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.

Endophytic fungi are fungi that colonize internal tissues of plants; several biologically active compounds have been isolated from these fungi. There are few studies of compounds isolated from endophytic fungi of Amazon plants. Thus, this study aimed the isolation and structural identification of ergosterol (1), ergosterol peroxide (2), mevalonolactone (3), cytochalasin B (4) and cytochalasin H (5) from Aspergillus sp. EJC 04, an endophytic fungus from Bauhinia guianensis. The cytochalasin B (4) and the diacetate derivative of cytochalasin B (4a) showed high lethality in the brine shrimp assay. This is the first occurrence of cytochalasins in Amazonian endophytic fungi from B. guianensis.

Los hongos endofíticos son hongos que colonizan los tejidos internos de las plantas; varios compuestos biológicamente activos se han aislado a partir de estos hongos. Existen pocos estudios de compuestos aislados de hongos endófitos de plantas amazónicas. Por lo tanto, este estudio tuvo como objetivo el aislamiento y la identificación estructural de ergosterol (1), peróxido de ergosterol (2), mevalonolactona (3), citocalasina B (4) y citocalasina H (5) a partir de Aspergillus spp. EJC 04, un hongo endofítico de Bauhinia guianensis. La citocalasina B (4) y el derivado diacetato de citocalasina B (4a) mostraron una alta letalidad en el ensayo de Artemia salina. Esta es la primera aparición de citocalasinas en hongos endófitos amazónica de B. guianensis.

O fungo Aspergillus flavus isolado como endofítico da planta Paspalum maritimum Trin. foi avaliado quanto ao seu potencial de aplicação em reações de biotransformações. Os compostos chalcona (1), 3,4,5-trimetoxichalcona (2) e 2,3,4,4'-tetrametoxichalcona (3) foram biotransformados, respectivamente, na diidrochalcona (4), 3,4,5-trimetoxidiidrochalcona (5) e 2,3,4,4'-tetrametoxidiidrochalcona (6). As estruturas destes compostos foram determinadas por análises de RMN uni e bidimensionais e por espectrometria de massas. As diidrochalconas 5 e 6 são substâncias inéditas.

The fungus Aspergillus flavus isolated as endophytic of the plant Paspalum maritimum Trin. was evaluated for its potential application in biotransformation reactions. The compounds chalcone (1), 3,4,5-trimethoxychalcone (2) and 2,3,4,4'-tetramethoxychalcone (3) were biotransformed, respectively, in dihydrochalcone (4), 3,4,5-trimethoxydihydrochalcone (5) and 2,3,4,4'-tetramethoxydihydrochalcone (6). The structures were elucidated by spectroscopic methods including 1D and 2D NMR techniques, and MS analysis. The dihydrochalcones 5 and 6 are new compounds.