In this study, we assessed the cytotoxic effect of 1,3-diphenyl-2-allyl-1,3-propanedione (DPAP) on B16F10 and Tm5 melanoma cells and investigated its interaction with DNA (deoxyribonucleic acid) using optical tweezers. The compound showed to be effective against B16F10 cells with selectivity index (SI) of 7.92 and interaction to the outer surface of the double helix, probably at the minor groove of DNA. This likely induced a bending deformation of the polymer chain, decreasing persistence length, and indicated that each DPAP molecule occupies a single base pair upon binding to the double helix.

In this paper, we have applied state-of-the-art technologies and new investigations were developed focusing on obtaining simple and inexpensive molecules for treating cardiovascular diseases, as they are considered the leading cause of death in the world. For the first time, the inclusion complex of sulcatone (SU) and β-cyclodextrin (β-CD) was achieved (using a spray drier) and characterized making use of spectroscopic, thermal and computational methods. In addition, the system was evaluated regarding its vasorelaxant properties. Evidence of the inclusion complex formation was provided using different techniques, such as X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), and 1H nuclear magnetic resonance (NMR) spectroscopies and then deduced by pharmacological experiments, which showed significant changes in relation to the initial material.

Croton zehntneri (Euphorbiaceae) é uma planta aromática nativa da região Nordeste do Brasil. O monoterpenóide Estragol (ESL) foi isolado por métodos cromatográficos clássicos a partir do óleo essencial (OE) das folhas de C. zehntneri e caracterizado por CG-DIC e CG-EM, tendo seu potencial antimicrobiano e citotóxico avaliado. A análise do OE permitiu a identificação de 100% dos constituintes integrados, cujo rendimento foi cerca de 1.8%. Os principais componentes identificados foram: eucaliptol, estragol (84.7%) e espatulenol. A dosagem de 50 μg/disco de ESL apresentou halos de inibição bastante expressivos frente a bactérias gram positiva e fungos. O ESL apresentou toxicidade frente a Artemia salina com CL50 e CL90 de 4,54 e 8,47 μg mL-1. Entretanto, nos testes de inibição tumoral (células humanas), não houve inibição satisfatória em nenhuma das linhagens de células humanas cancerígenas (MCF-7, HEP-2 e NCIH292).

Croton zehntneri (Euphorbiaceae) is a native aromatic plant from Northeast region of Brazil. The monoterpenoid estragole (ESL) has been isolated by classical chromatographic methods from the essential oil (EO) of C. zehnteneri leaves and characterized by GC-FID and GC-MS, its antimicrobial and cytotoxic potentials being assessed. The analysis of the EO enabled the identification of 100% of the integrated constituents, of which yield was about 1.8%. The main components identified were: eucalyptol, estragole (84.7%) and spathulenol. The dosage of 50 μg/disk of ESL presented fairly significant zones of inhibition against Gram-positive bacteria and fungi. The ESL presented toxicity against Artemia salina with LC50 and LC90 of 4,54 and 8,47 μg mL-1. However, in tumor inhibition assays (human cells), there were no rewarding inhibition in any of the human cancer cell lines (MCF-7, HEP-2 and NCI-H292).

Croton zehntneri, a plant native to northeastern Brazil, is widely used in folk medicine to treat gastrointestinal problems and has rich essential oil content. The essential oil of C. Zehntneri was analyzed by GC-MS, and its inclusion complex with β-cyclodextrin (β-CD) was characterized by both vibrational spectroscopy and differential scanning calorimetry (DSC). Estragol was the major component identified in the essential oil by the study. IR spectra indicated an interaction of β-CD with essential oil from C. zehntneri, a finding corroborated by the stability constant and scanning calorimetry. Microencapsulation within β-CD has the potential to mask sensory attributes and increase aqueous solubility of oils, thereby improving their applicability as drugs.

Apresentamos uma revisão de duas novas técnicas para estudar propriedades biofísicas de moléculas únicas e células únicas. Um laser incidindo em uma objetiva de microscópio de grande abertura numérica é capaz de aprisionar pequenas partículas dielétricas na região próxima ao foco. Este aparato é chamado de pinça óptica. Esta técnica tem a grande vantagem de permitir a manipulação de um objeto individual. Usamos a pinça óptica para medir a elasticidade entrópica de uma molécula única de DNA em sua interação com o fármaco Psoralen. A pinça óptica também é usada para segurar uma célula renal MDCK fora do substrato, permitindo medidas precisas do volume dessa célula única durante um choque osmótico. Este processo nos permite obter informações sobre a permeabilidade osmótica da membrana e o crescimento do volume regulatório. A microscopia de desfocalização é uma técnica recente inventada em nosso laboratório, que nos permite observar objetos transparentes simplesmente desfocalizando o microscópio de uma maneira controlada. Nosso modelo físico de um microscópio desfocalizado mostra que o contraste da imagem observado neste caso é proporcional à distância da desfocalização e à curvatura do objeto transparente. A microscopia de desfocalização é muito útil para estudar a motilidade e as propriedades mecânicas das células. Mostramos aqui a aplicação da microscopia de desfocalização em medidas de flutuações na superfície de macrófagos e sua influência na fagocitose.

We present a review on two new tools to study biophysical properties of single molecules and single cells. A laser incident through a high numerical aperture microscope objective can trap small dielectric particles near the focus. This arrangement is named optical tweezers. This technique has the advantage to permit manipulation of a single individual object. We use optical tweezers to measure the entropic elasticity of a single DNA molecule and its interaction with the drug Psoralen. Optical tweezers are also used to hold a kidney cell MDCK away from the substrate to allow precise volume measurements of this single cell during an osmotic shock. This procedure allows us to obtain information about membrane water permeability and regulatory volume increase. Defocusing microscopy is a recent technique invented in our laboratory, which allows the observation of transparent objects, by simply defocusing the microscope in a controlled way. Our physical model of a defocused microscope shows that the image contrast observed in this case is proportional to the defocus distance and to the curvature of the transparent object. Defocusing microscopy is very useful to study motility and mechanical properties of cells. We show here the application of defocusing microscopy to measurements of macrophage surface fluctuations and their influence on phagocytosis.