ANALYTICAL CHEMISTRY/MEDICINAL CHEMISTRY427 doi:10.2533/chimia.2007.427 CHIMIA 2007, 61,No. 7/8 Analytical Chemistry 41 Analytical Chemistry 42 Sensor Arrays forthe Analysis of Sugars in Aqueous Solution Investigation of Hypericum species by LC/MS Friederike Zaubitzer,Kay Severin G. Sibailly,K.Ndjoko,A.Marston, andK.Hostettmann* Institutdes Sciences et Ingénerie Chimiques, Ecole Polytechnique Fédérale LaboratoryofPharmacognosyand Phytochemistry, School of de Lausanne (EPFL),CH-1015 Lausanne, Switzerland Pharmaceutical Sciences,University of Geneva, University of Lausanne, Fluorescence sensors for sugars havereceived enormous interestinrecent Quai Ernest-Ansermet 30,CH-1211 Geneva 4, Switzerland years. Most efforts have focused on the development of sensors with a highly selectivityfor aparticular sugar. This is generally accomplished with thehelp of synthetic receptors, which display ahigh specificity. An interest- Acharacteristic of plant species fromthe genus Hypericum (Hypericaceae) ing alternative is the utilization of asensor array technology. In asensor is the presence of pigments belonging to the class of naphthodianthrones. array, severalnon-specific sensorsare combined and the analyteisthen Theseplants havemany traditional uses and, notably, Hypericum perfora- identified with patternrecognition tools. This technique has successfully tum is employedfor the treatment of mild depression. Severalstudiesdeal been appliedfor different analytical problems [1], but the utilization of sen- with the activitiesofthe numerous constituentsofthe genus or compare sor arrays for sugars is virtually unexplored [2]. We describeasensor array, different Hypericum species [1,2]. Thegenus is alsoreputed forcases of which is based on the reversible coupling of fluorescent hydrazides with the poisoningincattle(hypericism) which alsohave their origin in the presence aldehyde group of reducing sugars. of thesecompounds.Morerecently, the naphthodianthrones have assumed importance forthe photodynamic therapy of cancer. O O N In order to determine the relative contents of hypericin and pseudohypericin Fluorophore NH NH + O Sugar Fluorophore N Sugar 2 H Fluorophore in theseplants,extraction of several species of St.-John's wortwas per- Fig.1.: Schematic representation of afluorescence sensor for sugars formedbydifferent proceduresinordertooptimizethe yield of the active constituents. Discrimination is achieved by exploitation of differences in fluorescence HPLC-UV/DAD and HPLC-MS methods werethen developed forthe emission intensities whichdependonthe nature of the dye-sugar derivate analysis of naphthodianthrones in the plants. It was found that Hypericum and the reaction equilibria in solution. calycinum L. does not contain this classofcompounds. [1]K.J.Albert, N. S. Lewis, C. L. Schauer, G. A. Sotzing, S. E. Stitzel, [1] FicoG., VitaliniS., Colombo N.,TomeF., Hypericum perforatum L.,H. T.P. Vaid,D.R.Walt, Chem.Rev. 2000,100, 2595. maculatum Crantz. ,H.calycinum L .and H. pulchrum L .: phytochemical [2] J. W. Lee, J.-S. Lee, Y.-T. Chang, Angew. Chem. Int. Ed. 2006,45, andmorphological studies., 2006,1,1129-1132. 6485. [2]OzturkY., Testing the andipressant effects of Hypericum specieson animal models,Pharmacopsychiatry, 1998,31, 37. Medicinal Chemistry 43 Medicinal Chemistry 44 Thermodynamic and KineticConsiderations of theBinding Processof Novelguanidine-type 5-HT5A receptorantagonists MAG-Antagonists Jens-Uwe Peters ,* Alexander Alanine,AndreAlker,Francesca Blasco, StefanieMesch,DanielStrasser, Morena Spreafico, BrianCutting, Arnulf Dorn, Alain Gast, Luca Gobbi,Sabine Kolczewski, Nicole SachinShelke, Oliver Schwardt,Beat Ernst Kratochwil,Thomas Lübbers, PariMalherbe, Eric Prinssen, Diana Schuhbauer,Lucinda Steward Institute of MolecularPharmacy,University of Basel, Klingelbergstr. 50, 4050 Basel, Switzerland *Discovery Chemistry, F. Hoffmann-La Roche Ltd, CH-4070 Basel Theinjured adult mammalian central nervous system is an inhibitoryenvi- ronment foraxon regeneration due to specific inhibitoryproteins.The mye- Cl Cl lin-associated glycoprotein (MAG)[1] wasidentified as oneoftheseneurite NH Cl NH NH outgrowth inhibitory proteins [2]. It belongs to the siglec family (sialic-acid N N F H N NH N N bindingimmunoglobulin-like lectin). In earlier studies,weidentified the 2 H F lead structure 1 [3], which was further optimized yielding antagonists with 1 2 3 nM affinities. K i (5-HT 5A)=160 nM K i (5-HT 5A)=2nM K i (5-HT 5A)=3nM screening hit brain/plasma ~0.2 brain/plasma ~4 Cl H N OH COOH Theexpression of the 5-HT receptor in the limbic brain areas suggestsa OH 5A potential role in the modulation of psychiatric diseases. 1 Howeveruntil re- O O O AcHN cently, no selective 5-HT5A receptor ligands were available to study its HO pharmacology in detail. We screened the Roche compound librarytoiden- tifyselective antagonists forthis target, and found several guanidines such 1 as 1 among the mostselective compounds.Asystematic exploration of small substituents (Cl, Me,MeO,F)around the core structureled to 2 with Thekinetic and thermodynamic propertiesofthese high affinity ligands potent 5-HT5A antagonistic affinity in vitro ,and improved selectivity, apart wereelucidatedbyBiacorestudies.Inaddition, the binding mode wasex- from5-HT 7 .Compound 2 had good PK properties, however alow brain- amined through STDNMR experiments and docking studies. plasma ratio. Thebrain penetration was improved by the introduction of electron-withdrawing substituents,which afforded acompound with in- [1]Quarles, R. H., J. Neurochem. 2007, 100,1431. creased lipophilicity,and reduced basicity, 3 .The series refinement and [2]Crocker,R.H., Curr.Opin. Struct.Biol. 2002, 12,609. structure activity relationship elucidatedinprogressing from the initialhit 1 [3]Shelke, S.,Gao,G-P., Mesch, S.,Gäthje, H.,Kelm, S.,Schwardt, O., to lead compound 3 will be furtherdescribed in the presentation. Ernst, B., Bioorg. Med. Chem, in press . [1]Thomas,D.R. Pharmacol.Ther. 2006, 111(3), 707-714. MEDICINAL CHEMISTRY428 CHIMIA 2007, 61,No. 7/8 Medicinal Chemistry 45 Medicinal Chemistry 46 Identification of NovelMulti-functional Compounds for the Treatment Medicinal chemistryefforts towardsthe identificationand development of some Aging Related NeurodegenerativeDiseases of inhibitorsofphosphatidylinositol 3-kinases (PI3Ks)and related proteinkinases forcancer treatment. Juan Bravo,Saviana Di Giovanni,Delphine Cressend, Francesca Bertolini; Laura Novaroli,Antoine Daina,Marianne Reist, Pierre-Alain Carrupt Frédéric Stauffer ,CarlosGarcia-Echeverria, Pascal Furet, Hans-GeorgCapraro,Philipp Holzer,Christian Schnell, Unité de Pharmacochimie, Section dessciences pharmaceutiques, ChristineM.Fritsch &MichelMaira. Université de Genève,Université de Lausanne, Quai Ernest-Ansermet 30, CH-1211 Genève 4, Suisse Novartis Institutes forBioMedical Research, Klybeckstrasse 141, 4057 Basel, Switzerland. Aging related neurodegenerative disorders such as Parkinsondisease (PD) and Alzheimers disease(AD) arethe result of multiple pathophysi- Constitutive activation of the PI3K-pathwayseemstobeaprerequisite for a ological pathways that contribute to theneurodegenerativecascade. Hence, wide spectrumofcancers, either by loss /mutationsofPTEN,acquisition of multi-functionaldrug candidatesabletointeract with severaltargets areof activating mutations in the PI3K catalytic subunit, or amplification /over- great interest forthe treatment of such diseases.Therefore,anexperimental expression of receptor tyrosine kinases upstream of PI3K.Inthisrespect, andvirtualscreening pathwaytogeneratemulti-functionalhits promising components of the PI3K/PKB/mTor pathway such as membersofthe classI forthe treatment of PD or AD was suggested[1]. PI3Ks represent wellvalidated therapeutic targetsfor thediscoveryand de- Among the numerous potentialtargets,fivewereselected; two are velopment of new anticancer drugs.Although theyhave sub-optimal phar- common to both diseases,namely monoamine oxidaseB(MAO B) and oxi- maceutical properties,PI3Kinhibitors like the fungal metabolite wortman- dativestress, and threeare specificfor onlyone of thetwo disorders, nin and the morpholino derivative LY294002 have shown that this classof catechol-O-methyltransferase (COMT) forPDand acetylcholinesterase lipid kinasesis"drug-able".Inactivators of the TORC1 complex- (AChE)aswellas -amyloid deposition forAD, respectively. mTor/Raptor-, such as the rapamicinederivative RAD001, have shown anti- Suitable experimental and virtual screening methods to rapidly test cancer activity in clinical trials.Inaddition to TORC1,the TORC2 complex pre-focused compound librariesweredeveloped and validated. Thepro- -mTor/Rictor-has recently been linked to PKBphosphorylation and activa- posed rationalscreening strategy wasappliedtoalibrary of naturalcom- tion.1 pounds and some focusedsynthetic libraries, leading to some interesting Our medicinalchemistry efforts using the privilege kinaseinhibitor scaffold multi-functionalhits.Refinedmolecularmodelling approaches were also imidazo[4,5-c]quinoline to identify andoptimizenew inhibitors of the used to identifytheir binding modes and to suggestsome guidelinesfor the PI3K/PKB/mTor-pathwaywill be disclosed.From this chemotype,aclinical pharmacomodulation of retained hits in order to obtain multifunctional vir- candidatehas been selected. This inhibitor,which has suitablepharmacol- tual lead compounds. ogical properties forclinical development, shows an efficient controlofthe PI3K-pathway in tumor cells by inhibiting the phosphorylation and