Lactones 35 . Metabolism of iodolactones with cyclohexane ring in Absidia cylindrospora culture

Chalcone-Derived Lactones: Synthesis, Whole-Cell Biotransformation, and Evaluation of Their Antibacterial and Antifungal Activity

Four compounds with lactone moiety were synthesized from chalcone 1 in three- or four-step synthesis. γ-Bromo-δ-lactone 5 was the only product of bromolactonization of acid 4 whereas bromolactonization of ester 3, apart from lactone 5 also afforded its isomer 6 and two diastereoisomeric δ-hydroxy-γ-lactones 7 and 8. Lactone 8 was also obtained in 88% yield as a product of simultaneous dehalogenation and translactonization of γ-bromo-δ-lactone 5 by Penicillum frequentans AM 359. Chalcone-derived lactones 5-8 were subjected to the tests on antimicrobial activity and the results compared with activity of starting chalcone 1. Obtained lactones 5-8 in most cases limited the growth of tested bacterial and fungal strains. The highest activity was found for δ-hydroxy-γ-lactone 8 which completely inhibited the growth of Staphylococcus aureus, Fusarium graminearum, Aspergillus niger, and Alternaria sp. The introduction of lactone moiety into chalcone scaffold significantly improved antimicrobial activity of the compound: γ-bromo-δ-lactone 6 and δ-hydroxy-γ-lactone 8 were significantly stronger growth inhibitors of S. aureus and F. graminearum. In the case of the latter, a clear positive effect of the lactone function on the antifungal activity was also observed for γ-bromo-δ-lactone 5.

Microbial Transformations of Halolactones and Evaluation of Their Antiproliferative Activity

The microbial transformations of lactones with a halogenoethylocyclohexane moiety were performed in a filamentous fungi culture. The selected, effective biocatalyst for this process was the Absidia glauca AM177 strain. The lactones were transformed into the hydroxy derivative, regardless of the type of halogen atom in the substrate structure. For all lactones, the antiproliferative activity was determined toward several cancer cell lines. The antiproliferative potential of halolactones was much broader than that observed for the hydroxyderivative. According to the presented results, the most potent was chlorolactone, which exhibited significant activity toward the T-cell lymphoma line (CL-1) cell line. The hydroxyderivative obtained through biotransformation was not previously described in the literature.

New Bromo- and Iodo-Hydroxylactones with Two Methyl Groups Obtained by Biotransformation of Bicyclic Halolactones

The subject of the research was to determine the ability of the filamentous fungi to biotransform bicyclic halolactones containing two methyl groups in their structure. By chemical synthesis three bicyclic halolactones with two methyl groups, one in the cyclohexane ring and one in the lactone ring, were obtained: 2-chloro-4,7-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one, 2-bromo-4,7-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one, and 2-iodo-4,7-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one. These compounds were formed as mixtures of two diastereoisomers. The obtained halolactones (as mixture of two diastereoisomers) were subjected to screening biotransformation with the use of eight strains of filamentous fungi: Fusarium culmorum AM10, F. avenaceum AM12, F. semitectum AM20, F. solani AM203, Absidia coerulea AM93, A. cylindrospora AM336, Penicillium chermesinum AM113, P. frequentans AM351. Two of the substrates, 2-bromo-4,7-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one and 2-iodo-4,7-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one, were hydroxylated without removing the halogen atom from the molecule, giving 2-bromo-7-hydroxy-4,7-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one, 2-bromo-5-hydroxy-4,7-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one, and 2-iodo-7-hydroxy-4,7-dimethyl-9-oxabicyclo[4.3.0]nonan-8-one as products. The hydroxylation capacity was demonstrated by strains of Absidia cylindrospora AM336, Fusarium avenaceum AM12, and F. solani AM203. The structures of all lactones were determined on the basis spectroscopic data.

Biotechnological Approach for the Production of Enantiomeric Hydroxylactones Derived from Benzaldehyde and Evaluation of Their Cytotoxic Activity

The β-aryl-δ-halo-γ-lactones are known for their antiproliferative activity towards numerous cancer cell lines. The aim of this study was to obtain in the biotransformation process new β-aryl-δ-hydroxy-γ-lactones and compare their activity with the antiproliferative activity of parent compounds. The racemic cis-5-(1-iodoethyl)-4-phenyldihydrofuran-2-one as well as separate enantiomers were transformed in fungal cultures. Among ten tested biocatalysts, three (Absidia cylindrospora AM336, Absidia glauca AM254, and Fusarium culmorum AM10) were able to catalyze the hydrolytic dehalogenation process. The biotransformations processes were highly stereoselective and enantiomerically pure hydroxylactones were obtained (ee ≥ 99%). The iodo- and hydroxylactone enantiomers were subjected to cytotoxic activity evaluation on canine leukemia and lymphoma cell lines. The iodolactones exhibited higher biological potential towards tested cell lines than hydroxylactones. Higher cytotoxic potential was also characteristic for (+)-(4S,5S,6R)-enantiomer of iodolactone compared to its antipode.

Salt mine microorganisms used for the biotransformation of chlorolactones

The aim of the project was to find new catalysts capable of chlorolactone biotransformation. Three bicyclic chlorolactones with structures possessing one or two methyl groups in their cyclohexane ring were subjected to screening biotransformation using seven bacterial strains and one fungal strain from a salt mine. Three strains of bacteria (Micrococcus luteus Pb10, Micrococcus luteus WSP45, Gordonia alkanivorans Pd25) and one fungal strain (Aspergillus sydowii KGJ10) were able to catalyse hydrolytic dehalogenation of one substrate. The classification of the strains that were effective biocatalysts was confirmed by 16S rDNA analysis. The best result (76%) was obtained using Aspergillus sydowii KGJ10. All strains catalysed hydrolytic dehalogenation without changing the conformation. The equatorial position of the chlorine atom in the substrate turned out to be warrant of the positive result of the biotransformation process.

Regio- and enantioselective microbial hydroxylation and evaluation of cytotoxic activity of β-cyclocitral-derived halolactones

Three β-cyclocitral-derived halolactones, which exhibit antifeedant activity towards storage product pests, were subjected to microbial transformation processes. Among the thirty tested strains of filamentous fungi and yeast, the most effective biocatalysts were Absidia cylindrospora AM336, Mortierella isabellina AM212 and Mortierella vinaceae AM149. As a result of regio- and enantioselective hydroxylation four new oxygenated derivatives were obtained. Regardless of the biocatalyst applied, the δ-iodo- and δ-bromo-γ-lactones were hydroxylated in an inactivated position C-5 of cyclohexane ring. The analogous transformation of chlorolactone was observed in Mortierella isabellina AM212 culture but in the case of two other biocatalysts the hydroxy group was introduced at C-3 position. All obtained hydroxylactones were enantiomerically pure (ee = 100%) or enriched (ee = 50%). The highest enantioselectivity of hydroxylation was observed for M. isabellina AM212. The cytotoxic activity of halolactones was also examined by WST-1 assay wherein tested compounds did not exhibit significant effect on the viability of tumor HeLa and normal CHO-K1 cells.

Influence of structure of lactones with the methylcyclohexene and dimethylcyclohexene ring on their biotransformation and antimicrobial activity

The aim of this article is influence of the structure of lactones with the methylcyclohexene and dimethylcyclohexene ring on their biotransformation and antimicrobial activity. This work was based on the general remark that even the smallest change in the structure of a compound can affect its biological properties. The results of the biotransformation of four bicyclic unsaturated lactones with one or two methyl groups in the cyclohexene ring was tested using fifteen fungal strains (Fusarium species, Penicillium species, Absidia species, Cunninghamella japonica, and Pleurotus ostreatus) and five yeast strains (Yarrowia lipolytica, Rhodorula marina, Rhodorula rubra, Candida viswanathii, and Saccharomyces cerevisiae). During these transformations, new epoxylactone and hydroxylactone were obtained. The relationship between the substrate structure and the ability of the microorganisms to transform them were analysed. Only compounds with C-O bond of lactone ring in the equatorial position were transformed by fungus. All presented here lactones were examined also for their antimicrobial activity. It turned out that these compounds exhibited growth inhibition of bacteria and fungi, mainly Bacillus subtilis, Candida albicans, Aspergillus niger, and Penicillium expansum.

Dehalogenation Activity of Selected Fungi Toward δ-Iodo-γ-Lactone Derived from trans,trans-Farnesol

Time-course of biotransformation of racemic trans-4-((E)-4',8'-dimethylnona-3',7'-dien-1-yl)-5-iodomethyl-4-methyldihydrofuran-2-one (1) in fungal and yeast cultures was investigated. In these conditions, the substrate 1 was enantioselectively dehalogenated yielding 4-((E)-4',8'-dimethylnona-3',7'-dien-1-yl)-4-methyl-5-methylenedihydrofuran-2-one (2) and its structure was established based on the spectroscopic data. The most effective biocatalyst used was Didymosphaeria igniaria, which catalyzed the process with highest rate and enantioselectivity (ee of product = 76%). The antiproliferative activity of δ-iodo-γ-lactone 1, product of its biotransformation 2, and starting substrate (farnesol) were evaluated toward two cancer cell lines: A549 (human lung adenocarcinoma) and HL-60 (human promyelocytic leukemia).

Lactones with methylcyclohexane systems obtained by chemical and microbiological methods and their antimicrobial activity

Eight new lactones (δ-chloro-, δ-bromo- and δ-iodo-γ-lactones), each with a methylcyclohexane ring, were obtained by chemical means from (4-methylcyclohex-2-en-1-yl) acetic acid or (6-methylcyclohex-2-en-1-yl) acetic acid. Whole cells of ten fungal strains (Fusarium species, Syncephalastrum racemosum and Botrytis cinerea) were tested on their ability to convert these lactones into other products. Some of the tested fungal strains transformed chloro-, bromo- and iodolactone with a methyl group at C-5 into 2-hydroxy-5-methyl-9-oxabicyclo[4.3.0]nonan-8-one during hydrolytic dehalogenation. When the same lactones had the methyl group at C-3, no structural modifications of halolactones were observed. In most cases, the optical purity of the product was low or medium, with the highest rate for chlorolactone (45.4%) and iodolactone (45.2% and 47.6%). All of the obtained compounds were tested with reference to their smell. Seven halolactones and the hydroxylactone obtained via biotransformation of halolactones with 5-methylcyclohexane ring were examined for their antimicrobial activity. These compounds were capable of inhibiting growth of some bacteria, yeasts and fungi.

Microbial transformations of halolactones with p-menthane system

Biologically active piperitone-derived racemic iodo-, bromo- and chlorolactones (1-3) were transformed with the use of microbial enzymatic systems. Four strains of filamentous fungi Absidia glauca AM254, Absidia cylindrospora AM336, Mortierella vinaceae AM149 and Nigrospora oryzae AM8 transformed halolactones (1-3) to four new halohydroxylactones (4-7). In all biotransformations the hydroxy group was incorporated in inactivated methine carbon atom at isopropyl substituent. In N. oryzae AM8 culture the bromolactone with additional hydroxy group in α-position, relative to CO bond in γ-lactone ring, was also formed as a product. The structures of new compounds were established on the basis of spectral data.

The family structure of the Mucorales: a synoptic revision based on comprehensive multigene-genealogies

The Mucorales (Mucoromycotina) are one of the most ancient groups of fungi comprising ubiquitous, mostly saprotrophic organisms. The first comprehensive molecular studies 11 yr ago revealed the traditional classification scheme, mainly based on morphology, as highly artificial. Since then only single clades have been investigated in detail but a robust classification of the higher levels based on DNA data has not been published yet. Therefore we provide a classification based on a phylogenetic analysis of four molecular markers including the large and the small subunit of the ribosomal DNA, the partial actin gene and the partial gene for the translation elongation factor 1-alpha. The dataset comprises 201 isolates in 103 species and represents about one half of the currently accepted species in this order. Previous family concepts are reviewed and the family structure inferred from the multilocus phylogeny is introduced and discussed. Main differences between the current classification and preceding concepts affects the existing families Lichtheimiaceae and Cunninghamellaceae, as well as the genera Backusella and Lentamyces which recently obtained the status of families along with the Rhizopodaceae comprising Rhizopus, Sporodiniella and Syzygites. Compensatory base change analyses in the Lichtheimiaceae confirmed the lower level classification of Lichtheimia and Rhizomucor while genera such as Circinella or Syncephalastrum completely lacked compensatory base changes.

Fungal strains as catalysts for the biotransformation of halolactones by hydrolytic dehalogenation with the dimethylcyclohexane system

Bicyclic chloro-, bromo- and iodo-γ-lactones with dimethylcyclohexane rings were used as substrates for bioconversion by several fungal strains (Fusarium, Botrytis and Beauveria). Most of the selected microorganisms transformed these lactones by hydrolytic dehalogenation into the new compound cis-2-hydroxy-4,6-dimethyl-9-oxabicyclo[4.3.0]- nonan-8-one, mainly the (−)-isomer. When iodo-γ-lactone was used as the substrate, two products were observed: a hydroxy-γ-lactone and an unsaturated lactone. The structures of all substrates and products were established on the basis of their spectral data. The mechanism of dehalogenation of three halolactones was also studied.