>Magister Scientiae - MSc / Flavonoids, one of the biggest classes of secondary metabolites, are found abundantly in nature in a broad range of fruits, vegetables and beverages such as tea, coffee, beer, wine and fruit drinks. Flavonoids have been reported to exert multiple biological functions as well as tremendous pharmacological activity, including anticancer activity, protection, antioxidant activity, cardiovascular protection, antibacterial, antifungal and antiviral activity. The antioxidant activity of flavones is reported to be associated with those bearing hydroxyl functions. In the present study, several reaction steps have been carried out to synthesize three sub classes of flavonoids namely; chalcones, dihydrochalcones and flavanones with various substituents attached. The first step involved protection of hydroxyl groups of acetophenone and benaldehyde as starting materials. Thereafter the Clasien Schmidt condensation reaction, under basic conditions, was performed to afford chalcone intermediates. Treatment of these chalcones with sodium acetate, under reflux, afforded flavanones as a single product in high yields. Thereafter all protecting groups where removed to yield the final products. All products and intermediates where purified by column chromatography and were characterized by Nuclear Magnetic Resonance Spectroscopy (NMR) (1H NMR and 13C NMR). An electrochemical analysis on all flavonoid compounds was performed by Cyclic Voltammetry (CV) and Square Wave Voltammetry (SWV) to give information on the accessible redox couples identified by their oxidation potentials. Oxidation potentials, which gave valuable information about reducing ability and hence the antioxidant activity, where used to compare all compounds. The antioxidant activity was observed to increase with the addition of hydroxyl groups on the B-ring. Compounds with a combination of hydroxyl groups on the A-ring and methoxy groups on the B-ring showed increased antioxidant activity when compared to those with only hydroxyl groups on the base structure. 2, 5, 4’-trihydroxy dihydrochalcone showed moderate antioxidant ability. However the 2, 5, 4’-trihydroxychalcone, containing the α, β unsaturated double bond, proved to have the greatest antioxidant ability.

Parkinson’s disease is the second most common age-related neurodegenerative disease after Alzheimer’s disease. The characteristic pathological feature of Parkinson’s disease is the loss of neurons in the substantia nigra pars compacta (SNpc), which leads to a striatal dopamine deficiency responsible for the major symptoms of Parkinson’s disease. These symptoms include tremor at rest, postural instability, bradykinesia and in the later stages of Parkinson’s disease, even psychosis. Presently, there is still no cure for Parkinson’s disease and all treatments are only symptomatic. Current research is therefore directed towards the prevention of further dopaminergic neurodegeneration, while the ultimate aim is the reversal of neurodegeneration. Monoamine oxidase (MAO) enzymes are responsible for the regulation and metabolism of monoamine neurotransmitters, such as dopamine. There are two MAO isoforms, MAO-A and MAO-B. Since MAO-B has greater activity in the basal ganglia, it is of particular importance in movement disorders, which include Parkinson’s disease. The selective inhibition of MAO-B, increases dopamine available for binding, and thus reduces Parkinson’s disease symptoms. MAO inhibitors also have neuroprotective potential and thus may slow down, halt and even reverse neurodegeneration in Parkinson’s disease. It is still unclear exactly how MAO inhibitors protect neurons, but one theory suggests that MAO inhibition decreases oxidative stress by reducing the formation of hydrogen peroxide, a metabolic by-product of MAO oxidation of monoamines. Normally, hydrogen peroxide is inactivated by glutathione (GSH), however, in Parkinson’s disease, GSH levels are low, resulting in the accumulation of hydrogen peroxide, which then becomes available for the Fenton reaction. In the Fenton reaction, Fe2+ reacts with hydrogen peroxide and generates an active free radical, the hydroxyl radical. This radical depletes cellular anti-oxidants, damage lipids, proteins and DNA. MAO inhibitors reduce the formation of hydrogen peroxide thus decreasing the formation of hydroxyl radicals and oxidative stress. The MAO inhibitory potential of natural and synthetic chalcones have been illustrated. For example, in 1987, Tanaka and co-workers determined that natural chalcones, such as isoliquiritigenin, have MAO inhibitory activity in rat mitochondria. In 2009, Chimenti and co-workers synthesized a series of 1,3-diphenyl-2-propen-1-ones which exhibited human MAO-B (hMAO-B) selective inhibitory activity. On the other hand, Robinson and co-workers (2013), synthesized novel furanochalcones which also had hMAO-B selective inhibitory activity. A reversible, competitive mode of binding was demonstrated by these compounds. Since the effect of heterocyclic substitution, other than furan on the MAO inhibitory properties of the chalcone scaffold remains unexplored, the aim of this study was to synthesize and evaluate further heterocyclic chalcone analogues as inhibitors of hMAO. RESULTS Design and synthesis: Heterocyclic chalcone analogues that incorporated pyrrole, 5- methylthiophene, 5-chlorothiophene and 2-methoxypyridine substitution were synthesized using the Claisen-Schmidt condensation reaction. All compounds were characterized with 1H-NMR, 13CNMR, IR, MS, and melting points were recorded. Purity was determined with HPLC analysis. MAO inhibition studies: The 50% inhibitory concentration (IC50) values and selectivity index (SI) of all compounds were determined using a fluorometric assay and kynuramine as substrate. Eight out of the ten synthesized compounds exhibited IC50 values < 1 μM, and can thus be considered as potent MAO-B inhibitors, while all compounds showed selectivity for the MAO-B isoform. Compound 10i was the most potent MAO-B inhibitor with an IC50 value of 0.067 μM and the highest SI of 240.7. The most potent MAO-A inhibitor, compound 10f, had an IC50 value of 3.805 μM. Some structure-activity relationships were derived, for example; it was concluded that heterocyclic substitution with 5-methyl-thiophene ring resulted in optimal hMAO-B inhibition, while pyrrole substitution was less favourable. Further investigation is however required as this is only a preliminary study. Reversibility studies: To determine the reversibility of binding, the recovery of enzymatic activity after dilution of the enzyme inhibitor complexes were determined for selected compounds. Results indicated that the most potent MAO-A inhibitor, the pyrrole derivative 10f, had a reversible mode of binding to both the hMAO-B and hMAO-A isoforms, since the enzyme activities were completely recovered by dilution of the inhibitor concentration. In contrast, enzyme activity was only partially recovered after dilution of the most potent MAO-B inhibitor 10i, indicating that this methylthiophene derivative possibly exhibited tight binding to the hMAO-B isoform, and the inhibition caused by this compound was not readily reversed by dilution. In order to determine whether the tight binding as exhibited by compound 10i was due to the thiophene or phenyl moieties, reversibility of binding was also determined for the pyrrole derivative 10e. The results showed that 10e had a reversible mode of binding to the hMAO-B isoform, and enzyme activity was completely recovered by dilution of the inhibitor. Based on these results, it was concluded that the tight binding as exhibited by compound 10i was due to the presence of the thiophene moiety. To confirm that compound 10i exhibited tight, and not irreversible binding, reversibility of binding was also determined by dialysis of enzyme-inhibitor mixtures. For this purpose hMAO-B and 10i, at a concentration of 4 × IC50, were preincubated for a period of 15 min and subsequently dialyzed for 24 h. The results of this study showed that 10i had a reversible mode of binding for MAO-B, since enzyme activity was recovered to a level of 83% after dialysis. Mode of inhibition: To determine the mode of inhibition of compound 10f, Lineweaver-Burk plots were constructed for the inhibition of hMAO-A and hMAO-B. The lines of the Lineweaver-Burk plots intersected at a single point at the y-axis, indicating that 10f had a competitive mode of binding to both hMAO-B and hMAO-A isoforms. MTT viability assay: To determine the toxicity of the chalcones for cultured cells, selected compounds were evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) viability assay. The cytotoxicity of the test compounds were evaluated at concentrations of 1 and 10 μM, in HeLa cells. The results indicated that compound 10i was non-toxic at 1 and 10 μM, with 100% and 96% cell viability remaining after 24 h exposure of the compound to the cultured cells. Compound 10f, however, exhibited significant toxicity at 10 μM, with only 5% viable cells remaining. In contrast, compound 10e, with the same pyrrole moiety as 10f, was non-toxic at 1 μM and 10 μM, with 99% and 98%, cell viability remaining. It was concluded that the pyrrole moiety of 10f was not responsible for its higher degree of cytotoxicity, which suggests that the CF3 substituent may play a role in the higher degree of cytotoxicity observed for 10f. Further investigation is required to determine the mode of cytotoxicity, when cultured cells are exposed to 10f. Docking Studies: To complete this study and rationalise the results of the MAO inhibition studies, molecular modelling was carried out and all compounds were docked into the crystal structure of hMAO-B, by using the CDOCKER module of Discovery Studio. Some insights were obtained regarding the binding of compound 10i. This compound bound to MAO-B with the phenyl ring facing the FAD cofactor. This orientation allowed for the formation of pi-pi interaction with Tyr 398 as well as a pi-sigma interaction between the thiophene ring and Ile 199 (which is part of the gating switch of MAO-B). It is speculated that the tight binding component of hMAO-B inhibition by 10i may, at least in part, be attributed to the interaction of this compound with the gating switch amino acid, Ile 199. The docking results also showed that most compounds interacted with Tyr 326 or Tyr 398, while interactions with Cys 172, Gln 206, Ile 199 and Tyr 435 also occurred. In conclusion, novel heterocyclic chalcone analogues with promising MAO-B inhibitory activities were successfully synthesized and evaluated. / MSc (Pharmaceutical Chemistry) North-West University, Potchefstroom Campus, 2014

Parkinson’s disease is the second most common age-related neurodegenerative disease after Alzheimer’s disease. The characteristic pathological feature of Parkinson’s disease is the loss of neurons in the substantia nigra pars compacta (SNpc), which leads to a striatal dopamine deficiency responsible for the major symptoms of Parkinson’s disease. These symptoms include tremor at rest, postural instability, bradykinesia and in the later stages of Parkinson’s disease, even psychosis. Presently, there is still no cure for Parkinson’s disease and all treatments are only symptomatic. Current research is therefore directed towards the prevention of further dopaminergic neurodegeneration, while the ultimate aim is the reversal of neurodegeneration. Monoamine oxidase (MAO) enzymes are responsible for the regulation and metabolism of monoamine neurotransmitters, such as dopamine. There are two MAO isoforms, MAO-A and MAO-B. Since MAO-B has greater activity in the basal ganglia, it is of particular importance in movement disorders, which include Parkinson’s disease. The selective inhibition of MAO-B, increases dopamine available for binding, and thus reduces Parkinson’s disease symptoms. MAO inhibitors also have neuroprotective potential and thus may slow down, halt and even reverse neurodegeneration in Parkinson’s disease. It is still unclear exactly how MAO inhibitors protect neurons, but one theory suggests that MAO inhibition decreases oxidative stress by reducing the formation of hydrogen peroxide, a metabolic by-product of MAO oxidation of monoamines. Normally, hydrogen peroxide is inactivated by glutathione (GSH), however, in Parkinson’s disease, GSH levels are low, resulting in the accumulation of hydrogen peroxide, which then becomes available for the Fenton reaction. In the Fenton reaction, Fe2+ reacts with hydrogen peroxide and generates an active free radical, the hydroxyl radical. This radical depletes cellular anti-oxidants, damage lipids, proteins and DNA. MAO inhibitors reduce the formation of hydrogen peroxide thus decreasing the formation of hydroxyl radicals and oxidative stress. The MAO inhibitory potential of natural and synthetic chalcones have been illustrated. For example, in 1987, Tanaka and co-workers determined that natural chalcones, such as isoliquiritigenin, have MAO inhibitory activity in rat mitochondria. In 2009, Chimenti and co-workers synthesized a series of 1,3-diphenyl-2-propen-1-ones which exhibited human MAO-B (hMAO-B) selective inhibitory activity. On the other hand, Robinson and co-workers (2013), synthesized novel furanochalcones which also had hMAO-B selective inhibitory activity. A reversible, competitive mode of binding was demonstrated by these compounds. Since the effect of heterocyclic substitution, other than furan on the MAO inhibitory properties of the chalcone scaffold remains unexplored, the aim of this study was to synthesize and evaluate further heterocyclic chalcone analogues as inhibitors of hMAO. RESULTS Design and synthesis: Heterocyclic chalcone analogues that incorporated pyrrole, 5- methylthiophene, 5-chlorothiophene and 2-methoxypyridine substitution were synthesized using the Claisen-Schmidt condensation reaction. All compounds were characterized with 1H-NMR, 13CNMR, IR, MS, and melting points were recorded. Purity was determined with HPLC analysis. MAO inhibition studies: The 50% inhibitory concentration (IC50) values and selectivity index (SI) of all compounds were determined using a fluorometric assay and kynuramine as substrate. Eight out of the ten synthesized compounds exhibited IC50 values < 1 μM, and can thus be considered as potent MAO-B inhibitors, while all compounds showed selectivity for the MAO-B isoform. Compound 10i was the most potent MAO-B inhibitor with an IC50 value of 0.067 μM and the highest SI of 240.7. The most potent MAO-A inhibitor, compound 10f, had an IC50 value of 3.805 μM. Some structure-activity relationships were derived, for example; it was concluded that heterocyclic substitution with 5-methyl-thiophene ring resulted in optimal hMAO-B inhibition, while pyrrole substitution was less favourable. Further investigation is however required as this is only a preliminary study. Reversibility studies: To determine the reversibility of binding, the recovery of enzymatic activity after dilution of the enzyme inhibitor complexes were determined for selected compounds. Results indicated that the most potent MAO-A inhibitor, the pyrrole derivative 10f, had a reversible mode of binding to both the hMAO-B and hMAO-A isoforms, since the enzyme activities were completely recovered by dilution of the inhibitor concentration. In contrast, enzyme activity was only partially recovered after dilution of the most potent MAO-B inhibitor 10i, indicating that this methylthiophene derivative possibly exhibited tight binding to the hMAO-B isoform, and the inhibition caused by this compound was not readily reversed by dilution. In order to determine whether the tight binding as exhibited by compound 10i was due to the thiophene or phenyl moieties, reversibility of binding was also determined for the pyrrole derivative 10e. The results showed that 10e had a reversible mode of binding to the hMAO-B isoform, and enzyme activity was completely recovered by dilution of the inhibitor. Based on these results, it was concluded that the tight binding as exhibited by compound 10i was due to the presence of the thiophene moiety. To confirm that compound 10i exhibited tight, and not irreversible binding, reversibility of binding was also determined by dialysis of enzyme-inhibitor mixtures. For this purpose hMAO-B and 10i, at a concentration of 4 × IC50, were preincubated for a period of 15 min and subsequently dialyzed for 24 h. The results of this study showed that 10i had a reversible mode of binding for MAO-B, since enzyme activity was recovered to a level of 83% after dialysis. Mode of inhibition: To determine the mode of inhibition of compound 10f, Lineweaver-Burk plots were constructed for the inhibition of hMAO-A and hMAO-B. The lines of the Lineweaver-Burk plots intersected at a single point at the y-axis, indicating that 10f had a competitive mode of binding to both hMAO-B and hMAO-A isoforms. MTT viability assay: To determine the toxicity of the chalcones for cultured cells, selected compounds were evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) viability assay. The cytotoxicity of the test compounds were evaluated at concentrations of 1 and 10 μM, in HeLa cells. The results indicated that compound 10i was non-toxic at 1 and 10 μM, with 100% and 96% cell viability remaining after 24 h exposure of the compound to the cultured cells. Compound 10f, however, exhibited significant toxicity at 10 μM, with only 5% viable cells remaining. In contrast, compound 10e, with the same pyrrole moiety as 10f, was non-toxic at 1 μM and 10 μM, with 99% and 98%, cell viability remaining. It was concluded that the pyrrole moiety of 10f was not responsible for its higher degree of cytotoxicity, which suggests that the CF3 substituent may play a role in the higher degree of cytotoxicity observed for 10f. Further investigation is required to determine the mode of cytotoxicity, when cultured cells are exposed to 10f. Docking Studies: To complete this study and rationalise the results of the MAO inhibition studies, molecular modelling was carried out and all compounds were docked into the crystal structure of hMAO-B, by using the CDOCKER module of Discovery Studio. Some insights were obtained regarding the binding of compound 10i. This compound bound to MAO-B with the phenyl ring facing the FAD cofactor. This orientation allowed for the formation of pi-pi interaction with Tyr 398 as well as a pi-sigma interaction between the thiophene ring and Ile 199 (which is part of the gating switch of MAO-B). It is speculated that the tight binding component of hMAO-B inhibition by 10i may, at least in part, be attributed to the interaction of this compound with the gating switch amino acid, Ile 199. The docking results also showed that most compounds interacted with Tyr 326 or Tyr 398, while interactions with Cys 172, Gln 206, Ile 199 and Tyr 435 also occurred. In conclusion, novel heterocyclic chalcone analogues with promising MAO-B inhibitory activities were successfully synthesized and evaluated. / MSc (Pharmaceutical Chemistry) North-West University, Potchefstroom Campus, 2014

Os biofilmes constituem uma forma de crescimento que permite a maior sobrevivência e resistência de microrganismos a agentes de controle como antibióticos e desinfetantes. Apesar da grande disponibilidade de agentes antimicrobianos no mercado, há escassez de produtos específicos e efetivos na erradicação/inibição de biofilmes. Existe atualmente grande interesse na seleção de moléculas capazes de inibir o crescimento dos biofilmes ou removê-los quando já estabelecidos. Doenças como fibrose cística (P. aeruginosa) e cárie dentária (S. mutans), são patologias intrinsecamente ligadas à formação de biofilmes. O principal objetivo deste trabalho foi avaliar o potencial de chalconas sintéticas e derivados no controle e erradicação de biofilmes. As chalconas foram testadas quanto à capacidade de inibir a formação de biofilme e de remover biofilmes pré-estabelecidos. Os biofilmes de P. aeruginosa foram inibidos pela presença da molécula (E)-1-(3-hidroxinaftalen-2-il)-3-fenilprop-2-em-1-ona (11), mostrando redução de 48,8% na biomassa e 60,2% na viabilidade. A redução máxima na biomassa atingiu 70,9%. Já para o tratamento de biofilmes pré-estabelecidos, a molécula (1E,4E)-1,5-difenilpenta-1,4-dien-3-ona (10) mostrou redução de 53,5% na biomassa do biofilme de P. aeruginosa. Na formação do biofilme de S. mutans, a presença da molécula (1E, 4E)-1,5-bis(4-bromofenil)penta-1,4-dien-3-ona (15) reduziu a biomassa em 67,4%. Em concentrações elevadas essa redução chegou a 95,1%. Em biofilmes pré-estabelecidos de S. mutans, o tratamento com a molécula (2E,4E)-1,5-difenilpenta-2,4-dien-1-ona (12) reduziu a biomassa celular em 62,7%, e a viabilidade celular em 58,4%. Já a molécula (E)-3-(2-hidroxifenil)-1-fenilprop-2-en-1-ona (21), quando utilizada no tratamento de biofilmes pré-estabelecidos, mostrou redução de 26,4% na biomassa e 91,6% na viabilidade de S. mutans; além de evidenciar danos à estrutura celular do microrganismo. Todas as moléculas supracitadas promoveram redução na espessura dos biofilmes. Os antibióticos ampicilina e polimixina foram menos eficientes na remoção de biofilmes comparativamente às moléculas testadas. As moléculas não apresentaram CIM frente às bactérias, entretanto, afetaram a viabilidade celular. O tratamento da superfície de poliestireno com as chalconas não impediu a adesão das bactérias, e resultou na redução da hidrofobicidade do material. A superfície celular de S. mutans apresentou predomínio de cargas negativas e forte caráter hidrofóbico enquanto que P. aeruginosa apresentou baixa hidrofobicidade além de caráter básico. Os resultados evidenciam a potencialidade do uso das chalconas e seus derivados para o controle e erradicação de biofilmes Streptococcus mutans e Pseudomonas aeruginosa. / Biofilms constitute a growth mode which allows greatest survival and resistance of microorganisms to antibiotics and disinfectants. Despite the wide availability of antimicrobial agents in the market, there are few specific and effective products to the eradication / inhibition of biofilms. Thus, there is a great interest in the search of molecules able to inhibit biofilms or remove them once established. Diseases such as cystic fibrosis (P. aeruginosa) and dental caries (S. mutans), are intrinsically linked to the formation of biofilms. The aim of this study was to evaluate the potential of chalcones and their synthetic derivatives to the control and eradication of biofilms. The chalcones were tested for the ability to inhibit biofilm formation and also to remove pre-established biofilms. Biofilms of P. aeruginosa was inhibited by the presence of the molecule (E) -1- (3-hydroxynaphthalen-2-yl) -3-phenylprop-2-en-1-one (11) showing reduction of 48.8% biomass and 60.2% viability. The maximum reduction in biomass reached 70.9%. For the treatment of pre-established biofilms, the molecule (1E, 4E) -1,5-difenilpenta-1,4-dien-3-one (10) showed a 53.5% reduction in biomass of P. aeruginosa biofilm. Biofilms of S. mutans, growing in the the presence of the molecule (1E, 4E) -1,5-bis (4-bromophenyl) penta-1,4-dien-3-one (15) showed a biomass reduction of 67.4 %. At higher concentrations this reduction reached 95.1%. In pre-established biofilms of S. mutans, treatment with the molecule (2E, 4E) -1,5-difenilpenta-2,4-dien-1-one (12) reduced cell biomass in 62.7%, and cell viability by 58.4%. The molecule (E) -3- (2-hydroxyphenyl) -1-phenylprop-2-en-1-one (21), when used in the treatment of pre-established biofilms, showed 26.4% reduction in biomass and 91.6% in the viability of S. mutans; furthermore, the chalcone 21 caused damage to the cellular structure of the microorganism. All the aforementioned molecules promoted a reduction in the thickness of biofilms. The antibiotics polymyxin and ampicillin were less efficient on removing biofilms comparatively to the chalcones. The molecules affected cell viability however, no MIC was observed under the range of concentrations evaluated. The treatment of the polystyrene surface with chalcones did not prevent bacterial adhesion moreover, hydrophobicity of the material was reduced. S. mutans cell surface showed a predominance of negative charges and strong hydrophobic character while P. aeruginosa showed low hydrophobicity and basic character. The results demonstrate that synthetic chalcones and derivatives are potential candidates to the control and eradication of Streptococcus mutans and Pseudomonas aeruginosa biofilms.

Os biofilmes constituem uma forma de crescimento que permite a maior sobrevivência e resistência de microrganismos a agentes de controle como antibióticos e desinfetantes. Apesar da grande disponibilidade de agentes antimicrobianos no mercado, há escassez de produtos específicos e efetivos na erradicação/inibição de biofilmes. Existe atualmente grande interesse na seleção de moléculas capazes de inibir o crescimento dos biofilmes ou removê-los quando já estabelecidos. Doenças como fibrose cística (P. aeruginosa) e cárie dentária (S. mutans), são patologias intrinsecamente ligadas à formação de biofilmes. O principal objetivo deste trabalho foi avaliar o potencial de chalconas sintéticas e derivados no controle e erradicação de biofilmes. As chalconas foram testadas quanto à capacidade de inibir a formação de biofilme e de remover biofilmes pré-estabelecidos. Os biofilmes de P. aeruginosa foram inibidos pela presença da molécula (E)-1-(3-hidroxinaftalen-2-il)-3-fenilprop-2-em-1-ona (11), mostrando redução de 48,8% na biomassa e 60,2% na viabilidade. A redução máxima na biomassa atingiu 70,9%. Já para o tratamento de biofilmes pré-estabelecidos, a molécula (1E,4E)-1,5-difenilpenta-1,4-dien-3-ona (10) mostrou redução de 53,5% na biomassa do biofilme de P. aeruginosa. Na formação do biofilme de S. mutans, a presença da molécula (1E, 4E)-1,5-bis(4-bromofenil)penta-1,4-dien-3-ona (15) reduziu a biomassa em 67,4%. Em concentrações elevadas essa redução chegou a 95,1%. Em biofilmes pré-estabelecidos de S. mutans, o tratamento com a molécula (2E,4E)-1,5-difenilpenta-2,4-dien-1-ona (12) reduziu a biomassa celular em 62,7%, e a viabilidade celular em 58,4%. Já a molécula (E)-3-(2-hidroxifenil)-1-fenilprop-2-en-1-ona (21), quando utilizada no tratamento de biofilmes pré-estabelecidos, mostrou redução de 26,4% na biomassa e 91,6% na viabilidade de S. mutans; além de evidenciar danos à estrutura celular do microrganismo. Todas as moléculas supracitadas promoveram redução na espessura dos biofilmes. Os antibióticos ampicilina e polimixina foram menos eficientes na remoção de biofilmes comparativamente às moléculas testadas. As moléculas não apresentaram CIM frente às bactérias, entretanto, afetaram a viabilidade celular. O tratamento da superfície de poliestireno com as chalconas não impediu a adesão das bactérias, e resultou na redução da hidrofobicidade do material. A superfície celular de S. mutans apresentou predomínio de cargas negativas e forte caráter hidrofóbico enquanto que P. aeruginosa apresentou baixa hidrofobicidade além de caráter básico. Os resultados evidenciam a potencialidade do uso das chalconas e seus derivados para o controle e erradicação de biofilmes Streptococcus mutans e Pseudomonas aeruginosa. / Biofilms constitute a growth mode which allows greatest survival and resistance of microorganisms to antibiotics and disinfectants. Despite the wide availability of antimicrobial agents in the market, there are few specific and effective products to the eradication / inhibition of biofilms. Thus, there is a great interest in the search of molecules able to inhibit biofilms or remove them once established. Diseases such as cystic fibrosis (P. aeruginosa) and dental caries (S. mutans), are intrinsically linked to the formation of biofilms. The aim of this study was to evaluate the potential of chalcones and their synthetic derivatives to the control and eradication of biofilms. The chalcones were tested for the ability to inhibit biofilm formation and also to remove pre-established biofilms. Biofilms of P. aeruginosa was inhibited by the presence of the molecule (E) -1- (3-hydroxynaphthalen-2-yl) -3-phenylprop-2-en-1-one (11) showing reduction of 48.8% biomass and 60.2% viability. The maximum reduction in biomass reached 70.9%. For the treatment of pre-established biofilms, the molecule (1E, 4E) -1,5-difenilpenta-1,4-dien-3-one (10) showed a 53.5% reduction in biomass of P. aeruginosa biofilm. Biofilms of S. mutans, growing in the the presence of the molecule (1E, 4E) -1,5-bis (4-bromophenyl) penta-1,4-dien-3-one (15) showed a biomass reduction of 67.4 %. At higher concentrations this reduction reached 95.1%. In pre-established biofilms of S. mutans, treatment with the molecule (2E, 4E) -1,5-difenilpenta-2,4-dien-1-one (12) reduced cell biomass in 62.7%, and cell viability by 58.4%. The molecule (E) -3- (2-hydroxyphenyl) -1-phenylprop-2-en-1-one (21), when used in the treatment of pre-established biofilms, showed 26.4% reduction in biomass and 91.6% in the viability of S. mutans; furthermore, the chalcone 21 caused damage to the cellular structure of the microorganism. All the aforementioned molecules promoted a reduction in the thickness of biofilms. The antibiotics polymyxin and ampicillin were less efficient on removing biofilms comparatively to the chalcones. The molecules affected cell viability however, no MIC was observed under the range of concentrations evaluated. The treatment of the polystyrene surface with chalcones did not prevent bacterial adhesion moreover, hydrophobicity of the material was reduced. S. mutans cell surface showed a predominance of negative charges and strong hydrophobic character while P. aeruginosa showed low hydrophobicity and basic character. The results demonstrate that synthetic chalcones and derivatives are potential candidates to the control and eradication of Streptococcus mutans and Pseudomonas aeruginosa biofilms.

A combretastatina A4 é um promissor agente anticâncer. Na célula, inibe a polimerização dos microtúbulos, os quais são fundamentais nos processos de motilidade, manutenção estrutural e mitose. Essa inibição se dá a partir do sítio de interação da &alpha;&beta;-tubulina bloqueando o fluxo do sangue que alimenta os tumores, o que resulta na morte dos mesmos. Com estrutura semelhante às combretastatinas, as chalconas constituem uma classe de compostos que atuam no mesmo sítio de interação na tubulina. Baseando-se nos trabalhos experimentais de Ducki e colaboradores, estudou-se a estrutura molecular de 87 chalconas análogas à combretastatina A4 por meio do método quântico DFT com o propósito de desenvolver modelos de Relações Quantitativas Estrutura-Atividade (QSAR) aplicados a tais antagonistas. A partir dos métodos dos Mínimos Quadrados Parciais (PLS) e de Redes Neurais Artificiais (ANN), foram gerados modelos que conduzem à elucidação da relação dos compostos estudados com suas respectivas atividades biológicas. Os descritores eletrônicos e moleculares selecionados apresentam alta concordância com as características das moléculas, havendo predominância de comportamento linear com a atividade biológica, podendo, eventualmente, apresentar comportamento não-linear, o que torna o modelo gerado altamente consistente. / Combretastatin A4 is a promising anticancer agent. It inhibits the polymerization of microtubules in the cell, which are essential in the process of motility, structural maintenance and mitosis. This inhibition is given from the interaction site of &alpha;&beta;-tubulin blocking the blood flow that feeds the tumor, what results in its death. The chalcones, sharing a similar structure of the combretastatin, are also a class of compounds that act in the same site of interaction in the tubulin. Based on the experimental work of Ducki and co-workers, we proposed a molecular structure study of 87 chalcones similar to combretastatin A4 using the DFT method in order to develop Quantitative Structure-Activity Relationships (QSAR) applied to the given antagonists. Through Partial Least Squares (PLS) and Artificial Neural Network (ANN) methods, some models has been generated to lead the understanding on the relationship between the compounds studied and their respective biological activities. The electronic and molecular descriptors selected have high correlation with the molecule features, being linear most of the time, although with eventual non-linear behavior, which makes the generated model highly consistent.

Background and rationale - Parkinson’s disease is a neurodegenerative disorder characterised by reduced levels of dopamine in the brain. The cause of Parkinson's disease is still unknown; however several theories pertaining to the etiology exist. Current treatment mainly aims at dopamine replacement, with agents such as levodopa and dopamine agonists that provide patients with symptomatic relief. This relief is unfortunately only temporary as the progression of the disease is not halted. Furthermore, these therapies are associated with a range of side effects and novel approaches to the treatment are thus urgently required. Adenosine A2A receptor antagonists recently emerged as a promising non-dopaminergic alternative, not only as symptomatic treatment, but also as potential neuroprotective therapy. Adenosine A2A receptors are co-localised with dopamine D2 receptors in the striatum and other nuclei of the basal ganglia. Adenosine A2A stimulation decreases the affinity of dopamine for the D2 receptor, and increase cyclic AMP (cAMP) levels. The stimulation of dopamine D2 receptors, in contrast, decreases cAMP levels and therefore these receptors (A2A and D2), act in an opposing manner. Adenosine A2A antagonism will thus have similar effects as dopamine D2 agonism and will reduce the postsynaptic effects of dopamine depletion to give symptomatic relief. There are also several mechanisms where by adenosine A2A antagonists may be neuroprotective, for example by preventing glutamate excitotoxicity, that may cause damage to dopaminergic neurons. A number of adenosine A2A antagonists have already reached clinical trials and promising results were obtained, especially when combined with levodopa. Consequently, A2A antagonists are realistic prospects that have therapeutic potential in diseases with dopaminergic hypofunction, like Parkinson's disease. Many of the current A2A antagonists contain an amino-substituted heterocyclic scaffold, such as an aminopyrimidine. The primary aim of this study was the design, synthesis and evaluation of 2-aminopyrimidine derivatives as adenosine A2A receptor antagonists. Monoamine oxidase B (MAO-B) inhibitors are also promising candidates for the symptomatic treatment of Parkinson's disease, since MAO-B is the enzyme primarily responsible for the catabolism of dopamine in the brain. Irreversible inhibitors of MAO-B, such as selegeline and rasagiline, have been used clinically for the treatment of Parkinson's disease. This type of inhibition comes with certain disadvantages as it may take up to several weeks after termination of treatment for the enzyme activity to recover. Reversible inhibitors in contrast will have much better safety profiles seeing that they will not inactivate the enzyme permanently and allow for competition with the substrate. When dopamine is oxidized by MAO, toxic metabolic by-products, such as hydrogen peroxide (H2O2) forms, and this is believed to be a possible cause of Parkinson's disease. MAO-B inhibitors will therefore not only provide symptomatic relief but may also alter the progression of the disease by preventing the formation of these byproducts. Promising MAOB inhibitory activities have been reported for chalcones, and since the intermediates obtained in the synthesis of aminopyrimidines in this study are chalcones, a secondary aim of this study was the screening of selected chalcone intermediates as inhibitors of MAO–B. Results - Design and synthesis: A series of 2-aminopyrimidines were designed using known active structures and literature pharmacophores. A molecular modelling study (Discovery Studio 3.1, Accelrys) was further done to investigate the feasibility of these compounds as potential adenosine A2A antagonists. All of the designed aminopyrimidines were successfully docked in the binding site of the adenosine A2A receptor. Binding orientations and observed interactions with important residues in the active site were similar to those observed for known A2A antagonists. It was therefore concluded that these compounds may be potential A2A antagonists and the designed compounds were thus synthesised. Structures were primarily confirmed with nuclear magnetic resonance spectroscopy and mass spectrometry. MAO-B inhibition studies: Selected chalcones were evaluated using a fluorometric assay and kynuramine as substrate. The compounds were potent and selective inhibitors of the MAO-B enzyme with IC50 values ranging between 0.49-7.67 μM. (2E)-3-(3-Chlorophenyl)-1- (5-methyl-2-furyl)prop-2-en-1-one (1c) was the most potent compound with an IC50 value of 0.49 μM and was approximately 60 times more selective towards MAO-B than MAO-A. Some preliminary structure activity relationships were derived, for example, phenyl substitution with an electron withdrawing chlorine group generally resulted in better activity than substitution with electron donating methoxy groups. Further investigation of structure activity relationships are however required as a very small series of chalcones were screened. Reversibility studies and mode of inhibition: A dilution assay was used to determine whether compound (1c) binds reversibly or irreversibly to the MAO-B enzyme. This was done by measuring the recovery of enzymatic activity after a large dilution of the enzyme-inhibitor complex. The results from the reversibility studies showed that the inhibition of the most potent compound (1c) is reversible as the catalytic activities are recovered to approximately 80% and 50% respectively, compared to the control measured in the absence of an inhibitor. For the mode of inhibition, sets of Lineweaver–Burk plots were constructed. The Lineweaver- Burk plots intersected on the y-axis which indicates that compound 1c is a competitive inhibitor of the MAO-B enzyme. In vitro adenosine A2A assays: Radioligand binding assays were used to determine the affinity of the synthesised 2-aminopyrimidines for the adenosine A2A receptor. This assay was performed with the radioligand [3H]NECA in the presence of N6-cyclopentyladenosine (CPA). Compounds 2a - 2h showed moderate to weak affinity in the assay, while promising affinities were observed for compounds 2j - 2n, which all exhibited Ki values below 55 nM. The compound with the highest affinity was 4-(5-methylfuran-2-yl)-6-[3-(piperidine-1- carbonyl)phenyl]pyrimidin-2-amine (2m) with a Ki value of 5.76 nM, which is comparable to the Ki value of 2.10 nM obtained for the known amino-substituted heterocyclic adenosine A2A antagonist, ZM 241385. The higher affinities of compounds (2j – 2n) could, at least in part, be explained by the molecular modellling studies. In the docking experiments an additional hydrogen bond interaction was observed between the amide carbonyl and tyrosine 271 indicating that this structural feature is a major contributing factor to the improved affinity observed for these derivatives. In vivo adenosine A2A assays: The haloperidol induced catalepsy assay was used to determine whether the two compounds with the highest affinity for the adenosine A2A receptor (2m and 2k) are antagonists of the A2A receptor. These compounds caused a statistically significant reduction in catalepsy, which clearly illustrate that they are adenosine A2A antagonists. The objectives of this study as set out were thus successfully realised and promising results were obtained. During this study, several novel 2-aminopyrimidines and chalcones were synthesised, and the respective adenosine A2A antagonistic and monoamine oxidase inhibitory activities for all of the screened compounds were determined for the first time. / Thesis (MSc (Pharmaceutical Chemistry))--North-West University, Potchefstroom Campus, 2013

Background and rationale - Parkinson’s disease is a neurodegenerative disorder characterised by reduced levels of dopamine in the brain. The cause of Parkinson's disease is still unknown; however several theories pertaining to the etiology exist. Current treatment mainly aims at dopamine replacement, with agents such as levodopa and dopamine agonists that provide patients with symptomatic relief. This relief is unfortunately only temporary as the progression of the disease is not halted. Furthermore, these therapies are associated with a range of side effects and novel approaches to the treatment are thus urgently required. Adenosine A2A receptor antagonists recently emerged as a promising non-dopaminergic alternative, not only as symptomatic treatment, but also as potential neuroprotective therapy. Adenosine A2A receptors are co-localised with dopamine D2 receptors in the striatum and other nuclei of the basal ganglia. Adenosine A2A stimulation decreases the affinity of dopamine for the D2 receptor, and increase cyclic AMP (cAMP) levels. The stimulation of dopamine D2 receptors, in contrast, decreases cAMP levels and therefore these receptors (A2A and D2), act in an opposing manner. Adenosine A2A antagonism will thus have similar effects as dopamine D2 agonism and will reduce the postsynaptic effects of dopamine depletion to give symptomatic relief. There are also several mechanisms where by adenosine A2A antagonists may be neuroprotective, for example by preventing glutamate excitotoxicity, that may cause damage to dopaminergic neurons. A number of adenosine A2A antagonists have already reached clinical trials and promising results were obtained, especially when combined with levodopa. Consequently, A2A antagonists are realistic prospects that have therapeutic potential in diseases with dopaminergic hypofunction, like Parkinson's disease. Many of the current A2A antagonists contain an amino-substituted heterocyclic scaffold, such as an aminopyrimidine. The primary aim of this study was the design, synthesis and evaluation of 2-aminopyrimidine derivatives as adenosine A2A receptor antagonists. Monoamine oxidase B (MAO-B) inhibitors are also promising candidates for the symptomatic treatment of Parkinson's disease, since MAO-B is the enzyme primarily responsible for the catabolism of dopamine in the brain. Irreversible inhibitors of MAO-B, such as selegeline and rasagiline, have been used clinically for the treatment of Parkinson's disease. This type of inhibition comes with certain disadvantages as it may take up to several weeks after termination of treatment for the enzyme activity to recover. Reversible inhibitors in contrast will have much better safety profiles seeing that they will not inactivate the enzyme permanently and allow for competition with the substrate. When dopamine is oxidized by MAO, toxic metabolic by-products, such as hydrogen peroxide (H2O2) forms, and this is believed to be a possible cause of Parkinson's disease. MAO-B inhibitors will therefore not only provide symptomatic relief but may also alter the progression of the disease by preventing the formation of these byproducts. Promising MAOB inhibitory activities have been reported for chalcones, and since the intermediates obtained in the synthesis of aminopyrimidines in this study are chalcones, a secondary aim of this study was the screening of selected chalcone intermediates as inhibitors of MAO–B. Results - Design and synthesis: A series of 2-aminopyrimidines were designed using known active structures and literature pharmacophores. A molecular modelling study (Discovery Studio 3.1, Accelrys) was further done to investigate the feasibility of these compounds as potential adenosine A2A antagonists. All of the designed aminopyrimidines were successfully docked in the binding site of the adenosine A2A receptor. Binding orientations and observed interactions with important residues in the active site were similar to those observed for known A2A antagonists. It was therefore concluded that these compounds may be potential A2A antagonists and the designed compounds were thus synthesised. Structures were primarily confirmed with nuclear magnetic resonance spectroscopy and mass spectrometry. MAO-B inhibition studies: Selected chalcones were evaluated using a fluorometric assay and kynuramine as substrate. The compounds were potent and selective inhibitors of the MAO-B enzyme with IC50 values ranging between 0.49-7.67 μM. (2E)-3-(3-Chlorophenyl)-1- (5-methyl-2-furyl)prop-2-en-1-one (1c) was the most potent compound with an IC50 value of 0.49 μM and was approximately 60 times more selective towards MAO-B than MAO-A. Some preliminary structure activity relationships were derived, for example, phenyl substitution with an electron withdrawing chlorine group generally resulted in better activity than substitution with electron donating methoxy groups. Further investigation of structure activity relationships are however required as a very small series of chalcones were screened. Reversibility studies and mode of inhibition: A dilution assay was used to determine whether compound (1c) binds reversibly or irreversibly to the MAO-B enzyme. This was done by measuring the recovery of enzymatic activity after a large dilution of the enzyme-inhibitor complex. The results from the reversibility studies showed that the inhibition of the most potent compound (1c) is reversible as the catalytic activities are recovered to approximately 80% and 50% respectively, compared to the control measured in the absence of an inhibitor. For the mode of inhibition, sets of Lineweaver–Burk plots were constructed. The Lineweaver- Burk plots intersected on the y-axis which indicates that compound 1c is a competitive inhibitor of the MAO-B enzyme. In vitro adenosine A2A assays: Radioligand binding assays were used to determine the affinity of the synthesised 2-aminopyrimidines for the adenosine A2A receptor. This assay was performed with the radioligand [3H]NECA in the presence of N6-cyclopentyladenosine (CPA). Compounds 2a - 2h showed moderate to weak affinity in the assay, while promising affinities were observed for compounds 2j - 2n, which all exhibited Ki values below 55 nM. The compound with the highest affinity was 4-(5-methylfuran-2-yl)-6-[3-(piperidine-1- carbonyl)phenyl]pyrimidin-2-amine (2m) with a Ki value of 5.76 nM, which is comparable to the Ki value of 2.10 nM obtained for the known amino-substituted heterocyclic adenosine A2A antagonist, ZM 241385. The higher affinities of compounds (2j – 2n) could, at least in part, be explained by the molecular modellling studies. In the docking experiments an additional hydrogen bond interaction was observed between the amide carbonyl and tyrosine 271 indicating that this structural feature is a major contributing factor to the improved affinity observed for these derivatives. In vivo adenosine A2A assays: The haloperidol induced catalepsy assay was used to determine whether the two compounds with the highest affinity for the adenosine A2A receptor (2m and 2k) are antagonists of the A2A receptor. These compounds caused a statistically significant reduction in catalepsy, which clearly illustrate that they are adenosine A2A antagonists. The objectives of this study as set out were thus successfully realised and promising results were obtained. During this study, several novel 2-aminopyrimidines and chalcones were synthesised, and the respective adenosine A2A antagonistic and monoamine oxidase inhibitory activities for all of the screened compounds were determined for the first time. / Thesis (MSc (Pharmaceutical Chemistry))--North-West University, Potchefstroom Campus, 2013

Chalconas e flavonoides são compostos comumente presentes em plantas, e constituem uma grande família de produtos naturais com um amplo espectro de atividades farmacológicas. Mudanças na estrutura destas moléculas tem se provado úteis no desenvolvimento de novos agentes terapêuticos, sendo assim, esses compostos tem sido intensamente estudados. Métodos computacionais como a dinâmica molecular (DM) são ferramentas poderosas para o acesso a informações de difícil obtenção por outros meios experimentais. Campos de força acurados são essenciais para a descrição de sistemas biológicos em simulações de DM, assim, um conjunto de parâmetros associado a um composto necessita ser cuidadosamente calibrado para garantir a obtenção de resultados confiáveis. Considerando a relevância dessa família de moléculas e a falta de parâmetros validados para a estrutura básica de chalconas e flavonoides no campo de força GROMOS, o presente trabalho tem como objetivo prover um novo conjunto de parâmetros para a simulação destes compostos. Um protocolo que combina cálculos ab initio e simulações de DM foi aplicado para obter novas cargas atômicas e parâmetros torsionais Propriedades experimentais como densidade e entalpia de vaporização foram usadas como comparação aos valores obtidos em simulações, como forma de validação dos parâmetros. A comparação dos perfis torsionais obtidos por cálculos quânticos e por mecânica molecular auxiliou na geração de novos potenciais que permitem uma descrição conformacional mais acurada dos diedros de interesse. Diversos ajustes em grupos de cargas foram feitos, e os valores para propriedades termodinâmicas obtidos nas simulações estão em concordância com os dados experimentais. Simulações de metadinâmica foram realizadas para avaliar o comportamento conformacional de chalconas e flavonoides completos, e contatos de NOE foram medidos durante simulações de DM, obtendo uma reprodução quase completa das distâncias entre alguns grupos de prótons. O protocolo empregado gerou parâmetros de campo de força que reproduzem bem dados experimentais, e espera-se que estes resultados contribuam para a realização de estudos computacionais acurados envolvendo chalconas e flavonoides. / Chalcones and flavonoids are polyphenolic compounds extensively distributed in plants, constituting a large family of natural products with a broad spectrum of pharmacological activities. Changes in their structure have been proven useful for the development of new therapeutic agents, thus these biomolecules are being intensively studied and modified. Computational methods such as molecular dynamics (MD) simulations are powerful tools to assess information that is difficult to obtain experimentally. Accurate force fields are essential for describing biological systems in a MD simulation, thus a parameter set associated to a certain compound need to be carefully calibrated to ensure reliable results. Considering the relevance of this family of molecules and the lack of validated parameters for the basic structure of chalcones and flavonoids in the GROMOS force field, this work intends to provide a new parameter set for the simulation of these compounds. We employed a protocol combining ab initio calculations and MD simulations for the obtention of new atomic charges and torsional parameters Experimental properties such as density and enthalpy of vaporization were compared to the calculated values in order to validate the parameters. A fitting of molecular-mechanical to quantum-mechanical torsional profiles was performed for each of the dihedrals of interest in the structures, generating new torsional potentials that provide accurate description of conformational behavior. Additionally, adjustments in charge groups were made in topologies used for the MD simulations and the obtained values of the thermodynamic properties are in good agreement with experimental data. Metadynamics simulations were performed to evaluate the conformation of complete chalcones and flavonoids, and NOE contacts during MD simulations were measured, obtaining an almost complete reproduction of inter-proton interactions. The employed protocol generated force field parameters that reproduce well the target data and we expect they will contribute to more accurate computational studies on the biological role of chalcones and flavonoids.

Orientadora: Prof.ª Dr.ª Mirela Inês de Sairre / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Ciência e Tecnologia/Química, 2015. / As chalconas são de uma classe de produtos naturais pertencentes ao grupo dos flavonoides. Este grupo tem despertado o interesse dos pesquisadores por apresentarem várias atividades biológicas incluindo: antitumoral, antiparasitárias, antimalária, anti-inflamatória, entre outras. Os flavonoides tem sido alvo de estudos por apresentarem grande potencial farmacológico e, do ponto de vista sintético, há um grande interesse para o desenvolvimento de estruturas análogas, buscar novas moléculas e realizar uma investigação biológica para o tratamento de diversas patologias. A busca de novos medicamentos, despertou nosso interesse em desenvolver alguns compostos nitroderivados para serem testados em diversas doenças parasitárias. No entanto, a síntese das chalconas com o grupo nitro (NO2) ligado ao anel aromático, é de grande interesse e amplamente utilizadas como fármacos. Portanto, para viabilizar o processo de síntese das chalconas, foi utilizado o safrol como matéria-prima, e depois seguida de uma reação de isomerização e convertido em piperonal que depois foi submetido a uma reação de nitração aromática. A síntese da chalcona é baseada na reação de condensação de Claisen-Schimidt, empregando um catalisador básico (NaOH), solvente polar (EtOH), acetofenona e nitropiperonal. Todas as chalconas foram caracterizadas por análise de ressonância magnética nuclear (RMN), obtido o ponto de fusão e realizados os ensaios biológicos. A chalcona que tem o grupo nitro (NO2) ligado ao anel aromático apresentou um melhor resultado contra o parasita Schistosoma mansoni, responsável pela doença esquistossomose. / The chalcones are a class of natural products belonging to the group of flavonoids. This group has aroused the interest of researchers because they have several biological activities including: anti-tumor, anti-parasitic, anti-malarial, anti-inflammatory, among others. Flavonoids have been investigated for having great pharmacological potential, and the synthetic point of view, there is great interest for the development of similar structures, seek new molecules and perform a biological research for the treatment of various diseases. The search for new drugs, aroused our interest in developing some nitroderivatives compounds to be tested in several parasitic diseases. However, the synthesis of chalcones with the nitro group (NO2) attached to the aromatic ring, is of great interest and widely used as drugs. Therefore, to facilitate the process of synthesis of chalcones it was used safrole as a raw material, and then followed by an isomerization reaction and converted into piperonal which was then subjected to a reaction for aromatic nitration. The synthesis of chalcone is based on the reaction Claisen-Schmidt Condensation, using a basic catalyst (NaOH), polar solvent (EtOH), acetophenone and nitropiperonal. All chalcones were characterized by nuclear magnetic resonance analysis (NMR), the melting point obtained and biological tests conducted. The chalcone having nitro group (NO2) attached to the aromatic ring presented a better result against the parasite Schistosoma mansoni, responsible for the disease schistosomiasis. In this sense, the analysis by spectroscopy in the infrared region, indicated that no changes in the structure of the nanostructured chemical pulp, after sonication. Thermal analysis showed stability of nanostructured sonicated above the pulp fiber and untreated fiber obtained via chemical hydrolysis, indicating the possibility of use as matrix polymers with melting temperatures higher than those polyolefins. Since the morphological analysis showed a reduction in fiber dimensions and good dispersion of the fibers after compression molding cycles. Thus, the mechanical traction results are comparable to those observed in the literature for similar composites obtained by the extrusion process which allows better mixing and dispersion of the composite. The nanostructured cellulose obtained proved to be interesting for application in polymeric composites.