Tryptophan catabolites along the indoleamine 2,3-dioxygenase pathway as a biological link between depression and cancer.

Both depression and cancer are related to a dysregulation of inflammatory and immune pathways. Indeed, depression is associated with increased expression of interferon-γ, interleukin-1ß, and tumor necrosis factor α (TNF-α). In contrast, reductions of the activity of major histocompatibility complex protein molecules - class I and class II and natural killer cells are also observed. Similarly, cancers present elevated levels of TNF-α, reduced major histocompatibility complex class I and II, and natural killer cells. Indoleamine 2,3-dioxygenase (IDO), the rate-limiting enzyme of the tryptophan catabolite (TRYCAT) pathway, is induced by interferon-γ, interleukin-6, TNF-α, and oxidative stress. IDO catabolizes tryptophan, the amino acid precursor of serotonin and melatonin, to the metabolites collectively called TRYCATs. TRYCAT pathway activation is accompanied by downregulation of immune cell proliferation, function, and survival. The increase in IDO activity in tumor microenvironments is related to tumor cell escape from immune surveillance. Despite the evidence of inflammatory mechanisms underlying cancer and depression, it is important to emphasize that both diseases are heterogeneous and, as such, inflammatory mechanisms may not be relevant to all patients. Thus, the purpose of this review is to examine whether detrimental TRYCATs - synthesis of which increases in depression and cancer - are a pathophysiological link between the two diseases, and whether IDO is a potential pharmacological target for the treatment of the comorbid depression and cancer.

Synthesis, antibacterial and cytotoxic activities of new biflorin-based hydrazones and oximes.

Biflorin 1 is a biologically active quinone, isolated from Capraria biflora. Five new biflorin-based nitrogen derivatives were synthesized, of which two were mixtures of (E)- and (Z)- isomers: (Z)-2a, (Z)-2b, (Z)-3a, (Z)- and (E)-3b, (Z)- and (E)-3c. The antibacterial activity was investigated using the microdilution method for determining the minimum inhibitory concentration (MIC) against six bacterial strains. Tests have shown that these derivatives have potential against all bacterial strains. The cytotoxic activity was also evaluated against three strains of cancer cells, but none of the derivatives showed activity.

Mycoleptones A-C and polyketides from the endophyte Mycoleptodiscus indicus.

Three new azaphilones with an unusual methylene bridge, named mycoleptones A, B, and C (2, 4, and 5), were isolated from cultures of Mycoleptodiscus indicus, a fungus associated with the South American medicinal plant Borreria verticillata. Additionally, four known polyketides, austdiol (1), eugenitin (3), 6-methoxyeugenin (6), and 9-hydroxyeugenin (7), were also isolated. The structural characterization of compounds was carried out by nuclear magnetic resonance spectroscopy, high-resolution mass spectrometry, electronic circular dichroism spectroscopy, time-dependent density functional theory calculations, and X-ray crystallography. Compounds 1-9 were weakly active when tested in antileishmanial and cytotoxicity assays.

(4-Methoxyphenyl)(3,4,5-trimethoxyphenyl)methanone inhibits tubulin polymerization, induces G2/M arrest, and triggers apoptosis in human leukemia HL-60 cells.

(4-Methoxyphenyl)(3,4,5-trimethoxyphenyl)methanone (PHT) is a known cytotoxic compound belonging to the phenstatin family. However, the exact mechanism of action of PHT-induced cell death remains to be determined. The aim of this study was to investigate the mechanisms underlying PHT-induced cytotoxicity. We found that PHT displayed potent cytotoxicity in different tumor cell lines, showing IC50 values in the nanomolar range. Cell cycle arrest in G2/M phase along with the augmented metaphase cells was found. Cells treated with PHT also showed typical hallmarks of apoptosis such as cell shrinkage, chromatin condensation, phosphatidylserine exposure, increase of the caspase 3/7 and 8 activation, loss of mitochondrial membrane potential, and internucleosomal DNA fragmentation without affecting membrane integrity. Studies conducted with isolated tubulin and docking models confirmed that PHT binds to the colchicine site and interferes in the polymerization of microtubules. These results demonstrated that PHT inhibits tubulin polymerization, arrests cancer cells in G2/M phase of the cell cycle, and induces their apoptosis, exhibiting promising anticancer therapeutic potential.

Inhibition of DNA topoisomerase I activity and induction of apoptosis by thiazacridine derivatives.

Thiazacridine derivatives (ATZD) are a novel class of cytotoxic agents that combine an acridine and thiazolidine nucleus. In this study, the cytotoxic action of four ATZD were tested in human colon carcinoma HCT-8 cells: (5Z)-5-acridin-9-ylmethylene-3-(4-methylbenzyl)-thiazolidine-2,4-dione - AC-4; (5ZE)-5-acridin-9-ylmethylene-3-(4-bromo-benzyl)-thiazolidine-2,4-dione - AC-7; (5Z)-5-(acridin-9-ylmethylene)-3-(4-chloro-benzyl)-1,3-thiazolidine-2,4-dione - AC-10; and (5ZE)-5-(acridin-9-ylmethylene)-3-(4-fluoro-benzyl)-1,3-thiazolidine-2,4-dione - AC-23. All of the ATZD tested reduced the proliferation of HCT-8 cells in a concentration- and time-dependent manner. There were significant increases in internucleosomal DNA fragmentation without affecting membrane integrity. For morphological analyses, hematoxylin-eosin and acridine orange/ethidium bromide were used to stain HCT-8 cells treated with ATZD, which presented the typical hallmarks of apoptosis. ATZD also induced mitochondrial depolarisation and phosphatidylserine exposure and increased the activation of caspases 3/7 in HCT-8 cells, suggesting that this apoptotic cell death was caspase-dependent. In an assay using Saccharomyces cerevisiae mutants with defects in DNA topoisomerases 1 and 3, the ATZD showed enhanced activity, suggesting an interaction between ATZD and DNA topoisomerase enzyme activity. In addition, ATZD inhibited DNA topoisomerase I action in a cell-free system. Interestingly, these ATZD did not cause genotoxicity or inhibit the telomerase activity in human lymphocyte cultures at the experimental levels tested. In conclusion, the ATZD inhibited the DNA topoisomerase I activity and induced tumour cell death through apoptotic pathways.

Chemical constituents and anticancer effects of the essential oil from leaves of Xylopia laevigata.

Xylopia laevigata, popularly known as "meiú" and "pindaíba", is a medicinal plant used in the folk medicine of the Brazilian Northeast for several purposes. The chemical constituents of the essential oil from leaves of X. laevigata, collected from wild plants growing at three different sites of the remaining Atlantic forest in Sergipe State (Brazilian Northeast), were analyzed by GC/FID and GC/MS. The effect of the essential oil samples was assessed on tumor cells in culture, as well on tumor growth in vivo. All samples of the essential oil were dominated by sesquiterpene constituents. A total of 44 compounds were identified and quantified. Although some small differences were observed in the chemical composition, the presence of γ-muurolene (0.60-17.99%), δ-cadinene (1.15-13.45%), germacrene B (3.22-7.31%), α-copaene (3.33-5.98%), germacrene D (9.09-60.44%), bicyclogermacrene (7.00-14.63%), and (E)-caryophyllene (5.43-7.98%) were verified as major constituents in all samples of the essential oil. In the in vitro cytotoxic study, the essential oil displayed cytotoxicity to all tumor cell lines tested, with the different samples displaying a similar profile; however, they were not hemolytic or genotoxic. In the in vivo antitumor study, tumor growth inhibition rates were 37.3-42.5%. The treatment with the essential oil did not significantly affect body weight, macroscopy of the organs, or blood leukocyte counts. In conclusion, the essential oil from the leaves of X. laevigata is chemically characterized by the presence of γ-muurolene, δ-cadinene, germacrene B, α-copaene, germacrene D, bicyclogermacrene, and (E)-caryophyllene as major constituents and possesses significant in vitro and in vivo anticancer potential.

Antitumor effect of the essential oil from leaves of Guatteria pogonopus (Annonaceae).

Guatteria pogonopus Martius, a plant belonging to the Annonaceae family, is found in the remaining Brazilian Atlantic Forest. In this study, the chemical composition and antitumor effects of the essential oil isolated from leaves of G. pogonopus was investigated. The chemical composition of the oil was determined by GC-FID and GC/MS analyses. The in vitro cytotoxicity was evaluated against three different tumor cell lines (OVCAR-8, NCI-H358M, and PC-3M), and the in vivo antitumor activity was tested in mice bearing sarcoma 180 tumor. A total of 29 compounds was identified and quantified in the oil. The major compounds were γ-patchoulene (13.55%), (E)-caryophyllene (11.36%), ß-pinene (10.37%), germacrene D (6.72%), bicyclogermacrene (5.97%), α-pinene (5.33%), and germacrene B (4.69%). The essential oil, but neither (E)-caryophyllene nor ß-pinene, displayed in vitro cytotoxicity against all three tumor cell lines tested. The obtained average IC50 values ranged from 3.8 to 20.8 µg/ml. The lowest and highest values were obtained against the NCI-H358M and the OVCAR-8 cell lines, respectively. The in vivo tumor-growth-inhibition rates in the tumor-bearing mice treated with essential oil (50 and 100 mg/kg/d) were 25.3 and 42.6%, respectively. Hence, the essential oil showed significant in vitro and in vivo antitumor activity.

Activity of amlodipine against Staphylococcus aureus: association with oxacillin and mechanism of action.

Aim: This study was designed to evaluate the in vitro antimicrobial activity of amlodipine against Staphylococcus aureus strains. Materials & methods: The antimicrobial activity of amlodipine was evaluated by the broth microdilution method and its interaction with oxacillin was evaluated by checkerboard assay. The possible mechanism of action was evaluated by flow cytometry and molecular docking techniques. Results: Amlodipine showed activity against S. aureus between 64 and 128 µg/ml, in addition to showing synergism in approximately 58% of the strains used. Amlodipine also showed good activity against forming and mature biofilms. The possible mechanism of action may be attributed to its ability to lead to cell death. Conclusion: Amlodipine has antibacterial activity against S. aureus.

Sertraline has fungicidal activity against Candida spp. and acts by inhibiting membrane and cell wall biosynthesis.

Aim: Our study evaluated the activity of sertraline (SER) alone and associated with antifungal drugs in planktonic Candida spp. strains, and investigated its mechanism of action. Materials & methods: Broth microdilution method and minimum fungicidal concentration/MIC ratio were used to assess SER anticandidal activity, and the interaction with antifungals was determined by fractional inhibitory concentration index. The mechanism of action was investigated by flow cytometry and in silico tests. Results: SER inhibited Candida spp. strains at low concentrations by the fungicidal effect and showed no loss of effectiveness when combined. Its action seemed to be related to the membrane and cell wall biosynthesis inhibition. Conclusion: SER has activity against Candida spp. isolated and associated with antifungals, and acts by causing cell wall and membrane damage.

Antibacterial activity of paroxetine against Staphylococcus aureus and possible mechanisms of action.

Aim: To evaluate the antibacterial activity of paroxetine alone and associated with oxacillin against isolates of methicillin-sensitive and -resistant Staphylococcus aureus. Materials & methods: The broth microdilution and checkerboard techniques were used, with investigation of possible mechanisms of action through flow cytometry, fluorescence microscopy and molecular docking, in addition to scanning electron microscopy for morphological analysis. Results: Paroxetine showed a MIC of 64 µg/ml and bactericidal activity, mostly additive interactions in combination with oxacillin, evidence of action on genetic material and membrane, morphological changes in microbial cells and influence on virulence factors. Conclusion: Paroxetine has antibacterial potential from the perspective of drug repositioning.

Synergistic effect of hydralazine associated with triazoles on Candida spp. in planktonic cells.

Objective: To evaluate the antifungal activity of hydralazine hydrochloride alone and in synergy with azoles against Candida spp. and the action mechanism. Methods: We used broth microdilution assays to determine the MIC, checkerboard assays to investigate synergism, and flow cytometry and molecular docking tests to ascertain action mechanism. Results: Hydralazine alone had antifungal activity in the range of 16-128 µg/ml and synergistic effect with itraconazole versus 100% of the fungal isolates, while there was synergy with fluconazole against 11.11% of the isolates. There was molecular interaction with the receptors exo-B(1,3)-glucanase and CYP51, causing reduced cell viability and DNA damage. Conclusion: Hydralazine is synergistic with itraconazole and triggers cell death of Candida spp. at low concentrations, demonstrating antifungal potential.

In vitro and in vivo antitumor effects of the essential oil from the leaves of Guatteria friesiana.

Guatteria friesiana (W. A. Rodrigues) Erkens & Maas (synonym Guatteriopsis friesiana W. A. Rodrigues), popularly known as "envireira", is a medicinal plant found in the Brazilian and Colombian Amazon basin that is used in traditional medicine for various purposes. Recent studies on this species have demonstrated antimicrobial activity. In this study, the antitumor activity of the essential oil from the leaves of G. friesiana (EOGF) and its main components ( α-, ß-, and γ-eudesmol) were determined using experimental models. In the in vitro study, EOGF and its components α-, ß-, and γ-eudesmol displayed cytotoxicity against tumor cell lines, showing IC50 values in the range of 1.7 to 9.4 µg/mL in the HCT-8 and HL-60 cell lines for EOGF, 5.7 to 19.4 µg/mL in the HL-60 and MDA-MB-435 cell lines for α-eudesmol, 24.1 to > 25 µg/mL in the SF-295 and MDA-MB-435 cell lines for ß-eudesmol, and 7.1 to 20.6 µg/mL in the SF-295 and MDA-MB-435 cell lines for γ-eudesmol, respectively. In the in vivo study, the antitumor effect of EOGF was evaluated in mice inoculated with sarcoma 180 tumor cells. Tumor growth inhibition rates were 43.4-54.2 % and 6.6-42.8 % for the EOGF treatment by intraperitoneal (50 and 100 mg/kg/day) and oral (100 and 200 mg/kg/day) administration, respectively. The treatment with EOGF did not significantly affect body mass, macroscopy of the organs, or blood leukocyte counts. Based on these results, we can conclude that EOGF possesses significant antitumor activity and has only low systemic toxicity. These effects could be assigned to its components α-, ß-, and γ-eudesmol.

Evaluation of the cytotoxic activity of some Brazilian medicinal plants.

Plants are promising sources of new bioactive compounds. The aim of this study was to investigate the cytotoxic potential of nine plants found in Brazil. The species studied were: Annona pickelii Diels (Annonaceae), Annona salzmannii A. DC. (Annonaceae), Guatteria blepharophylla Mart. (Annonaceae), Guatteria hispida (R. E. Fr.) Erkens & Maas (Annonaceae), Hancornia speciosa Gomes (Apocynaceae), Jatropha curcas L. (Euphorbiaceae), Kielmeyera rugosa Choisy (Clusiaceae), Lippia gracilis Schauer (Verbenaceae), and Hyptis calida Mart. Ex Benth (Lamiaceae). Different types of extractions from several parts of plants resulted in 43 extracts. Their cytotoxicity was tested against HCT-8 (colon carcinoma), MDA-MB-435 (melanoma), SF-295 (glioblastoma), and HL-60 (promielocitic leukemia) human tumor cell lines, using the thiazolyl blue test (MTT) assay. The active extracts were those obtained from G. blepharophylla, G. hispida, J. curcas, K. rugosa, and L. gracilis. In addition, seven compounds isolated from the active extracts were tested; among them, ß-pinene found in G. hispida and one coumarin isolated from K. rugora showed weak cytotoxic activity. In summary, this manuscript contributes to the understanding of the potentialities of Brazilian plants as sources of new anticancer drugs.

Efficacy of the Mentha crispa in the treatment of women with Trichomonas vaginalis infection.

PURPOSE: The aim of this study was to evaluate the efficacy of Mentha crispa in the treatment of women with Trichomonas vaginalis infection (TVI). METHODS: This was a randomized, double-blind, and controlled clinical trial consisting of three phases, pre-treatment, treatment, and post-treatment. Sixty female patients were randomized to a treatment group, M. crispa (24 mg) or secnidazole (2,000 mg), both consisting of single dose. RESULTS: After treatment the proportion of patients without TVI in secnidazole group was 96.6% and in the M. crispa group was 90%, no difference was found between groups (P = 0.6120). We observed improvement in vaginal discharge, malodorous vaginal secretion, dyspareunia, dysuria, pelvic pain, and burning and itching in the genital area in patients of both groups of treatment, with no statistically significant differences between them (P > 0.05). Adverse effects were significantly higher (P = 0.0006) in the secnidazole group (66.6%) than in the M. crispa group (20%), that being mostly nausea and metallic taste with statistically significant differences between treatment groups (P < 0.001). CONCLUSION: This study is the first to show that M. crispa is effective and safe, representing an alternative for the treatment of TVI in women.

Involvement of intrinsic mitochondrial pathway in neosergeolide-induced apoptosis of human HL-60 leukemia cells: the role of mitochondrial permeability transition pore and DNA damage.

CONTEXT: Quassinoids are biologically active secondary metabolites found exclusively in the Simaroubaceae family of plants. These compounds generally present important biological properties, including cytotoxic and antitumor properties. OBJECTIVE: In the present study, the cytotoxic effects of neosergeolide, a quassinoid isolated from Picrolemma sprucei Hook. f., were evaluated in human promyelocytic leukemia cells (HL-60). MATERIALS AND METHODS: Cytotoxicity and antiproliferative effects were evaluated by the MTT assay, May-Grünwald-Giemsa's staining, BrdU incorporation test, and flow cytometry procedures. The comet assay and micronuclei analysis were applied to determine the genotoxic and mutagenic potential of neosergeolide. RESULTS: After 24 h exposure, neosergeolide strongly inhibited cancer cell proliferation (IC50 0.1 µM), and its activity seemed to be selective to tumor cells because it had no antiproliferative effect on human peripheral blood mononuclear cells (PBMC) at tested concentrations. Apoptosis was induced at submicromolar concentrations (0.05, 0.1, and 0.2 µM) as evidenced by morphological changes, mitochondrial depolarization, phosphatidylserine externalization, caspases activation, and internucleosomal DNA fragmentation. Additionally, neosergeolide effects were prevented by cyclosporine A (CsA), an inhibitor of the mitochondrial permeability transition (MPT) pore, which reinforced the participation of intrinsic pathways in the apoptotic process induced by this natural quassinoid. Direct DNA damage was further confirmed by comet assay and cytokinesis-block micronucleus test. DISCUSSION AND CONCLUSION: The present study provided experimental evidence to support the underlying mechanism of action involved in the neosergeolide-mediated apoptosis. In addition, no antiproliferative effect or DNA damage effect of neosergeolide was evident in PBMC, highlighting its therapeutic potential.

Gallic acid leads to cell death of Candida albicans by the apoptosis mechanism.

Aim: To evaluate the antifungal activity of gallic acid (GA) against the strains of Candida spp. resistant to fluconazole and to determine its mechanism of action. Materials & methods: Antifungal activity was evaluated using the broth microdilution and flow cytometry techniques. Results: GA presented minimum inhibitory concentrations ranging from 16 to 72 µg/ml, causing alterations of the membrane integrity and mitochondrial transmembrane potential, production of reactive oxygen species and externalization of phosphatidylserine. Conclusion: GA has potential antifungal activity against Candida spp.

Antifungal activity of dexamethasone against fluconazole-resistant Candida albicans and its activity against biofilms.

Objective: The present study investigated the antifungal action of dexamethasone disodium phosphate (Dex). Methodology: Susceptibility testing was performed using the Clinical & Laboratory Standards Institute protocol; M27-A3, checkerboard test and biofilm were evaluated with two isolates of Candida albicans, hyphal production test, molecular docking analysis and flow cytometry analysis. Result: Dex and fluconazole (FLC) together had a synergistic effect. Mature biofilm was reduced when treated with Dex alone or in combination. Dex and FLC promoted a decrease in the production of hyphae and changes in the level of mitochondrial depolarization, increased generation of reactive oxygen species, loss of membrane integrity, increased phosphatidylserine externalization and molecular docking; there was interaction with ALS3 and SAP5 targets. Conclusion: Dex showed antifungal activity against FLC-resistant C. albicans strains.

This study aimed to evaluate the antifungal action of dexamethasone against FLC-resistant C. albicans strains.

Preclinical genotoxicology of nor-ß-lapachone in human cultured lymphocytes and Chinese hamster lung fibroblasts.

Nor-ß-lapachone has shown several biological properties. Regarding cytotoxic activity against cancer cell lines, it has been recognized as an important prototype. However, quinonoid drugs present a major challenge because of their toxicity. In this study, we evaluated the cytotoxicity and genetic toxicity of nor-ß-lapachone in human lymphocytes and HL-60 leukemia cells and murine V79 fibroblasts, to shed some light on its selectivity toward cancer cells. As measured by MTT test, exposure of V79 cells to nor-ß-lapachone resulted in a weak cytotoxicity (IC(50) = 13.41 µM), and at a concentration up to 21.9 µM, no cytotoxic effect was observed in lymphocytes, while in HL-60 cells, nor-ß-lapachone elicited significantly greater cytotoxicity (IC(50) = 1.89 µM). Cultures coexposed to GSH-OEt showed an increased viability, which may indicate a neutralization of ROS generated by quinonoid treatment. In fact, only the highest concentrations of nor-ß-lapachone (10 or 20 µM) caused an increase in oxidative stress in nontumor levels cells as measured by TBARS and nitrite/nitrate detection. This was accompanied by an alteration in intracellular thiol content. However, NAC pre-exposure restored the redox equilibrium of the cells and the concentration of thiol levels to control values. Nor-ß-lapachone at 2.5 and 5 µM failed to induce DNA damage in nontumor cells, but at the highest concentrations tested, it induced single and double DNA strand breaks and increased the frequency of chromosomal aberrations. Interestingly, these damages were prevented by NAC pretreatment or exacerbated by prior exposure to the GSH-depleting agent 1-bromoheptane. In electrochemical experiments, nor-ß-lapachone at the same concentrations as those used in genotoxic tests did not damage DNA directly, but at the highest concentration tested (200 µM), it caused a very weak DNA interaction. Corroborating electrochemical data, oxidative modifications of DNA bases were observed, as checked by DNA repair enzymes EndoIII and FPG, which reinforced the indirect actions caused by nor-ß-lapachone through ROS generation and not via DNA intercalation. The DNA repair capacities were higher for nontumor cells than for leukemia cells, which may be related to the selective cytoxicity of nor-ß-lapachone toward cancer cells. Our data suggest that ROS play an important role in nor-ß-lapachone toxicity and that its DNA-damaging effect occurs only at concentrations several times higher than that needed for its antiproliferative effect on cancer cells.

Synthesis of new 9-hydroxy-α- and 7-hydroxy-ß-pyran naphthoquinones and cytotoxicity against cancer cell lines.

A synthetic method to obtain α- and ß-pyran naphthoquinones 10 and 11 with a hydroxyl substituent on the aromatic ring was developed. Two series of α- and ß-pyran naphthoquinones were obtained from the 8-hydroxy-lawsone, and their anticancer properties were evaluated against four tumor cell lines. In general, the new compounds displayed good activity, possibly indicating that these compounds have increased pro-oxidant capacity. The 9-hydroxy-α-lapachone and 7-hydroxy-ß-lapachone analogues of the natural products α-lapachone and ß-lapachone were successfully produced by this methodology.

Cytotoxic clerodane diterpenes from Casearia rupestris.

Four new clerodane diterpenes, casearupestrins A-D (1-4), were isolated from the leaves of Casearia rupestris. Compounds 1 and 4 were acetylated to yield 2,7-di-O-acetylcasearupestrin A (5) and 2,6-di-O-acetylcasearupestrin D (6). All compounds were evaluated for cytotoxicity against a small panel of human cancer cell lines. Casearupestrin A (1) exhibited the most potent activity against MDA/MB-435 (human melanoma) and SF-295 (human glioblastoma) cells, superior to that of the standard drug doxorubicin.