There are at least two models describing how the enzymes of metabolic pathways are arranged in living cells. The first is a stochastic model, where enzymes are freely-diffusing in the aqueous environment of the cell, and the second, the metabolon model, has pathway enzymes organized as enzyme complexes. Both are valid scientific hypotheses in that they make predictions that can be tested regarding pathway regulation, localization, and function. The goal of the work presented here was to test the metabolon model using the flavonoid biosynthetic pathway in Arabidopsis, which has been hypothesized to exist as a metabolic enzyme complex. Five novel mutants of the gene encoding the first enzyme of flavonoid biosynthesis, chalcone synthase (CHS), were characterized in an effort to develop tools for investigating the organization of flavonoid metabolism in Arabidopsis. A variety of mutant CHS genotypes were identified in this allelic series, including ones that displayed both null and temperature-sensitive phenotypes, based on endproduct analysis. Characterization of protein and RNA levels indicated that the stability of the CHS enzyme was reduced in some of the mutants as compared to wild type. In several of the alleles, homodimerization of CHS was also impaired. Effects of the mutations at the amino acid level were predicted from the three-dimensional crystal structure of the highly-homologous alfalfa CHS, which indicated substitutions at diverse sites on the enzyme, including ones that may disrupt folding and/or active site function. This allelic series should provide a useful genetic resource for ongoing studies of flavonoid enzyme structure, function, and subcellular organization. In an effort to determine the in planta location of the first two enzymes in flavonoid biosynthesis, CHS and chalcone isomerase (CHI), immunolocalization experiments were performed. Results indicate that CHS and CHI are abundant in epidermal and cortex cells of the root elongation zone and the root tip, consistent with the accumulation of flavonoid endproducts at these sites. At the subcellular level, both of these enzymes were found to localize to the endoplasmic reticulum (ER), consistent with the hypothesis that the enzymes of flavonoid biosynthesis are organized as a membrane-associated enzyme complex. Analysis of the tt7(88) mutant, which lacks the cytosolic domain of the putative 'anchor' P450 enzyme, flavonoid 3'-hydroxylase, showed an altered distribution of CHS and CHI as compared to wild type, however CHS and CHI were still found to be associated with ER. These results suggest that complex interactions occur within the flavonoid enzyme complex to mediate the subcellular distribution of its constituents. Also evident from these studies was the asymmetric distribution of CHS and CHI in cortex cells of the elongation zone, a finding that may provide clues about the physiological function of flavonoids in roots. Together, these immunolocalization data support the metabolon model for the organization of flavonoid biosynthesis in Arabidopsis. In an effort to develop tools to investigate the in vivo dynamics of flavonoid biosynthesis, fusion proteins between CHS or CHI and the reporter, green fluorescent protein (GFP), were produced. Transient transfection assays in epidermal cells from onion root bulbs and Arabidopsis seedlings indicated that the GFP component of the fusion constructs was functional, as determined via GFP fluorescence. To investigate the spatial and temporal dynamics of these fusion proteins in all cell types, Arabidopsis plants stably transformed with the CHI-GFP fusion constructs were generated. The analysis of these transgenic plants should provide information regarding the localization and dynamics of flavonoid biosynthesis in vivo, and thereby serve to offer new insights into the function and regulation of this important plant metabolic pathway. Overall, the research presented here represents a significant contribution toward understanding how subcellular organization may be important in regulating metabolism. / Ph. D.

Flavonoid biosynthesis is an important secondary metabolic pathway in higher plants with a range of vital functions in plants and animals. This pathway has been developed as a model system for the study of multi-enzyme complexes. The goal of the work presented here was to structurally characterize a series of loss-of-function chalcone synthase (CHS) alleles and to define the molecular basis of the interaction between CHS and the second enzyme of flavonoid biosynthesis, chalcone isomerase (CHI). CHS proteins encoded by five previously characterized alleles were characterized by homology modeling in an effort to explain the alterations in function, stability, and dimerization exhibited by these variants. Four of the encoded proteins have a single amino acid substitution and the fifth is a truncated protein resulting from a frameshift. Models for each of these proteins were generated in silico and analyzed after molecular dynamics simulations. This analysis suggested reasons for changes in catalytic ability and stability for three of the five CHS variants. To characterize the molecular basis of the CHS-CHI interaction, a model was developed using X-ray crystallography, small-angle neutron scattering (SANS), in silico docking, molecular dynamics simulations, and yeast 2-hybrid analyses. These enzymes appear to be interacting in a manner that could facilitate the flow of intermediates from one active site to another. These experiments also identified a series of amino acids that appear to be involved in the interaction, which are currently undergoing alteration and analysis using a yeast 2-hybrid assay to verify the authenticity of the model. The data presented herein could be used in future engineering experiments to alter pathway flux to control the levels or types of flavonoid endproducts, resulting in more nutritious plants or flowers with novel pigments. These experiments advance the study of the structure of multi-enzyme complexes, an area that currently contains little information. As well, this is the first known use of SANS for the investigation of the architecture of metabolons. The techniques described herein could easily be applied to other systems in an effort to better understand the organization of multi-enzyme complexes and the implications of these assemblies on metabolic regulation. / Ph. D.

The chalcone motif is a privileged structure present in an extensive range of biologically active molecules. The chalcone structure can also serve as a versatile starting material for more complex molecules in medicinal chemistry. Eleutherobin, isolated from the Australian coral Eleutherobia and sarcodictyin, isolated from the Mediterranean coral Sarcodictyon roseum are natural products displaying nanomolar cytotoxicity against a range of cancer cell lines including Taxol®-resistant cell lines. Both natural products act as microtubule stabilising agents and will be valuable additions to the clinic, however their limited availability and lengthy total syntheses prevent further development. The urocanic ester side chain present in eleutherobin and sarcodictyin was identified as being critical for biological activity. We discuss the design, synthesis and biological evaluation of fourteen chalcone analogues based on this urocanic motif with the lead chalcone displaying promising antiproliferative activity in a range of cancer cell lines. Combretastatin A-4 is a promising microtubule destabiliser under clinical development. The Z configuration is vital for biological activity, however it can isomerise to the inactive E configuration. We report a library of twenty pyrazolines synthesised from chalcones as “Z restricted” combretastatin analogues with the lead pyrazoline displaying potent antiproliferative activity in cancer cell lines due to the disruption of tubulin. Tissue engineering is a diverse interdisciplinary field that applies engineering principles to the biological sciences with the aim of maintaining or replacing tissue function. Recent developments have revealed metal chelation to be a valuable tool to control the architecture of tissue engineering scaffolds. We report a library of ten novel pyrazolines and their potential as metal chelators. Maltol is a well established Fe3+ chelator with a low toxicity profile. We report a novel maltol hydrazide which can be attached to the cell surface which upon addition of Fe3+ results in cellular aggregation due to metal chelation. Further studies revealed that this process can be applied to form heterocellular aggregates composed of two different cancer types with valuable applications in tissue engineering and cancer research.

Le projet a consisté à développer une nouvelle stratégie thérapeutique basée sur les spécificités moléculaires intrinsèques des tumeurs solides afin de personnaliser le traitement en le reliant directement au diagnostic de la tumeur (theranostic). Les tumeurs cérébrales et les tumeurs de vessies sont deux exemples de tumeurs solides particulièrement agressives. Ces deux types de tumeurs sont classés en plusieurs sous-groupes ayant leur propre profil moléculaire. Les microARN (ou miR) sont des molécules synthétisées naturellement par les cellules. Ces molécules peuvent avoir un rôle d’oncogène ou de suppresseur de tumeurs et leur expression est fortement dérégulée dans les tumeurs. Ainsi la mesure des taux d’expression de quelques microARN dans un échantillon de tissu tumoral permet de réaliser la distinction des gliomes de haut grade par rapport à ceux de bas grade. Dans le cadre du traitement, la thérapie envisagée consiste à moduler l’expression des microARN dérégulés dans les tumeurs. L’approche évaluée consiste à contrer l’expression de microARN oncogènes surexprimés à l’aide d’un antimicroARN (antimiR). Ce type de molécule est chimiquement semblable aux molécules d’ARN naturellement présentes dans la cellule. Pour une meilleure efficacité de cette stratégie thérapeutique, l’autre partie du projet a consisté à optimiser le transport de l’antimiR et l’effet de la thérapie. Pour introduire l’antimicroARN au plus près du coeur de la tumeur, il a été prévu de réaliser un couplage entre un antimiR et un dérivé de chalcones pénétrant facilement dans les cellules et doué de propriétés antitumorales, cette combinaison paraît prometteuse. / Solid malignant tumors have molecular characteristics that clearly distinguish them from healthy tissue. The project is to develop a new therapeutic strategy based on these molecular characteristics. We set up a new therapeutic approach so as to customize treatment by connecting it directly to the diagnosis of the tumor (theranostic approach).Brain tumours and bladder tumours are two examples of particularly aggressive solid tumours. These two types of tumors are classified into several subgroups that have their own molecular profiles. The microRNAs (miR) are molecules naturally synthesized by cells. These molecules may have a role of oncogene or tumour suppressors whose expression is strongly deregulated in tumours. So the assessment of the expression levels of few microRNA allows the distinction of gliomas of high grade compared to low grade.To set up the new therapy we needed to modulate the expression of microRNAs deregulated in tumors. The proposed approach was to counter the expression of oncogenic microRNAs overexpressed using an antimicroARN (antimiR). This type of molecule is chemically similar to the naturally occurring RNA molecules in the cells. For a better efficiency of this new therapeutic strategy, we tried to optimize the transport of the antimiR to increase the therapeutic effect. To vectorize the therapeitic antimiR to the heart of the tumor, we envisioned to chemically combine the antimiR to a cell-penetrating antitumoral compound. Chalcones derivatives which are hydrophobic have this capability. A combination of the two molecules (antimicroARN and chalcone) was evaluated and the results appeared promising.

Pyrolysis of 3- (o-methoxyphenyl)-1-phenylprop-2-en-1-one(49) ¡B1- (o-methoxyphenyl)-3-phenylprop-2-en-1-one (50) and 1-(o-methoxyphenyl)-3-phenylprop -2-yn-1-one (51) gave the expected cyclic products 2-phenylbenzo[b]furan (11) and flavone (73). Furthermore, compounds 49-51 gave phenanthrene-9,10-dione (71)¡Bfluoren-9-one (14) and others as the minor products at high temperture. Under photolytic condition, compounds 49-51 gave photocyclic product (73) all in low yields and recovered mostly the starting materials.

Submitted by ANA CERREJÓN PALANCO null (anacerrejon@live.com) on 2016-09-29T21:40:59Z No. of bitstreams: 1 Mestrado-Ana-Cerrejón-Palanco.pdf: 2202083 bytes, checksum: 3d49fc49aae6a457cad301dea9e43240 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-10-04T19:11:41Z (GMT) No. of bitstreams: 1 carrejonpalanco_a_me_arafcf.pdf: 2202083 bytes, checksum: 3d49fc49aae6a457cad301dea9e43240 (MD5) / Made available in DSpace on 2016-10-04T19:11:41Z (GMT). No. of bitstreams: 1 carrejonpalanco_a_me_arafcf.pdf: 2202083 bytes, checksum: 3d49fc49aae6a457cad301dea9e43240 (MD5) Previous issue date: 2016-09-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A criptococose é uma infecção fúngica sistêmica e oportunista, causada pelas leveduras capsuladas das espécies Cryptococcus neoformans e Cryptococcus gattii, afetando tanto pacientes imunocompetentes quanto imunocomprometidos. Uma propriedade importante do gênero Cryptococcus é a capacidade de formação de biofilmes. A resistência dos biofilmes aos agentes antifúngicos traz a necessidade da busca de novas terapias. Desta forma, o nosso grupo vem trabalhando com moléculas antifúngicas derivadas de fontes naturais, como as chalconas, onde foi verificado que C. neoformans é sensível a algumas destas moléculas. Assim, o objetivo desse trabalho foi testar a 3’- chalcona como antifúngico contra C. gattii em situação planctônica e biofilme, como também a eficiência e toxicidade em modelos animais alternativos como Danio rerio (Zebrafish) e Galleria mellonella, propondo uma nova alternativa para o tratamento. In vitro, os resultados para a forma planctônica do fungo mostraram que a 3’- chalcona foi mais eficaz para a cepa 118, com concentração inibitória mínima (CIM) de 0,96 µg/mL e para a cepa 56990 de C. gattii, a molécula mostrou ação potente com CIM entre 1,95 e 3,90 µg/mL. No ensaio de formação do biofilme com as duas cepas, observou-se uma atividade metabólica crescente até 72 horas e uma biomassa e matriz extracelular que alcançou seu máximo nas 48 horas. Em seguida, foi feita a avaliação da atividade da 3’- chalcona contra a formação do biofilme maduro após 48 horas, apresentando uma inibição a uma concentração de 62,5 µg/mL para cepa ATCC e de 31,2 µg/mL frente ao isolado 118. Também foi avaliado o crescimento do biofilme frente à anfotericina B (AmB), obtendo como resultado, inibição em todas as concentrações por parte das duas cepas e, frente ao fluconazol, apresentaram-se resistentes. In vivo, os resultados de toxicidade em embriões de Zebrafish revelaram uma concentração letal 50% (CL50) de 3,42±0,6 µg/mL em 48 horas pós-fertilização (hpf). No modelo G. mellonella as doses testadas de 3’- chalcona (2 a 160 mg/Kg) não foram tóxicas. Entretanto, nas larvas infectadas com as duas cepas de C. gattii, a molécula não apresentou eficácia antifúngica. Assim, considerando o potencial antifúngico in vitro, inclusive contra o biofilme de C. gattii, a 3’- chalcona pode passar por modificações moleculares que aumentem sua distribuição e eficácia in vivo. / Criptococose is a fungal, systemic and opportunistic infection mainly caused by capsulated yeast of the species Cryptococcus neoformans e Cryptococcus gattii, affecting immunocompetent and immunocompromised patients. An important property of the genus Cryptococcus is the biofilm formation, which can be considered a virulence factor and resistance. The resistance of biofilms to antifungal agents brings the need to search new therapies. Thus, our group has been working with antifungal molecules derived from natural sources such as chalcones, where it was found that C. neoformans is sensitive to some of these molecules. For this fact, the objective of this study was to test the 3'- chalcone as antifungal against C. gattii in planktonic and biofilm forms, as well as efficiency and toxicity in alternative animal models like Danio rerio (Zebrafish) and Galleria mellonella, proposing a new alternative for treatment. In vitro, the results for the planktonic form of the fungus showed that the 3'- chalcone was more effective for the 118 strain, the minimum inhibitory concentration (MIC) was 0.96 µg/mL. For the strain 56990 of C. gattii the molecule showed potent activity with MIC values between 1.95 and 3.90 µg/mL. Biofilm formation assay for both strains had an increased metabolic activity within 72 hours and a biomass and extracellular matrix which reached its maximum in 48 hours. Then, the evaluation of the activity of the 3'-chalcone against the formation of mature biofilm was made after 48 hours, showing inhibition at a concentration of 62.5 µg/mL for ATCC strain and 31.2 µg/mL against the isolated 118. Also, the growth of biofilm against to amphotericin B (AmB) was evaluated, obtained as a result of inhibition at all concentrations for the two strains and against fluconazole were resistant. In vivo, the results of toxicity in zebrafish embryos revealed a lethal concentration 50% (LC50) of 3.42 ± 0.6 µg/mL at 48 hours post-fertilization (hpf). In the model G. mellonella tested doses of 3’- chalcona (2 to 160 mg/kg) were not toxic. However, in larvae infected with the two strains of C. gattii, the molecule did not show efficacy of antifungal agents. Thus, considering the potential antifungal in vitro, including against biofilms of C. gattii, 3'- chalcone can experiment molecular changes that increase their distribution and efficacy in vivo.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2017-10-30T10:24:52Z No. of bitstreams: 2 Tese - Mirian Rita Carrilho de Castro - 2017.pdf: 7039906 bytes, checksum: 5d352db979557bb35c672dba708ae0e8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-10-30T10:26:18Z (GMT) No. of bitstreams: 2 Tese - Mirian Rita Carrilho de Castro - 2017.pdf: 7039906 bytes, checksum: 5d352db979557bb35c672dba708ae0e8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-10-30T10:26:18Z (GMT). No. of bitstreams: 2 Tese - Mirian Rita Carrilho de Castro - 2017.pdf: 7039906 bytes, checksum: 5d352db979557bb35c672dba708ae0e8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-09-01 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / The chalcones are key intermediates for the biosynthesis of flavonoids and have shown an abundance of pharmacological effects including the antitumor effect. Thus, the synthesis and characterization of several chalcones and derivatives become important to develop a new class of compounds having antitumor activity. In the present work, the synthesis of chalcones, nitrochalcone sulfonamides and quinolinones was performed. By adjusting the reaction time and the sequence of the reactions, hybrids of open-chain chalcone sulfonamide whose molecular hybridization occurred at the ortho position of the benzoyl chalcone group through the Claisen- Schmidt condensation of acetophenone sulfonamide and nitrobenzaldehyde can be obtained at shorter reaction times, whereas quinolinone from cyclization at β carbon can be achieved if the reaction is stopped sequentially later. It is also noted that a novel structure, a chalcone (bis) sulfonamide, was prepared when chalcone was first synthesized and then reacted with benzenesulfonyl chloride. From the sulfonamide chalcones prepared with the m- aminoacetophenone sulfonamide and the o-, m- and p-nitrobenzaldehyde, a single product was formed. Among the 21 compounds prepared, five were ketone sulfonamides and sixteen were hybrid compounds (chalcones, chalcones, sulfonamides and quinolinones), which were purified by extraction, recrystallization and column chromatography and characterized by small molecule crystallography, melting point, Proton Nuclear Magnetic Resonance ( 1 H NMR) and infrared IV (IR). The antitumor activity was evaluated against three cancer cell lines: SF-295 (human glioblastoma), PC-3 (prostate) and HCT-116 (colon). Compounds 39, 40, 42, 43, 45a, 48a, 48b, 48c, 49 and 51 were cytotoxic to the three tumor cell lines tested. However, the quinolinones showed no relevant cytotoxic effect. It is also worth noting that compound 45a with a higher cytotoxic effect than doxorubicin, a drug used today against the three cancer cell lines evaluated, was a promising prototype for a new drug. / As chalconas são compostos intermediários da biossíntese de flavonóides e têm demonstrado uma variedade de efeitos farmacológicos entre eles o efeito antitumoral. Assim a síntese e caracterização de várias chalconas e derivados se tornam importantes para o desenvolvimento de uma nova classe de compostos com atividade antitumoral. No presente trabalho foi realizada a síntese de chalcona, nitro chalconas sulfonamidas e quinolinonas. Ajustando o tempo e a ordem das reações, os híbridos de chalcona sulfonamida de cadeia aberta, cuja hibridação molecularocorreu na posição orto do grupo de chalcona benzoíla através da condensação Claisen-Schmidt da acetofenona sulfonamida e nitrobenzaldeído, podem ser obtidos em tempos de reação mais curtos, enquanto que a quinolinona proveniente da ciclização no carbono β pode ser alcançada se a reação for parada sequencialmente mais tarde. Destaca-se uma nova estrutura, uma chalcona (bis) sulfonamida, foi formada quando se sintetizou a chalcona primeiramente e então reagiu-a com o cloreto de benzenosulfonila. A partir das chalconas sulfonamidas preparadas com a m- aminoacetofenona sulfonamida e o o-, m- e p-nitrobenzaldeído, formou-se apenas um produto. Dos 21 compostos preparados 5 são cetonas-sulfonamidas e 16 compostos híbridos (chalconas, chalconas sulfonamidas e quinolinonas), que foram purificados por extração, recristalização e coluna de separação, e caracterizados por cristalografia de pequenas moléculas, ponto de fusão ressonância magnética de prótons ( 1 H-RMN) e infravermelho (IV). A atividade antitumoral foi avaliada frente a três linhagens de células cancerosas: SF-295 (glioblastoma - humano), PC-3 (próstata) e HCT-116 (colón). Os compostos 39, 40, 42, 43, 45a, 48a, 48b, 48c, 49 e 51, apresentaram citotoxicidade nas três linhagens de células tumorais testadas. Já as quinolinonas não apresentaram efeito citotóxico relevante. Destaca-se ainda que o composto 45a com maior efeito citotóxico do que a doxorrubicina, medicamento utilizado hoje contra as três linhagens celulares de câncer avaliadas, mostra-se como um promissor protótipo a um novo fármaco.

No description available.

Polyclonal antibodies against the first two enzymes of the Arabidopsis thaliana flavonoid biosynthetic pathway were developed using conventional and phage antibody technology. cDNAs from Arabidopsis coding regions of chalcone synthase (CHS) and chalcone isomerase (CHI) were sub-cloned in frame into a bacterial expression vector as fusions with glutathione Stransferase (GST) using standard directional cloning techniques. Analysis of crude extracts of Escherichia coli containing GST .. CHS or GST .. CHI fusion protein indicated that the cells expressed equivalent amounts per volume of culture. CHS and CHI were purified to near homogeneity, yielding approximately 100 micrograms of GST .. CHS and 1 milligram of GST-CHI per liter of culture. The purified fusion proteins were injected into chickens and polyclonal lgY·s were purified from egg yolk Accumulation of CHS and CHI, as well as products of the pathway, were compared during the first eight days of Arabidopsis development. CHS and CHI are sequentially induced and reach maximal accumulation levels by day 5. Anthocyanidin levels are offset by one reaching maximal levels at day 6. The fusion proteins were also used to screen a phage-display library for Fabl fragments that recognize CHS and CHI epitopes. Preliminary data indicated that enrichment of phage displaying antibodies against CHS and CHI was successful. Phage-derived antibodies against CHS and CHI provide valuable tools for future experiments addressing Western blot analysis, immunolocalization experiments, and disruption of the flavonoid biosynthetic pathway by introduction of the corresponding genes into transgenic Arabidopsis plants. / Master of Science

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-05-09T14:28:22Z No. of bitstreams: 1 2016 - Leonardo Santos de Barros.pdf: 6766023 bytes, checksum: 16ce8cf6e87d3cfab0a3d73fc9a6e46c (MD5) / Made available in DSpace on 2017-05-09T14:28:22Z (GMT). No. of bitstreams: 1 2016 - Leonardo Santos de Barros.pdf: 6766023 bytes, checksum: 16ce8cf6e87d3cfab0a3d73fc9a6e46c (MD5) Previous issue date: 2016-11-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The photochemical reactivity of chalcone (CH) nanocrystals and its fluorinated derivatives (CH4F, CH23F, CH25F, CH26F, CH34F, CH35F, PFCB and the DFC) in a suspension of aqueous CTAB (0.04 mM) was studied by ultraviolet spectroscopy (UV), hydrogen nuclear magnetic resonance (H1NMR) and dynamic light scattering (DLS). The suspension of chalcone nanocrystals was prepared by the reprecipitation method in an aqueous solution of CTAB. The ultraviolet spectrum for the chalcone nanocrystals prior to irradiation showed hypochromic and bathochromic effects when compared to the methanolic solution. The DLS spectrum for CH CH23F, CH25F, CH26F and PFCB nanocrystals in aqueous CTAB showed a polydispersed system containing three different particle sizes, whereas CH34F, CH35F and DFC nanocrystals showed a clear monodispersivity. After irradiation, the DLS spectrum for these nanocrystals did not show significant changes, however for the monodispersed chalcones a shift towards larger particle sizes was observed. After irradiation the UV spectrum for the chalcone nanocrystals indicated a hypochromic effect on the longer wavelength band, which may be related to the consumption of their E-isomer. The kinetic monitoring of the E-isomer consumption for the chalcones CH, CH4F, CH23F, CH25F, CH26F CH34F, CH35F, PFCB and DFC as a function of irradiation time indicated that after a certain time the reaction reaches a steady state, with no more changes on their absorbance. The H1NMR spectrum for the irradiation product of CH4F and CH23F showed the formation of a mixture of ?-, ??-, and ?-truxillic dimers. On the other hand, irradiation of CH25F and CH26F derivatives led to the formation of the ?-truxinic dimer. Photolysis of CH34F and CH35F nanocrystals showed the conversion of the reactant to a cyclobutane through a stereospecific reaction. For CH35F only the ?-truxillic dimer has been formed, in nearly 100% conversion. However, for nanocrystals of the chalcone CH34F the Z-isomer is formed together with the ?-truxillic dimer CH34F, which may be related to a chalcone fraction that was solubilized in the CTAB containing aqueous phase. Irradiation of DFC nanocrystals occurred at a conversion of almost 100% to the cycloaddition product, the ?-truxillic dimer. For chalcone (CH) a high yield formation of the Z-chalcone isomer and dimers that are not formed from its E-isomer was observed, while PFCB appeared as a stable molecule during the irradiation process, and the presence of the five fluorine atoms on the benzyl ring can account for its stability / A reatividade fotoqu?mica de nanocristais de chalcona (CH) e seus derivados fluorados (CH4F, CH23F, CH25F, CH26F, CH34F, CH35F, PFCB e DFC) foi estudada por espectroscopia de ultravioleta (UV), Resson?ncia magn?tica nuclear de hidrog?nio (RMN1H) e Espalhamento de luz din?mico (DLS). A suspens?o dos nanocristais das chalconas foi preparada pelo m?todo de reprecipita??o em uma solu??o aquosa de CTAB. Os espectros no ultravioleta para a suspens?o dos nanocristais das chalconas antes da irradia??o mostraram um efeito hipocr?mico e batocr?mico em rela??o ? solu??o metan?lica. Os espectros de DLS para os nanocristais da suspens?o das chalconas em solu??o aquosa de CTAB se apresentaram como um sistema polidisperso apresentando 3 tamanhos de part?culas para CH, CH23F, CH25F, CH26F, PFCB e monodisperso para CH34F, CH35F e DFC. Ap?s a irradia??o n?o se observou mudan?as significativas na estrutura dos espectros de DLS para os nanocristais, ocorrendo um deslocamento para tamanhos de part?culas maiores nas chalconas monodispersas. O espectro de UV para a suspens?o dos nanocristais das chalconas ap?s a irradia??o indicou um efeito hipocr?mico da banda de maior absor??o, o que pode estar relacionado ao consumo dos compostos de configura??o E. O acompanhamento cin?tico do consumo do is?mero E das chalconas CH, CH4F, CH23F, CH25F, CH26F CH34F, CH35F, PFCB e DFC contra tempo de irradia??o de uma suspens?o dos nanocristais destas chalconas em solu??o aquosa de CTAB (0,04 mM) indicou que a partir de um determinado tempo a rea??o atinge um estado estacion?rio, n?o apresentando mais mudan?as em sua absorb?ncia. Os espectros de RMN1H para o produto da irradia??o dos nanocristais das chalconas contendo fl?or na posi??o 4 (CH4F) e nas posi??es 2 e 3 (CH23F) mostraram a forma??o de uma mistura de d?meros ?????? e ?-trux?licos. A irradia??o dos derivados CH25F e CH26F levou ? forma??o do d?mero do tipo ?-trux?nico. Para os derivados CH34F e CH35F a convers?o dos reagentes ao fotociclobutano foi feita em uma forma estereoespec?fica, tendo sido formado somente o d?mero ?-trux?lico, com uma convers?o de quase 100% para o CH35F. No entanto, para os nanocristais da chalcona CH34F o is?mero Z-CH34F foi formado juntamente com o d?mero ?-trux?lico, o que pode estar relacionado a fra??es da chalcona que ficaram solubilizadas na fase aquosa contendo CTAB e n?o formaram suspens?o de nanocristais. A irradia??o dos nanocristais da chalcona DFC ocorreu com uma convers?o de quase 100% ao produto de fotocicloadi??o, sendo o d?mero formado o do tipo ?-trux?lico. Para chalcona (CH) observou-se um elevado rendimento de forma??o do is?mero Z-chalcona e de d?meros que n?o s?o provenientes do is?mero E, enquanto que PFCB apresentou-se como uma mol?cula est?vel durante o processo de irradia??o, com a presen?a dos cinco ?tomos de fl?or no anel benz?lico podendo ser respons?vel pela sua estabilidade