A new synthetic antitumor naphthoquinone induces ROS-mediated apoptosis with activation of the JNK and p38 signaling pathways.

Quinones are plant-derived secondary metabolites that present diverse pharmacological properties, including antibacterial, antifungal, antiviral, anti-inflammatory, antipyretic and anticancer activities. In the present study, we evaluated the cytotoxic effect of a new naphthoquinone 6b,7-dihydro-5H-cyclopenta [b]naphtho [2,1-d]furan-5,6 (9aH)-dione) (CNFD) in different tumor cell lines. CNFD displayed cytotoxic activity against different tumor cell lines, especially in MCF-7 human breast adenocarcinoma cells, which showed IC50 values of 3.06 and 0.98 µM for 24 and 48 h incubation, respectively. In wound-healing migration assays, CNFD promoted inhibition of cell migration. We have found typical hallmarks of apoptosis, such as cell shrinkage, chromatin condensation, phosphatidylserine exposure, increase of caspases-9 and-3 activation, increase of internucleosomal DNA fragmentation without affecting the cell membrane permeabilization, increase of ROS production, and loss of mitochondrial membrane potential induced by CNFD. Moreover, gene expression experiments indicated that CNFD increased the expression of the genes CDKN1A, FOS, MAX, and RAC1 and decreased the levels of mRNA transcripts of several genes, including CCND1, CDK2, SOS1, RHOA, GRB2, EGFR and KRAS. The CNFD treatment of MCF-7 cells induced the phosphorylation of c-jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases (MAPKs) and inactivation of extracellular signal-regulated protein kinase 1/2 (ERK1/2). In a study using melanoma cells in a murine model in vivo, CNFD induced a potent anti-tumor activity. Herein, we describe, for the first time, the cytotoxicity and anti-tumor activity of CNFD and sequential mechanisms of apoptosis in MCF-7 cells. CNFD seems to be a promising candidate for anti-tumor therapy.

Biflorin inhibits the proliferation of gastric cancer cells by decreasing MYC expression.

Gastric cancer is the third leading cause of cancer-related death worldwide. To evaluate the anticancer potential and molecular mechanism of biflorin, a prenyl-ortho-naphthoquinone obtained from Capraria biflora L. roots, we used ACP02, a gastric cancer cell line established from a primary diffuse gastric adenocarcinoma. In this study, biflorin was shown to be a potent cytotoxic agent against ACP02 by Alamar Blue and Trypan Blue assays. Morphological analysis indicated cell death with features of necrosis. Furthermore, a decrease in colony formation, migration and invasion of ACP02 cells was observed after treatment with biflorin (1.0, 2.5 and 5.0 µM). Regarding the underlying molecular mechanism of biflorin in ACP02 cells, we observed a decrease in MYC expression and telomere length using FISH. Our findings suggest a novel molecular target of biflorin in ACP02 cells, which may be a significant therapeutic approach for gastric cancer management.

Dentin Cleaning Ability of an Amazon Bioactive: Evaluation by Scanning Electron Microscopy.

UNLABELLED: The role of dentin cleaning is to remove debris that may impair adaptation and marginal sealing, quantitatively reducing microorganisms. The aim of this study was to investigate through scanning electron microscopy (SEM) the morphology of the dentin surface, cut and treated with copaiba oil emulsions (CO) and suspension of ethanol extract of propolis (EP). Twenty four upper pre-molars teeth, divided into eight groups (n=3), were used: G1: no cleaning, G2: air/water spray, G3: 10% CO, G4: 10% CO + A, G5: 30% CO, G6: 30% CO + A, G7: 1% EP, G8: 2% Chlorhexidine. The specimens were dentin discs (1 mm Ø). The SEM photomicrographs were classified and the results were: G1 - Debris dentin on the entire image / countless microorganisms, G2 and G7 - 50-100 debris / countless microorganisms and G3, G4, G5, G6 and G8 - 0-50 debris / countable microorganisms (50-100 colonies). CONCLUSION: The present results suggest that copaiba oil emulsions (CO) and suspension of ethanol extract of propolis (EP) have feasibility to be used as bioactive dental cleaning agents.

Antioxidant activity and peroxidase inhibition of Amazonian plants extracts traditionally used as anti-inflammatory.

BACKGROUND: The Amazon is the largest rainforest in the world and is home to a rich biodiversity of medicinal plants. Several of these plants are used by the local population for the treatment of diseases, many of those with probable anti-inflammatory effect. The aim of the present investigation was to evaluate the in vitro antioxidant and anti-peroxidases potential of the ethanol extracts of five plants from the Brazilian Amazon (Byrsonima japurensis, Calycophyllum spruceanum, Maytenus guyanensis, Passiflora nitida and Ptychopetalum olacoides). METHODS: DPPH, ABTS, superoxide anion radical, singlet oxygen and the ß-carotene bleaching methods were employed for characterization of free radical scavenging activity. Also, total polyphenols were determined. Antioxidant activities were evaluated using murine fibroblast NIH3T3 cell. Inhibition of HRP and MPO were evaluated using amplex red® as susbtract. RESULTS: The stem bark extracts of C. spruceanum and M. guyanensis provided the highest free radical scavenging activities. C. spruceanum exhibited IC50 = 7.5 ± 0.9, 5.0 ± 0.1, 18.2 ± 3.0 and 92.4 ± 24.8 µg/mL for DPPH(•), ABTS(+•), O2 (-•) and (1)O2 assays, respectively. P. olacoides and C. spruceanum extracts also inhibited free radicals formation in the cell-based assay. At a concentration of 100 µg/mL, the extracts of C. spruceanum, B. japurensis inhibited horseradish peroxidase by 62 and 50 %, respectively. C. spruceanum, M. guyanensis, B. japurensis also inhibited myeloperoxidase in 72, 67 and 56 %, respectively. CONCLUSIONS: This work supports the folk use these species that inhibited peroxidases and exhibited significant free radical scavenging and antioxidant activities what can be related to treatment of inflammation.

Synthesis and antimalarial activity of quinones and structurally-related oxirane derivatives.

A series of eighteen quinones and structurally-related oxiranes were synthesized and evaluated for in vitro inhibitory activity against the chloroquine-sensitive 3D7 clone of the human malaria parasite Plasmodium falciparum. 2-amino and 2-allyloxynaphthoquinones exhibited important antiplasmodial activity (median inhibitory concentrations (IC50) < 10 µM). Oxiranes 6 and 25, prepared respectively by reaction of α-lapachone and tetrachloro-p-quinone with diazomethane in a mixture of ether and ethanol, exhibited the highest antiplasmodial activity and low cytotoxicity against human fibroblasts (MCR-5 cell line). The active compounds could represent a good prototype for an antimalarial lead molecule.

In vitro and in vivo anti-malarial activity of plants from the Brazilian Amazon.

BACKGROUND: The anti-malarials quinine and artemisinin were isolated from traditionally used plants (Cinchona spp. and Artemisia annua, respectively). The synthetic quinoline anti-malarials (e.g. chloroquine) and semi-synthetic artemisinin derivatives (e.g. artesunate) were developed based on these natural products. Malaria is endemic to the Amazon region where Plasmodium falciparum and Plasmodium vivax drug-resistance is of concern. There is an urgent need for new anti-malarials. Traditionally used Amazonian plants may provide new treatments for drug-resistant P. vivax and P. falciparum. Herein, the in vitro and in vivo antiplasmodial activity and cytotoxicity of medicinal plant extracts were investigated. METHODS: Sixty-nine extracts from 11 plant species were prepared and screened for in vitro activity against P. falciparum K1 strain and for cytotoxicity against human fibroblasts and two melanoma cell lines. Median inhibitory concentrations (IC50) were established against chloroquine-resistant P. falciparum W2 clone using monoclonal anti-HRPII (histidine-rich protein II) antibodies in an enzyme-linked immunosorbent assay. Extracts were evaluated for toxicity against murine macrophages (IC50) and selectivity indices (SI) were determined. Three extracts were also evaluated orally in Plasmodium berghei-infected mice. RESULTS: High in vitro antiplasmodial activity (IC50 = 6.4-9.9 µg/mL) was observed for Andropogon leucostachyus aerial part methanol extracts, Croton cajucara red variety leaf chloroform extracts, Miconia nervosa leaf methanol extracts, and Xylopia amazonica leaf chloroform and branch ethanol extracts. Paullinia cupana branch chloroform extracts and Croton cajucara red variety leaf ethanol extracts were toxic to fibroblasts and or melanoma cells. Xylopia amazonica branch ethanol extracts and Zanthoxylum djalma-batistae branch chloroform extracts were toxic to macrophages (IC50 = 6.9 and 24.7 µg/mL, respectively). Andropogon leucostachyus extracts were the most selective (SI >28.2) and the most active in vivo (at doses of 250 mg/kg, 71% suppression of P. berghei parasitaemia versus untreated controls). CONCLUSIONS: Ethnobotanical or ethnopharmacological reports describe the anti-malarial use of these plants or the antiplasmodial activity of congeneric species. No antiplasmodial activity has been demonstrated previously for the extracts of these plants. Seven plants exhibit in vivo and or in vitro anti-malarial potential. Future work should aim to discover the anti-malarial substances present.

Anti-inflammatory action of Justicia acuminatissima leaves

AbstractIn Amazonas State (Brazil), Justicia acuminatissima (Miq.) Bremek., Acanthaceae, leaf teas are used in folk medicine to treat several inflammatory illnesses. In order to validate this medicinal application, we analyzed the acute toxicity and antioxidant, antiedematogenic and antinociceptive potentials of an aqueous extract of this species, using culture cells and animal models. The aqueous extract did not cause toxic effects on human lymphocytes in high concentration (400 μg/ml), neither on mice treated with high doses (5000 mg/kg) in an acute toxicity analysis by oral route, and also did not cause lesions in the gastric mucosa of animals treated with 300 mg/kg, which was the maximal dose used in the anti-inflammatory screening. The aqueous extract caused inhibition of inflammatory pain in formalin-induced paw licking test with all tested doses, 30, 100 and 300 mg/kg, and antiedematogenic activity at 100 and 300 mg/kg. Additionally, the aqueous extract presented statistically significant action on the release of nitric oxide by lipopolysaccharide-activated macrophages. These results and other preliminary studies support the folk use of this species, and further investigation of its action mechanism by inhibition of COX-2 or related metabolite would be interesting.

Biological activities and cytotoxicity of diterpenes from Copaifera spp. Oleoresins.

Copaifera spp. are Amazonian species widely studied and whose oleoresins are used by local people for various medicinal purposes. However, a detailed study of the activity of the main phytochemical components of these oleoresins remains to be done. Here, we studied the cytotoxicity and in vitro anti-inflammatory effects of six diterpene acids: copalic, 3-hydroxy-copalic, 3-acetoxy-copalic, hardwickiic, kolavic-15-metyl ester, and kaurenoic, isolated from the oleoresins of Copaifera spp. The diterpenes did not show cytotoxicity in normal cell lines, nor did they show significant changes in viability of tumoral line cells. The 3-hydroxy-copalic was able to inhibit the enzyme tyrosinase (64% ± 1.5%) at 250 µM. The kolavic-15-metyl ester at 200 µM showed high inhibitory effect on lipoxygenase (89.5% ± 1.2%). Among the diterpenes tested, only kaurenoic and copalic acids showed significant hemolytic activities with 61.7% and 38.4% at 100 µM, respectively. In addition, it was observed that only the copalic acid (98.5% ± 1.3%) and hardwickiic acid (92.7% ± 4.9%) at 100 mM inhibited nitric oxide production in macrophages activated by lipopolysaccharide. In this assay, the diterpenes did not inhibit tumor necrosis factor-α production. The acids inhibited the production of IL-6, 3-acetoxy-copalic (23.8% ± 8.2%), kaurenoic (11.2% ± 5.7%), kolavic-15-methyl ester (17.3% ± 4.2%), and copalic (4.2% ± 1.8%), respectively, at 25 µM. The kaurenoic, 3-acetoxy-copalic and copalic acids increased IL-10 production. This study may provide a basis for future studies on the therapeutic role of diterpenic acids in treating acute injuries such as inflammation or skin disorders.

In vitro and in vivo anti-malarial activity of limonoids isolated from the residual seed biomass from Carapa guianensis (andiroba) oil production.

BACKGROUND: Carapa guianensis is a cultivable tree used by traditional health practitioners in the Amazon region to treat several diseases and particularly symptoms related to malaria. Abundant residual pressed seed material (RPSM) results as a by-product of carapa or andiroba oil production. The objective of this study was to evaluate the in vitro and in vivo anti-malarial activity and cytotoxicity of limonoids isolated from C. guaianensis RPSM. METHODS: 6α-acetoxyepoxyazadiradione (1), andirobin (2), 6α-acetoxygedunin (3) and 7-deacetoxy-7-oxogedunin (4) (all isolated from RPSM using extraction and chromatography techniques) and 6α-hydroxy-deacetylgedunin (5) (prepared from 3) were evaluated using the micro test on the multi-drug-resistant Plasmodium falciparum K1 strain. The efficacy of limonoids 3 and 4 was then evaluated orally and subcutaneously in BALB/c mice infected with chloroquine-sensitive Plasmodium berghei NK65 strain in the 4-day suppressive test. RESULTS: In vitro, limonoids 1-5 exhibited median inhibition concentrations (IC50) of 20.7-5.0 µM, respectively. In general, these limonoids were not toxic to normal cells (MRC-5 human fibroblasts). In vivo, 3 was more active than 4. At oral doses of 50 and 100 mg/kg/day, 3 suppressed parasitaemia versus untreated controls by 40 and 66%, respectively, evidencing a clear dose-response. CONCLUSION: 6α-acetoxygedunin is an abundant natural product present in C. guianensis residual seed materials that exhibits significant in vivo anti-malarial properties.

Antiplasmodial activity of synthetic ellipticine derivatives and an isolated analog.

Ellipticine has been shown previously to exhibit excellent in vitro antiplasmodial activity and in vivo antimalarial properties that are comparable to those of the control drug chloroquine in a mouse malaria model. Ellipticine derivatives and analogs exhibit antimalarial potential however only a few have been studied to date. Herein, ellipticine and a structural analog were isolated from Aspidosperma vargasii bark. A-ring brominated and nitrated ellipticine derivatives exhibit good in vitro inhibition of Plasmodium falciparum K1 and 3D7 strains. Several of the compounds were found not to be toxic to human fetal lung fibroblasts. 9-Nitroellipticine (IC50=0.55µM) exhibits greater antiplasmodial activity than ellipticine. These results are further evidence of the antimalarial potential of ellipticine derivatives.

Synthesis of 1H-1,2,3-triazoles and study of their antifungal and cytotoxicity activities.

We report herein the results of antifungal activity of fifteen 1,2,3-triazoles against Candida albicans, Candida krusei, Candida parapsilosis, Candida kefyr, Candida tropicalis, Candida dubliniensis, Tricophyton rubrum, Microporum canis and Aspergillus niger. All of the 1,2,3-triazoles were prepared from 1,3-dipolar cyclizations between aryl azides and alkynes catalyzed by Cu(I), and several of the compounds exhibited antifungal activity with low cytotoxicity. The results demonstrated the potential and importance of developing new 1,2,3-triazoles compounds with antifungal activity.

The in-vitro and in-vivo inhibitory activity of biflorin in melanoma.

Biflorin, an ortho-naphthoquinone, is an active compound found in the roots of Capraria biflora L. It has been reported that biflorin presents anticancer activity, inhibiting both tumor cell line growth in culture and tumor development in mice. The aim of this study was to examine the effectiveness of biflorin treatment using both in-vitro and in-vivo melanoma models. Biflorin displayed considerable cytotoxicity against all tested cell lines, with half maximal inhibitory concentration values ranging from 0.58 µg/ml in NCI H23 (human lung adenocarcinoma) to 14.61 µg/ml in MDA-MB-231 (human breast cancer) cell lines. In a second set of experiments using B16 melanoma cells as a model, biflorin reduced cell viability but did not cause significant increase in the number of nonviable cells. In addition, the DNA synthesis was significantly inhibited. Flow cytometry analysis showed that biflorin may lead to an apoptotic death in melanoma cells, inducing DNA fragmentation and mitochondria depolarization, without affecting membrane integrity. In B16 melanoma-bearing mice, administration of biflorin (25mg/day) for 10 days inhibited tumor growth, and also increased the mean survival rate from 33.3±0.9 days (control) to 44.5±3.4 days (treated). Our findings suggest that biflorin may be considered as a promising lead compound for designing new drugs to be used in the treatment of melanoma.

Evaluation of the cytotoxic and antimutagenic effects of biflorin, an antitumor 1,4 o-naphthoquinone isolated from Capraria biflora L.

Biflorin is a natural quinone isolated from Capraria biflora L. Previous studies demonstrated that biflorin inhibits in vitro and in vivo tumor cell growth and presents potent antioxidant activity. In this paper, we report concentration-dependent cytotoxic, genotoxic, antimutagenic, and protective effects of biflorin on Salmonella tiphymurium, yeast Saccharomyces cerevisiae, and V79 mammalian cells, using different approaches. In the Salmonella/microsome assay, biflorin was not mutagenic to TA97a TA98, TA100, and TA102 strains. However, biflorin was able to induce cytotoxicity in haploid S. cerevisiae cells in stationary and exponential phase growth. In diploid yeast cells, biflorin did not induce significant mutagenic and recombinogenic effects at the employed concentration range. In addition, the pre-treatment with biflorin prevented the mutagenic and recombinogenic events induced by hydrogen peroxide (H(2)O(2)) in S. cerevisiae. In V79 mammalian cells, biflorin was cytotoxic at higher concentrations. Moreover, at low concentrations biflorin pre-treatment protected against H(2)O(2)-induced oxidative damage by reducing lipid peroxidation and DNA damage as evaluated by normal and modified comet assay using DNA glycosylases. Our results suggest that biflorin cellular effects are concentration dependent. At lower concentrations, biflorin has significant antioxidant and protective effects against the cytotoxicity, genotoxicity, mutagenicity, and intracellular lipid peroxidation induced by H(2)O(2) in yeast and mammalian cells, which can be attributed to its hydroxyl radical-scavenging property. However, at higher concentrations, biflorin is cytotoxic and genotoxic.

Piplartine induces genotoxicity in eukaryotic but not in prokaryotic model systems.

Piplartine {5,6-dihydro-1-[(2E)-1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propen-1-yl]-2(1H)-pyridinone} is an alkamide present in Piper species that exhibits promising anticancer properties. It was previously shown that piplartine is mutagenic in yeast and cultured mammalian cells. This study was performed to increase the knowledge on the mutagenic potential of piplartine using the Salmonella/microsome assay, V79 cell micronucleus and chromosome aberration assays, and mouse bone-marrow micronucleus tests. Piplartine was isolated from the roots of Piper tuberculatum. This extracted compound was unable to induce a mutagenic response in any Salmonella typhimurium strain either in the presence or absence of metabolic activation. Piplartine showed mutagenic effects in V79 cells, as there was an increased frequency of aberrant cells and micronuclei formation. In addition, piplartine administered at 50mg/kg did not induce micronucleus formation in vivo, but a dose of 100mg/kg induced an increase in the levels of micronucleus polychromatic erythrocytes (MNPCEs). Overall, these results provide further support that piplartine induces in vivo and in vitro mutagenicity in eukaryotic models.

Synthesis and biological evaluation of cytotoxic properties of stilbene-based resveratrol analogs.

This work deals with the preparation of stilbene-based resveratrol analogs by employing the Perkin reaction, aiming at synthesizing potential antitumor lead compounds and evaluating their pharmacological activities. The proliferation inhibitor test against tumor cell lines identified analogs 9 and 11 as the most active among all synthesized derivatives, presenting IC(50) in micromolar range for certain cell lines. For study on the embryonic development, compounds 8 and 9 at the lowest tested concentration (41.7 microM) that inhibited sea urchin egg development, but only after third cleavage were used. Both the compounds inhibited 100% of normal development since first cleavage. These data partially corroborated the results obtained with MTT assay using tumor cell lines. None of the tested compounds revealed hemolytic action in assay with mouse erythrocytes.

Genotoxicity of 15-deoxygoyazensolide in bacteria and yeast.

Sesquiterpene lactones (SLs) present a wide range of pharmacological activities. The aim of our study was to investigate the genotoxicity of 15-deoxygoyazensolide using the Salmonella/microsome assay and the yeast Saccharomyces cerevisiae. We also investigated the nature of induced DNA damage using yeast strains defective in DNA repair pathways, such as nucleotide excision repair (RAD3), error prone repair (RAD6), and recombinational repair (RAD52), and in DNA metabolism, such as topoisomerase mutants. 15-deoxygoyasenzolide was not mutagenic in Salmonella typhimurium, but it was mutagenic in S. cerevisiae. The hypersensitivity of the rad52 mutant suggests that recombinational repair is critical for processing lesions resulting from 15-deoxygoyazensolide-induced DNA damage, whereas excision repair and mutagenic systems does not appear to be primarily involved. Top 1 defective yeast strain was highly sensitive to the cytotoxic activity of 15-deoxygoyazensolide, suggesting a possible involvement of this enzyme in the reversion of the putative complex formation between DNA and this SL, possibly due to intercalation. Moreover, the treatment with this lactone caused dose-dependent glutathione depletion, generating pro-oxidant status which facilitates oxidative DNA damage, particularly DNA breaks repaired by the recombinational system ruled by RAD52 in yeast. Consistent with this finding, the absence of Top1 directly affects chromatin remodeling, allowing repair factors to access oxidative damage, which explains the high sensitivity to top1 strain. In summary, the present study shows that 15-deoxygoyazensolide is mutagenic in yeast due to the possible intercalation effect, in addition to the pro-oxidant status that exacerbates oxidative DNA damage.

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 micro/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.