Bauhinia guianensis is a typical plant in the Amazon region belonging to the family Leguminosea, used by local populations for the treatment of infectious and renal diseases. Previous work on the plant B. guianensis led to the isolation of substances with anti-inflammatory and analgesic activities. Thus, compounds isolated from B. guianensis with antimicrobial activities had not been identified. Given that there is a possibility of biological activity reported for a given plant being found in the endophytic fungi, we decided to isolate endophytic fungi from B. guianensis and test their antimicrobial activities. The alkaloids known as fumigaclavine C and pseurotin A were isolated by column chromatography and identified by 1D and 2D NMR techniques and mass spectrometry. The alkaloids are first reported as broad-spectrum antibacterial agents with good activity.

Antibiotic resistance results in higher medical costs, prolonged hospital stays and increased mortality and is rising to dangerously high levels in all parts of the world. Therefore, this study aims to search for new antimicrobial agents through bioprospecting of extracts of endophytic fungi from Bauhinia guianensis, a typical Amazonian plant used in combating infections. Seventeen (17) fungi were isolated and as result the methanolic extract of the fungus Exserohilum rostratum showed good activity against the bacteria tested. The polyketide monocerin was isolated by the chromatographic technique, identified by NMR and MS, showing broad antimicrobial spectrum.

Chemotherapy is limited in the treatment of leishmaniasis due to the toxic effects of drugs, low efficacy of alternative treatments, and resistance of the parasite. This work assesses the in vitro activity of flavopereirine on promastigote cultures of Leishmania amazonensis. In addition, an in silico evaluation of the physicochemical characteristics of this alkaloid is performed. The extract and fractions were characterized by thin-layer chromatography and HPLC-DAD, yielding an alkaloid identified by NMR. The antileishmanial activity and cytotoxicity were assayed by cell viability test (MTT). The theoretical molecular properties were calculated on the Molinspiration website. The fractionation made it possible to isolate a beta-carboline alkaloid (flavopereirine) in the alkaloid fraction. Moreover, it led to obtaining a fraction with greater antileishmanial activity, since flavopereirine is very active. Regarding the exposure time, a greater inhibitory effect of flavopereirine was observed at 24 h and 72 h (IC50 of 0.23 and 0.15 μg/mL, respectively). The extract, fractions, and flavopereirine presented low toxicity, with high selectivity for the alkaloid. Furthermore, flavopereirine showed no violation of Lipinski’s rule of five, showing even better results than the known inhibitor of oligopeptidase B, antipain, with three violations. Flavopereirine also interacted with residue Tyr-499 of oligopeptidase B during the molecular dynamics simulations, giving a few insights of a possible favorable mechanism of interaction and a possible inhibitory pathway. Flavopereirine proved to be a promising molecule for its antileishmanial activity.

Endophytic fungi are fungi that colonize internal tissues of plants. There are few studies of compounds isolated from endophytic fungi of Amazon plants. Thus, the aim this study was the isolation and structural identification of sitosterol (1), stigmasterol (2), sitostenone (3), squalene (4), ergosterol (5) and ergosterol peroxide (6) from fungus Colletotrichum gloeosporioides isolated as endophytic from Virola michelli, a typical Amazon plant, used in folk medicine against skin infection. Compounds were isolated by chromatography column on silica and identified by 1 H and 13 C NMR and MS. The presence of phytosterols in fungi is rare and this is the first report of the isolation of the phytosterols sitosterol, stigmasterol and sitostenone from the genus Colletotrichum. KEYWORDS: Sterols, secondary metabolites, Amazon fungi. Fotoesteróis isolados do fungo endofítico Colletotrichum gloeosporioides (Melanconiaceae) RESUMOFungos endofíticos são fungos que colonizam os tecidos internos das plantas. Existem poucos estudos de compostos isolados de fungos endofíticos de plantas da Amazônia. Assim, o objetivo deste estudo foi o isolamento e identificação estrutural de sitosterol (1), estigmasterol (2), sitostenona (3), esqualeno (4), ergosterol (5) e peroxido de ergosterol (6) do fungo Colletotrichum gloeosporioides isolado como endofítico de Virola michelli, uma planta típica da Amazônia, usada na medicina popular no combate a infecções de pele. Os compostos foram isolados por cromatografia em coluna de sílica e identificados por RMN 1 H e 13 C e EM. A presença de fitoesteróis em fungos é rara e este é o primeiro relato do isolamento dos fitoesteróides sitosterol, estigmasterol e sitostenona do gêreno Colletotrichum. PALAVRAS-CHAVE: Esteróides, metabolitos secundários, fungos da Amazônia. (Melanconiaceae) Phytosterols isolated from endophytic fungus Colletotrichum gloeosporioides

The present work reports the isolation of five compounds from Aspergillus sp EJC08 isolated as endophytic from Bauhinia guianensis, a tipical plant of the Amazon. The compounds ergosterol (1), ergosterol peroxide (2), mevalolactone (3), monomethylsulochrin (4) and trypacidin A (5) were isolated by chromatographic procedures and identified by spectral methods of 1D and 2D NMR and MS. Compounds 3, 4 and 5 were tested against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus and showed good activity.

The natural compound ravenelin was isolated from the biomass extracts of Exserohilum rostratum fungus, and its antimicrobial, antiplasmodial, and trypanocidal activities were evaluated. Ravenelin was isolated by column chromatography and HPLC and identified by NMR and MS. The susceptibility of Gram-positive and Gram-negative bacteria strains to ravenelin was determined by microbroth dilution assay. Cytotoxicity was evaluated in hepatocarcinoma cells (HepG2) and BALB/c peritoneal macrophages by using MTT. SYBR Green I-based assay was used in the asexual stages of Plasmodium falciparum. Trypanocidal activity was tested against the epimastigote and intracellular amastigote forms of Trypanosoma cruzi. Ravenelin was active against Gram-positive bacteria strains, with emphasis on Bacillus subtilis (MIC value of 7.5 µM). Ravenelin’s antiparasitic activities were assessed against both the epimastigote (IC50 value of 5 ± 1 µM) and the intracellular amastigote forms of T. cruzi (IC50 value of 9 ± 2 µM), as well as against P. falciparum (IC50 value of 3.4 ± 0.4 µM). Ravenelin showed low cytotoxic effects on both HepG2 (CC50 > 50 µM) and peritoneal macrophage (CC50 = 185 ± 1 µM) cells with attractive selectivity for the parasites (SI values > 15). These findings indicate that ravenelin is a natural compound with both antibacterial and antiparasitic activities, and considerable selectivity indexes. Therefore, ravenelin is an attractive candidate for hit-to-lead development.

The paper describes the isolation of ergosterol peroxide, monocerin, annularin I and annularin J compounds of Exserohilum rostratum biomass extracts. Compounds were isolated by silica gel column chromatography in polarity gradient and the structures were determined by nuclear magnetic resonance (NMR) and mass spectrometry (MS) methods. Monocerin, annularin I and annularin J compounds were tested against Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis bacteria and showed moderate activity. Annularin I and annularin J compounds are new natural products. Keywords: annularins, polyketides, E. rostratum, endophytic fungi IntroductionEndophytic microorganisms live in plants internal tissues without causing apparent disease to their hosts. 1 Endophyte microbial colonization can be demonstrated by isolating plant tissues disinfected through histological cut and by DNA amplification technique. 2 In tropical and temperate forests (which cover only 1.5% of the terrestrial surface), there are approximately 300,000 (three hundred thousand) plant species analyzed so far, homing more than 60% of the world's biodiversity. 3 Extreme diversity allows for the opportunity to discover new microorganisms that may be potential bioactive compounds producers for agriculture, industry and medicine. 4 There is a great interest in the study of endophytic microorganisms, including their application in pest biocontrol. Fungi are good secondary metabolite producers, and many have the same biological activity, 5-8 especially polyketides. For example, the polyketide citrinin isolated from Penicillium janthinellum completely inhibited the growth of Leishmania braziliensis.9 Some fungi species of Penicillium and Pestalotiopsis genera produce high diversity of polyketides with antimicrobial activity. 10,11In another study with a variety of endophytes isolated from Vigueira arenaria and Tithonia diversifolia fungal extracts, important antiparasitic and antimicrobial activities were observed in fungal extracts. 12 In the Nodulisporium sp. (Xylariaceae) fungus extract, which was isolated from the woody plant species Erica arborea (Ericaceae), nodulisporina D, E and F compounds were obtained, having antifungal, antibacterial and algaecide activity.13 From the endophytic fungus Ampelomyces sp., isolated from the medicinal plant Urospermum picroides (Asteraceae), 6-O-methylalaternina and altersolanol A compounds were isolated, which showed antimicrobial activity against Gram-positive pathogens Staphylococcus aureus, S. epidermidis and Enteorococcus faecalis.14 Brazil is estimated to be home of about 20% of the world's biodiversity and is considered the country in the world with the largest number of endemic species.15 About 270,000 plant species on this planet are estimated to harbor about 13.6 million unique endophytic fungal species, in addition to approximately 100,000 fungi species already known to date. Therefore, there are great chances of finding Pinheiro et al. 1433 Vol. 27, No. 8, 2016 new substances produced by endophytic fun...

Atividade Antibacteriana de Austidiol Isolado de Mycoleptodiscus indicus Contra Xanthomonas axonopodis pv. passiflorae Resumo: Doenças de plantas causadas por bactérias resultam em perdas graves para a agricultura. O estudo químico de fungos endofíticos representa uma área em potencial no desenvolvimento de pesticidas biológicos. Assim, o presente trabalho teve como objetivo verificar a atividade antibacteriana do extrato do fungo endofítico Mycoleptodiscus indicus NF12 de Morinda citrifolia contra Xanthomonas axonopodis pv. passiflorae, bactéria causadora da mancha bacteriana do maracujazeiro, bem como, determinar qual composto é responsável pela atividade observada. O composto austidiol (1) foi isolado através de métodos cromatográficos do extrato metanólico da biomassa do fungo endofítico M. indicus NF12 e apresentou atividade bacteriostática em todas as concentrações testadas sobre cinco isolados de X. axonopodis pv. passiflorae.