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Ji Q, Xiang H, Wang WG, Matsuda Y. Mechanism Behind the Programmed Biosynthesis of Heterotrimeric Fungal Depside Thielavin A. Angew Chem Int Ed Engl 2024; 63:e202402663. [PMID: 38467568 DOI: 10.1002/anie.202402663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 03/08/2024] [Accepted: 03/11/2024] [Indexed: 03/13/2024]
Abstract
Thielavin A (1) is a fungal depside composed of one 3-methylorsellinic acid and two 3,5-dimethylorsellinic acid units. It displays diverse biological activities. However, the mechanism underlying the assembly of the heterotrimeric structure of 1 remains to be clarified. In this study, we identified the polyketide synthase (PKS) involved in the biosynthesis of 1. This PKS, designated as ThiA, possesses an unusual domain organization with the C-methyltransferase (MT) domain situated at the C-terminus following the thioesterase (TE) domain. Our findings indicated that the TE domain is solely responsible for two rounds of ester bond formation, along with subsequent chain hydrolysis. We identified a plausible mechanism for TE-catalyzed reactions and obtained insights into how a single PKS can selectively yield a specific heterotrimeric product. In particular, the tandem acyl carrier protein domains of ThiA are critical for programmed methylation by the MT domain. Overall, this study highlighted the occurrence of highly optimized domain-domain communication within ThiA for the selective synthesis of 1, which can advance our understanding of the programming rules of fungal PKSs.
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Affiliation(s)
- Qiaolin Ji
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Hao Xiang
- Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal Endophytes, State Ethnic Affairs Commission; Key Laboratory of Chemistry in Ethnic Medicinal Resources, Ministry of Education, Yunnan Minzu University, Kunming, 650031, Yunnan, China
| | - Wei-Guang Wang
- Key Laboratory of Natural Products Synthetic Biology of Ethnic Medicinal Endophytes, State Ethnic Affairs Commission; Key Laboratory of Chemistry in Ethnic Medicinal Resources, Ministry of Education, Yunnan Minzu University, Kunming, 650031, Yunnan, China
| | - Yudai Matsuda
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
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Castañeta G, Sepulveda B, Areche C. Liquid chromatography-electrospray ionization-mass spectrometry/mass spectrometry characterization of depsides and depsidones from the Chilean lichen Parmotrema perlatum. Eur J Mass Spectrom (Chichester) 2024; 30:125-132. [PMID: 38523368 DOI: 10.1177/14690667241240477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
Lichens are recognized by their unique compounds and diverse applications in food, medicines, and cosmetics. Using ultra-high pressure liquid chromatography, coupled with a high-resolution mass spectrometer, metabolomic profiling of the lichen Parmotrema perlatum, from a methanolic extract, was performed. Based on characteristic fragmentation patterns, twenty-five lichenic substances were tentatively identified including 5 depsides, 12 depsidones, 2 diphenyl ethers, 1 aromatic considered as possible artifact, 1 dibenzofuran, 1 carbohydrate, 1 organic acid, and 2 undefined compounds. To the best of our knowledge, this is a more complete report of their phytochemistry from P perlatum. Our findings of the P perlatum profile may contribute and complement the current data of the Parmotrema genus.
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Affiliation(s)
- Grover Castañeta
- Facultad de Ciencias Puras y Naturales, Instituto de Investigaciones Químicas, Universidad Mayor de San Andrés, La Paz, Bolivia
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Beatriz Sepulveda
- Departamento de Ciencias Químicas, Universidad Andrés Bello, Campus Viña del Mar, Viña del Mar, Chile
| | - Carlos Areche
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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Ferron S, Jéhan P, Guillory X, Uriac P. Intramolecular transesterification of depsides yields fluorescent 1H-isochromen-1-ones: Application as a chemical probe for lichen determination. Phytochemistry 2022; 198:113139. [PMID: 35276218 DOI: 10.1016/j.phytochem.2022.113139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/18/2022] [Accepted: 02/19/2022] [Indexed: 06/14/2023]
Abstract
The reactivity of eight purified depsides obtained from six european lichens and that display as 2-oxoalkyl chain in ortho-position of the ester bond was explored. These depsides were found to lead to 1H-Isochromen-1-ones, which exhibit a distinctive blue fluorescence at 365 nm, in the presence of a 10% aqueous solution of KOH. A mechanistic explanation, involving the formation of an enolate intermediate and intramolecular transesterification, was proposed and validated by DFT. By exploiting this fluorescent phenomenon, we conceived a chemical probe (the KUV probe) that is useful for lichen determination, as exemplified on a selection of European Porpidia species.
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Affiliation(s)
- S Ferron
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, COrInt, F-35000, Rennes, France
| | - P Jéhan
- Univ Rennes, CNRS, ScanMat - UMS 2001, CRMPO (Centre Régional de Mesures Physiques de l'Ouest, F-35000, Rennes, France
| | - X Guillory
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, COrInt, F-35000, Rennes, France; INSERM U1242, Univ Rennes, France
| | - P Uriac
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, COrInt, F-35000, Rennes, France.
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Norouzi H, Azizi A, Gholami M, Sohrabi M, Boustie J. Chemotype variations among lichen ecotypes of Umbilicaria aprina as revealed by LC-ESI-MS/MS: a survey of antioxidant phenolics. Environ Sci Pollut Res Int 2020; 27:40296-40308. [PMID: 32661964 DOI: 10.1007/s11356-020-10053-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
In the present study, we characterized the phytochemical properties, which were specifically associated with phenolic compounds and antioxidant activities in six distinct ecotypes of Umbilicaria aprina Nyl. from Iran (including Kivarestan, Mishan, Takht-e Nader, Tochal, Sabalan, and Sahand) to detect diversities within the species. Total phenolic concentration (TPC) and radical scavenging capacities of U. aprina ecotypes were evaluated. Moreover, qualitative differences between chemical profiles were surveyed using liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Relatively moderate TPCs (Kivarestan = 36.12 ± 2.1, Mishan = 41.59 ± 2.2, Takht-e Nader = 31.85 ± 1.3, Tochal = 37.55 ± 2.3, Sabalan = 28.91 ± 2.5, and Sahand = 31.59 ± 2.2) were observed for ecotypes, but a very strong correlation (r = -0/842) was obtained between TPCs and IC50 values. Based on the results of LC-ESI-MS/MS, the following chemical substances were identified: orsellinic acid (1), lecanoric acid (2), evernic acid (3), gyrophoric acid (4), umbilicaric acid (5), hiascic acid (6), stictic acid (7) methyl hiascic acid (8), and an unknown substance (9). The MS/MS fragmentation scheme for each substance was determined and proposed. Wide discrepancies were observed in the chemical profiles of lichen ecotypes, which may corroborate the influence of ecological locality conditions, for example, altitude and slope aspects on secondary metabolism of lichen species U. aprina. The north-facing and east-facing ecotypes (Sabalan and Mishan, respectively) lacked depsidones (stictic acid) mainly because they receive the least direct radiation. Mishan ecotype, as the only east-facing ecotype, showed the most different chemical profile.
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Affiliation(s)
- Hooman Norouzi
- Department of Horticultural Sciences, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran
| | - Ali Azizi
- Department of Horticultural Sciences, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran.
| | - Mansour Gholami
- Department of Horticultural Sciences, Faculty of Agriculture, Bu-Ali Sina University, Hamedan, Iran
| | - Mohammad Sohrabi
- Department of Biotechnology, Iranian Research Organization for Science and Technology, Tehran, Iran
| | - Joel Boustie
- Institute of Chemistry of Rennes, ISCR, UMR CNRS 6226, University of Rennes 1, 2 Av. du Pr. Leon Bernard, 35043, Rennes Cedex, France
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Brahmi-Chendouh N, Piccolella S, Crescente G, Pacifico F, Boulekbache L, Hamri-Zeghichi S, Akkal S, Madani K, Pacifico S. A nutraceutical extract from Inula viscosa leaves: UHPLC-HR-MS/MS based polyphenol profile, and antioxidant and cytotoxic activities. J Food Drug Anal 2019; 27:692-702. [PMID: 31324285 PMCID: PMC9307043 DOI: 10.1016/j.jfda.2018.11.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 11/23/2018] [Accepted: 11/27/2018] [Indexed: 02/06/2023] Open
Abstract
Nowadays, advanced extraction techniques and highly sensitive metabolic profiling methods are effectively employed to get new information on plant chemical constituents. Among them wild medicinal plants or their parts, with large and ancient use in folk medicine, are investigated for their potential functional use and cultivation. In this context, Inula viscosa leaves engaged our attention. A simple experimental design, based on Soxhlet extraction and chromatographic fractionation, allowed us to obtain the investigated polyphenol fraction (IvE). UHPLC-HRMS analyses revealed shikimoyl depsides of caffeic acid and unusual dihydrobenzofuran lignans as main secondary metabolites. These compounds, together with cinchonain-type phenols, and hydroxycinnamoyl flavonol glycosides, are reported for the first time in inula. Overall, forty-three secondary metabolites were identified. The extract exerted a remarkable antiradical activity towards DPPH• and ABTS+•. Furthermore, it was able to inhibit cell viability and mitochondrial redox activity of neuroblastoma, hepatoblastoma and colon carcinoma cells, whereas it did not affect cell density of HaCaT cells immortalized human keratinocytes. As detected by the oxidant-sensing probe 2′,7′-dichlorodihydrofluorescein diacetate, the inhibitory responses seemed to be related to IvE-induced increase of intracellular reactive oxygen species (ROS). The obtained results highlighted that inula leaves, nowadays even undervalued and unexplored, could be considered a renewable source of nutraceutical compounds.
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Affiliation(s)
- Nabila Brahmi-Chendouh
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, I-81100, Caserta, Italy; Laboratory of 3BS, Faculty of Life and Nature Sciences, University of Bejaia, 06000, Bejaia, Algeria
| | - Simona Piccolella
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, I-81100, Caserta, Italy
| | - Giuseppina Crescente
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, I-81100, Caserta, Italy
| | - Francesca Pacifico
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, I-81100, Caserta, Italy
| | - Lila Boulekbache
- Laboratory of 3BS, Faculty of Life and Nature Sciences, University of Bejaia, 06000, Bejaia, Algeria
| | - Sabrina Hamri-Zeghichi
- Laboratory of 3BS, Faculty of Life and Nature Sciences, University of Bejaia, 06000, Bejaia, Algeria
| | - Salah Akkal
- Valorization of Natural Resources, Bioactive Molecules and Biological Analysis Unit, Department of Chemistry, University of Mentouri Constantine 1, 25000, Constantine, Algeria
| | - Khodir Madani
- Laboratory of 3BS, Faculty of Life and Nature Sciences, University of Bejaia, 06000, Bejaia, Algeria
| | - Severina Pacifico
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi 43, I-81100, Caserta, Italy.
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Paluszczak J, Kleszcz R, Studzińska-Sroka E, Krajka-Kuźniak V. Lichen-derived caperatic acid and physodic acid inhibit Wnt signaling in colorectal cancer cells. Mol Cell Biochem 2018; 441:109-124. [PMID: 28887754 PMCID: PMC5843697 DOI: 10.1007/s11010-017-3178-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 09/01/2017] [Indexed: 12/24/2022]
Abstract
Lichens are a source of secondary metabolites which possess important biological activities, including antioxidant, antibacterial, anti-inflammatory, and cytotoxic effects. The anticancer activity of lichens was shown in many types of tumors, including colorectal cancers (CRC). Several studies revealed that the application of lichen extracts diminished the proliferation of CRC cells and induced apoptosis. Colon carcinogenesis is associated with aberrations in Wnt signaling. Elevated transcriptional activity of β-catenin induces cell survival, proliferation, and migration. Thus, the inhibition of Wnt signaling is a promising therapeutic strategy in colorectal cancer. The aim of this study was the evaluation of the effects of lichen-derived depsides (atranorin, lecanoric acid, squamatic acid) and depsidones (physodic acid, salazinic acid) and a poly-carboxylic fatty acid-caperatic acid, on Wnt signaling in HCT116 and DLD-1 colorectal cancer cell lines. HCT116 cells were more sensitive to the modulatory effects of the compounds. PKF118-310, which was used as a reference β-catenin inhibitor, dose-dependently reduced the expression of the classical β-catenin target gene-Axin2 in both cell lines. Lecanoric acid slightly reduced Axin2 expression in HCT116 cells while caperatic acid tended to reduce Axin2 expression in both cell lines. Physodic acid much more potently decreased Axin2 expression in HCT116 cells than in DLD-1 cells. Physodic acid and caperatic acid also diminished the expression of survivin and MMP7 in a cell line and time-dependent manner. None of the compounds affected the nuclear translocation of β-catenin. This is the first report showing the ability of caperatic acid and physodic acid to modulate β-catenin-dependent transcription.
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Affiliation(s)
- Jarosław Paluszczak
- Department of Pharmaceutical Biochemistry, Poznan University of Medical Sciences, ul. Święcickiego 4, 60-781, Poznan, Poland.
| | - Robert Kleszcz
- Department of Pharmaceutical Biochemistry, Poznan University of Medical Sciences, ul. Święcickiego 4, 60-781, Poznan, Poland
| | - Elżbieta Studzińska-Sroka
- Department of Pharmacognosy, Poznan University of Medical Sciences, ul. Święcickiego 4, 60-781, Poznan, Poland
| | - Violetta Krajka-Kuźniak
- Department of Pharmaceutical Biochemistry, Poznan University of Medical Sciences, ul. Święcickiego 4, 60-781, Poznan, Poland
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Szopa A, Starzec A, Ekiert H. The importance of monochromatic lights in the production of phenolic acids and flavonoids in shoot cultures of Aronia melanocarpa, Aronia arbutifolia and Aronia × prunifolia. J Photochem Photobiol B 2018; 179:91-97. [PMID: 29351879 DOI: 10.1016/j.jphotobiol.2018.01.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/27/2017] [Accepted: 01/08/2018] [Indexed: 11/18/2022]
Abstract
Shoot cultures of Aronia melanocarpa, A. arbutifolia and A. × prunifolia were maintained on Murashige and Skoog medium with 1 mg/l each of BA and NAA under monochromatic lights (far-red, red, blue lights, UV-A-irradiation), in darkness, and under white light (control). HPLC-DAD analyses of 19 phenolic acids and 11 flavonoids in methanolic extracts from the shoots revealed in all of them the presence of three depsides (chlorogenic, neochlorogenic and rosmarinic acids), protocatechuic acid, four flavonoid glycosides (cynaroside, quercitrin, hyperoside and rutoside), and additionally, in A. arbutifolia, 3,4-dihydroxyphenylacetic acid. Depending on light quality, the total amounts of these metabolites increased 1.8-5.9 times, reaching maximum values under blue light: 527.40 and 144.61 mg 100 g-1 DW (A. melanocarpa), 543.27 and 85.82 mg 100 g-1 DW (A. arbutifolia) and 1615.18 and 220.65 mg 100 g-1 DW (A. × prunifolia), respectively. The maximum total amounts were 1.3-3.6 times higher than under white light. The quantities of individual metabolites changed from 1.2 to 11.0 times, with high amounts of neochlorogenic acid and quercitrin in A. melanocarpa (243.35 and 75.64 mg 100 g-1 DW), and of chlorogenic and rosmarinic acids and quercitrin in A. arbutifolia (236.52, 219.35 and 51.01 mg 100 g-1 DW). Extremely high amounts of depsides (418.83, 644.68, 548.86 mg 100 g-1 DW) and quercitrin (165.88 mg 100 g-1 DW) were produced in cultures of the hybrid - A. × prunifolia. The results are potentially useful for practical applications. This is the first report documented the importance of light quality on the production of phenolic acids and flavonoids in three aronia in vitro cultures.
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Affiliation(s)
- Agnieszka Szopa
- Chair and Department of Pharmaceutical Botany, Jagiellonian University, Collegium Medicum, ul. Medyczna 9, 30-688 Kraków, Poland.
| | - Anna Starzec
- Chair and Department of Pharmaceutical Botany, Jagiellonian University, Collegium Medicum, ul. Medyczna 9, 30-688 Kraków, Poland
| | - Halina Ekiert
- Chair and Department of Pharmaceutical Botany, Jagiellonian University, Collegium Medicum, ul. Medyczna 9, 30-688 Kraków, Poland.
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de Medeiros LS, Abreu LM, Nielsen A, Ingmer H, Larsen TO, Nielsen KF, Rodrigues-Filho E. Dereplication-guided isolation of depsides thielavins S-T and lecanorins D-F from the endophytic fungus Setophoma sp. Phytochemistry 2015; 111:154-162. [PMID: 25586883 DOI: 10.1016/j.phytochem.2014.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 11/13/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
Dereplication methodology using UHPLC-DAD-QTOFMS was applied during the metabolic profiling investigation of the endophyte Setophoma sp., a fungus isolated from symptomless guava fruits. The approach performed allowed a fast analysis of the microbial secondary metabolites. From this fungus, seven highly C-alkylated depsides were isolated and identified as polyketides thielavins S, T, U and V and lecanorins D, E and F. Their structures were elucidated through spectroscopic methods including NMR, HRMS and especially with assistance of HRMS/MS experiments. The compounds were tested for quorum sensing regulation activity in the virulence gene expression of Staphylococcus aureus, but no inhibitory effect was detected. Nevertheless, moderate antibacterial activity was encountered in three of tested depsides, particularly with thielavin T, whose MIC was 6.25 μg/mL against S. aureus.
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Affiliation(s)
- Lívia S de Medeiros
- Department of Chemistry, Universidade Federal de São Carlos, LaBioMMi, Rod. Washington Luís, Km 265, 13565-905 São Carlos, SP, Brazil.
| | - Lucas M Abreu
- Department of Phytopathology, Universidade Federal de Lavras, 37200-000 Lavras, MG, Brazil
| | - Anita Nielsen
- Department of Veterinary Disease Biology, Food Safety and Zoonoses Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, DK-1870 Frederiksberg, Copenhagen, Denmark
| | - Hanne Ingmer
- Department of Veterinary Disease Biology, Food Safety and Zoonoses Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, DK-1870 Frederiksberg, Copenhagen, Denmark
| | - Thomas O Larsen
- Department of Systems Biology, Center for Microbial Biotechnology, Technical University of Denmark, Søltofts Plads Building 221, 2800 Kgs. Lyngby, Denmark
| | - Kristian F Nielsen
- Department of Systems Biology, Center for Microbial Biotechnology, Technical University of Denmark, Søltofts Plads Building 221, 2800 Kgs. Lyngby, Denmark
| | - Edson Rodrigues-Filho
- Department of Chemistry, Universidade Federal de São Carlos, LaBioMMi, Rod. Washington Luís, Km 265, 13565-905 São Carlos, SP, Brazil
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Lorenz P, Conrad J, Stintzing FC. Metabolic fate of depsides and alkaloid constituents in aqueous extracts from Mercurialis perennis L. during fermentation. Chem Biodivers 2014; 10:1706-23. [PMID: 24078603 DOI: 10.1002/cbdv.201200424] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Indexed: 11/11/2022]
Abstract
Dog's mercury (Mercurialis perennis L.) is an old medicinal plant, nowadays used in complementary medicine. Aqueous fermented extracts of the plant are being mainly applied in remedies to treat external inflammations, but a thorough phytochemical characterization is still lacking. Therefore, the conversion of characteristic compound classes from M. perennis extracts during fermentation and storage was investigated. The microbial transformation of the two main depsides phaselic acid (=(2R)-O-[(E)-caffeoyl]malic acid; 1) and mercurialis acid (=(2R)-[(E)-caffeoyloxy]glutaric acid; 2) was monitored by HPLC-DAD. The degradation followed a second-order kinetic, and the calculated half-life periods of both constituents were 67 and 30 months, respectively. Several depside metabolites were detected by GC/MS in AcOEt extracts as (t) BuMe2 Si (TBDMS) derivatives after derivatization, mainly dihydrocinnamic acids. Moreover, numerous α-hydroxy acids were found, allegedly as degradation products from amino acids or peptides. The microbial alteration of the main alkaloid hermidin was also examined. After three days of fermentation, three novel N-metabolites were formed and thoroughly assigned in CH2 Cl2 extracts as a mixture of 3-ethylhermidin, 3-ethylhermidin quinone, and (E/Z)-3-ethylidenehermidin by GC/MS and NMR methods, as well as by means of total synthesis. A mechanism for the formation of these N-metabolites starting from dimeric hermidin oxidation products is proposed. The obtained results reveal the complex pathways plant constituents may undergo during the fermentation of the extracts.
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Affiliation(s)
- Peter Lorenz
- WALA Heilmittel GmbH, Section Phytochemical Research, Dorfstrasse 1, DE-73087 Bad Boll/Eckwälden (phone: +49-(0)7164930-6661; fax: +49(0)7164930-228).
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