prepared and evaluated for antiviral activity. Compounds were evaluated in vitro in cell-based assays for cytotoxicity and against a wide spectrum of viruses. In the antiviral screening, several compounds showed to be fairly active against viruses belonging to the Flaviviridae family. The Pestiviruses (bovine viral diarrhoea virus) were inhibited by 4a cis (CC(50) > 100 µm; EC(50) = 14 µm), compounds 4c cis and 6a showed a significant activity against Flaviviruses (Yellow Fever Virus) (CC(50) > 100 µm; EC(50) = 18µm, CC(50) > 100 µm; EC(50) = 10 µm). Among these, compound 6a displayed great inhibitory activity against Hepaciviruses (hepatitis C virus) in replicon assay [CC(50) > 100 µm; EC(50) (1b) = 4 µm]. In vitro inhibitory activity against the HCV RNA-dependent RNA polymerase (NS5B) of title compounds is discussed. The antiviral screening of viral strains indicated that compound 6a can be selected as promising tool in novel anti-flaviviruses development.

Structure-based design, synthesis and preliminary anti-inflammatory activity of bolinaquinone analogues.

As a part of our drug discovery efforts we developed a series of simplified derivatives of bolinaquinone (BLQ), a hydroxyquinone marine metabolite, showing potent anti-inflammatory activity. Thirteen new hydroxyquinone derivatives closely related to BLQ were synthesized and tested on mouse macrophage-like RAW 264.7 cell line in order to investigate their ability to modulate the production of Prostaglandin E2 (PGE2). This optimization process led to the identification of three strictly correlated compounds with comparable and higher inhibitory potency than BLQ on PGE2 production. To evaluate the affinity of BLQ and its analogues for hsPLA2, surface plasmon resonance (SPR) experiments were performed.

Synthesis and anti-hepatitis C virus activity of novel ethyl 1H-indole-3-carboxylates in vitro.

A series of ethyl 1H-indole-3-carboxylates 9a(1)(-)(6) and 9b(1)(-)(2) were prepared and evaluated in Huh-7.5 cells. Most of the compounds exhibited anti-hepatitis C virus (HCV) activities at low concentration. The selectivity indices of inhibition on entry and replication of compounds 9a(2) (>10; >16.7) and 9b(1) (>6.25; >16.7) were higher than those of the other evaluated compounds, including the lead compound Arbidol (ARB, 6; 15). Moreover, the selective index of inhibition on entry of compound 9a(3) (>6.25) was higher than that of ARB (6). Of these three initial hits, compound 9a(2) was the most potent.

Design, synthesis and biological evaluation of novel bicyclo[1.1.1]pentane-based omega-acidic amino acids as glutamate receptors ligands.

A novel series of bicyclo[1.1.1]pentane-based omega-acidic amino acids, including (2S)- and (2R)-3-(3'-carboxybicyclo[1.1.1]pentyl)alanines (8 and 9), (2S)- and (2R)-2-(3'-carboxymethylbicyclo[1.1.1]pentyl)glycines (10 and 11), and (2S)- and (2R)-3-(3'-phosphonomethylbicyclo[1.1.1]pentyl)glycines (12 and 13), were synthesized and evaluated as glutamate receptor ligands. Among them, (2R)-3-(3'-phosphonomethylbicyclo[1.1.1]pentyl)glycine (13) showed relatively high affinity and selectivity at the NMDA receptor. The results are also discussed in light of pharmacophoric modelling studies of NMDA agonists and antagonists.

Antiproliferative oleanane saponins from Meryta denhamii.

Eight new oleanane saponins (1- 8) together with four know saponins (9-12) were isolated from the aerial parts of Meryta denhamii. Their structures were elucidated by 1D and 2D NMR experiments including 1D TOCSY, DQF-COSY, ROESY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis. The antiproliferative activity of all compounds was evaluated using three murine and human cancer cell lines: J774.A1, HEK-293, and WEHI-164.

Synthesis, physicochemical properties and in vitro permeation studies of new ketorolac ester derivatives.

Six new 1-alkylazacycloalkan-2-one esters of ketorolac (1-6) were synthesized and evaluated as potential dermal prodrugs. In vitro experiments were carried out to evaluate their chemical and enzymatic stability and permeation through excised human skin. Furthermore, partition coefficients n-octanol-water of ketorolac and its esters were determined to obtain information about their lipophilicity. Esters 1-6 showed increased lipophilicity compared to the parent drug, good stability in phosphate buffer pH 7.4, and were readily hydrolyzed in human plasma. Results from in vitro percutaneous absorption studies showed that, among all esters synthesized, only for esters 2 and 4 did a higher cumulative amount of drug penetrate through the skin, compared with that obtained after topical application of ketorolac.

Synthesis and antiproliferative properties of N3/8-disubstituted 3,8-diazabicyclo[3.2.1]octane analogues of 3,8-bis[2-(3,4,5-trimethoxyphenyl)pyridin-4-yl]methyl-piperazine.

A series of novel N(3/8)-disubstituted-3,8-diazabicyclo[3.2.1]octanes in order to improve the in vitro activity of the prototype 3,8-bis[2-(3,4,5-trimethoxyphenyl)pyridyl-4-yl)methylpiperazine (1) were synthesized and evaluated by assays of growth inhibition against several tumor cell lines. Compounds 2a,b,f and m demonstrated not only growth-inhibitory activities against leukemia cancer cells, but also fairly good activities against the growth of certain solid tumors. Among them, 2a is the most potent one with IC(50) values in the low micromolar range. Moreover, compound 2a has been selected for in vitro testing on MCF-7 cell to evaluate the mode of action of this lead compound.

Evaluation of alternative strategies to optimize ketorolac transdermal delivery.

In the present study, 2 alternative strategies to optimize ketorolac transdermal delivery, namely, prodrugs (polyoxyethylene glycol ester derivatives, I-IV) and nanostructured lipid carriers (NLC) were investigated. The synthesized prodrugs were chemically stable and easily degraded to the parent drug in human plasma. Ketorolac-loaded NLC with high drug content could be successfully prepared. The obtained products formulated into gels showed a different trend of drug permeation through human stratum corneum and epidermis. Particularly, skin permeation of ester prodrugs was significantly enhanced, apart from ester IV, compared with ketorolac, while the results of drug release from NLC outlined that these carriers were ineffective in increasing ketorolac percutaneous absorption owing to a high degree of mutual interaction between the drug and carrier lipid matrix. Polyoxyethylene glycol esterification confirmed to be a suitable approach to enhance ketorolac transdermal delivery, while NLC seemed more appropriate for sustained release owing to the possible formation of a drug reservoir into the skin.

Antiproliferative triterpene saponins from Entada africana.

Nine new ester saponins (1-9) were isolated from the roots of Entada africana. Their structures were elucidated by 1D and 2D NMR experiments including 1D and 2D TOCSY, DQF-COSY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis, and chemical methods. The aglycon moieties were found to be echinocystic acid for compounds 1, 2, 4-6, 8, and 9 and acacic acid for 3 and 7. All isolated compounds were tested for their antiproliferative activity against the J774.A1, HEK-293, and WEHI-164 cell lines. Moderate to high cytotoxic potency was found for almost all compounds tested.

Galactosyl derivatives of L-arginine and D-arginine: synthesis, stability, cell permeation, and nitric oxide production in pituitary GH3 cells.

Nitric oxide (NO) is critical for the normal physiological regulation of the nervous system and other tissues. L-Arginine, but not D-arginine, is the natural substrate for nitric oxide synthase (NOS), for it is enzymatically converted to NO and L-citrulline. However, recent evidence suggests that D-arginine can also produce NO and NO-derivatives via a different pathway. The aim of the present paper was to raise NO levels in the cells by increasing the cell permeation of its precursors. To this aim, two galactosyl prodrugs, L-arginine-D-galactos-6'-yl ester (L-ArgGal) and D-arginine-D-galactos-6'-yl ester (D-ArgGal) were synthesized. Remarkably, using the HPLC-ESI/MS technique, we found that L-ArgGal and D-ArgGal prodrugs both increased the concentration levels of L- and D-arginine and their derivatives in pituitary GH3 cells. Furthermore, we found that D-ArgGal (1) penetrated cell membranes more rapidly than its precursor D-arginine, (2) released arginine more slowly and in greater amounts than L-ArgGal, and (3) produced much higher levels of DAF-2 monitored NO and nitrite than did L-ArgGal under the same experimental conditions. In conclusion, these results indicate that an increase in the cell permeation of L- and D-arginine by L-ArgGal and D-ArgGal can lead to an increase in NO levels.

Synthesis and preliminary biological evaluation of a new pyridocarbazole derivative covalently linked to a thymidine nucleoside as a potential targeted antitumoral agent. I.

The therapy of human cancer is one of the more pursued goals by medicinal chemistry research. Most of the compounds clinically used as a treatment owe their efficacy to their cytotoxic interaction (direct or indirect) with nuclear DNA. This interaction results in the inhibition of DNA synthesis and the degradation of nucleic strands. Ellipticine is a naturally occurring 6H-pyrido[4,3-b]carbazole alkaloid endowed with antitumor activity, and several ellipticine derivatives have been used in clinical trials. We previously reported some 1,4-dimethyl-9H-carbazole derivatives structurally related to ellipticine. The purpose of our research was to transform the pyridocarbazole in a prodrug so that it would have more penetration in the tumor cells and block their replication. Our prodrug is slowly hydrolyzed in human plasma in the corresponding acid. From these preliminary results, we deduce that our compound can block cellular replication. Our hypothesis is that the antitumoral activity is probably related to the induction of damage to DNA, without cellular lysis in the short term.

Glycosyl derivatives of dopamine and L-dopa as anti-Parkinson prodrugs: synthesis, pharmacological activity and in vitro stability studies.

Novel glycosyl derivatives of dopamine and L-dopa (I-IV) are synthesized in order to overcome the problem of blood-brain barrier low permeability of dopamine and of low bioavailability of its precursor L-dopa. Esters synthesized link dopamine and L-dopa, by a succinyl linker, to C-3 position of glucose (I and II) and to C-6 of galactose (II and IV). The chemical and enzymatic stabilities of esters synthesized were evaluated in order to determine both their stability in aqueous medium and their feasibility in undergoing enzymatic cleavage by rat plasma to regenerate the original drug. Furthermore, we have shown the central effects of esters I-IV on classic dopaminergic models, such as morphine induced locomotion and reserpine-induced hypolocomotion. From the result obtained compounds I-IV appeared moderately stable in a pH 7.4 buffered solution and in rat plasma. Furthermore, pharmacological studies showed that both dopamine derivatives (I and II) were equiactive in reversing reserpine-induced hypolocomotion in rats, and both were more active than L-dopa or ester III and IV, while II and III were more potent in reducing morphine-induced locomotion than I and IV. The minimal vascular effects of these derivatives allow us to underline the possibility to use them in pathologies, such as Parkinson disease, characterised by an evident decreasing of dopamine concentration in the brain.

Enantiomeric separation by HPLC of 1,4-dihydropyridines with vancomycin as chiral selector.

The macrocyclic antibiotics represent a relatively new class of chiral selectors in CE, HPLC, and TLC. We have examined the use of the macrocyclic antibiotic vancomycin as a chiral selector in HPLC for the separation of 1,4-dihydropyridines (DHPs) calcium antagonists (CAs). Chromatographic data of six 1,4-dihydropyridine calcium channel blockers obtained on the vancomycin chiral stationary phase (Chirobiotic V) were compared with those obtained on an alpha(1)-acid glycoprotein (AGP) HPLC stationary phase. Optimization of pH and organic modifier was carried out in order to modulate the retention properties of each system. All chiral neutral DHPs were resolved on the AGP column, whereas on Chirobiotic V only basic DHPs showed a split peak. The analytical chromatographic procedure on Chirobiotic V proved suitable for semipreparative separation, since the separation factor on the analytical column was high enough to obtain pure enantiomers with high yields.

Synthesis and in vitro chemical and enzymatic stability of glycosyl 3'-azido-3'-deoxythymidine derivatives as potential anti-HIV agents.

New glycosyl derivatives of 3'-azido-3'-deoxythymidine (AZT) (1 and 2) were synthesized in order to improve AZT retention in the blood and to guarantee its sustained release, overcoming the necessity of multiple drug administrations. The esters synthesized (1 and 2) link AZT, by a succinyl linker, to the C-3 position of glucose and to C-6 of galactose. Furthermore, the chemical and enzymatic stabilities of esters 1 and 2 were evaluated in order to determine both their stability in aqueous medium and their feasibility to undergo enzymatic cleavage by esterase to regenerate the original drug. The pharmacokinetic profiles of esters 1 and 2, obtained after systemic administration, showed an interesting controlled release, in particular for ester 2, compared to the pharmacokinetic profile of AZT.