Synergistic activity of diclofenac sodium with oxacillin against planktonic cells and biofilm of methicillin-resistant Staphylococcus aureus strains.

Aim: To evaluate the activity of diclofenac sodium and synergism with oxacillin against clinical strains of SARM in plactonic cells, antibiofilm and biofilm. Materials & methods: Synergism activity was assessed using the fractional inhibitory concentration index and its possible mechanism of action by flow cytometry. Results: The synergistic activity of diclofenac sodium with oxacillin was observed against plactonic cells, antibiofilm and in biofilm formed from clinical methicillin-resistant Staphylococcus aureus strains. Conclusion: This combination caused damage to the integrity of the membrane and ruptures in the DNA of the cells, leading to apoptosis.

Evaluation of the antifungal activity in vitro of midazolam against fluconazole-resistant Candida spp. isolates.

Aim: The purpose of this study was to evaluate the antifungal activity of midazolam, alone and in association with azoles, against isolates of clinical Candida spp. in planktonic and biofilm form. Materials & methods: The antifungal activity was observed using the broth microdilution technique. Flow cytometry tests were performed to investigate the probable mechanism of action and the comet test and cytotoxicity test were applied to evaluate DNA damage. Results: Midazolam (MIDAZ) showed antifungal activity against planktonic cells (125-250 µg/ml) and reduced the viability of Candida spp. biofilms (125 a 2500 µg/ml). The interaction of MIDAZ against Candida spp. biofilms was observed through scanning electron microscopy, causing alteration of their appearance. Therefore, MIDAZ has antifungal potential against Candida spp.

Antifungal activity of ß-lapachone against azole-resistant Candida spp. and its aspects upon biofilm formation.

Aim: The purpose of this study was to assess the antifungal effect of ß-lapachone (ß-lap) on azole-resistant strains of Candida spp. in both planktonic and biofilm form. Materials & methods: The antifungal activity of ß-lap was evaluated by broth microdilution, flow cytometry and the comet assay. The cell viability of the biofilms was assessed using the MTT assay. Results: ß-lap showed antifungal activity against resistant strains of Candida spp. in planktonic form. In addition, ß-lap decreased the viability of mature biofilms and inhibited the formation of biofilms in vitro. Conclusion: ß-lap showed antifungal activity against Candida spp., suggesting that the compound can be utilized as an adjunct agent in the treatment of candidiasis.

Etomidate inhibits the growth of MRSA and exhibits synergism with oxacillin.

Aim: The purpose of this study was to evaluate the antimicrobial activity of the anesthetic etomidate against strains of MRSA and biofilms. Materials & methods: The antibacterial effect of etomidate was assessed by the broth microdilution method. To investigate the probable action mechanism of the compound flow cytometry techniques were used. Results: MRSA strains showed MIC equal to 500 and 1000 µg/ml of etomidate. Four-fifths (80%) of the tested MRSA strains demonstrated synergistic effect with oxacillin. Etomidate also showed activity against MRSA biofilm at concentration of 250 µg/ml. Cytometric analysis revealed that the cells treated with etomidate leading to cell death, probably by apoptosis. Conclusion: Etomidate showed antibacterial activity against MRSA.

Antitumor Potential of the Isoflavonoids (+)- and (-)-2,3,9-Trimethoxypterocarpan: Mechanism-of-Action Studies.

Synthetically derived samples of (+)-(6aS,11aS)-2,3,9-trimethoxypterocarpan [(+)-1] and its enantiomer [(-)-1], both of which are examples of naturally occurring isoflavonoids, were evaluated, together with the corresponding racemate, as cytotoxic agents against the HL-60, HCT-116, OVCAR-8, and SF-295 tumor cell lines. As a result it was established that compound (+)-1 was particularly active with OVCAR-8 cells being the most sensitive and responding in a dose-dependent manner. A study of cell viability and drug-induced morphological changes revealed the compound causes cell death through a mechanism characteristic of apoptosis. Finally, a computational study of the interactions of compound (+)-1 and (S)-monastrol, an established, synthetically derived, potent, and cell-permeant inhibitor of mitosis, with the kinesin-type protein Eg5 revealed that both bind to this receptor in a similar manner. Significantly, compound (+)-1 binds with greater affinity, an effect attributed to the presence of the associated methoxy groups.

Synergistic anticandidal activity of etomidate and azoles against clinical fluconazole-resistant Candida isolates.

Aim: The purpose of this study was to evaluate the effect of etomidate alone and in combination with azoles on resistant strains of Candida spp. in both planktonic cells and biofilms. Materials & methods: The antifungal activity of etomidate was assessed by the broth microdilution test; flow cytometric procedures to measure fungal viability, mitochondrial transmembrane potential, free radical generation and cell death; as well detection of DNA damage using the comet assay. The interaction between etomidate and antifungal drugs (itraconazole and fluconazole) was evaluated by the checkerboard assay. Results: Etomidate showed antifungal activity against resistant strains of Candida spp. in planktonic cells and biofilms. Etomidate also presented synergism with fluconazole and itraconazole in planktonic cells and biofilms. Conclusion: Etomidate showed antifungal activity against Candida spp., indicating that it is a possible therapeutic alternative.

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.

Annonalide and derivatives: Semisynthesis, cytotoxic activities and studies on interaction of annonalide with DNA.

The cytotoxic activity of the pimarane diterpene annonalide (1) and nine of its semisynthetic derivatives (2-10) was investigated against the human tumor cell lines HL-60 (leukemia), PC-3 (prostate adenocarcinoma), HepG2 (hepatocellular carcinoma), SF-295 (glioblastoma) and HCT-116 (colon cancer), and normal mouse fibroblast (L929) cells. The preparation of 2-10 involved derivatization of the side chain of 1 at C-13. Except for 2, all derivatives are being reported for the first time. Most of the tested compounds presented IC50s below 4.0 µM, being considered potential antitumor agents. The structures of all new compounds were elucidated by spectroscopic analyses including 2D NMR and HRMS. Additionally, the interaction of annonalide (1) with ctDNA was evaluated using spectroscopic techniques, and the formation of a supramolecular complex with the macromolecule was confirmed. Competition assays with fluorescent probes (Hoechst and ethidium bromide) and theoretical studies confirmed that 1 interacts preferentially via DNA intercalation with stoichiometric ratio of 1:1 (1:ctDNA). The ΔG value was calculated as -28.24 kJ mol-1, and indicated that the interaction process occurs spontaneously. Docking studies revealed that van der Walls is the most important interaction in 1-DNA and EB-DNA complexes, and that both ligands (1 and EB) interact with the same DNA residues (DA6, DA17 and DT19).

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.

Antifungal activity of naphthoquinoidal compounds in vitro against fluconazole-resistant strains of different Candida species: a special emphasis on mechanisms of action on Candida tropicalis.

In recent decades, the incidence of candidemia in tertiary hospitals worldwide has substantially increased. These infections are a major cause of morbidity and mortality; in addition, they prolong hospital stays and raise the costs associated with treatment. Studies have reported a significant increase in infections by non-albicans Candida species, especially C. tropicalis. The number of antifungal drugs on the market is small in comparison to the number of antibacterial agents available. The limited number of treatment options, coupled with the increasing frequency of cross-resistance, makes it necessary to develop new therapeutic strategies. The objective of this study was to evaluate and compare the antifungal activities of three semisynthetic naphthofuranquinone molecules against fluconazole-resistant Candida spp. strains. These results allowed to us to evaluate the antifungal effects of three naphthofuranquinones on fluconazole-resistant C. tropicalis. The toxicity of these compounds was manifested as increased intracellular ROS, which resulted in membrane damage and changes in cell size/granularity, mitochondrial membrane depolarization, and DNA damage (including oxidation and strand breakage). In conclusion, the tested naphthofuranquinones (compounds 1-3) exhibited in vitro cytotoxicity against fluconazole-resistant Candida spp. strains.

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.

Overview of the therapeutic potential of piplartine (piperlongumine).

Piplartine (piperlongumine, 5,6-dihydro-1-[(2E)-1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propenyl]-2(1H)-pyridinone) is a biologically active alkaloid/amide from peppers, as from long pepper (Piper longum L. - Piperaceae). Long pepper is one of the most widely used in Ayurvedic medicine, which is used to treat many diseases, including tumors. The purpose of the current paper is to address to the chemical structure establishment and to systematically survey the published articles and highlight recent advances in the knowledge of the therapeutic potential of piplartine, establishing new goals for future research. The reported pharmacological activities of piplartine include cytotoxic, genotoxic, antitumor, antiangiogenic, antimetastatic, antiplatelet aggregation, antinociceptive, anxiolytic, antidepressant, anti-atherosclerotic, antidiabetic, antibacterial, antifungal, leishmanicidal, trypanocidal, and schistosomicidal activities. Among the multiple pharmacological effects of piplartine, its anticancer property is the most promising. Therefore, the preclinical anticancer potential of piplartine has been extensively investigated, which recently resulted in one patent. This compound is selectively cytotoxic against cancer cells by induction of oxidative stress, induces genotoxicity, as an alternative strategy to killing tumor cells, has excellent oral bioavailability in mice, inhibits tumor growth in mice, and presents only weak systemic toxicity. In summary, we conclude that piplartine is effective for use in cancer therapy and its safety using chronic toxicological studies should be addressed to support the viability of clinical trials.

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.

Avaliação citotóxica em três linhagens de células tumorais das frações obtidas da casca do caule de Salacia crassifolia (MART. ex. Schult.) G. Dom. (Celastraceae) / Assessment of cytotoxicity in three tumor cell lines of the fractions attained from the stem bark of Salacia crassifolia (Mart. ex. Schult.) G. Dom (Celastraceae)

A utilização de plantas pela humanidade com fins medicinais é uma das formas mais antigas para tratamento, cura e prevenção de doenças, dentre elas o câncer, cujas espécies vegetais são encontradas em elevada diversidade no ecossistema. Com essa perspectiva, se optou por um arbusto típico do Cerrado, Salacia crassifolia (Celastraceae), para um screening inicial na determinação do potencial citotóxico desta espécie in vitro. Na medicina popular, S. crassifolia é utilizada no tratamento de problemas renais, tosse crônica, dores de cabeça, cicatrizantes, ulcerogênicas e na terapia da malaria. As frações: hidroalcoólica (SCCcM-W), diclorometânica(SCCcM-D), hexânica (SCCcM-H) e acetato de etila (SCCcM-A) da casca do caule foram submetidas a testes de citotoxicidade in vitro frente às linhagens MDA-MB-435(melanoma), HCT-8 (cólon-humano) e SF-295 (sistema nervoso central) utilizando o método colorimétrico MTT. As frações hexânica (SCCcM-H) e de acetato de etila(SCCcM-A) foram aquelas que proporcionaram citotoxicidade significativas frente às células tumorais analisadas.

For millennia humans have been using plants for medicinal purposes to treat, cure, or prevent diseases, including cancer. Brazilian ecosystem has a high diversity of plant species. From this perspective, a species found in the Cerrado, Salacia crassifolia (Celastraceae), was selected, for an initial screening to determine the cytotoxic potential of this species "in vitro". S. crassifolia has been widely used in traditional medicine to treat kidney diseases, chronic cough, headaches, healing, ulcerogenic, and for treatment of malaria. The fractions: hydroalcoholic (SCCcM-W), dichloromethane(SCCcM-D), hexane (SCCcM-H) and ethyl acetate (SCCcM-A) from the stem bark were tested for cytotoxicity "in vitro" to within MDA -MB-435(melanoma), HCT-8 (human-colon), and SF-295 (CNS) using the MTT colorimetric method. The hexane (SCCcM-H) and ethyl acetate (SCCcM-A) fractions were those that provided significant cytotoxicity against analyzed tumor cells.

Polysaccharide isolated from Passiflora edulis: Characterization and antitumor properties.

A hot water-extracted polysaccharide fraction (PFCM) of Passiflora edulis was characterized by microanalysis, infrared spectroscopy, NMR and high performance size-exclusion chromatography. The major component in PFCM is (1→4) linked galacturonic acid (esterified and unesterified). Neutral sugars such as arabinose, glucose, rhamnose, mannose, and fucose were also present. Traces of xylose and ribose were detected. The PFCM sample had a similar molar mass to that of pectin extracted from P. edulis under acidic conditions. Sarcoma 180 tumors treated with PFCM showed a growth inhibition ratio ranging from 40.59% to 48.73% depending on the dosage and type of PFCM administration (oral or intraperitoneal). Toxicological analysis shows that PFCM increases the cell types involved in primary defense mechanisms and no significant changes in the biochemical parameters and organs (e.g., kidney and liver) were observed. However, the use of PFCM treatment increased the spleen weight when compared with the use of 5-fluorouracil.

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.

Synthesis and anticancer activities of some novel 2-(benzo[d]thiazol-2-yl)-8-substituted-2H-pyrazolo[4,3-c]quinolin-3(5H)-ones.

A series of 2-(benzo[d]thiazol-2-yl)-8-substituted-2H-pyrazolo[4,3-c]quinolin-3(5H)-ones (3a-g) have been synthesized and evaluated for their in vitro antiproliferative activities against four human cancer cell lines: MDA-MB-435 (breast), HL-60 (leukemia), HCT-8 (colon) and SF-295 (central nervous system). The results showed that the compounds 3b (2-(benzo[d]thiazol-2-yl)-8-methyl-2H-pyrazolo[4,3-c]quinolin-3(5H)-one) and 3c (2-(benzo[d]thiazol-2-yl)-8-bromo-2H-pyrazolo[4,3-c]quinolin-3(5H)-one) exhibited good cytotoxicity for three cell lines with IC(50) values lower than 5 µg/mL. Analysis of theoretical toxicity risks have shown medium tumorigenic and irritant risks related to 3b and 3c in contrast to doxorubicin, the positive control.

Synthesis and evaluation of quinonoid compounds against tumor cell lines.

Thirty two compounds were synthesized in moderate to high yields and showed activity against cancer cells HL-60 (leukemia), MDA-MB435 (melanoma), HCT-8 (colon) and SF295 (central nervous system), with IC(50) below 2 µM for some compounds. The ß-lapachone-based 1,2,3-triazoles showed the best cytoxicity profile and emerge as promising anticancer prototypes. Insights about the reactive oxygen species (ROS) mechanism of anticancer action for some compounds were obtained by addition of 1-bromoheptane that deplete reduced glutathione (GSH) content and by using N-acetylcysteine that protects cells against apoptotic cellular death, as well by analysis of thiobarbituric acid reactive substances (TBARS) formation, and oxidative DNA damage after treatment detected by the comet assay with the bacterial enzymes formamidopyrimidine DNA-glycosylase (FPG) and endonuclease III (ENDOIII).

Novel platinum(II) complexes of 3-(aminomethyl)naphthoquinone Mannich bases: synthesis, crystal structure and cytotoxic activities.

The first examples of platinum(II) complexes of 3-(aminomethyl)naphthoquinone Mannich bases have been synthesised and their crystal structures are described. Neutral and charged complexes have been obtained, fully characterised and their cytotoxic activities have also been investigated. 3-[(R(1)-amino)(pyridin-2-yl)methyl]-2-hydroxy-1,4-naphthoquinones (R(1) = n-Bu, HL1; Bn, HL2; furfuryl, HL3; n-heptyl, HL4 and n-decyl, HL5) coordinate to platinum(II) through the two nitrogen atoms. The neutral complexes cis-[Pt(HL)Cl(2)] 1a-5a are analogous to cisplatin with the bidentate ligand HL and two chlorine atoms occupying cis positions. In the charged complexes cis-[Pt(L(-))(NH(3))(2)]NO(3)1b-5b the deprotonated form of the ligand L(-) also coordinates via the nitrogen atoms, and the other two positions around the platinum(II) ion are completed with NH(3) ligands. The cytotoxic activities of all compounds have been tested for six different cancer cell lines: MDA-MB-435 (melanoma), HL-60 (promyelocytic leukaemia), HCT-8 (colon), SF-295 (brain), OVCAR-8 (ovary) and PC-3 (prostate). Proligands HL4 and HL5 have exhibited high activity against HL-60 (IC(50) = 1.9 and 3.8 µmol L(-1), respectively), HCT-8 (IC(50) = 1.6 and 1.7 µmol L(-1), respectively) and SF-295 (IC(50) = 1.1 and 1.7 µmol L(-1), respectively). The chlorido complexes 1a-5a have shown high to moderate cytotoxic activities, complex 4a (R(1) = n-heptyl) being more active than proligand HL4 against melanoma (IC(50) = 6.4 and > 40 µmol L(-1), respectively) and more active than cisplatin against all tested cell lines. Among the amine charged complexes only 4b and 5b have exhibited significant cytotoxic activity against the tested cell lines, although they were only moderately active against the PC-3 cell line (IC(50) = 29.9 and 15.6 µmol L(-1), respectively). In general the compounds with the longest carbon chains (R(1) = n-heptyl and n-decyl) have exhibited the highest activities.