Microbial Modifications of Androstane and Androstene Steroids by Penicillium vinaceum

Bio-oxidation of progesterone by Penicillium oxalicum CBMAI 1185 and evaluation of the cytotoxic activity

We report the biotransformation of progesterone 1 by whole cells of Brazilian marine-derived fungi. A preliminary screening with 12 fungi revealed that the strains Penicillium oxalicum CBMAI 1996, Mucor racemous CBMAI 847, Cladosporium sp. CBMAI 1237, Penicillium oxalicum CBMAI 1185 and Aspergillus sydowii CBMAI 935 were efficient in the biotransformation of progesterone 1 in the first days of the reaction, with conversion values ranging from 75 % to 99 %. The fungus P. oxalicum CBMAI 1185 was employed in the reactions in quintuplicate to purify and characterize the main biotransformation products of progesterone 1. The compounds testololactone 1a, 12β-hydroxyandrostenedione 1b and 1β-hydroxyandrostenedione 1c were isolated and characterized by NMR, MS, [α]D and MP. In addition, the chromatographic yield of compound 1a was determined by HPLC-PDA in the screening experiments. In this study, we show a biotransformation pathway of progesterone 1, suggesting the presence of several enzymes such as Baeyer-Villiger monooxygenases, dehydrogenases and cytochrome P450 monooxygenases in the fungus P. oxalicum CBMAI 1185. In summary, the results obtained in this study contribute to the synthetic area and have environmental importance, since the marine-derived fungi can be employed in the biodegradation of steroids present in wastewater and the environment. The cytotoxic results demonstrate that the biodegradation products were inactive against the cell lines, in contrast to progesterone.

Biotransformation of testosterone by the filamentous fungus Penicillium pinophilum

The microbial biotransformation is a robust procedure in developing steroids and fungi are practical tools in this process; therefore, the fungal modification of testosterone by Penicillium pinophilum was investigated. The three prominent metabolites, including 14α-hydroxyandrost-4-en-3,17-dione (II), 14α-hydroxytestosterone (III), and 11α-hydroxytestosterone (IV), were isolated and characterized by chromatographic and spectroscopic methods. The time course profile showed that the content of the metabolites II and III began to decrease after 96 and 24 h, respectively. In comparison, the content of the metabolite IV remained stable after 24 h. In silico studies showed that the probability of binding to the androgen receptor remains high for all three metabolites. However, the probability of binding to the estrogen receptors α and β increased for metabolite IV but decreased for metabolite III. Penicillium pinophilum as a potentially viable biocatalyst could hydroxylate C-11α and C-14α positions and oxidize the C-17β hydroxyl group to 17-ketone in testosterone molecule.

Hydroxylation of Progesterone and Its Derivatives by the Entomopathogenic Strain Isaria farinosa KCh KW1.1

Progesterone biotransformation is worth studying because of the high industrial value of its derivatives. This study investigated the catalytic ability of the entomopathogenic filamentous fungus strain Isaria farinosa KCh KW1.1 to transform progesterone derivatives: 11α-hydroxyprogesterone, 17α-hydroxyprogesterone, 16α,17α-epoxyprogesterone and pregnenolone. In the culture of Isaria farinosa KCh KW1.1, 11α-hydroxyprogesterone was effectively transformed into only one product: 6β,11α-dihydroxyprogesterone. Transformation of 17α-hydroxyprogesterone gave three hydroxy derivatives: 6β,17α-dihydroxyprogesterone, 12β,17α-dihydroxyprogesterone and 6β,12β,17α-trihydroxyprogesterone. Two products: 6β-hydroxy-16α,17α-epoxyprogesterone and 6β,11α-dihydroxy-16α,17α-epoxyprogesterone, were obtained from the 16α,17α-epoxyprogesterone transformation. We isolated two compounds from the biotransformation medium with pregnenolone: 11α-hydroxy-7-oxopregnenolone and 5α,6α-epoxy-3β,11α-dihydroxypregnan-7,20-dione. In this study, we observed only mono- and dihydroxy derivatives of the tested substrates, and the number of obtained products for each biotransformation did not exceed three.

Biotransformation of Androstenedione by Filamentous Fungi Isolated from Cultural Heritage Sites in the State Tretyakov Gallery

Simple Summary

Microorganisms are able to grow on substrates of the most diverse nature. One of the most practical habitats, in terms of cultural heritage conservation, is fine art objects such as tempera or oil paintings on canvas. Since tempera paints are produced on the basis of egg yolk, which is one of the richest sources of cholesterol in nature (up to 2% of dry weight), and in the process of aging of tempera materials, changes in cholesterol do not affect the core structure of the steroid nucleus, the group of fungi that we have isolated are tempera painting destructors is seen as a promising object for screening for their possible steroid-transforming activities. In this regard, the purpose of our work was to determine the ability to transform pharmaceutically significant steroids with dominant fungi-destructors of tempera paintings, previously isolated in the State Tretyakov Gallery. Consequently, we have demonstrated for the first time that fungi-destructors of tempera paintings have steroid-transforming activity and are promising microorganisms for screening for biotechnologically significant transformations of steroids with further industrial use.

Abstract

The transformation of steroids by microorganisms is widely used in medical biotechnology. A huge group of filamentous fungi is one of the most promising taxa for screening new biocatalytic reactions in order to obtain pharmaceutically significant steroids. In this work, we screened 10 filamentous fungi-destructors of egg tempera for the ability to biotransform androst-4-en-3,17-dione (AD) during cultivation in a liquid nutrient medium or in a buffer solution. These taxonomically unrelated strains, belonging to the classes Eurotiomycetes, Dothideomycetes and Sordariomycetes, are dominant representatives of the microbiome from halls where works of tempera painting are stored in the State Tretyakov Gallery (STG, Moscow, Russia). Since the binder of tempera paints, egg yolk, contains about 2% cholesterol, these degrading fungi appear to be a promising group for screening for steroid converting activity. It turned out that all the studied fungi-destructors are able to transform AD. Some strains showed transformation efficiency close to the industrial strain Curvularia lunata RNCIM F-981. In total, 33 steroids formed during the transformation of AD were characterized, for 19 of them the structure was established by gas chromatography/mass spectrometry analysis. In this work, we have shown for the first time that fungi-destructors of tempera paintings can efficiently transform steroids.

The catalytic activity of mycelial fungi towards 7-oxo-DHEA - an endogenous derivative of steroidal hormone dehydroepiandrosterone

Seventeen species of fungi belonging to thirteen genera were screened for the ability to carry out the transformation of 7-oxo-DHEA (7-oxo-dehydroepiandrosterone). Some strains expressed new patterns of catalytic activity towards the substrate, namely 16β-hydroxylation (Laetiporus sulphureus AM498), Baeyer-Villiger oxidation of ketone in D-ring to lactone (Fusicoccum amygdali AM258) and esterification of the 3β-hydroxy group (Spicaria divaricata AM423). The majority of examined strains were able to reduce the 17-oxo group of the substrate to form 3β,17β-dihydroxy-androst-5-en-7-one. The highest activity was reached with Armillaria mellea AM296 and Ascosphaera apis AM496 for which complete conversion of the starting material was achieved, and the resulting 17β-alcohol was the sole reaction product. Two strains of tested fungi were also capable of stereospecific reduction of the conjugated 7-keto group leading to 7β-hydroxy-DHEA (Inonotus radiatus AM70) or a mixture of 3β,7α,17β-trihydroxy-androst-5-ene and 3β,7β,17β-trihydroxy-androst-5-ene (Piptoporus betulinus AM39). The structures of new metabolites were confirmed by MS and NMR analysis. They were also examined for their cholinesterase inhibitory activity in an enzymatic-based assay in vitro test.