Hamilton Ishiki | Universidade do Oeste Paulista (original) (raw)

Papers by Hamilton Ishiki

DOAJ (DOAJ: Directory of Open Access Journals), Mar 1, 2018

O crescimento industrial mundial esta cada vez mais interligado com os diversos meios sustentavei... more O crescimento industrial mundial esta cada vez mais interligado com os diversos meios sustentaveis, a fim de diminuir os problemas ambientais causados pelo crescimento desenfreado ocorrido ate o momento, um meio alternativo encontrado foi a substituicao parcial do agregado miudo pelo polimero elastomerico. O concreto piloto apresentou uma resistencia de 20,5 MPa apos o termino do periodo de cura aos 28 dias de idade, ja nos concretos confeccionados com a adicao do polimero, observou-se uma perda de resistencia. Verificou-se tambem a queda da massa especifica, aumento do indice de vazios e absorcao de agua conforme se adicionava o polimero. Com os resultados entao coletados pode-se indicar as possiveis areas de atuacao, tais com: guias, sarjetas e mobiliarios urbanos.

Natural Product Communications, May 1, 2014

The aim of this work was to predict the anticancer potential of 3 atisane, and 3 trachylobane dit... more The aim of this work was to predict the anticancer potential of 3 atisane, and 3 trachylobane diterpene compounds extracted from the roots of Xylopia langsdorffiana. The prediction of anticancer activity as expressed against PC-3 tumor cells was made using a PLS model built with 26 diterpenes in the training set. Significant statistical measures were obtained. The six investigated diterpenes were applied to the model and their activities against PC-3 cells were calculated. All the diterpenes were active, with atisane diterpenes showing the higher pIC 50 values. In human prostate carcinoma PC-3 cells, the apoptosis mechanism is related to an inhibition of IKK/NF-B. Antioxidant potential implies a greater electronic molecular atmosphere (increased donor electron capacity), which can reduce radical reactivity, and facilitate post donation charge accommodation. Molecular surfaces indicated a much greater electronic cloud over atisane diterpenes.

Current Pharmaceutical Design, May 30, 2016

Primeiramente agradeço a Deus por todas as oportunidades fornecidas em minha vida, em especial a ... more Primeiramente agradeço a Deus por todas as oportunidades fornecidas em minha vida, em especial a de desenvolver este trabalho e pela saúde dada para que eu o completasse. À Prof. Antonia Tavares do Amaral pela orientação neste estudo e pela paciência e compreensão nestes anos em que trabalhamos juntos.

Fórum Ambiental da Alta Paulista, Nov 10, 2013

Combinatorial Chemistry & High Throughput Screening, Jun 6, 2017

Current Topics in Medicinal Chemistry, Sep 14, 2020

: Computer-Aided Drug Design (CADD) techniques have garnered a great deal of attention in academi... more : Computer-Aided Drug Design (CADD) techniques have garnered a great deal of attention in academia and industry because of their great versatility, low costs, possibilities of cost reduction in in vitro screening and in the development of synthetic steps; these techniques are compared with highthroughput screening, in particular for candidate drugs. The secondary metabolism of plants and other organisms provide substantial amounts of new chemical structures, many of which have numerous biological and pharmacological properties for virtually every existing disease, including cancer. In oncology, compounds such as vimblastine, vincristine, taxol, podophyllotoxin, captothecin and cytarabine are examples of how important natural products enhance the cancer-fighting therapeutic arsenal. : In this context, this review presents an update of Ligand-Based Drug Design and Structure-Based Drug Design techniques applied to flavonoids, alkaloids and coumarins in the search of new compounds or fragments that can be used in oncology. : A systematical search using various databases was performed. The search was limited to articles published in the last 10 years. : The great diversity of chemical structures (coumarin, flavonoids and alkaloids) with cancer properties, associated with infinite synthetic possibilities for obtaining analogous compounds, creates a huge chemical environment with potential to be explored, and creates a major difficulty, for screening studies to select compounds with more promising activity for a selected target. CADD techniques appear to be the least expensive and most efficient alternatives to perform virtual screening studies, aiming to selected compounds with better activity profiles and better “drugability”.

Colloquium Exactarum, Aug 23, 2017

RESUMO-O crescimento industrial mundial está cada vez mais interligado com os diversos meios sust... more RESUMO-O crescimento industrial mundial está cada vez mais interligado com os diversos meios sustentáveis, a fim de diminuir os problemas ambientais causados pelo crescimento desenfreado ocorrido até o momento, um meio alternativo encontrado foi a substituição parcial do agregado miúdo pelo polímero elastomérico. O concreto piloto apresentou uma resistência de 20,5 MPa após o término do período de cura aos 28 dias de idade, já nos concretos confeccionados com a adição do polímero, observou-se uma perda de resistência. Verificou-se também a queda da massa específica, aumento do índice de vazios e absorção de água conforme se adicionava o polímero. Com os resultados então coletados pode-se indicar as possíveis áreas de atuação, tais com: guias, sarjetas e mobiliários urbanos.

Mini-reviews in Medicinal Chemistry, Mar 12, 2015

Chemosphere, Mar 1, 2005

The photocatalytic degradation of imazethapyr, a herbicide of the imidazolinone family, was inves... more The photocatalytic degradation of imazethapyr, a herbicide of the imidazolinone family, was investigated in an aqueous suspension of titanium dioxide used as a catalyst. A pseudo-first order kinetic model was employed to discuss the results. The effect of catalyst loading, initial concentration of imazethapyr, hydrogen peroxide, pH value, and temperature were investigated. Imazethapyr disappearance as a function of irradiation time was analyzed by HPLC. The ammonium ion formation was determined spectrophotometrically at 694 nm. The degradation was observed to proceed more favorably at natural pH (ca. 4.4) when the pH was varied in the range from 2 to 11. The addition of hydrogen peroxide to the TiO2 suspension enhanced the degradation rate constant up to 5.0x10(-3) mol l-1, but decreased it at higher concentrations. The degradation rate constants decreased by 19% with a temperature increase from 20 to 40 degrees C in the TiO2 suspension, whereas a 16% increase in imazethapyr direct photolysis was observed for the same temperature range. This behavior indicates the occurrence of physisorption between TiO2 and imazethapyr molecules.

Mini-reviews in Organic Chemistry, Aug 22, 2017

With the aim of offering patients a more effective drug therapy and with few side effects, it was... more With the aim of offering patients a more effective drug therapy and with few side effects, it was believed in the perfect and unique interaction of the bioactive compound and the receptor or target macromolecule. This concept has changed, and multifunctional compounds show greater efficiency, particularly in the therapy of complex diseases, with a sum of origin. Among these ills, we quote: neurodegenerative diseases, cancer, parasitic and inflammatory. To fight these diseases, studies with multitarget flavonoids have been reported. Flavonoid compounds are natural products traditionally used as chemotherapy because of their numerous therapeutic activities. Here, we gather studies with multitarget in drug discovery flavonoids.

Natural Product Communications, Jul 1, 2014

Many studies of the scientific literature discuss the anticancer activity of diterpenes inhibitin... more Many studies of the scientific literature discuss the anticancer activity of diterpenes inhibiting the Akt/IKK/NF-B pro-survival signaling cascade, mainly by the activation of serine/threonine phosphatase PP2A. The aim of this work was to evaluate and compare the anticancer potential of three atisane, three kaurane and three trachylobane diterpenes extracted from the roots of Xylopia langsdorffiana. Thus, we investigated the reactivity (H-L GAP parameter), HOMO atmosphere favorable to neutralize the radical reactivity, and the docking of compounds with PP2A. With all approaches, this theoretical study showed that atisane diterpenes have favorable characteristics for antitumor activity, like electron donating ability and greater hydrophilic interactions with the enzyme, by inhibition of Akt/IKK/NF-B, and activation of PP2A.

Elsevier eBooks, 2018

In silico methods or computer-aided drug design (CADD) studies, which involve an understanding of... more In silico methods or computer-aided drug design (CADD) studies, which involve an understanding of molecular interactions from both a qualitative and quantitative point of view, are increasingly being used in both industrial and academic settings. Analysis of the molecular structure of a given system allows relevant information to be extracted, and the potential of bioactive compounds to be predicted. In silico tools used in medicinal chemistry include chemometric methods, structure–activity relationships (SAR), mole cular modeling, and quantitative structure–activity relationships (QSAR), which correlate the structural or property descriptors of compounds to several types of biological activities. This chapter will report some studies to show how computational chemistry can be used to predict important chemical structure information and how these techniques can be applied in food research.

Current Topics in Medicinal Chemistry, Jul 31, 2018

Journal of Organic Chemistry, Mar 1, 1999

Flavonoids are a class of low molecular weight phenolic compounds widely distributed in the plant... more Flavonoids are a class of low molecular weight phenolic compounds widely distributed in the plant kingdom.1 They have displayed potential pharmacological applications as antibacterial, antioxidant, anticancer, and antiallergy agents.2-6 Furthermore, there has been a considerable recent interest in flavonoids since substantial evidence has been accumulated that they exhibit anti-HIV activity.7,8 These compounds consists of a benzene ring fused with a γ-pyrone ring, which are usually denoted Aand C-rings, respectively. The most important chemical property of these compounds is the enhanced reactivity of the C-ring, which was discovered more than 30 years ago.9-12 More specifically, the strong acid/base properties of the C-ring were considered particularly relevant since protonation of substrates occurs during numerous biochemical processes and, in some cases, is the key step of the entire process. On the other hand, the molecular geometries and the electronic structures of 1-3 were investigated at both semiempirical13,14 and ab initio levels using a minimal basis set.15 Furthermore, the solvation of 1 was recently investigated using combined SCRF/ Discrete methods.16 Nevertheless, there are some questions related to chemical properties of flavonoids that remain unknown. Thus, the site of protonation of flavonoids is obscure, although experimental studies in γ-pyrone derivatives10-12 suggest that the protonation occurs not in the heterocyclic oxygen but on the carbonyl oxygen. On the other hand, the possible existence of π-conjugation in the C-ring has not been ascertained. These points are of crucial interest to understand both the chemical and biological properties of flavonoids. This work describes the results of a quantum mechanical study about the acid/base properties of flavonoids in the gas phase and aqueous solution. For this purpose, three of the most important flavonoids were selected: 4H-1-benzopyran-4-one (1), 2-hydroxy-4H-1-benzopyran-4-one (2), and 3-hydroxy-4H-1-benzopyran-4-one (3). Furthermore, the existence of π-conjugation in the C-ring has been also investigated.