Biotransformation of flurbiprofen by Cunninghamella species

What are the 100 most cited fungal genera?

The global diversity of fungi has been estimated between 2 to 11 million species, of which only about 155 000 have been named. Most fungi are invisible to the unaided eye, but they represent a major component of biodiversity on our planet, and play essential ecological roles, supporting life as we know it. Although approximately 20 000 fungal genera are presently recognised, the ecology of most remains undetermined. Despite all this diversity, the mycological community actively researches some fungal genera more commonly than others. This poses an interesting question: why have some fungal genera impacted mycology and related fields more than others? To address this issue, we conducted a bibliometric analysis to identify the top 100 most cited fungal genera. A thorough database search of the Web of Science, Google Scholar, and PubMed was performed to establish which genera are most cited. The most cited 10 genera are Saccharomyces, Candida, Aspergillus, Fusarium, Penicillium, Trichoderma, Botrytis, Pichia, Cryptococcus and Alternaria. Case studies are presented for the 100 most cited genera with general background, notes on their ecology and economic significance and important research advances. This paper provides a historic overview of scientific research of these genera and the prospect for further research. Citation: Bhunjun CS, Chen YJ, Phukhamsakda C, Boekhout T, Groenewald JZ, McKenzie EHC, Francisco EC, Frisvad JC, Groenewald M, Hurdeal VG, Luangsa-ard J, Perrone G, Visagie CM, Bai FY, Błaszkowski J, Braun U, de Souza FA, de Queiroz MB, Dutta AK, Gonkhom D, Goto BT, Guarnaccia V, Hagen F, Houbraken J, Lachance MA, Li JJ, Luo KY, Magurno F, Mongkolsamrit S, Robert V, Roy N, Tibpromma S, Wanasinghe DN, Wang DQ, Wei DP, Zhao CL, Aiphuk W, Ajayi-Oyetunde O, Arantes TD, Araujo JC, Begerow D, Bakhshi M, Barbosa RN, Behrens FH, Bensch K, Bezerra JDP, Bilański P, Bradley CA, Bubner B, Burgess TI, Buyck B, Čadež N, Cai L, Calaça FJS, Campbell LJ, Chaverri P, Chen YY, Chethana KWT, Coetzee B, Costa MM, Chen Q, Custódio FA, Dai YC, Damm U, de Azevedo Santiago ALCM, De Miccolis Angelini RM, Dijksterhuis J, Dissanayake AJ, Doilom M, Dong W, Alvarez-Duarte E, Fischer M, Gajanayake AJ, Gené J, Gomdola D, Gomes AAM, Hausner G, He MQ, Hou L, Iturrieta-González I, Jami F, Jankowiak R, Jayawardena RS, Kandemir H, Kiss L, Kobmoo N, Kowalski T, Landi L, Lin CG, Liu JK, Liu XB, Loizides M, Luangharn T, Maharachchikumbura SSN, Makhathini Mkhwanazi GJ, Manawasinghe IS, Marin-Felix Y, McTaggart AR, Moreau PA, Morozova OV, Mostert L, Osiewacz HD, Pem D, Phookamsak R, Pollastro S, Pordel A, Poyntner C, Phillips AJL, Phonemany M, Promputtha I, Rathnayaka AR, Rodrigues AM, Romanazzi G, Rothmann L, Salgado-Salazar C, Sandoval-Denis M, Saupe SJ, Scholler M, Scott P, Shivas RG, Silar P, Souza-Motta CM, Silva-Filho AGS, Spies CFJ, Stchigel AM, Sterflinger K, Summerbell RC, Svetasheva TY, Takamatsu S, Theelen B, Theodoro RC, Thines M, Thongklang N, Torres R, Turchetti B, van den Brule T, Wang XW, Wartchow F, Welti S, Wijesinghe SN, Wu F, Xu R, Yang ZL, Yilmaz N, Yurkov A, Zhao L, Zhao RL, Zhou N, Hyde KD, Crous PW (2024). What are the 100 most cited fungal genera? Studies in Mycology 108: 1-411. doi: 10.3114/sim.2024.108.01.

Dissecting the genome sequence of a clinical isolated Cunninghamella bertholletiae Z2 strain with rich cytochrome P450 enzymes (Article)

Mucormycosis is receiving much more attention because of its high morbidity and extremely high mortality rate in immunosuppressed populations. In this study, we isolated a Cunnignhamella bertholletiae Z2 strain from a skin lesion of a 14 year, 9 months old girl with acute lymphoblastic leukemia who die of infection from the Z2 strain. Genome sequencing was performed after isolation and amplification of the Z2 strain to reveal potential virulence factors and pathogenic mechanisms. The results showed that the genome size of the Z2 strain is 30.9 Mb with 9213 genes. Mucoral specific virulence factor genes found are ARF, CalN, and CoTH, while no gliotoxin biosynthesis gene cluster was found, which is a known virulence factor in Aspergillus fumigatus adapted to the environment. The Z2 strain was found to have 69 cytochrome P450 enzymes, which are potential drug resistant targets. Sensitivity testing of Z2 showed it was only inhibited by amphotericin B and posaconazole. Detailed genomic information of the C. bertholletiae Z2 strain may provide useful data for treatment.

Biotransformation of fluorinated drugs and xenobiotics by the model fungus Cunninghamella elegans

Some species of the genus Cunninghamella (C. elegans, C. echinulata and C. blaskesleeana) produce the same phase I and phase II metabolites when incubated with xenobiotics as mammals, and thus are considered microbial models of mammalian metabolism. This had made these fungi attractive for metabolism studies with drugs, pesticides and environmental pollutants. As a substantial proportion of pharmaceuticals and agrochemicals are fluorinated, their biotransformation has been studied in Cunninghamella fungi and C. elegans in particular. This article details the methods employed for cultivating the fungi in planktonic and biofilm cultures, and extraction and analysis of fluorinated metabolites. Furthermore, protocols for the heterologous expression of Cunninghamella cytochromes P450 (CYPs), which are the enzymes associated with phase I metabolism, are described.

Mass Spectrometry Applications to Study Human Microbiome

Microbiotas are an adaptable component of ecosystems, including human ecology. Microorganisms influence the chemistry of their specialized niche, such as the human gut, as well as the chemistry of distant surroundings, such as other areas of the body. Metabolomics based on mass spectrometry (MS) is one of the primary methods for detecting and identifying small compounds generated by the human microbiota, as well as understanding the functional significance of these microbial metabolites. This book chapter gives basic knowledge on the kinds of untargeted mass spectrometry as well as the data types that may be generated in the context of microbiome study. While data analysis remains a barrier, the emphasis is on data analysis methodologies and integrative analysis, particularly the integration of microbiome sequencing data. Mass spectrometry (MS)-based techniques have resurrected culture methods for studying the human gut microbiota, filling in the gaps left by high-throughput sequencing methods in terms of culturing minor populations.

Metabolism of natural and synthetic bioactive compounds in Cunninghamella fungi and their applications in drug discovery

Investigation of xenobiotic metabolism is a key step for drug discovery. Since the in vivo investigations may be associated with harmful effects attributed to production of toxic metabolites, it is deemed necessary to predict their structure especially at the preliminary clinical studies. Furthermore, the application of microorganisms that are capable of metabolizing drugs mimic human metabolism and consequently may predict possible metabolites. The genus Cunninghamella has been proven to be a potential candidate, which mimics xenobiotic metabolism occurring inside the human body, including phase I and II metabolic reactions. Moreover, biotransformation with Cunninghamella showed chemical diversity, where a lot of products were detected in relation to the initial substrates after being modified by oxidation, hydroxylation, and conjugation reactions. Some of these products are more bioactive than the parent compounds. The current review presents a comprehensive literature overview regarding the Cunninghamella organisms as biocatalysts, which simulate mammalian metabolism of natural secondary and synthetic compounds.

Fluorotelomer alcohols are efficiently biotransformed by Cunninghamella elegans

Cunninghamella elegans is a well-studied fungus that biotransforms a range of xenobiotics owing to impressive cytochrome P450 (CYP) activity. In this paper, we report the biotransformation of 6:2 fluorotelomer alcohol (6:2 FTOH) by the fungus, yielding a range of fluorinated products that were detectable by fluorine-19 nuclear magnetic resonance spectroscopy (¹⁹F NMR), gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). Upon incubation with the pre-grown cultures, the substrate (100 mg/L) was completely consumed within 48 h, which is faster biotransformation than other fungi that have hitherto been studied. The main metabolite formed was the 5:3 fluorotelomer carboxylic acid (5:3 FTCA), which accumulated in the culture supernatant. When the cytochrome P450 inhibitor 1-aminobenzotriazole was included in the culture flasks, there was no biotransformation of 6:2 FTOH, indicating that these enzymes are key to the catalysis. Furthermore, when exogenous 5:3 FTCA was added to the fungus, the standard biotransformation of the drug flurbiprofen was inhibited, strongly suggesting that the main fluorotelomer alcohol biotransformation product inhibits CYP activity and accounts for its accumulation.

Biosynthesis using cytochrome P450 enzymes: Focus on synthesis of drug metabolites

While modern synthetic chemistry provides the ability to synthesize an incredible variety of new structures, the natural world provides unmatched chemical diversity. This diversity can be employed in the drug discovery process either through isolation of an organic molecule from a biological source as a drug candidate, usually referred to as natural product chemistry, or by providing enzymes that are capable to performing chemistry not available through synthetic chemistry approaches. Natural or engineered enzymes can be used in candidate discovery to generate chemical diversity in conjunction with synthetic efforts. As a candidate progresses into develop there is often a need to characterize metabolites, thus a need for metabolite standard synthesis. Metabolite synthesis is best accomplished with a flexible application of both chemical and biosynthetic approaches. This overview of the use of biosynthesis to aid in the drug discovery and development process will cover multiple methodologies with a focus on the use of microbes as a flexible and cost-effective resource.

Human Gut Microbiota and Drug Metabolism

The efficacy of drugs widely varies in individuals, and the gut microbiota plays an important role in this variability. The commensal microbiota living in the human gut encodes several enzymes that chemically modify systemic and orally administered drugs, and such modifications can lead to activation, inactivation, toxification, altered stability, poor bioavailability, and rapid excretion. Our knowledge of the role of the human gut microbiome in therapeutic outcomes continues to evolve. Recent studies suggest the existence of complex interactions between microbial functions and therapeutic drugs across the human body. Therapeutic drugs or xenobiotics can influence the composition of the gut microbiome and the microbial encoded functions. Both these deviations can alter the chemical transformations of the drugs and hence treatment outcomes. In this review, we provide an overview of (i) the genetic ecology of microbially encoded functions linked with xenobiotic degradation; (ii) the effect of drugs on the composition and function of the gut microbiome; and (iii) the importance of the gut microbiota in drug metabolism.

Oxidative biotransformation of stemofoline alkaloids

Biotransformations of stemofoline (1a), (2'S)-hydroxystemofoline (2a), (11Z)-1',2'-didehydrostemofoline (3a) and stemocurtisine (4) were studied through fermentation with Cunninghamella elegans TISTR 3370. Three new stemofoline derivatives; 6 R-hydroxystemofoline (1b), (2'S, 6 R)-dihydroxystemofoline (2b) and (11Z,6R)-1',2'-didehydro-6-hydroxystemofoline (3b), together with the known compound 1',2'-didehydrostemofoline-N-oxide (3c), were produced by C-hydroxylation and N-oxidation reactions. Stemocurtisine was not biotransformed under these conditions. The transformed product 1b was four times more potent (IC50 = 11.01 ± 1.49 µM) than its precursor 1a (IC50 = 45.1 ± 5.46 µM) as an inhibitor against acetylcholinesterase.

Cunninghamella spp. produce mammalian-equivalent metabolites from fluorinated pyrethroid pesticides

Cunninghamella spp. are fungi that are routinely used to model the metabolism of drugs. In this paper we demonstrate that they can be employed to generate mammalian-equivalent metabolites of the pyrethroid pesticides transfluthrin and β-cyfluthrin, both of which are fluorinated. The pesticides were incubated with grown cultures of Cunninghamella elegans, C. blakesleeana and C. echinulata and the biotransformation monitored using fluorine-19 nuclear magnetic resonance spectroscopy. Transfluthrin was initially absorbed in the biomass, but after 72 h a new fluorometabolite appeared in the supernatant; although all three species yielded this compound, it was most prominent in C. blakesleeana. In contrast β-cyfluthrin mostly remained in the fungal biomasss and only minor biotransformation was observed. Gas chromatography-mass spectrometry (GC-MS) analysis of culture supernatant extracts revealed the identity of the fluorinated metabolite of transfluthrin to be tetrafluorobenzyl alcohol, which arose from the cytochrome P450-catalysed cleavage of the ester bond in the pesticide. The other product of this hydrolysis, dichlorovinyl-2,2-dimethylcyclopropane carboxylic acid, was also detected by GC-MS and was a product of β-cyfluthrin metabolism too. Upon incubation with rat liver microsomes the same products were detected, demonstrating that the fungi can be used as models of mammalian metabolism of fluorinated pesticides.

Regulation of Cunninghamella spp. biofilm growth by tryptophol and tyrosol

Fungi belonging to the genus Cunninghamella are often used as microbial models of mammalian metabolism owing to their ability to transform a range of xenobiotic compounds. Furthermore, under specific growth conditions species such as Cunninghamellaelegans and Cunninghamellaechinulata grow as biofilms enabling a convenient semi-continuous production of valuable drug metabolites. However, the molecular mechanism of biofilm regulation is not understood, thus controlling biofilm thickness limits the productive applications of it. In this paper we describe the identification of two molecules, tyrosol and tryptophol, that were identified in C. blakesleeana cultures, but not in C. elegans and C. echinulata. The molecules are known quorum sensing molecules (QSMs) in yeast and their potential role in Cunninghamella biofilm regulation was explored. Both were present in higher concentrations in C. blakesleeana planktonic cultures compared with biofilms; they inhibited the growth of the fungus on agar plates and selectively inhibited biofilm growth in liquid cultures. The molecules had a comparatively minor impact on the biofilm growth of C. elegans and C. echinulata and on the growth of these fungi on agar plates. Finally, when exogenous tyrosol or tryptophol was added to previously grown C. blakesleeana biofilm, detachment was visible and new additional planktonic culture was measured, confirming that these molecules specifically regulate biofilm growth in this fungus.

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Tyrosol and tryptophol were identified in culture supernatants of Cunninghamella blakesleeana.

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Concentrations of the compounds were substantially higher in planktonic cultures compared with biofilms.

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Bioassays revealed that tyrosol and tryptophol inhibited growth of C. blakesleeana on agar plates.

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Biofilm growth was inhibited by exogenous addition of the compounds whereas planktonic growth was unaffected.

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The compounds caused detachment of previously grown biofilms.

19F NMR as a tool in chemical biology

We previously reviewed the use of 19F NMR in the broad field of chemical biology [Cobb, S. L.; Murphy, C. D. J. Fluorine Chem. 2009, 130, 132-140] and present here a summary of the literature from the last decade that has the technique as the central method of analysis. The topics covered include the synthesis of new fluorinated probes and their incorporation into macromolecules, the application of 19F NMR to monitor protein-protein interactions, protein-ligand interactions, physiologically relevant ions and in the structural analysis of proteins and nucleic acids. The continued relevance of the technique to investigate biosynthesis and biodegradation of fluorinated organic compounds is also described.

3-Hydroxytyrosol regulates biofilm growth in Cunninghamella elegans

In contrast to yeast biofilms, those of filamentous fungi are relatively poorly understood, in particular with respect to their regulation. Cunninghamella elegans is a filamentous fungus that is of biotechnological interest as it catabolises drugs and other xenobiotics in an analogous manner to animals; furthermore, it can grow as a biofilm enabling repeated batch biotransformations. Precisely how the fungus switches from planktonic to biofilm growth is unknown and the aim of this study was to shed light on the possible mechanism of biofilm regulation. In dimorphic yeasts, alcohols such as tyrosol and 2-phenylethanol are known to control the yeast-to-hypha switch, and a similar molecule might be involved in regulating biofilm in C. elegans. Gas chromatography-mass spectrometry analysis of crude ethyl acetate extracts from supernatants of 72 h planktonic and biofilm cultures revealed 3-hydroxytyrosol as a prominent metabolite. Further quantification revealed that the amounts of the compound in planktonic cultures were substantially higher (>10-fold) than in biofilm cultures. In the presence of exogenous 3-hydroxytyrosol the growth of aerial mycelium was inhibited, and there was selective inhibition of biofilm when it was added to culture medium. There was no biotransformation of the compound when it was added to 72 h-old cultures, in contrast to the related compounds tyrosol and 2-phenylethanol, which were oxidised to a number of products. Therefore, we propose that 3-hydroxytyrosol is a new signalling molecule in fungi, which regulates biofilm growth.

Siderophore piracy enhances Vibrio cholerae environmental survival and pathogenesis

Vibrio cholerae, the aetiological agent of cholera, possesses multiple iron acquisition systems, including those for the transport of siderophores. How these systems benefit V. cholerae in low-iron, polymicrobial communities in environmental settings or during infection remains poorly understood. Here, we demonstrate that in iron-limiting conditions, co-culture of V. cholerae with a number of individual siderophore-producing microbes significantly promoted V. cholerae growth in vitro. We further show that in the host environment with low iron, V. cholerae colonizes better in adult mice in the presence of the siderophore-producing commensal Escherichia coli. Taken together, our results suggest that in aquatic reservoirs or during infection, V. cholerae may overcome environmental and host iron restriction by hijacking siderophores from other microbes.

Metabolism of insecticide diazinon by Cunninghamella elegans ATCC36112

The fungal metabolism of diazinon was investigated and the microbial model (Cunninghamella elegans ATCC36112) could effectively degrade the organophosphorus pesticide (diazinon) mediated by cytochrome P450, which was mainly involved in oxidation and hydrolysis of phase I metabolism. Approximately 89% of diazinon was removed within 7 days and was not observed after 13 days with concomitant accumulation of eight metabolites. Structures of the metabolites were fully or tentatively identified with GC-MS and 1H, 13C NMR. The major metabolites of diazinon were diethyl (2-isopropyl-6-methylpyrimidin-4-yl) phosphate (diazoxon) and 2-isopropyl-6-methyl-4-pyrimidinol (pyrimidinol), and formation of minor metabolites was primarily the result of hydroxylation. To determine the responsible enzymes in diazinon metabolism, piperonyl butoxide and methimazole were treated, and the kinetic responses of diazinon and its metabolites by Cunninghamella elegans were measured. Results indirectly demonstrated that cytochrome P450 and flavin monooxygenase were involved in the metabolism of diazinon, but methimazole inhibited the metabolism less effectively. Based on the metabolic profiling, a possible metabolic pathway involved in phase I metabolism of diazinon was proposed, which would contribute to providing insight into understanding the toxicological effects of diazinon and the potential application of fungi on organophosphorus pesticides.

NSAID-Gut Microbiota Interactions

Nonsteroidal anti-inflammatory drugs (NSAID)s relieve pain, inflammation, and fever by inhibiting the activity of cyclooxygenase isozymes (COX-1 and COX-2). Despite their clinical efficacy, NSAIDs can cause gastrointestinal (GI) and cardiovascular (CV) complications. Moreover, NSAID use is characterized by a remarkable individual variability in the extent of COX isozyme inhibition, therapeutic efficacy, and incidence of adverse effects. The interaction between the gut microbiota and host has emerged as a key player in modulating host physiology, gut microbiota-related disorders, and metabolism of xenobiotics. Indeed, host-gut microbiota dynamic interactions influence NSAID disposition, therapeutic efficacy, and toxicity. The gut microbiota can directly cause chemical modifications of the NSAID or can indirectly influence its absorption or metabolism by regulating host metabolic enzymes or processes, which may have consequences for drug pharmacokinetic and pharmacodynamic properties. NSAID itself can directly impact the composition and function of the gut microbiota or indirectly alter the physiological properties or functions of the host which may, in turn, precipitate in dysbiosis. Thus, the complex interconnectedness between host-gut microbiota and drug may contribute to the variability in NSAID response and ultimately influence the outcome of NSAID therapy. Herein, we review the interplay between host-gut microbiota and NSAID and its consequences for both drug efficacy and toxicity, mainly in the GI tract. In addition, we highlight progress towards microbiota-based intervention to reduce NSAID-induced enteropathy.

The CYPome of the model xenobiotic-biotransforming fungus Cunninghamella elegans

The fungus Cunninghamella elegans is recognised as a microbial model of mammalian drug metabolism owing to its ability to catabolise xenobiotic compounds in an analogous fashion to animals. Its ability to produce phase I (oxidative) metabolites of drugs is associated with cytochrome P450 (CYP) activity; however, almost nothing is known about these enzymes in the fungus. In this paper we report the in silico analysis of the genome sequence of C. elegans B9769, which contains 32 genes putatively coding for CYPs. Based on their predicted amino acid sequences these were classified as belonging to CYP509, 5203, 5208, 5313, 5210, 61 and 51 families. Reverse transcription-quantitative PCR revealed that the gene coding for CYP5313D1 was significantly upregulated when C. elegans DSM1908 was cultivated in sabouraud dextrose in contrast to its expression in cells grown in Roswell Park Memorial Institute medium. This corresponded to the fungus' xenobiotic biotransformation ability when grown in the two media. Heterologous expression of cyp5313D1 in Pichia pastoris resulted in a recombinant strain that biotransformed flurbiprofen to 4'-hydroxyflurbiprofen, the same metabolite generated by C. elegans cultures. This is the first report of a xenobiotic-biotransforming CYP from this biotechnologically important fungus.

A Microbial Transformation Model for Simulating Mammal Metabolism of Artemisinin

Artemisinin (ART) is a highly effective antimalarial agent isolated from the traditional Chinese herb Qinghao. Metabolism of ART and its derivatives in the body is one of the most pressing issues for pharmaceutical scientists. Herein, an efficient in vitro microorganism model for simulation of metabolism of ART in vivo was developed employing Cunninghamella elegans. Metabolites in the microbial transformation system and plasma of mice pre-administrated ART orally were analyzed by ultra-performance liquid chromatography (UPLC)-electrospray ionization (ESI)-quadrupole time-of-flight (Q-TOF)-mass spectrometry (MS^E) combined with UNIFI software. Thirty-two metabolites were identified in vitro and 23 were identified in vivo. After comparison, 16 products were found to be common to both models including monohydroxylated ART, dihydroxylated ART, deoxyartemisinin, hydroxylated deoxyartemisinin, hydroxylated dihydroartemisinin (DHA), and hydroxylated deoxy-DHA. These results revealed that C. elegans CICC 40250 functioned as an appropriate model to mimic ART metabolism in vivo. Moreover, an overall description of metabolites of ART from C. elegans CICC 40250 has been provided. Notably, DHA was detected and identified as a metabolite of ART in mouse plasma for the first time.

Cyhalothrin biodegradation in Cunninghamella elegans

The insecticide λ-cyhalothrin was incubated with planktonic and biofilm cultures of the fungus Cunninghamella elegans. ¹⁹F nuclear magnetic resonance spectroscopy demonstrated that the compound was initially biosorbed to the biomass and more slowly degraded by the fungus. Furthermore, the presence of trifluoromethyl-containing metabolites was observed. Analysis of culture extracts by gas chromatography-mass spectrometry (GC-MS) identified non-fluorinated metabolites that suggested the likely catabolic pathway. The hydroxylated metabolites were probably generated from the action of cytochromes P450 (CYPs), as the presence of CYP inhibitors resulted in the absence of biodegradation. Planktonic cells were measurably faster at degrading the pesticide compared with biofilm.

Biotransformation of 4-fluoro-N-(1-{2-[(propan-2-yl)phenoxy]ethyl}-8-azabicyclo[3.2.1]octan-3-yl)-benzenesulfonamide, a novel potent 5-HT7 receptor antagonist with antidepressant-like and anxiolytic properties: In vitro and in silico approach

The aim of the study was to investigate the metabolism of 4-fluoro-N-(1-{2-[(propan-2-yl)phenoxy]ethyl}-8-azabicyclo[3.2.1]octan-3-yl)-benzenesulfonamide (PZ-1150), a novel 5-HT₇ receptor antagonist with antidepressant-like and anxiolytic properties, by the following three ways: in vitro with microsomes; in vitro employing Cunninghamella echinulata, and in silico using MetaSite. Biotransformation of PZ-1150 with microsomes resulted in five metabolites, while transformation with C. echinulata afforded two metabolites. In both models, the predominant metabolite occurred due to hydroxylation of benzene ring. In silico data coincide with in vitro experiments, as three MetaSite metabolites matched compounds identified in microsomal samples. In human liver microsomes PZ-1150 exhibited in vitro half-life of 64 min, with microsomal intrinsic clearance of 54.1 μL/min/mg and intrinsic clearance of 48.7 mL/min/kg. Therefore, PZ-1150 is predicted to be a high-clearance agent. The study demonstrated the applicability of using microsomal model coupled with microbial model to elucidate the metabolic pathways of compounds and comparison with in silico metabolite predictions.

In Vitro Biotransformation, Safety, and Chemopreventive Action of Novel 8-Methoxy-Purine-2,6-Dione Derivatives

Metabolic stability, mutagenicity, antimutagenicity, and the ability to scavenge free radicals of four novel 8-methoxy-purine-2,6-dione derivatives (compounds 1–4) demonstrating analgesic and anti-inflammatory properties were determined. Metabolic stability was evaluated in Cunninghamella and microsomal models, mutagenic and antimutagenic properties were assessed using the Ames and the Vibrio harveyi tests, and free radical scavenging activity was evaluated with 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. In the Cunninghamella model, compound 2 did not undergo any biotransformation; whereas 3 and 4 showed less metabolic stability: 1–9 and 53–88% of the parental compound, respectively, underwent biotransformation reactions in different Cunninghamella strains. The metabolites detected after the biotransformation of 3 and 4 were aromatic hydroxylation and N-dealkylation products. On the other hand, the N-dealkylation product was the only metabolite formed in microsome assay. Additionally, these derivatives do not possess mutagenic potential in microbiological models (Vibrio harveyi and Salmonella typhimurium) considered. Moreover, all compounds showed a strong chemopreventive activity in the modified Vibrio harveyi strains BB7X and BB7M. However, radical scavenging activity was not the mechanism which explained the observed chemopreventive activity.

Biotransformation of fluorophenyl pyridine carboxylic acids by the model fungus Cunninghamella elegans

1. Fluorine plays a key role in the design of new drugs and recent FDA approvals included two fluorinated drugs, tedizolid phosphate and vorapaxar, both of which contain the fluorophenyl pyridyl moiety. 2. To investigate the likely phase-I (oxidative) metabolic fate of this group, various fluorinated phenyl pyridine carboxylic acids were incubated with the fungus Cunninghamella elegans, which is an established model of mammalian drug metabolism. 3. ¹⁹F NMR spectroscopy established the degree of biotransformation, which varied depending on the position of fluorine substitution, and gas chromatography-mass spectrometry (GC-MS) identified alcohols and hydroxylated carboxylic acids as metabolites. The hydroxylated metabolites were further structurally characterised by nuclear magnetic resonance spectroscopy (NMR), which demonstrated that hydroxylation occurred on the 4' position; fluorine in that position blocked the hydroxylation. 4. The fluorophenyl pyridine carboxylic acids were not biotransformed by rat liver microsomes and this was a consequence of inhibitory action, and thus, the fungal model was crucial in obtaining metabolites to establish the mechanism of catabolism.

Microbial degradation of fluorinated drugs: biochemical pathways, impacts on the environment and potential applications

Since the discovery over 60 years ago of fluorocortisone's biological properties (9-α-Fluoro derivatives of cortisone and hydrocortisone; Fried J and Sabo EF, J Am Chem Soc 76: 1455-1456, 1954), the number of fluorinated drugs has steadily increased. With the improvement in synthetic methodologies, this trend is likely to continue and will lead to the introduction of new fluorinated substituents into pharmaceutical compounds. Although the biotransformation of organofluorine compounds by microorganisms has been well studied, specific investigations on fluorinated drugs are relatively few, despite the increase in the number and variety of fluorinated drugs that are available. The strength of the carbon-fluorine bond conveys stability to fluorinated drugs; thus, they are likely to be recalcitrant in the environment or may be partially metabolized to a more toxic metabolite. This review examines the research done on microbial biotransformation and biodegradation of fluorinated drugs and highlights the importance of understanding how microorganisms interact with this class of compound from environmental, clinical and biotechnological perspectives.

Production of drug metabolites by immobilised Cunninghamella elegans: from screening to scale up

Cunninghamella elegans is a fungus that has been used extensively as a microbial model of mammalian drug metabolism, whilst its potential as a biocatalyst for the preparative production of human drug metabolites has been often proposed, little effort has been made to enable this. Here, we describe a workflow for the application of C. elegans for the production of drug metabolites, starting from well-plate screening assays leading to the preparative production of drug metabolites using fungus immobilised either in alginate or as a biofilm. Using 12- and 96-well plates, the simultaneous screening of several drug biotransformations was achieved. To scale up the biotransformation, both modes of immobilisation enabled semi-continuous production of hydroxylated drug metabolites through repeated addition of drug and rejuvenation of the fungus. It was possible to improve the productivity in the biofilm culture for the production of 4'-hydroxydiclofenac from 1 mg/l h to over 4 mg/l h by reducing the incubation time for biotransformation and the number of rejuvenation steps.

The microbial cell factory

Microorganisms have been used for decades as sources of antibiotics, vitamins and enzymes and for the production of fermented foods and chemicals. In the 21st century microorganisms will play a vital role in addressing some of the problems faced by mankind. In this article three of the current applications in which microbes have a significant role to play are highlighted: the discovery of new antibiotics, manufacture of biofuels and bioplastics, and production of fine chemicals via biotransformation.

Production of human metabolites of the anti-cancer drug flutamide via biotransformation in Cunninghamella species

Fungi belonging to the genus Cunninghamella have enzymes similar to those employed by mammals for the detoxification of xenobiotics, thus they are useful as models of mammalian drug metabolism, and as a source for drug metabolites. We report the transformation of the anti-cancer drug flutamide in Cunninghamella sp. The most predominant phase I metabolites present in the plasma of humans, 2-hydroxyflutamide and 4-nitro-3-(trifluoromethyl)aniline, were also produced in Cunninghamella cultures. Other phase I and phase II metabolites were also detected using a combination of HPLC, GC-MS and (19)F-NMR.