Withalutin, a new cytotoxic withanolide from Athenaea velutina (Sendtn.) D'Arcy.

Bioassay-guided fractionation of dichloromethane extract from Athenaea velutina leaves led to the isolation of three withanolides, all being reported for the first time in this species. They were identified as withacnistin (1), withacnistin acetate (2) and a new withanolide, designated as withalutin (3). The structures were established by spectral data analysis, including MS, 1D and 2D NMR. In addition, in silico ADMET studies were employed to understand the pharmacokinetic properties of these withanolides. The withanolides isolated from A. velutina reduced cancer cell viability with IC50 values ranging from 1.52 to 5.39 µM. In silico prediction revealed that withanolides have good gastrointestinal absorption or oral bioavailability properties; and are not likely to be mutagenic or hepatotoxic. These findings revealed that A. velutina is an important source of cytotoxic withanolides.

Cytotoxic, Antitumor and Toxicological Profile of Passiflora alata Leaf Extract.

Passiflora alata or passion fruit is a native flowering plant from Amazon, geographically spread from Peru to Brazil. The plant has long been used in folks medicine for its pharmacological properties and is included in the Brazilian Pharmacopoeia since 1929. The aim of this study was to evaluate the potential cytotoxic and antitumor activities of Passiflora alata leaf extract (PaLE) in S180-tumor bearing mice. The percentage of cell proliferation inhibition (% CPI) and IC50 in relation to 4 tumor cell lines were determined in PC3, K-562, HepG2 and S180 cell lines using the MTT assay. PaLE showed a CPI > 75% and greater potency (IC50 < 30 µg/mL) against PC3 and S180 cell lines. PaLE showed antitumor activity in treatments intraperitoneally (36.75% and 44.99% at doses of 100 and 150 mg/kg/day, respectively). Toxicological changes were shown in the reduced body mass associated with reduced food consumption, increased spleen mass associated with histopathological increase in the white pulp of the spleen and increased number of total leukocytes with changes in the percentage relationship between lymphocytes and neutrophils. Our outcomes corroborate the conclusion that PaLE has antitumor activity in vitro and in vivo with low toxicity.

A chloroquinoline derivate presents effective in vitro and in vivo antileishmanial activity against Leishmania species that cause tegumentary and visceral leishmaniasis.

The identification of new therapeutics to treat leishmaniasis is desirable, since available drugs are toxic and present high cost and/or poor availability. Therefore, the discovery of safer, more effective and selective pharmaceutical options is of utmost importance. Efforts towards the development of new candidates based on molecule analogs with known biological functions have been an interesting and cost-effective strategy. In this context, quinoline derivatives have proven to be effective biological activities against distinct diseases. In the present study, a new chloroquinoline derivate, AM1009, was in vitro tested against two Leishmania species that cause leishmaniasis. The present study analyzed the necessary inhibitory concentration to preclude 50% of the Leishmania promastigotes and axenic amastigotes (EC50 value), as well as the inhibitory concentrations to preclude 50% of the murine macrophages and human red blood cells (CC50 and RBC50 values, respectively). In addition, the treatment of infected macrophages and the inhibition of infection using pre-treated parasites were also investigated, as was the mechanism of action of the molecule in L. amazonensis. To investigate the in vivo therapeutic effect, BALB/c mice were infected with L. amazonensis and later treated with AM1009. Parasitological and immunological parameters were also evaluated. Clioquinol, a known antileishmanial quinoline derivate, and amphotericin B (AmpB), were used as molecule and drug controls, respectively. Results in both in vitro and in vivo experiments showed a better and more selective action of AM1009 to kill the in vitro parasites, as well as in treating infected mice, when compared to results obtained using clioquinol or AmpB. AM1009-treated animals presented significantly lower average lesion diameter and parasite burden in the infected tissue and organs evaluated in this study, as well as a more polarized antileishmanial Th1 immune response and low renal and hepatic toxicity. This result suggests that AM1009 should be considered a possible therapeutic target to be evaluated in future studies for treatment against leishmaniasis.

In vitro and in vivo antileishmanial activity of a fluoroquinoline derivate against Leishmania infantum and Leishmania amazonensis species.

New therapeutics against leishmaniasis are desirable, since the current drugs applied against this disease complex presents problems, such as the toxicity, high cost and/or parasite resistance. In the present study, a new fluoroquinoline derivate, namely 7-chloro-N-(4-fluorophenethyl)quinolin-4-amine or GF1061, was evaluated regarding to its in vitro antileishmanial action against Leishmania infantum and L. amazonensis species, as well as by its toxicity in mammalian cells and efficacy in the treatment of infected macrophages. The mechanism of action of this molecule in L. amazonensis and the therapeutic efficacy in infected BALB/c mice were also evaluated. Results showed that GF1061 was effective against both parasite species, showing selectivity index (SI) of 38.7 and 42.7 against L. infantum and L. amazonensis promastigotes, respectively, and of 45.0 and 48.9 against the amastigotes, respectively. Amphotericin B (AmpB), used as control, showed SI values of 6.6 and 8.8 against L. infantum and L. amazonensis promastigotes, respectively, and of 2.2 and 2.7 against the amastigotes, respectively. The molecule was effective in treat infected macrophages, as well as it induced alterations in the mitochondrial membrane potential, increase in the reactive oxygen species production, and in the cell integrity of the parasites. Regarding to the in vivo experiments, BALB/c mice (n = 8 per group) were subcutaneously infected with 106L. amazonensis stationary promastigotes and, 60 days post-infection, they received saline or were treated during 10 days, once a day, with AmpB (1 mg/kg body weight) or GF1061 (5 mg/kg body weight). One day after the treatment, the infected tissue, spleen, liver, and draining lymph node (dLN) of the animals were collected, and the parasite load was evaluated. GF1061-treated mice, as compared to the saline and AmpB groups, showed significant reductions in the parasitism in the infected tissue (66% and 62%, respectively), liver (69% and 44%, respectively), spleen (71% and 38%, respectively), and dLN (72% and 48%, respectively). In conclusion, results suggested that GF1061 may be considered as a possible therapeutic target to be evaluated against leishmaniasis in other mammalian hosts.

Aqueous extract of Baccharis trimera improves redox status and decreases the severity of alcoholic hepatotoxicity

ABSTRACT The metabolism of ethanol occurs mainly in the liver, promoting increase of reactive oxygen species and nitrogen, leading to redox imbalance. Therefore, antioxidants can be seen as an alternative to reestablish the oxidizing/reducing equilibrium. The aim of this study was to evaluate the antioxidant and hepatoprotective effect of aqueous extract of Baccharis trimera (Less.) DC., Asteraceae, in a model of hepatotoxicity induced by ethanol. The extract was characterized and in vitro tests were conducted in HepG2 cells. It was evaluated the cells viability exposed to aqueous extract for 24 h, ability to scavenging the radical DPPH, besides the production of reactive oxygen species and nitric oxide, and the influence on the transcriptional activity of transcription factor Nrf2 (12 and 24 h) after exposure to 200 mM ethanol. The results showed that aqueous extract was non-cytotoxic in any concentration tested; moreover, it was observed a decrease in ROS and NO production, also promoting the transcriptional activity of Nrf2. In vivo, we pretreatment male rats Fisher with 600 mg/kg of aqueous extract and 1 h later 5 ml/kg of absolute ethanol was administrated. After two days of treatment, the animals were euthanized and lipid profile, hepatic and renal functions, antioxidant status and oxidative damage were evaluated. The treatment with extract improved liver function and lipid profile, reflecting the reduction of lipid microvesicules in the liver. It also promoted an increase of glutathione peroxidase activity, decrease of oxidative damage and MMP-2 activity. These results, analyzed together, suggest the hepatoprotective effect of B. trimera aqueous extract.

Anti-malarial activity and toxicity assessment of Himatanthus articulatus, a plant used to treat malaria in the Brazilian Amazon.

BACKGROUND: Plasmodium falciparum has become resistant to some of the available drugs. Several plant species are used for the treatment of malaria, such as Himatanthus articulatus in parts of Brazil. The present paper reports the phyto-chemistry, the anti-plasmodial and anti-malarial activity, as well as the toxicity of H. articulatus. METHODS: Ethanol and dichloromethane extracts were obtained from the powder of stem barks of H. articulatus and later fractionated and analysed. The anti-plasmodial activity was assessed against a chloroquine resistant strain P. falciparum (W2) in vitro, whilst in vivo anti-malarial activity against Plasmodium berghei (ANKA strain) was tested in mice, evaluating the role of oxidative stress (total antioxidant capacity--TEAC; lipid peroxidation--TBARS, and nitrites and nitrates--NN). In addition, cytotoxicity was evaluated using the HepG2 A16 cell-line. The acute oral and sub-chronic toxicity of the ethanol extract were evaluated in both male and female mice. RESULTS: Plumieride was isolated from the ethyl acetate fraction of ethanol extract, Only the dichloromethane extract was active against clone W2. Nevertheless, both extracts reduced parasitaemia in P. berghei-infected mice. Besides, a significant reduction in pulmonary and cerebral levels of NN (nitrites and nitrates) was found, as well as in pulmonary TBARS, indicating a reduced oxidative damage to these organs. The ethanol extract showed low cytotoxicity to HepG2 A16 cells in the concentrations used. No significant changes were observed in the in vivo toxicity studies. CONCLUSIONS: The ethanol extract of H. articulatus proved to be promising as anti-malarial medicine and showed low toxicity.

Chemical constituents of Distictella elongata (Vahl) Urb. (Bignoniaceae).

Pectolinarin, a flavone heteroside, was isolated from Distictella elongata (Vahl) Urb. leaves ethanol extract, along with a mixture of ursolic, pomolic and oleanolic acids, besides ß-sitosterol. Their structures were established on the basis of spectral analysis (1H and 13C NMR, 1D and 2D) and they were compared with literature. This is the first report on the occurrence of this flavonoid in a species of the Bignoniaceae family.

Cytotoxicity of Wedelia paludosa D.C. extracts and constituents / Citotoxidade de extratos e constituintes de Wedelia paludosa D.C

Wedelia paludosa D.C. (Asteraceae) is an ornamental species occurring in many regions of Brazil. Aiming to find new cytotoxic compounds, the hydromethanol extract of W. paludosa (HME), as well as the dichloromethane (DF) and water (WF) fractions resulting from its partition, were submitted to the brine shrimp lethality bioassay (BSLB) in order to evaluate their cytotoxicity. Dichloromethane fraction (DF) was shown to be the most cytotoxic fraction (LC50 = 140.6 μg/mL), and its analysis by reversed phase high performance liquid chromatography (RP-HPLC) revealed ent-kaurenoic (1, 6.22 ± 0.23 percent) and grandiflorenic (2, 3.22 ± 0.31 percent) acids as important constituents. HME (LC50 = 980 μg/mL), DF (LC50 = 140.6 μg/mL), 1 (LC50 = 15.9 μg/mL) and 2 (LC50 = 29.8 μg/mL) were found to be cytotoxic, while the water fraction (WF, LC50 >> 1000 μg/mL) was inactive. As conclusion, the cytotoxicity observed for HME and DF is mainly due to the presence of 1 and 2 in their constitution.

Wedelia paludosa D.C. (Asteraceae) é uma planta ornamental facilmente encontrada em várias regiões do Brasil, principalmente nos estados de Santa Catarina, São Paulo, Minas Gerais, Bahia e Pernambuco. Objetivando descobrir novas substâncias citotóxicas a partir desta espécie, o extrato hidrometanólico de W. paludosa (HME) e as frações diclorometânica (FD) e aquosa (FA) resultantes de sua partição em CH2Cl2-H2O foram avaliados utilizando-se o bioensaio em Artemia salina. A fração diclorometânica (FD) apresentou a maior atividade citotóxica (CL50 = 140,6 μg/mL), e sua análise por cromatografia líquida de alta eficiência empregando-se fase reversa (FR-CLAE) revelou os ácidos caurenóico (1, 6,22 ± 0,23 por cento) e grandiflorênico (2, 3,22 ± 0,31 por cento) como constituintes majoritários. As amostras HME (CL50 = 980 μg/mL), FD (CLC50 = 140,6 μg/mL), 1 (CL50 = 15,9 μg/mL) e 2 (CL50 = 29,8 μg/mL) foram citotóxicas contra A. salina, enquanto que a fração aquosa (FA, CL50 >> 1000 μg/mL) mostrou-se inativa. Conclui-se que a citotoxidade observada para HME e FD pode ser atribuída à presença dos ácidos caurenóico (1) e grandiflorênico (2) nestes extratos.