Studio del meccanismo d'azione di composti ad attività antiproliferativa

The research focused on the identification and the study of the mechanism of action of new compounds endowed with antiproliferative activity and characterized by three different chemical structures: twelve benzo- and pyrido-thiopyranoindol derivatives (Group A); twenty one 2-aryl substituted benzothiopyrano-fused pyrimidines (Group B); and fourteen triphenylethylenic derivatives (Group C). As preliminary evaluation, the ability of compounds to inhibit cell proliferation on human tumor cell lines was estimated and in particular, the GI50 values (concentration of compound able to induce 50% cell death with respect to a control), were calculated for each compound. For compounds characterized by the most significant antiproliferative activitiy, the mechanism of action has been investigated, with the aim to establish the intracellular targets involved in the cytotoxic effect. In this connection, both macromolecules and intracellular organelles have been taken into consideration as potential molecular targets responsible for the cytotoxicity. In detail, the ability to form a molecular complex with DNA, along with the capacity to interfere with the catalytic activity of both topoisomerases I and II, were evaluated. Furthermore, the effect on the tyrosin kinase receptor, VEGFR-2 (KDR), involved in the angiogenesis process which participates to the tumor growth, was investigated. Finally, the death pathway induced by the studied compounds was determined by cytofluorimetric analyses. The occurrence of apoptotic process, such as the contribution of the intrinsic pathway, through the mitochondrial depolarization, allowed to draw for each group of compounds the mechanism involved in the cytotoxicit

Calmness of Linear Constraint Systems under Structured Perturbations with an Application to the Path-Following Scheme

Publisher Copyright: © 2021, The Author(s).We are concerned with finite linear constraint systems in a parametric framework where the right-hand side is an affine function of the perturbation parameter. Such structured perturbations provide a unified framework for different parametric models in the literature, as block, directional and/or partial perturbations of both inequalities and equalities. We extend some recent results about calmness of the feasible set mapping and provide an application to the convergence of a certain path-following algorithmic scheme. We underline the fact that our formula for the calmness modulus depends only on the nominal data, which makes it computable in practice.Peer reviewe

A new scaffold of topoisomerase I inhibitors : Design, synthesis and biological evaluation

The synthesis of a new hexacyclic system was realized starting from tryptamines and exploiting as a key step a sequential Pd-catalyzed N-arylation/acylation reaction. Having topoisomerases as biological target and the campthotecins class as benchmark, the new scaffold was decorated with substituents having different polarity and tested as Topoisomerase I inhibitors

Studio del meccanismo d'azione di composti ad attività antiproliferativa

The research focused on the identification and the study of the mechanism of action of new compounds endowed with antiproliferative activity and characterized by three different chemical structures: twelve benzo- and pyrido-thiopyranoindol derivatives (Group A); twenty one 2-aryl substituted benzothiopyrano-fused pyrimidines (Group B); and fourteen triphenylethylenic derivatives (Group C). As preliminary evaluation, the ability of compounds to inhibit cell proliferation on human tumor cell lines was estimated and in particular, the GI50 values (concentration of compound able to induce 50% cell death with respect to a control), were calculated for each compound. For compounds characterized by the most significant antiproliferative activitiy, the mechanism of action has been investigated, with the aim to establish the intracellular targets involved in the cytotoxic effect. In this connection, both macromolecules and intracellular organelles have been taken into consideration as potential molecular targets responsible for the cytotoxicity. In detail, the ability to form a molecular complex with DNA, along with the capacity to interfere with the catalytic activity of both topoisomerases I and II, were evaluated. Furthermore, the effect on the tyrosin kinase receptor, VEGFR-2 (KDR), involved in the angiogenesis process which participates to the tumor growth, was investigated. Finally, the death pathway induced by the studied compounds was determined by cytofluorimetric analyses. The occurrence of apoptotic process, such as the contribution of the intrinsic pathway, through the mitochondrial depolarization, allowed to draw for each group of compounds the mechanism involved in the cytotoxicityL'attività di ricerca svolta ha riguardato l'individuazione e lo studio del meccanismo d'azione di composti ad attività antiproliferativa appartenenti a tre gruppi strutturalmente distinti: gruppo A formato da dodici derivati benzo- e pirido-tiopiranoindolici; gruppo B costituito da ventuno derivati benzotiopiranopirimidinici; e il gruppo C al quale appartengono quattordici derivati trifeniletilenici. Su tutti i composti è stata effettuata una prima determinazione con l'obiettivo di valutare la capacità inibitoria sulla proliferazione cellulare. A questo scopo sono state utilizzate linee cellulari tumorali umane e sono stati determinati i valori di GI50 (concentrazione di composto in grado di provocare il 50% di morte cellulare rispetto ad una coltura di controllo). Successivamente, dei composti dotati di attività antiproliferativa più significativa, è stato studiato il meccanismo d'azione, allo scopo di individuare i bersagli intracellulari coinvolti nella morte cellulare. Nell'ambito dell'individuazione dei bersagli molecolari responsabili dell'attività, sono state prese in considerazione sia macromolecole che organelli intracellulari. In particolare è stata valutata la capacità di complessarsi con il DNA, così come di interferire con i processi metabolici della macromolecola stessa mediati dagli enzimi nucleari topoisomerasi I e II. Analogamente si è considerata la possibile interferenza con enzimi recettoriali ad attività tirosinchinasica, quale VEGFR-2 o KDR, strettamente coinvolto nel processo neoangiogenico tumorale. Infine la tipologia di morte cellulare indotta dai composti in esame è stata determinata attraverso una serie di studi di citofluorimetria. La valutazione dell'attivazione del processo apoptotico, così come il contributo della via intrinseca, determinato a livello mitocondriale, hanno consentito di definire in modo completo per ciascun gruppo di composti il meccanismo coinvolto nell'effetto citotossic

Synthesis, spectroscopic and antimicrobial studies of some novel cyanine dyes based on bis-coumarin heterocycles derivatives

Novel symmetrical and unsymmetrical cyanine dyes, incorporating merocyanine monomethine like, pentamethine cyanine, monomethine-meso-substituted-pentamethine and mono-5[2(4)]-methine cyanine dye have been prepared through the synthesis of new starting compound derivatives named as 1,3-bis-(2-oxo-2H-chromen-3-yl) propane-1,3-dione and (3-oxo1,3-bis(2-oxo-2H-chromen-3-yl)prop-1-enyloxy) copper, cobalt and nickel chloride salt complexes. Structure determination of the new compounds has been characterized on the basis of elemental analysis, IR, 1H NMR and MS spectra. Structure photosensitization relationship of new dyes have been discussed on the basis of their spectral behavior as criteria of photosensitizing effect through the UV visible-absorption spectra of all synthesized dyes which investigated in 95% ethanol. Antimicrobial properties of some selected cyanine dyes have been investigated against Streptococcus sp, Staphylococcus sp, Salmonella sp. and Shigella sp

Free radical scavenging activity from Casimiroa spp. extracts

Free radicals, particularly reactive oxygen species (ROS), are involved in the pathogenesis of several chronical and degenerative diseases. This study was designed to investigate the antioxidative properties of natural extracts and isolated compounds of Casimiroa edulis and Casimiroa pubescens Llave et Lex (Rutaceae). The genus Casimiroa is widely spread in the tropical and subtropical areas of central America: the decoction of leaves and seeds, together with the consumption of the edible fruits are quite diffused as folk remedies to relieve hypertensive ailments, insomnia, rheumatisms and arthritic pains. To the best of our knowledge, there are no available scientific data directly related to the benefit of scavenging activity toward radical-mediated disease prevention, such as for coronary heart disease, cancer, Alzheimer, arthritis and diabetes as well as degenerative processes associated with aging (Haliwell et al. 1992), in consequence of membrane damage, protein modification, enzyme inactivation and DNA damage induced by free radicals. The antioxidant effect was evaluated by \uf061,\uf061-diphenyl-\uf062-picrylhydrazyl (DPPH.) decolorization, according to the method reported by Brand-Williams et al. (1995); the assay was performed first with TLC plate as positive antioxidant control and then with a spectrophotometric analysis to measure the effective in vitro scavenging activity. We used N-acetyl-L-cysteine, pyrogallic acid, \uf061-tocopherol, L-ascorbic acid and quercetin as antioxidative standards. Casimiroa edulis hexanic leaf extract (Ce5), seed extract (Ce7) and methanolic seed extract (Ce8) at 600 \uf06dg/ml showed an antiradical activity of 77.0\uf0b19.2%, 24.2\uf0b12.9% and 72.0\uf0b15.6% respectively. Also C. pubescens methanolic leaf extract (Cp10) and seed extract (Cp12) at the same concentrations pointed out an antioxidant activity of 84.7\uf0b10.2% and 58.4\uf0b14.3% respectively. According to the phytochemical composition of the extracts, the DPPH. screening was performed also with several organic compounds specifically identified in the genus, such as imperatorin, herniarin, 7-methoxy-3-(2-methylbut-3-en-2-yl)cumarin and pentamethoxyflavone. Imperatorin and pentamethoxyflavone (5mM) revealed an antioxidant activity of 71.3\uf0b10.2% and 30.7\uf0b11.3%, while the cumarin derivatives showed a very low antioxidant profile. Experimental evidences indicated a non-linear relationship between the antioxidant concentration and the DPPH. radical scavenging activity: as a consequence, the measurement of the EC50 seemed quite problematic. For this reason we used a mathematical software to process the data and then to obtain a relation between antioxidant activity and sample concentration (Locatelli et al. 2009). Hence, Casimiroa extracts and some isolated constituents - mainly imperatorin and pentamethoxyflavone - have shown a remarkable radical scavenging activity; research is progressing to characterize their effects on LDL oxidation. References Brand-Williams W et al. (1995) LWT-Food Science and Technology 28:25 Haliwell B et al. (1992) J. Lab. Clin. Med. 119:598 Locatelli M et al. (2009) Food Chemistry 114:88

Vasorelaxation by extracts of Casimiroa spp. in rat resistance vessels and pharmacological study of cellular mechanisms

AIM OF THE STUDY: Casimiroa spp. are Mexican plants traditionally used for treatment of hypertension. To study their antihypertensive action, we determined the arterial dilatation induced by extracts from leaves and seeds of Casimiroa calderoniae F. Chiang & Medrano, Casimiroa edulis Llave et Lex, and Casimiroa pubescens Ramirez. MATERIALS AND METHODS: The vascular effects of Casimiroa spp. extracts were investigated on rat caudal and aortic arteries. In addition, the extracts were characterized by HPLC using heraclenol, isopimpinellin, heraclenin and phellopterin as external standards. The methanolic extract of Casimiroa pubescens seeds (Cp12) was also studied by H-NMR and LC-MS (ESI-TOF) for the determination of casimiroin and zapotin. RESULTS: The hexanic and methanolic extracts of Casimiroa spp. (20 \u3bcg/ml) showed vasorelaxation in arterial tissues precontracted by phenylephrine (0.5 \u3bcM); the extracts from seeds always caused a greater relaxation in comparison to those from leaves. The most active were the methanolic seed extracts of Casimiroa edulis (Ce8) and Casimiroa pubescens (Cp12). To study the pharmacological mechanisms of vasodilatation we used various inhibitors selective to different receptor subtypes or intracellular enzymes. The vasorelaxant effect of Ce8 (20 \u3bcg/ml) remained unaffected by the pretreatment with pyrilamine (10 \u3bcM), an antagonist of histamine H(1) receptors, but was inhibited by atropine (0.1 \u3bcM), a muscarinic receptor antagonist. Therefore, to determine muscarinic receptor subtypes, we used pirenzepine (1 \u3bcM), a selective inhibitor of M(1) receptor, and 4-diphenylacetoxyl-N-methylpiperidine methiodide (DAMP, 0.01 \u3bcM), a selective inhibitor of M(3) receptor. Only the latter reduced the vasodilatation by Ce8 and Cp12. To investigate the role of the nitric oxide synthase (NOS), we used N(G)-nitro-l-arginine methyl ester (l-NAME, 10 \u3bcM), a selective NOS inhibitor, which decreased the dilatation induced by Ce8 and Cp12. Finally, we studied the action of (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) (ODQ, 3 \u3bcM), a selective guanylyl cyclase inhibitor, which inhibited the dilatation by Casimiroa extracts. CONCLUSION: The data show that methanolic seed extracts of Casimiroa edulis (Ce8) and Casimiroa pubescens (Cp12) induce vasorelaxation by M(3) receptor through the activation of cGMP-dependent NO signaling. These results support the traditional use of Casimiroa decoctions for antihypertensive treatments in the Mexican ethnomedicine

Novel benzoquinoline derivatives via unpredicted condensation of ethyl propiolate and naphthylamines: Synthesis and topoisomerase inhibition activity

An unpredicted condensation of naphthylamine with two molecules of ethyl propiolate yields directly carbethoxy benzoquinoline in high yield. Some benzoquinoline carboxamide derivatives with protonatable side chains were then synthesized and evaluated for antiproliferative activity on human tumor cell lines. The most active compound (7a) demonstrated to intercalate into DNA and to inhibit the relaxation activity mediated by topoisomerase II

Azione Farmacologica in vitro di Casamiroa edulis in tessuti vascolari a resistenza

l’ipertensione. Alcuni Autori hanno evidenziato in vari modelli sperimentali sia effetti ipotensivi che ipertensivi ma i dati presenti in letteratura sono piuttosto discordanti. La sperimentazione a tale riguardo è limitata; per chiarire i possibili effetti vascolari di C. edulis abbiamo studiato l’azione degli estratti di foglie e di semi, ottenuti con metanolo e con esano, sul tono vascolare arterioso. Gli studi sperimentali in vitro sono stati quindi eseguiti in preparati costituiti da segmenti di arterie caudali di circa 3 mm ottenute da ratti maschi Wistar di 3-5 mesi del peso di 250-350 grammi. Gli estratti CE5, CE6, CE7 e CE8, alla concentrazione di 20 μg/ml, sperimentati sul tono basale dell’arteria caudale non hanno indotto alcuna modificazione della tensione vascolare. Successivamente si sono studiati gli stessi estratti in preparati precontratti con fenilefrina (0.5 μM); in tale condizione si è osservata un’evidente azione vasorilasciante, riproducibile e di elevata entità. L’estratto CE7, estratto dei semi di C. edulis in esano, risultò il più attivo rilasciando il tessuto arterioso pressoché completamente. Nel seme oltre ad essere stata identificata istamina e suoi derivati, sono stati isolati alcaloidi quali eduleina, casimiroidina ed altri. Si sono identificati anche flavonoidi come zapotina e zapotinina e triterpeni come zapoterina. L’attività vasorilasciante evidenziata durante la sperimentazione potrebbe dipendere da uno o più di questi componenti. Per chiarire questo interessante punto, ulteriori studi sono in atto per determinare l’azione di singoli costituenti, isolati da C. edulis, allo scopo di evidenziare quali di questi possa essere il responsabile dell’elevato effetto vasorilasciante osservato in questo studio. Ancora una volta l’attività tradizionale ascritta a una droga vegetale trova importanti riscontri mediante studi sperimentali riproponendo l’impiego delle droghe vegetali in ambito terapeutico e per lo sviluppo di nuovi farmaci