Gardenia C.G. Militão

Cytotoxicity and slow release of the anti-cancer drug doxorubicin from ZIF-8

Metal–organic frameworks are emerging as a powerful platform for the delivery and controlled release of several drug molecules. Herein, we report the incorporation of the anti-cancer drug doxorubicin into the zeolitic imidazolate framework (ZIF-8) with high-load and progressive release. Adsorption measurements show that doxorubicin is incorporated into ZIF-8 with a load of 0.049 g doxorubicin g−1 dehydrated ZIF-8. Doxorubicin is released in a highly controlled and progressive fashion with 66% of the drug released after 30 days. We also characterize the antitumoral potential and cytotoxicity of the doxorubicin-ZIF-8 (DOXO-ZIF-8) complex towards the mucoepidermoid carcinoma of human lung (NCI-H292), human colorectal adenocarcinoma (HT-29), and human promyelocytic leukemia (HL-60) cell lines. It is shown that the complex doxorubicin-ZIF-8 exhibits lower cytotoxicity than pure doxorubicin for the tested cells, possibly due to the slower release of the incorporated drug. Furthermore, host–guest interactions have been addressed from a microscopic perspective through molecular docking simulations. In conjunction with our experimental characterization, the calculations suggest that doxorubicin binds preferentially to the surface rather than into the pores of ZIF-8, whose entry diameter is at least half the size of the shortest axis of the drug. These findings are also consistent with high-resolution X-ray crystallography and NMR spectroscopy studies of ZIF-8 which shows that this framework is very rigid under constant pressure in contrast to previous experimental and theoretical studies of ZIF-8 under gas pressure.

Effects of lipoic acid on oxidative stress in rat striatum after pilocarpine-induced seizures

The relationship between free radical and scavenger enzymes has been found in the epilepsy and reactive oxygen species have been implicated in seizure-induced neurodegeneration. It has been suggested that pilocarpine-induced seizures is mediated by increases in oxidative stress. Current researches have suggested that antioxidant compounds may afford some level of neuroprotection against the neurotoxicity of seizures in cellular level. The objective of the present study was to evaluate the neuroprotective effects of lipoic acid (LA) in rats, against the observed oxidative stress during seizures induced by pilocarpine. Wistar rats were treated with 0.9% saline (i.p., control group), LA (20mg/kg, i.p., LA group), pilocarpine (400mg/kg, i.p., P400 group), and the association of LA (20mg/kg, i.p.) plus pilocarpine (400mg/kg, i.p.), 30 min before of administration of LA (LA plus P400 group). After the treatments all groups were observed for 1h. The enzyme activities as well as the lipid peroxidation and nitrite concentrations were measured using spectrophotometric methods and the results compared to values obtained from saline and pilocarpine-treated animals. Protective effects of LA were also evaluated on the same parameters. In P400 group there was a significant increase in lipid peroxidation, nitrite level and glutathione peroxidase (GPx) activity. However, no alteration was observed in superoxide dismutase (SOD) and catalase activities. Antioxidant treatment significantly reduced the lipid peroxidation level and nitrite content as well as increased the SOD, catalase and GPx activities in rat striatum after seizures. Our findings strongly support the hypothesis that oxidative stress in striatum occurs during seizures induced by pilocarpine, proving that brain damage induced by the oxidative process plays a crucial role in seizures pathogenic consequences, and also imply that strong protective effect could be achieved using LA.

Induction of cancer cell death by apoptosis and slow release of 5-fluoracil from metal-organic frameworks Cu-BTC.

This study aimed to evaluate the mechanism associated with cytotoxic activity displayed by the drug 5-fluorouracil incorporated in Cu-BTC MOF and its slow delivery from the Cu-BTC MOF. Structural characterization encompasses elemental analysis (CHNS), differential scanning calorimetry (DSC), thermogravimetric analysis (TG/DTG), Fournier transform infrared (FIT-IR) and X-ray diffraction (XRD) was performed to verify the process of association between the drug 5-FU and Cu-BTC MOF. Flow cytometry was done to indicate that apoptosis is the mechanism responsible for the cell death. The release profile of the drug 5-FU from Cu-BTC MOF for 48 hours was obeisant. Also, the anti-inflammatory activity was evaluated by the peritonitis testing and the production of nitric oxide and pro-inflammatory cytokines were measured. The chemical characterization of the material indicated the presence of drug associated with the coordination network in a proportion of 0.82 g 5-FU per 1.0 g of Cu-BTC MOF. The cytotoxic tests were carried out against four cell lines: NCI-H292, MCF-7, HT29 and HL60. The Cu-BTC MOF associated drug was extremely cytotoxic against the human breast cancer adenocarcinoma (MCF-7) cell line and against human acute promyelocytic leukemia cells (HL60), cancer cells were killed by apoptosis mechanisms. The drug demonstrated a slow release profile where 82% of the drug was released in 48 hours. The results indicated that the drug incorporated in Cu-BTC MOF decreased significantly the number of leukocytes in the peritoneal cavity of rodents as well as reduced levels of cytokines and nitric oxide production.

Preliminary antifungal and cytotoxic evaluation of synthetic cycloalkyl(b)thiophene derivatives with PLS-DA analysis

Preliminary antifungal and cytotoxic evaluation of synthetic cycloalkyl[b]thiophene derivatives with PLS-DA analysis A series of 2-[(arylidene)amino]-cycloalkyl[b]thiophene-3-carbonitriles (2a-x) was synthesized by incorporation of substituted aromatic aldehydes in Gewald adducts (1a-c). The title compounds were screened for their antifungal activity against Candida krusei and Criptococcus neoformans and for their antiproliferative activity against a panel of 3 human cancer cell lines (HT29, NCI H-292 and HEP). For antiproliferative activity, the partial least squares (PLS) methodology was applied. Some of the prepared compounds exhibited promising antifungal and proliferative properties. The most active compounds for antifungal activity were cyclohexyl[b]thiophene derivatives, and for antiproliferative activity cycloheptyl[b]thiophene derivatives, especially 2-[(1H-indol-2-yl-methylidene)amino]- 5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carbonitrile (2r), which inhibited more than 97 % growth of the three cell lines. The PLS discriminant analysis (PLS-DA) applied generated good exploratory and predictive results and showed that the descriptors having shape characteristics were strongly correlated with the biological data. Preliminarno ispitivanje antimikotskog i citotoksičnog djelovanja derivata cikloalkil[b]tiofena PLS-DA analizom Koristeći supstituirane aromatske aldehide u Gewaldovim aduktima 1a-c sintetizirani su derivati 2-[(ariliden)amino]-cikloalkil[b]tiofen-3-karbonitrila (2a-x). Ispitano je antimikotsko djelovanje tih spojeva na gljivice Candida krusei i Criptococcus neoformans te antiproliferativno djelovanje na tri humane tumorske stanične linije (HT29, NCI H-292 i HEP). Za antiproliferativno djelovanje primijenjena je metoda parcijalnih najmanjih kvadrata (PLS) koristeći softverski program Pentacle. Neki od ispitanih spojeva pokazuju obećavajuće antimikotsko i antiproliferativno djelovanje. Najjače antimikotsko djelovanje imaju cikloheksil[b]tiofen derivati, a najjače antiproliferativno djelovanje cikloheptil[b]tiofen derivati, posebice 2-[(1H-indol-2-il-metiliden)amino]-5,6,7,8-tetrahidro-4H-ciklohepta[b]tiofen-3-karbonitril (2r), koji inhibira više od 97 % rast svih triju ispitivanih staničnih linija. Primijenjena PLS diskriminirajuća analiza dala je dobre istraživačke i prognostičke rezultate i pokazala da deskriptori dobro koreliraju s biološkim rezultatima.

Pterocarpanquinones, aza-pterocarpanquinone and derivatives: Synthesis, antineoplasic activity on human malignant cell lines and antileishmanial activity on Leishmania amazonensis

Pterocarpanquinones (1a-e) and the aza-pterocarpanquinone (2) were synthesized through palladium catalyzed oxyarylation and azaarylation of conjugate olefins, and showed antineoplasic effect on leukemic cell lines (K562 and HL-60) as well as colon cancer (HCT-8), gliobastoma (SF-295) and melanoma (MDA-MB435) cell lines. Some derivatives were prepared (3-8) and evaluated, allowing establishing the structural requirements for the antineoplasic activity in each series. Compound 1a showed the best selectivity index in special for leukemic cells while 2 showed to be more bioselective for HCT-8, SF-295 and MDA-MB435 cells. Pterocarpanquinones 1a and 1c-e, as well as 8 were the most active on amastigote form of Leishmania amazonensis in culture. Compounds 1a, 1c and 8 showed the best selectivity index.

Cytotoxic and leishmanicidal properties of garcinielliptone FC, a prenylated benzophenone from Platonia insignis.

Garcinielliptone FC (GFC), a natural prenylated benzophenone, was extracted from Platonia insignis Mart. (Clusiaceae), a native plant commonly known as bacuri and used in traditional Brazilian medicine for the treatment of skin diseases. The aim of this study was to evaluate the cytotoxic and leishmanicidal effects of GFC using in vitro models. The experimental data demonstrated that the polyisoprenylated benzophenone GFC possesses cytotoxic and leishmanicidal activities.

In vitro and in vivo anticancer properties of cucurbitacin isolated from Cayaponia racemosa.

Context: Cucurbitacins are a group of triterpenoids that have a cucurbitane skeleton with a wide range of biological activities. Objectives: This study evaluated the anticancer properties of one cucurbitacin isolated from Cayaponia racemosa Cong. (Cucurbitaceae), 2β,3β,16α,20(R),25-pentahydroxy-22-oxocucurbita-5-en (1), with in vitro and in vivo models. Materials and methods: In vitro cytotoxic activity was determined with human leukemia (HL60) and normal blood cells (PBMC). Sarcoma 180 was used as in vivo model. Results: The cucurbitacin (1) reduced the number of viable cells; however, there was no changed in the number of non-viable cells at 5 µg/mL. Selectivity towards cancer cells was suggested by the absence of activity on normal proliferating lymphocytes at the concentrations tested (IC50 >25 µg/ml). Morphological analysis of compound 1-treated cells showed typical apoptotic features, such as intense deposition of granules in the cytoplasm (eosinophilia), DNA fragmentation and irregularities in the plasma membrane. In addition, the cells treated with compound 1 presented intense vacuolization and disruption of the plasma membrane. Acridine orange/Ethidium bromide staining confirmed these findings, revealing an increased number of apoptotic cells. In the Sarcoma 180 tumor model, compound 1 showed 52 and 62% of antitumor activity, either alone (25 mg/kg/day) or in association with the chemotherapeutic agent 5-FU (10 + 10 mg/kg/day), respectively. Moreover, either alone or associated with 5-FU, treatment with compound 1 caused an increase in spleen weight and morphological alterations related to immunostimulatory properties. Conclusion: These data indicate that these naturally occurring compounds have anticancer potential.

Bioactivity of Biflorin, a Typical o-Naphthoquinone Isolated from Capraria biflora L.

Capraria biflora L. (Scrophulariaceae) is a perennial shrub widely distributed in several countries of tropical America. The present work verified the cytotoxic and antioxidant potential of biflorin, an o-naphthoquinone isolated from C. biflora collected in the northeast region of Brazil. The cytotoxicity was tested on three different animal cell models: mouse erythrocytes, sea urchin embryos and tumor cells, while the antioxidant activity was assayed by the thiocyanate method. Biflorin lacked activity on mouse erythrocytes as well as on the development of sea urchin eggs, but strongly inhibited the growth of all five tested tumor cell lines, especially the skin, breast and colon cancer cells with IC50 of 0.40, 0.43 and 0.88 μg/ml for B16, MCF-7 and HCT-8, respectively. Biflorin also showed potent antioxidant activity against autoxidation of oleic acid in a water/alcohol system.

Morphological and biochemical alterations activated by antitumor clerodane diterpenes

Casearia sylvestris Swartz (Salicaceae) is a plant commonly widespread in the Americas. It has oxygenated tricyclic bioactive clerodane diterpenes with antimicrobial, antiulcer, larvicidal, chemopreventive, anti-inflammatory, antioxidant and antiproliferative properties. Due to this requirement for the developing of new anticancer drugs, it was initially evaluated the cytotoxic activity of a fraction with Casearins (FC) and its clerodane diterpenes Casearin B (Cas B), D (Cas D), X (Cas X) and Caseargrewiin F (Cas F) isolated from C.sylvestris leaves against 7 tumor cell lines, Sarcoma 180 cells (S180) and on normal peripheral blood mononuclear cells (PBMC). All substances tested showed cytotoxic potential. Cas F and X were the most active compounds. Cell death analyzes with Cas F (0.5 and 1μM) and Cas X (0.7 and 1.5μM) using the HL-60 leukemia line as experimental model showed DNA synthesis and membrane integrity reduction, DNA fragmentation and mitochondrial depolarization, specially after 24h exposure, cell cycle arrest in G0/G1 phase caused by Cas X, activation of the initiator -8/-9 and effector -3/-7 caspases and phosphatidylserine externalization, all biochemical features of apoptosis corroborated by chromatinic condensation, karyorrhexis, cytoplasmic vacuolation and rarefaction and cellular shrinkage, morphological findings specially observed after 12 and 24h of incubation. Therefore, Cas X and F were the most functional molecules with more pronounced lethal and discriminating effects on tumor cells and antiproliferative action predominantly mediated by apoptosis, highlighting clerodane dipertenes as promising lead antineoplastic compounds.

In Vitro Antioxidant and Cytotoxic Activity of Some Synthetic Riparin-Derived Compounds

This study aimed to study the in vitro antioxidant activity and cytotoxicity on tumor cells lines of six synthetic substances derived from riparins. All the substances showed antioxidant activity and riparins C, D, E, F presented cell growth inhibition rates greater than 70%, suggesting that these molecules have antitumor properties. These substances also caused greater than 80% releases of cytoplasmic lactate dehydrogenase enzyme (LDH). Although the antioxidant and antitumor properties presented herein require further assessment, the outcomes indicate that these novel riparins are promising biologically active compounds.