DEFAR - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531
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Item New multicomponent crystal forms of adiphenine with low hygroscopicity.(2022) Ribeiro, Thiago; Silva, Alisson Moraes e; Araujo Neto, João Honorato de; Viana, André Luis Machado; Faria, Henrique Dipe de; Ruela, André Luís Morais; Doriguetto, Antônio Carlos; Oliveira, Cecilia Maria Alves; Martins, Felipe TerraAdiphenine is an acetylcholine receptor inhibitor used as an antispasmodic drug due to its strong smooth muscle relaxant action. Adiphenine hydrochloride is largely marketed in drug associations to treat muscle spasms and relieve pain in colic and cramps. However, it presents serious problems with hygroscopicity and chemical stability under high humidity conditions, which have limited its use as an active pharmaceutical ingredient (API). Here, we have solved the adiphenine solid-state hygroscopicity problem through the preparation of stable, nonhygroscopic multicomponent crystal forms thereof. Two new salts of adiphenine were designed by recognition of intermolecular interaction patterns in the Cambridge Structural Database (CSD) and ΔpKa rules. Two generically recognized as safe (GRAS) coformers, namely, citric acid and oxalic acid, were chosen and formed monobasic salts with adiphenine. Crystal structure elucidation reveals that adiphenine adopts different conformations in our salts, while in the literature, hydrochloride adopts one, which is related to different intermolecular arrays. In the dynamic vapor sorption (DVS) analysis, it was verified that adiphenine citrate and adiphenine oxalate starts to incorporate water slowly from 50 to 70% of relative humidity (RH), increasing up to 3.2 and 2.6% of their initial masses in 90% of RH, respectively. At the end of the desorption cycle (RH = 0%), the samples retained only 0.12 and 0.08% of water relative to their initial masses. On the other hand, adiphenine hydrochloride exhibits a classical high hygroscopicity behavior, which retains water fast from 50% of relative humidity (RH), increasing up to 22% of its initial mass in 90% of RH and a net mass gain of 5% at the end of the desorption cycle (RH = 0%). Notably, both carboxylic acid salts had similar solubility as a function of medium pH, while the hydrochloride one was more soluble than them by factors ranging from 6.7 (relative to citrate in pH 1.2) to 28.2 (relative to oxalate in pH 4.5). Nevertheless, the pharmacokinetic parameters of adiphenine after oral administration of the capsules containing the salt forms did not reflect these solubility differences, since all adiphenine salt forms can be considered highly soluble drugs according to the Biopharmaceutics Classification System (dose/solubility ratio < 250 mL). It was observed that the rats treated with capsules containing adiphenine hydrochloride had an increase in AUC0−∞ (1537 vs 914 vs 991 min μg mL−1 ) compared with rats treated with adiphenine citrate and oxalate capsules, respectively, even though the same tmax (48 min) was observed. However, dosage tuning can bring the bioavailability of our salts into that of the hydrochloride salt, with the advantage of nonhygroscopicity and higher chemical stability.Item A novel platinum complex containing a piplartine derivative exhibits enhanced cytotoxicity, causes oxidative stress and triggers apoptotic cell death by ERK/p38 pathway in human acute promyelocytic leukemia HL-60 cells.(2019) Oliveira, Maiara de Souza; Barbosa, Marília Imaculada Frazão; Souza, Thiago Belarmino de; Moreira, Diogo Rodrigo de Magalhães; Martins, Felipe Terra; Villarreal, Wilmer; Machado, Rafael Pereira; Doriguetto, Antônio Carlos; Soares, Milena Botelho Pereira; Bezerra, Daniel PereiraPiplartine (piperlongumine) is a plant-derived compound found in some Piper species that became a novel potential antineoplastic agent. In the present study, we synthesized a novel platinum complex containing a piplartine derivative cis-[PtCl(PIP-OH)(PPh3)2]PF6 (where, PIP-OH = piplartine demethylated derivative; and PPh3 = triphenylphosphine) with enhanced cytotoxicity in different cancer cells, and investigated its apoptotic action in human promyelocytic leukemia HL-60 cells. The structure of PIP-OH ligand was characterized by X-ray crystallographic analysis and the resulting platinum complex was characterized by infrared, molar conductance measurements, elemental analysis and NMR experiments. We found that the complex is more potent than piplartine in a panel of cancer cell lines. Apoptotic cell morphology, increased internucleosomal DNA fragmentation, without cell membrane permeability, loss of the mitochondrial transmembrane potential, increased phosphatidylserine externalization and caspase-3 activation were observed in complex-treated HL-60 cells. Treatment with the complex also caused a marked increase in the production of reactive oxygen species (ROS), and the pretreatment with N-acetyl-L-cysteine, an antioxidant, reduced the complex-induced apoptosis, indicating activation of ROS-mediated apoptosis pathway. Important, pretreatment with a p38 MAPK inhibitor (PD 169316) and MEK inhibitor (U-0126), known to inhibit ERK1/2 activation, also prevented the complex-induced apoptosis. The complex did not induce DNA intercalation in cell-free DNA assays. In conclusion, the complex exhibits more potent cytotoxicity than piplartine in a panel of different cancer cells and triggers ROS/ERK/p38-mediated apoptosis in HL-60 cells.Item Epikatonic acid from Austroplenckia populnea : structure elucidation by nmr spectroscopy and x-ray crystallography.(2002) Silva, Grácia Divina de Fátima; Duarte, Lucienir Pains; Viera Filho, Sidney Augusto; Doriguetto, Antônio Carlos; Mascarenhas, Yvone PrimeranoFrom the chloroform extract of Austroplenckia populnea, epikatonic acid, friedelin, populnonic acid, abruslactone A, salaspermic acid and 22b-epi-maytenfolic acid were isolated. The structure and stereochemistry of epikatonic acid were established by two-dimensional NMR spectroscopic techniques (HMQC, HMBC and NOESY) and later confirmed by single crystal X-ray diffraction as 3b-hydroxyolean- 12-en-29-oic acid, which unambiguously established the configuration of the hydroxyl group at C-3 as 3b-OH and the carboxyl group at C-20 as 20a-COOH. The crystal structure shows two independent molecules in the asymmetric unit. The crystal packing is stabilized by four O–H· · ·O intermolecular hydrogen bonds, which give rise to infinite double chains along the c axis.