Synthesis and pharmacological investigation of new N-hydroxyalkyl-2-aminophenothiazines exhibiting marked MDR inhibitory effect

Novel N-hydroxyalkyl-2-aminophenothiazines implying a tetrazole moiety at the alkyl chain have been synthesized by hydroboration-oxidation of dienes followed by Buchwald-Hartwig cross-coupling reaction. Also, some sulfoxide and sulfone derivatives have been prepared by selective oxidations. MDR inhibition studies on rat hepatocyte cell culture revealed that some derivatives exhibit marked biological efficacy exceeding that of the standard verapamil (e.g. 3h, 4h, 16). Selected derivatives were subjected to chemical resolution to provide both enantiomers which were shown of similar activity on P-gp interaction measurements. The new compounds exhibited no toxicit

Új szintézismódszerek kidolgozása és alkalmazása célzott hatásterületen aktív heterociklusos molekulák szintézisére = Elaboration and application of new synthetic methodologies for the synthesis of heterocyclic molecules of aimed biological activity

Pályázati kutatásunk alapvető célja az volt, hogy néhány, a legutóbbi időkben felismert új szintézis-lehetőséget laboratóriumunkban meghonosítsunk, saját magunk új módszereket dolgozzunk ki, és mindezek segítségével felfedező kutatásokat végezzünk kiemelten fontos területen ható biológiailag aktív molekulák megtalálására és szintézisére. Beszámolhatunk arról, hogy palládium-katalizált C-C és C-N keresztkapcsolások segítségével új gyűrűvázakhoz jutottunk, és alapvető új átalakulásokat kezdeményeztünk az organokatalízis és fluoros technika területén. Módszereink segítségével főként a multidrog-rezisztenciát gátló vegyületek családjában értünk el figyelemre méltó eredményt. Kimutattuk, hogy néhány újszerűen szubsztituált fenotiazin-származék hatása meghaladja a kontrollként vizsgált verapamil hatását. A rezisztencia gátlása különösen a mikróbás fertőzések és tumoros betegségek leküzdésében kiemelt jelentőségű. A leghatékonyabb származékokat egy jövőbeli gyógyszerfejlesztés lead-molekulájaként tekintjük. Munkánk elvégzésébe nagy számban vontunk be graduális és posztgraduális hallgatókat. A kutatási eredményekből 7 PhD értekezés született, ezek közül 4 már sikeres védésre került, emellett két egyetemi záródolgozat is elkészült. Munkánk tudományos értékét a megjelent 18 közlemény fémjelzi, összesített hatástényezőjük 57.5. | The basic aim of the present project activity was to establish recently recognized new synthetic methodologies in our laboratory, to elaborate new procedures, and to apply these novel approaches for identification and synthesis of compounds exhibiting biological activity in important areas of drug research. It is to be emphasized that application of palladium-catalyzed C-C and C-N cross coupling reactions allowed the synthesis of new ring systems, whereas basically new transformations have been initiated in the areas of organocatalysis and fluorous techniques.. The new methods provided the most outstanding reaults in the area of multidrug resistance inhibition. Results of some phenothiazines with unusual substitution pattern exceeded the effect of verapamil used as a reference compound. Resistance inhibition is of primary importance in treatment of microbial infections and tumor diseases. Those synthesized compounds exhibiting the highest effectivity can be regarded as lead compounds for the future drug development. Great number of MSc and PhD students were involved into accomplishment of the project. Seven PhD dissertations were born, four of these have already been successfully defended and, furthermore, two master theses have also been finalized. The scientific value of the research activity is coined by the 18 scientific publications with a cumulative impact factor of 57.5

Aortarepedés - egy létező probléma a brojlerpulyka állományokban. Irodalmi áttekintés és saját vizsgálatok

A tudomány jelen állása alapján a brojler bak pulykák aortarepedése egy multifaktoriális kórkép. Ezt előre jelezni vagy a repedés kialakulásakor sikeresen beavatkozni nem lehet. A megelőzésre kell nagy hangsúlyt fektetni. A kórkép előidézésében nagy szerepet játszik a stressz, a különleges aortaalakulás, a megfelelő takarmányozási és tartási körülmények hiánya

Multidrug Resistance Reversing Activity of Newly Developed Phenothiazines on P-glycoprotein (ABCB1)-related Resistance of Mouse T-Lymphoma Cells

BACKGROUND: Phenothiazines have anticancer properties and are able to reverse the multidrug resistance of neoplastic cells by inhibiting the ATP-binding cassette, sub-family B (MDR/TAP), member 1 protein (ABCB1 or P-glycoprotein) activity. MATERIALS AND METHODS: A series of new phenothiazine derivatives was investigated regarding their ABCB1-modulating effect on multidrug resistant mouse T-lymphoma cells by rhodamine 123 accumulation assay and real-time ethidium bromide accumulation assay. RESULTS: The phenothiazine derivatives exhibited a potent anticancer effect on the parental cell line and on its multidrug-resistant mouse T-lymphoma subline overexpressing the ABCB1 transporter. The inhibition of the ABCB1 transporter in the presence of the newly-developed phenothiazines was greater than that for the known ABCB1 inhibitors thioridazine and verapamil. CONCLUSION: Based on the chemical structures and biological activity, compounds with bivalent sulfur atom in the phenothiazine ring demonstrated marked ABCB1-modulating effect, however, other derivatives with halogen or amide substitutions were ineffective

Efflux Pump Inhibiting Properties of Racemic Phenothiazine Derivatives and their Enantiomers on the Bacterial AcrAB-TolC System

Background/Aim: Bacterial resistance to antibiotics has become a serious problem in antibacterial chemotherapy and resistance of bacteria to chemicallyunrelated anti-microbial agents can be associated with the over-expression of efflux pumps. The simultaneous therapy with efflux pump inhibitors (EPIs) could be a solution to improve the effectiveness of antibiotics. The response of an organism to an EPI often depends on how that molecule fits a particular site of a protein. Because enantiomers of a given compound rotate plane-polarized light in a solution by the same angle but in opposite directions, the rational drug design should take the chirality into account if there is a difference between the racemic compound and its enantiomers. Materials and Methods: The main goal of the present study was to elucidate the role of chirality of Nhydroxyalkyl- 2-aminophenothiazines as effective EPIs by an automated method that uses the general efflux pump substrate ethidium bromide (EB) for the assessment of AcrAB-TolC system of wild-type Escherichia coli K-12 AG100. It has been shown that the most active EPIs among the N-hydroxyalkyl-2-aminophenothiazines were the compounds rac-3i, (+)-3i, and (–)-3i by modulating the AcrAB-TolC efflux pump. Conclusion: Comparison of effects of enantiomeric pairs revealed that their activities were similar to that of racemic derivatives. Moreover, there was no significant difference between the racemic compounds and their enantiomers related to their antibacterial and efflux pump inhibiting effects

Selective hydroboration of dieneamines. Formation of hydroxyalkylphenothiazines as MDR modulators

N-dienylphenothiazines synthesized from tetrazolo[1,5-a]pyridinium salts by treatment with phenothiazine were subjected to catalytic hydrogenation to yield N-butylphenothiazines, whereas transformation of these dienes with borane dimethyl sulfide (BH 3 × Me 2S) resulted in selective hydroboration of one double bond and full reduction of the other double bond to give 2-hydroxybutylphenothiazines. Position of the hydroxyl group was supported by NMR spectroscopy and verified by X-ray analysis. Comparison of MDR modulatory activity of the new derivatives revealed that the hydroxybutyl compounds are promising candidates for development of novel MDR inhibitors. © 2012 Elsevier Ltd. All rights reserved

Reversal of ABCB1-related Multidrug Resistance of Colonic Adenocarcinoma Cells by Phenothiazines

BACKGROUND: The most common mechanism that reduces the efficacy of anticancer agents is overexpression of ATP-binding cassette (ABC) drug transporters. Phenothiazines and structurally-related compounds can sensitize multidrug-resistant (MDR) cells to chemotherapeutics. MATERIALS AND METHODS: Phenothiazine derivatives were investigated regarding their anticancer and MDR-reversing effect on colonic adenocarcinoma cells. The anti-proliferative and cytotoxic effects of the derivatives were assessed by the thiazolyl blue tetrazolium bromide (MTT) method, the modulation of the ABCB1 activity was measured by rhodamine 123 accumulation assay using flow cytometry. RESULTS: All phenothiazines exhibited potent cytotoxic effect on the sensitive and MDR colon adenocarcinoma cell lines. The inhibition of the ABCB1 transporter was greater in the presence of the phenothiazine derivatives than for the known ABCB1 inhibitor verapamil. CONCLUSION: It can be concluded that these derivatives show synergism in the presence of doxorubicin and could have potential as ABCB1 inhibitors