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.

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...

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.

Constituintes Químicos e Atividade Antimicrobiana do Fungo de Solo Aspergillus sp. FRIZ12 Resumo: O presente trabalho relata o isolamento de nove compostos da biomassa do fungo de solo Aspergillus sp. FRIZ12. Os compostos 2-benzil-4H-piran-4-ona (1), flavasperona (2), 5-(hidroximetil) furfural (3), uridina (4), ergosterol (5), peróxido de ergosterol (6), cerivisterol (7), estigmasterol (8) e sitosterol (9) foram isolados por métodos cromatográficos, e as estruturas foram identificadas por RMN, EM e comparação com dados da literatura. O composto 1 está sendo relatado pela primeira vez no gênero Aspergillus e pela segunda vez como um produto natural. Os compostos 1 e 2 mostraram moderada atividade antimicrobiana