Abstract Biotransformations are chemical reactions carried out by microorganisms on organic substrates. Biotransformations can be regio-, chemo-, stereo- and enantio-selective. Bioreductions are of great interest to the food and pharmaceutical industries as they help to reduce costs and impacts on the environment. In this work, the following biotransformations of chalcones were performed: (2E)-1-(4-hydroxy-phenyl)-3-(2-methoxy-phenyl)-prop-2-en-1-one (1), (2E)-1-(4-hydroxy-phenyl)-3-(4-methoxy-phenyl)-prop-2-en-1-one (2), and (2E)-1-(4-hydroxy-phenyl)-3-phenyl-prop-2-en-1-one (3) by the fungus Scedosporium aspiospermum, leading to formation through chemo-selective reduction of dihydrochalcones 1-(4-hydroxy-phenyl)-3-(2-methoxy-phenyl)-propan-1-one (4), 1-(4-hydroxy-phenyl)-3-(4-methoxy-phenyl)-propan-1-one (5), and 1-(4-hydroxy-phenyl)-3-phenyl-propan-1-one (6). Compounds 1-6 had their antimicrobial activities tested and were observed better activity to the biotransformation products compared with substrates. This is the first report of chemo-selective bioreduction by fungi of the genus Scedosporium in biotransformation reactions.

Resumen Las biotransformaciones son reacciones químicas llevadas a cabo por microorganismos sobre sustratos orgánicos. Las biotransformaciones pueden ser regio-, quimio-, estereo- y enantio-selectivas. Las biorreducciones son de gran interés para la industria alimentaria y farmacéutica, ya que ayudan a reducir costes e impactos sobre el medio ambiente. En este trabajo se realizaron las siguientes biotransformaciones de las chalconas: (2E)-1-(4-hidroxi-fenil)-3-(2-metoxi-fenil)-prop-2-en-1-ona (1), ( 2E)-1-(4-hidroxi-fenil)-3-(4-metoxi-fenil)-prop-2-en-1-ona (2) y (2E)-1-(4-hidroxi-fenil)-3-fenil-prop-2-en-1-ona ( 3 ) por el hongo Scedosporium aspiospermum, que conduce a la formación mediante reducción quimio-selectiva de dihidrocalconas 1-(4-hidroxi-fenil)-3-(2-metoxi-fenil)-propan-1-ona (4), 1-(4-hidroxi-fenil)-3-(4-metoxi-fenil)-propan-1-ona (5) y 1-(4-hidroxi-fenil)-3-fenil-propan-1-ona (6). Se ensayaron las actividades antimicrobianas de los compuestos 1-6 y se observó una mejor actividad para los productos de biotransformación en comparación con los sustratos. Este es el primer informe de biorreducción quimio-selectiva por hongos del género Scedosporium en reacciones de biotransformación.

The fungus Aspergillus sp. was isolated from copper mining rejects and cultured in a liquid culture medium (potato dextrose, PD) enriched with CuSO4.5H2O and Pb(NO3)2 in different concentrations. By flame atomic absorption spectrometry (FAAS) it was observed that fungus absorbed 86% of both copper and lead, with initial concentrations of 100, 500 and 1000 mg L-1. The additional results provided by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction showed ability of the microorganism to act as a biosorbent as well as its capacity to transform the tested salts into other inorganic compounds. Chromatographic profile comparison of extracts obtained from the biotic, abiotic control and the cultivation enriched with the metals showed changes in the profile of the secondary metabolism. When the copper and lead salts were tested separately, there was an increase in the production of the compounds as function of the increase of the concentration and when associated promoted the decrease and disappearance of some substances produced by Aspergillus sp.

Leishmaniasis is a neglected infectious disease caused by different species of the Leishmania parasite and is one of the major public health problems in developing countries. Despite the progress in fundamental knowledge about the Leishmania parasite, current therapy against leishmaniasis is still unsatisfactory due to limited efficacy, prolonged treatment, high cost and undesirable adverse effects. Thus, the research for new prototypes compounds of antileishmaniasis drugs remains a matter of current importance. The objective of this study was to evaluate the leishmanicidal activity of cytochalasin B, a natural compound isolated by our group in a previous study, against L. amazonensis, using experimental tests and computational simulation methodologies. The results of the biological evaluation showed that cytochalasin B has antileishmanial activity against the promastigote form of Leishmania amazonensis. These results are corroborated by the docking and molecular dynamics that showed that the activity occurs due to the inactivation of the trypanothione reductase enzyme (TryR).

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.