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BACKGROUND Chagas disease, which is caused by the protozoan Trypanosoma cruzi, is endemic to Latin America and mainly affects low-income populations. Chemotherapy is based on two nitrocompounds, but their reduced efficacy encourages the continuous search for alternative drugs. Our group has characterised the trypanocidal effect of naphthoquinones and their derivatives, with naphthoimidazoles derived from β-lapachone (N1, N2 and N3) being the most active in vitro. OBJECTIVES In the present work, the effects of N1, N2 and N3 on acutely infected mice were investigated. METHODS in vivo activity of the compounds was assessed by parasitological, biochemical, histopathological, immunophenotypical, electrocardiographic (ECG) and behavioral analyses. FINDINGS Naphthoimidazoles led to a decrease in parasitaemia (8 dpi) by reducing the number of bloodstream trypomastigotes by 25-50% but not by reducing mortality. N1 protected mice from heart injury (15 dpi) by decreasing inflammation. Bradycardia was also partially reversed after treatment with N1 and N2. Furthermore, the three compounds did not reverse hepatic and renal lesions or promote the improvement of other evaluated parameters. MAIN CONCLUSION N1 showed moderate trypanocidal and promising immunomodulatory activities, and its use in combination with benznidazole and/or anti-arrhythmic drugs as well as the efficacy of its alternative formulations must be investigated in the near future.

Background Candida albicans is the most important fungal pathogen that causes infections in humans, and the search for new therapeutic strategies for its treatment is essential. Objective The aim of this study was to evaluate the activity of seven naphthoquinones (β-lapachone, β-nor-lapachone, bromide-β-lapachone, hydroxy-β-lapachone, α-lapachone, α-nor-lapachone and α-xyloidone) on the growth of a fluconazole-resistant C. albicans oral clinical isolate and the effects of these compounds on the viability of mammalian cells, on yeast's morphogenesis, biofilm formation and cell wall mannoproteins availability. Results All the compounds were able to completely inhibit the yeast growth. β-lapachone and α-nor-lapachone were the less cytotoxic compounds against L929 and RAW 264.7 cells. At IC50, β-lapachone inhibited morphogenesis in 92%, while the treatment of yeast cells with α-nor-lapachone decreased yeast-to-hyphae transition in 42%. At 50 μg/ml, β-lapachone inhibited biofilm formation by 84%, whereas α-nor-lapachone reduced biofilm formation by 64%. The treatment of yeast cells with β-lapachone decreased cell wall mannoproteins availability in 28.5%, while α-nor-lapachone was not able to interfere on this virulence factor. Taken together, data show that β-lapachone and α-nor-lapachone exhibited in vitro cytotoxicity against a fluconazole-resistant C. albicans strain, thus demonstrating to be promising candidates to be used in the treatment of infections caused by this fungus.

// Kelly C.G. Manfrere 1 , Marina P. Torrealba 1 , Denis R. Miyashiro 2 , Natalli Z. Pereira 1 , Fabio S.Y. Yoshikawa 1 , Luana de M. Oliveira 1 , Jade Cury-Martins 2 , Alberto J.S. Duarte 1 , Jose A. Sanches 2, * and Maria N. Sato 1, * 1 Laboratory of Medical Investigation, LIM-56, Department of Dermatology, Tropical Medicine Institute of Sao Paulo, University of Sao Paulo Medical School, Sao Paulo, Brazil 2 Cutaneous Lymphoma Clinic, Hospital das Clinicas, Department of Dermatology, University of Sao Paulo Medical School, Sao Paulo, Brazil * These authors share the mentorship, critical revision and supervision of this study Correspondence to: Maria N. Sato, email: marisato@usp.br Keywords: Sezary syndrome, natural killer cells, Toll-like receptor 7/8, memory NK cells, differentially expressed genes Received: July 06, 2017 Accepted: August 27, 2017 Published: September 18, 2017 ABSTRACT Sezary syndrome (SS), an aggressive and leukemic form of cutaneous T-cell lymphoma, usually results in shortened survival. Improving innate immunity in SS by targeting natural killer (NK) cells with Toll-like receptor (TLR) agonists could be an interesting modulatory strategy. We evaluated the NK cell populations in SS patients assessing activating and inhibitory receptors expression and profiled the differential expression of TLR signaling pathway genes in unstimulated NK cells and after TLR7/8 stimulation. We observed preserved CD56 bright NK cells and a low percentage of CD56 dim NK cells in the peripheral blood of SS patients compared to those in the healthy control group. Both NK cell populations showed down-modulation of NKG2C and NKG2D expression, which was associated with high serum levels of the soluble form of NKG2D ligands. In contrast, an expansion of “memory” CD57+ NKG2C+ NK cells and high cytomegalovirus antibody titers were detected in SS patients. Profiling of the TLR signaling genes in NK cells from SS patients showed an abundance of differentially expressed genes (DEGs) in NK cells in the unstimulated condition, with mostly up-regulation of NFκB/JNK p38 pathway genes, but there was down-regulation of type I (IFN-α/β) and II (IFN-γ) interferon and IL-12A. After activation of NK cells with TLR7/8 agonist, the down-regulated genes correlated with the IFN response, and IL-12 became up-regulated, together with other antitumor factors. NK cell activation with a dual agonist for TLR7 and TLR8 is able to induce the expression of IFN-γ and type I IFN, which can improve immunity in SS patients.

// Kelly C. G. Manfrere 1 , Marina P. Torrealba 1 , Denis R. Miyashiro 2 , Luanda M. S. Oliveira 1 , Gabriel C. de Carvalho 1 , Josenilson F. Lima 1 , Anna Claudia C. C. Branco 1 , Natalli Z. Pereira 1 , Juliana Pereira 3 , Jose A. Sanches, Jr 2,* and Maria N. Sato 1,* 1 Department of Dermatology, Laboratory of Medical Investigation, LIM 56, Tropical Medicine Institute of Sao Paulo, University of Sao Paulo Medical School, Brazil 2 Department of Dermatology, Cutaneous Lymphoma Clinic, Hospital das Clinicas, University of Sao Paulo, Medical School, Brazil 3 Department of Hematology, University of Sao Paulo Medical School, Brazil * These authors share the mentorship, critical revision and supervision of this study Correspondence to: Maria N. Sato, email: // Keywords : Se,zary syndrome, innate immunity, Toll-like receptor agonists, cytokines, type I interferon, Immunology and Microbiology Section, Immune response, Immunity Received : July 28, 2016 Accepted : October 14, 2016 Published : October 21, 2016 Abstract Sezary syndrome (SS) carries a poor prognosis, and infections represent the most frequent cause of death in SS patients. Toll-like receptors (TLRs) are a family of innate immune receptors that induce protective immune responses against infections. We sought to evaluate the ability of TLR agonists to induce inflammatory cytokine, Th2 cytokine, and type I interferon (IFN-I) production by peripheral blood mononuclear cells (PBMC) of untreated SS patients. We detected impaired IL-6, IL-10 and IL-13 secretion by PBMC induced by the agonists for TLR5, TLR3, TLR7 and TLR9 in SS patients, while it was partially recovered by TLR2/TLR4 and TLR7/8 agonists TNF secretion was restored following stimulation with TLR2/TLR4 agonists. IFN-γ was scarcely produced upon TLR activation in SS cells, albeit TLR 7/8 (CL097) enhanced their secretion at lower levels than the control group. TLR9 agonist efficiently induced IFN-I in SS patients, although this positive regulation was not observed for other cytokines, in direct contrast to the broad activity of CL097. Among the TLR agonists, TLR4 was able to induce pro-inflammatory, IL-10 and Th2 secretion, while TLR7-8 agonist induced the inflammatory cytokines, IFN-I and IFN-γ. These findings reveal a dysfunctional cytokine response upon both extracellular and intracellular TLR activation in SS patients, which was partially restored by TLRs agonists.

Despite being a curable disease, tuberculosis (TB) remains a public health problem worldwide mainly due to lengthy treatment, as well as its toxic effects, TB/HIV co-infection and the emergence of resistant Mycobacterium tuberculosis strains. These barriers reinforcing the need for development of new antimicrobial agents, that ideally should reduce the time of treatment and be active against susceptible and resistant strains. Quinones are compounds found in natural sources and among them, the naphthoquinones show antifungal, antiparasitic, and antimycobacterial activity. Thus, we evaluated the potential antimycobacterial activity of six 1,4-naphthoquinones derivatives. We determined the minimum inhibitory concentration (MIC) of the compounds against three M. tuberculosis strains: a pan-susceptible H37Rv (ATCC 27294); one mono-resistant to isoniazid (ATCC 35822); and one mono-resistant to rifampicin (ATCC 35838); the cytotoxicity in the J774A.1 (ATCC TIB-67) macrophage lineage; performed in silico analysis about absorption, distribution, metabolism, and excretion (ADME) and docking sites. All evaluated naphthoquinones were active against the three strains with MIC between 206.6 and 12.5 μM, and the compounds with lower MIC values have also showed low cytotoxicity. Moreover, two naphthoquinones derivatives 5 and 6 probably do not exhibit cross resistance with isoniazid and rifampicin, respectively, and regarding ADME analysis, no compound violated the Lipinski's rule-of-five. Considering the set of findings in this study, we conclude that these naphthoquinones could be promising scaffolds to develop new therapeutic strategies to TB.

Tuberculosis (TB) is the cause of more than one million deaths worldwide, and despite being a curable disease, some factors can make therapy difficult, emphasizing the need for the development of new drugs that may potentiate the action of the classic anti-TB antimicrobials. Naphthoimidazoles show a broad spectrum of biological activities, including antimycobacterial activity. The aim of this study was to evaluate the anti-Mycobacterium tuberculosis activity of nine naphthoimidazoles, alone and combined with isoniazid (INH) and rifampicin (RIF). We evaluated the minimum inhibitory concentration (MIC) of the compounds, the fractional inhibitory concentration of the combinations of the naphthoimidazoles with INH or RIF, and the cytotoxicity of these compounds. Eight compounds showed MICs ranging from 1.56 to 25 μg/mL and the presence of substituents on phenyl groups shown to be essential for antimycobacterial activity. Four compounds showed additivity with both INH and RIF and showed SI values higher than 10, indicating safety. Thus, considering the antimycobacterial activity and the absence of antagonism between naphthoimidazoles and the two main drugs for TB treatment, these compounds could be scaffolds for the development of new anti-TB drugs.

// Marina Passos Torrealba 1 , Kelly Cristina Manfrere 1 , Denis R. Miyashiro 2 , Josenilson F. Lima 1 , Luana de M. Oliveira 1 , Natalli Z. Pereira 1 , Jade Cury-Martins 2 , Juliana Pereira 3 , Alberto J.S. Duarte 1 , Maria N. Sato 1, * and Jose A. Sanches 2, * 1 Medical Investigation Laboratory (LIM-56), Tropical Medicine Institute of Sao Paulo, Department of Dermatology, University of Sao Paulo Medical School, Sao Paulo, Brazil 2 Cutaneous Lymphoma Clinic, Hospital das Clinicas, Department of Dermatology, University of Sao Paulo Medical School, Sao Paulo, Brazil 3 Hematology Department, Hospital das Clinicas, University of Sao Paulo Medical School, Sao Paulo, Brazil * These authors share the mentorship, critical revision and supervision of this study Correspondence to: Marina Passos Torrealba, email: marinatorrealba@usp.br Keywords: Sezary syndrome; CD8+ T cells; chronic activation markers; sCD38; sCD127 Received: October 12, 2017 Accepted: December 01, 2017 Published: December 16, 2017 ABSTRACT Sezary syndrome (SS) is a leukemic variant of cutaneous T cell lymphoma (CTCL), and the neoplastic CD4+ T cells of SS patients undergo intense clonal proliferation. Although Sezary cells have been studied extensively, studies on adaptive immunity regarding CD8+T cells are scarce. This study aimed to investigate activation marker expression in CD8+ T cells according to the differentiation stages and IL-7/IL7Rα axis responses of patients with SS. Moreover, this study aimed to verify the soluble forms of CD38, sCD127 and IL-7 in serum. Although the SS patients of our cohort had reduced numbers of CD8+ T cells, they exhibited higher percentages of CD8+CD38+ T cells, mainly effector/memory CD8+ T cells, than the control group. In contrast, down-regulated expression of the activation markers CD127/IL-7R and CD26 was found in the CD8+ T cells of SS patients. High serum levels of sCD38 and sCD127 and scarce serum levels of IL-7 were detected, emphasizing the immune activation status of SS patients. Moreover, CD8+ T cells from SS patients exhibited IL-7 unresponsiveness to STAT5 phosphorylation and Bcl-2 expression, and IL-7 priming partially restored IFNγ production. Our findings showed a chronic activation profile of CD8+ T cells, as an attenuated cytotoxic profile and impaired IL-7 responsiveness was observed, suggesting chronic activation status of CD8+ T cells in SS patients.

Fine shale particles and retorted shale are waste products generated during the oil shale retorting process. These by-products are small fragments of mined shale rock, are high in silicon and also contain organic matter, micronutrients, hydrocarbons and other elements. The aims of this study were to isolate and to evaluate fungal diversity present in fine shale particles and retorted shale samples collected at the Schist Industrialization Business Unit (Six)—Petrobras in Sa˜o Mateus do Sul, State of Parana´, Brazil. Combining morphology and internal transcribed spacer (ITS) sequence, a total of seven fungal genera were identified, including Acidiella, Aspergillus, Cladosporium, Ochroconis, Penicillium, Talaromyces and Trichoderma. Acidiella was the most predominant genus found in the samples of fine shale particles, which are a highly acidic substrate (pH 2.4–3.6), while Talaromyces was the main genus in retorted shale (pH 5.20–6.20). Talaromyces sayulitensis was the species most frequently found in retorted shale, and Acidiella bohemica in fine shale particles. The presence of T. sayulitensis, T. diversus and T. stolli in oil shale is described herein for the first time. In conclusion, we have described for the first time a snapshot of the diversity of filamentous fungi colonizing solid oil shale by-products from the Irati Formation in Brazil. CAPES

Candida species can cause infections that range from superficial to life-threatening events. Candida albicans is an opportunistic pathogen of human microbiota, and it is frequently described as a commensal organism, but in many cases, it can assume a pathogenic behavior. The increasing number of immunocompromised patients has promoted an increase in the incidence of microorganisms that are resistant to conventional therapy. Additionally, the limited number of antifungal drugs has made the search for new compounds extremely relevant. In this study, we determined the minimal inhibitory concentrations (MICs) of two synthetic imidazoles derived from β-lapachone, namely 3-indol carboxaldehyde and p-N(CH3)2-benzaldehyde against a clinical isolate of C. albicans resistant to fluconazole and the reference strain ATCC 10231. Both strains had their growth affected by 3-indol carboxaldehyde, and the MICs were calculated as 31.7 and 41 μg ml−1 for ATCC 10231 and the clinical isolate, respectively. However, the p-N(CH3)2-benzaldehyde MIC values were above 100 μg ml−1 for both strains. Morphogenesis assays revealed that 3-indol carboxaldehyde inhibited significantly the germ tube transformation process. Moreover, this azole was also able to interfere significantly with biofilm formation of both strains, and also demonstrated the ability to disaggregate mature biofilms. The results obtained in this study indicate that 3-indol carboxaldehyde may be considered a viable alternative in modulating C. albicans biofilm and viability.

Individuals who remain HIV-seronegative despite repeated unprotected exposure to the virus are defined as exposed seronegative (ESN) individuals. Innate and adaptive immunity, as well as genetic factors, provide ESNs with important advantages that allow for low infection susceptibility. The majority of HIV-1-infected individuals undergo antiretroviral therapy, which can decrease the level of HIV-1 exposure in ESNs. We analyzed type I interferon (IFN)-related antiviral and regulatory factors in peripheral blood mononuclear cells (PBMCs) and oral epithelial cells from serodiscordant couples. Our findings revealed that ESNs did not induce the expression of antiviral factors (APOBEC-3G, TRIM5-α, SAMDH1, STING, TBk1) or regulatory factors (Trex, Foxo3, Socs3, IL-10) in PBMCs, unlike their HIV-1-infected partners. In contrast, ESNs upregulated APOBEC-3G and type I/III IFNs (IFNs-α,-β/-λ) in oral mucosal epithelial cells similar to their HIV-infected partners. The serodiscordant groups exhibited an increased expression of type I IFN-induced regulators, such as Trex and Foxo3, in oral epithelial cells. TLR7, TLR8 and TLR9 were expressed in oral epithelial cells of both ESNs and HIV-1-infected subjects. These findings revealed evidence of antiviral factors, type I/III interferon and regulatory factor expression only in the oral mucosal compartment of ESNs, while HIV-1-infected partners systemically and oral mucosal expressed the antiviral profile.

Background The obligate intracellular protozoan Trypanosoma cruzi is the causative agent of Chagas disease, a neglected illness affecting millions of people in Latin America that recently entered non-endemic countries through immigration, as a consequence of globalization. The chemotherapy for this disease is based mainly on benznidazole and nifurtimox, which are very efficient nitroderivatives against the acute stage but present limited efficacy during the chronic phase. Our group has been studying the trypanocidal effects of naturally occurring quinones and their derivatives, and naphthoimidazoles derived from β-lapachone N1, N2 and N3 were the most active. To assess the molecular mechanisms of action of these compounds, we applied proteomic techniques to analyze treated bloodstream trypomastigotes, which are the clinically relevant stage of the parasite. Methodology/Principal Findings The approach consisted of quantification by 2D-DIGE followed by MALDI-TOF/TOF protein identification. A total of 61 differentially abundant protein spots were detected when comparing the control with each N1, N2 or N3 treatment, for 34 identified spots. Among the differentially abundant proteins were activated protein kinase C receptor, tubulin isoforms, asparagine synthetase, arginine kinase, elongation factor 2, enolase, guanine deaminase, heat shock proteins, hypothetical proteins, paraflagellar rod components, RAB GDP dissociation inhibitor, succinyl-CoA ligase, ATP synthase subunit B and methionine sulfoxide reductase. Conclusion/Significance Our results point to different modes of action for N1, N2 and N3, which indicate a great variety of metabolic pathways involved and allow for novel perspectives on the development of trypanocidal agents., Author Summary Trypanosoma cruzi is the etiological agent of Chagas disease, an important illness for Latin American countries that is now afflicting other continents due to the immigration of infected people. The available chemotherapy is limited to the chronic phase of the disease, being the development of novel active compounds essential, and the search for specific molecular targets for drugs in T. cruzi is necessary. In this context, our group has synthesized and screened many compounds ranging from natural to semi-synthetic naphthoquinones and derivatives on T. cruzi, displaying naphthoimidazoles N1, N2 and N3 the highest activity. Previous studies correlated phenotypic alterations by cell biology techniques as well as investigated mode of action by proteomic approaches in insect stage epimastigotes as a model. However, T. cruzi presents three morphologically distinct life stages with their own specific biological peculiarities and requirements that could be potential targets to drug intervention. Here, we evaluated the mechanism of action of N1, N2 and N3 in clinical relevant form of the parasite, bloodstream trypomastigotes, by proteomics. Our data pointed to 61 differentially abundant protein spots, being these proteins involved with cellular trafficking, protein synthesis, transduction signaling and energetic metabolism, among others, open interesting perspectives for trypanocidal strategies.

Lichen planus (LP) is a chronic inflammatory mucocutaneous disease. The inflammatory status of LP may be related to S100A8 (myeloid-related protein 8; MRP8) activation of cytotoxic cells. The aims of this study were to evaluate S100A8 expression in skin lesions and the in vitro effects of S100A8 on CD8+ T cells and natural killer (NK) cells in LP. Increased levels of S100A8/S100A9 were detected in the skin lesions as well as in the sera of subjects with LP. S100A8 expression induced an increased cytotoxic response by peripheral blood CD8+CD107a+ T cells as well as by NK CD56bright cells in patients with LP. Increased expression of interleukin (IL)-1β, tumour necrosis factor (TNF) and IL-6 in the CD8+ T cells of patients with LP was induced by S100A8, in contrast to the control group that produced IL- 10 and interferon (IFN) type I genes. These data suggest that, in individuals with LP, S100A8 may exert distinct immunomodulatory and cytotoxicity functions.

The biological activities of the naphthoquinones lapachol and its cyclization product beta-lapachone, extracted from trees of the genus Tabebuia, have been intensively studied. Given continuity to the studies about heterocyclic derivatives obtained from the reaction of these naphtoquinones with amino-containing reagents, 22 derivatives of beta-lapachone, nor-beta-lapachone and lapachol were synthesised and their activities against trypomastigote forms of T. cruzi were evaluated. The compounds were grouped as oxazolic, imidazolic, phenoxazinic, indolic, pyranic and cyclopentenic derivatives. The variability of the new structures is based on the great electrophilicity of 1,2-quinoidal carbonyls towards reagents containing nitrogen or carbon as nucleophilic centres. In relation to the trypanocidal activity of the synthesised compounds, in view of their structural diversity, tendencies only could be verified. Among the cyclofunctionalised products the oxazolic and imidazolic derivatives showed +/- 1.5 to 34.8 times higher activity than crystal violet, the standard drug for the sterilization of stored blood. These results corroborate the tendency of trypanocidal activity in imidazolic skeletons, and indicate that this moiety could be used as a guide for architectural delineation of molecules with potential value for the chemotherapy of Chagas disease.

Several quinonoid and phenazine compounds were synthesized in moderate to high yields and showed activity against H37Rv, rifampicin and isoniazid-resistance strains of Mycobacterium tuberculosis. The cytotoxity of the compounds were evaluated against human peripheral blood mononuclear cells (PBMC) and these substances emerge as promising antitubercular prototypes.

The increase of incidence of tuberculosis (TB) with resistant strains and HIV co-infection has reinforced the necessity of developing new drugs for its treatment. The reaction of naphthoquinones with aromatic or aliphatic aldehydes in the presence of ammonium acetate led to the synthesis of the three β-lapachone derivatives (naphthoimidazoles) that were tested in this study. Phenazines were prepared by the reaction of the respective naphtoquinone with o-phenylenediamine in acetic acid under reflux. The antimicrobial activity of the derivatives was evaluated in vitro against Mycobacterium tuberculosis H37Rv (ATCC 27294) and the rifampicin-resistant strain (ATCC 35338) containing a His-526-Tir mutation in the rpoB gene. Using the Resazurin Microtiter Assay (REMA) method, bioactive molecules were observed in the susceptible and resistant strains with MICs ranging from 2.2 μM to 17 μM. The naphthoimidazoles with p-toluyl and indolyl group attached to the imidazole ring were more active against the H37Rv strain (MIC 9.12 μM and 4.2 μM, respectively) than the rifampicin-resistant strain (MIC 8.3 μM and 17 μM, respectively). The phenazine with the allyl-pyran group was most active among the two strains and had an MIC of 2.2 mM. These results show the potential of these molecules as prototypes for future drugs used in treating TB.

The reaction of naphthoquinone-oximes (3) and (4) with diazomethane yields directly, in one step, the oxazoles (5) and (6), respectively.A reação das naphthoquinona-oximas (3) e (4) com diazometano fornece diretamente, em uma etapa, os oxazóis (5) e (6), respectivamente.

This work describes the use of high-speed counter-current chromatography as an efficient and economic method in the separation and purification of new naphthoxazolic heterocyclic derivatives from lapachol (1), a naturally occurring naphtoquinone from different species of Tabebuia. A series of naphthoxazoles was obtained by nucleophilic condensation of lapachol (1) with aromatic aldehydes in ammonium medium. Each reaction led to the formation of two main products, derivatives from β-xyloidone, and the naphthoxazoles with the isoprenyl side chain of lapachol (1). Reaction products were purified by counter-current chromatography, using hexane–acetonitrile–methanol (2:2:1, v/v/v) as a non-aqueous solvent system.

— Peroxidation of the phenazine of -lapachone using m -ClC 6 H 4 CO 3 H/CH 2 Cl 2 furnished a macrolactone with a rigid10-membered ring, and the corresponding N-oxide, originating from the oxidative cleavage of the aromatic double bond at thesite of fusion of the dihydropyrane moiety with the phenazine component. A third compound, a dihydrobenzophenazine-5-one,was also generated probably by hydrolysis of an intermediate epoxide-acetal or -hydroxy-hemiacetal formed at the same site. Allof the new compounds were fully characterized by X-ray diffractometry and spectroscopic methods. © 2003 Elsevier Science Ltd.All rights reserved. The naturally occurring ortho -naphthoquinone -lapa-chone (2,2-dimethyl-3,4-dihydro-2 H -benzo[ h ]chro-mene-5,6-dione) ( 1 ) exhibits a variety of biologicalactivities including anti-cancer, 1,2 in vitro inhibition ofDNA topoisomerases 3 and induction of topoisomeraseII mediated DNA cleavage. 4 In combination withtaxol, -lapachone has shown to be highly effectiveagainst established human ovarian and prostatetumours implanted in immunosuppressed mice.

The use of other natural quinones, such as lapachol (1), in the synthesis of new heterocycles becomes important in the development of new bioactive substances, either in the combat of Chagas`s disease or in the treatment of other diseases. Silica gel column chromatography is the chromatographic method conventionally used for the purification of these derivates, however it consumes much time and large amounts of solvent. In order to improve the isolation procedure, high speed countercurrent chromatography was used instead. 3

The structure of ‘lapachol peroxide’ was published by Hooker in 1936; however, we recently discovered a mistake in the originally proposed structure; the correct structure, according to X-ray spectroscopy, is given here.