Roberto Parise-Filho

Oleanolic acid (OA) as an antileishmanial agent: Biological evaluation and in silico mechanistic insights

Although a worldwide health problem, leishmaniasis is considered a highly neglected disease, lacking efficient and low toxic treatment. The efforts for new drug development are based on alternatives such as new uses for well-known drugs, in silico and synthetic studies and naturally derived compounds. Oleanolic acid (OA) is a pentacyclic triterpenoid widely distributed throughout the Plantae kingdom that displays several pharmacological activities. OA showed potent leishmancidal effects in different Leishmania species, both against promastigotes (IC(50 L. braziliensis) 30.47 ± 6.35 μM; IC(50 L. amazonensis) 40.46 ± 14.21 μM; IC(50 L. infantum) 65.93 ± 15.12 μM) and amastigotes (IC(50 L. braziliensis) 68.75 ± 16.55 μM; IC(50 L. amazonensis) 38.45 ± 12.05 μM; IC(50 L. infantum) 64.08 ± 23.52 μM), with low cytotoxicity against mouse peritoneal macrophages (CC(50) 235.80 ± 36.95 μM). Moreover, in silico studies performed to evaluate OA molecular properties and to elucidate the possible mechanism of action over the Leishmania enzyme sterol 14α-demethylase (CYP51) suggested that OA interacts efficiently with CYP51 and could inhibit the ergosterol synthesis pathway. Collectively, these data indicate that OA is a good candidate as leading compound for the development of a new leishmaniasis treatment.

Novel capsaicin analogues as potential anticancer agents: synthesis, biological evaluation, and in silico approach.

A novel class of benzo[d][1,3]dioxol‐5‐ylmethyl alkyl/aryl amide and ester analogues of capsaicin were designed, synthesized, and evaluated for their cytotoxic activity against human and murine cancer cell lines (B16F10, SK‐MEL‐28, NCI‐H1299, NCI‐H460, SK‐BR‐3, and MDA‐MB‐231) and human lung fibroblasts (MRC‐5). Three compounds (5f, 6c, and 6e) selectively inhibited the growth of aggressive cancer cells in the micromolar (µM) range. Furthermore, an exploratory data analysis pointed at the topological and electronic molecular properties as responsible for the discrimination process regarding the set of investigated compounds. The findings suggest that the applied designing strategy, besides providing more potent analogues, indicates the aryl amides and esters as well as the alkyl esters as interesting scaffolds to design and develop novel anticancer agents.

RPF151, a novel capsaicin-like analogue: in vitro studies and in vivo preclinical antitumor evaluation in a breast cancer model

Capsaicin, the primary pungent component of the chili pepper, has antitumor activity. Herein, we describe the activity of RPF151, an alkyl sulfonamide analogue of capsaicin, against MDA-MB-231 breast cancer cells. RPF151 was synthetized, and molecular modeling was used to compare capsaicin and RPF151. Cytotoxicity of RPF151 on MDA-MB-231 was also evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5diphenyltetrazolium bromide (MTT) assay. Cell cycle analysis, by flow cytometry, and Western blot analysis of cycle-related proteins were used to evaluate the antiproliferative mechanisms. Apoptosis was evaluated by phosphatidyl-serine externalization, cleavage of Ac-YVAD-AMC, and Bcl-2 expression. The production of reactive oxygen species was evaluated by flow cytometry. RPF151 in vivo antitumor effects were investigated in murine MDA-MB-231 model. This study shows that RPF151 downregulated p21 and cyclins A, D1, and D3, leading to S-phase arrest and apoptosis. Although RPF151 has induced the activation of TRPV-1 and TRAIL-R1/DR4 and TRAIL-2/DR5 on the surface of MDA-MB-231 cells, its in vivo antitumor activity was TRPV-1-independent, thus suggesting that RPF151 should not have the same pungency-based limitation of capsaicin. In silico analysis corroborated the biological findings, showing that RPF151 has physicochemical improvements over capsaicin. Overall, the activity of RPF151 against MDA-MB-231 and its lower pungency suggest that it may have a relevant role in cancer therapy.

Toward chelerythrine optimization: Analogues designed by molecular simplification exhibit selective growth inhibition in non-small-cell lung cancer cells.

A series of novel chelerythrine analogues was designed and synthesized. Antitumor activity was evaluated against A549, NCI-H1299, NCI-H292, and NCI-H460 non-small-cell lung cancer (NSCLC) cell lines in vitro. The selectivity of the most active analogues and chelerythrine was also evaluated, and we compared their cytotoxicity in NSCLC cells and non-tumorigenic cell lines, including human umbilical vein endothelial cells (HUVECs) and LL24 human lung fibroblasts. In silico studies were performed to establish structure-activity relationships between chelerythrine and the analogues. The results showed that analogue compound 3f induced significant dose-dependent G0/G1 cell cycle arrest in A549 and NCI-H1299 cells. Theoretical studies indicated that the molecular arrangement and electron characteristics of compound 3f were closely related to the profile of chelerythrine, supporting its activity. The present study presents a new and simplified chelerythrinoid scaffold with enhanced selectivity against NSCLC tumor cells for further optimization.

INTERAÇÕES FÁRMACO-RECEPTOR: APLICAÇÕES DE TÉCNICAS COMPUTACIONAIS EM AULA PRÁTICA SOBRE A EVOLUÇÃO DOS INIBIDORES DA ENZIMA CONVERSORA DE ANGIOTENSINA

Teaching classes and events regarding the molecular aspects of drug-receptor interactions is not an easy task. The ligand stereochemistry and the spatial arrangement of the macromolecular targets highly increase the complexity of the process. In this context, the use of alternative and more playful approaches could allow students to gain a more thorough understanding of this important topic in medicinal chemistry. Herein, we describe a practical teaching approach that uses computational strategies as a tool for drug-receptor interaction studies performed for angiotencsin converting enzyme inhibitors (ACEi). Firstly, the students learn how to find the crystallographic structure (enzyme-ligand complex). Then, they proceed to the treatment of crude crystallographic data. Thereafter, they learn how to analyze the positioning of the drug on the active site of the enzyme, looking for regions related to the molecular recognition. At the end of the study, students can summarize the molecular requirements for the interaction and the structure-activity relationships of the studied drugs.

Synthesis, Molecular Modeling, and Evaluation of Novel Sulfonylhydrazones as Acetylcholinesterase Inhibitors for Alzheimer's Disease

Alzheimers disease (AD) is the most common type of dementia and related to the degeneration of hippocampal cholinergic neurons, which dramatically affects cognitive ability. Acetylcholinesterase (AChE) inhibitors are employed as drugs for AD therapy. Three series of sulfonylhydrazone compounds were designed, and their ability to inhibit AChE was evaluated. Fifteen compounds were synthesized and twelve of them had IC50 values of 0.64–51.09 μM. The preliminary structure–activity relationships indicated that the methylcatechol moiety and arylsulfonyl substituents generated better compounds than both the benzodioxole and alkylsulfonyl chains. Molecular dynamics studies of compound 6d showed that the interaction with the peripheral binding site of AChE was similar to donepezil, which may explain its low IC50 (0.64 μM). Furthermore, the drug‐likeness of 6d suggests that the compound may have appropriate oral absorption and brain penetration. Compound 6d also presented antiradical activity and was not cytotoxic to LL24 cells, suggesting that this compound might be considered safe. Our findings indicate that arylsulfonylhydrazones may be a promising scaffold for the design of new drug candidates for the treatment of AD.

Entendendo o processo químico de bioativação da sinvastatina por métodos experimentais e computacionais: uma aula prática

Cholesterol is a lipid which in high concentration can be an important risk factor for coronary diseases and atherosclerotic lesions. This lipid presents an endogenous biosynthesis that involves several steps; one of them is modulated by the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase). HMG-CoA reductase is inhibited by statins, such as simvastatin, in order to reduce seric become active. The structure of simvastatin has a lactone ring that undergoes enzymatic hydrolysis giving the 3,5-dihydroxy-heptanoate metabolite. This group is essential for simvastatin antilipemic activity, but significantly increases their water solubility. Make students understand the influence of chemical groups and organic functions on physicochemical properties and pharmacokinetic profiles of drugs, as simvastatin, is not an easy task. In this context, combine practical strategies and theoretical presentations of the concepts involved on drug biotransformation certainly could improve the teaching learning process. This manuscript correlates organic strategies and in silico techniques throught simvastatin hydrolysis followed by comparative ClogP measurement. This approach intends to allow students to have contact with a cross-platform and multidisciplinary learning, making it ludic, easier and more interesting than theoretical classes.

Multi-Spectroscopic and Theoretical Analysis on the Interaction between Human Serum Albumin and a Capsaicin Derivative—RPF101

The interaction between the main carrier of endogenous and exogenous compounds in the human bloodstream (human serum albumin, HSA) and a potential anticancer compound (the capsaicin analogue RPF101) was investigated by spectroscopic techniques (circular dichroism, steady-state, time-resolved, and synchronous fluorescence), zeta potential, and computational method (molecular docking). Steady-state and time-resolved fluorescence experiments indicated an association in the ground state between HSA:RPF101. The interaction is moderate, spontaneous (ΔG° < 0), and entropically driven (ΔS° = 0.573 ± 0.069 kJ/molK). This association does not perturb significantly the potential surface of the protein, as well as the secondary structure of the albumin and the microenvironment around tyrosine and tryptophan residues. Competitive binding studies indicated Sudlow’s site I as the main protein pocket and molecular docking results suggested hydrogen bonding and hydrophobic interactions as the main binding forces.

Synthesis and crystal structure of a new anticancer candidate: RPF151

University of São Paulo, School of Pharmaceutical Sciences, Department of Pharmacy, São Paulo, Brazil, University of São Paulo, Institute of Biomedical Sciences, Department of Immunology, São Paulo, Brazil, Butantan Institute, Biochemistry and Biophysical Laboratory, São Paulo, Brazil, Butantan Institute, Laboratory of Genetics, São Paulo, Brazil, Federal University of ABC (UFABC), Center of Natural Sciences and Humanities (CCNH), Federal University of ABC (UFABC), Santo André, Brazil