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Feng DH, Cui JL. Progress on metabolites of Astragalus medicinal plants and a new factor affecting their formation: Biotransformation of endophytic fungi. Arch Pharm (Weinheim) 2024:e2400249. [PMID: 38838334 DOI: 10.1002/ardp.202400249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/13/2024] [Accepted: 05/16/2024] [Indexed: 06/07/2024]
Abstract
It is generally believed that the main influencing factors of plant metabolism are genetic and environmental factors. However, the transformation and catalysis of metabolic intermediates by endophytic fungi have become a new factor and resource attracting attention in recent years. There are over 2000 precious plant species in the Astragalus genus. In the past decade, at least 303 high-value metabolites have been isolated from the Astragalus medicinal plants, including 124 saponins, 150 flavonoids, two alkaloids, six sterols, and over 20 other types of compounds. These medicinal plants contain abundant endophytic fungi with unique functions, and nearly 600 endophytic fungi with known identity have been detected, but only about 35 strains belonging to 13 genera have been isolated. Among them, at least four strains affiliated to Penicillium roseopurpureum, Alternaria eureka, Neosartorya hiratsukae, and Camarosporium laburnicola have demonstrated the ability to biotransform four saponin compounds from the Astragalus genus, resulting in the production of 66 new compounds, which have significantly enhanced our understanding of the formation of metabolites in plants of the Astragalus genus. They provide a scientific basis for improving the cultivation quality of Astragalus plants through the modification of dominant fungal endophytes or reshaping the endophytic fungal community. Additionally, they open up new avenues for the discovery of specialized, green, efficient, and sustainable biotransformation pathways for complex pharmaceutical intermediates.
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Affiliation(s)
- Ding-Hui Feng
- Institute of Applied Chemistry, Shanxi University, Taiyuan, Shanxi, People's Republic of China
- The Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Modern Research Center for Traditional Chinese Medicine, Shanxi University, Taiyuan, Shanxi, People's Republic of China
- State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijng, People's Republic of China
| | - Jin-Long Cui
- Institute of Applied Chemistry, Shanxi University, Taiyuan, Shanxi, People's Republic of China
- The Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Modern Research Center for Traditional Chinese Medicine, Shanxi University, Taiyuan, Shanxi, People's Republic of China
- State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijng, People's Republic of China
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2
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Yang WQ, Lu QP, Chen CX, Zhu LP, Zhang X, Xu W, Hu LS, Chen J, Zhao ZX. Six undescribed 23-norursane triterpenoids from the biotransformation of ilexgenin a by endophytic fungi and their vascular protective activity. Fitoterapia 2024; 176:106053. [PMID: 38838828 DOI: 10.1016/j.fitote.2024.106053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 06/01/2024] [Accepted: 06/01/2024] [Indexed: 06/07/2024]
Abstract
Biotransformation of ursane-type triterpenoid ilexgenin A by endophytic fungi Lasiodiplodia sp. MQD-4 and Pestalotiopsis sp. ZZ-1, isolated from Ilex pubescences and Callicarpa kwangtungensis respectively, was investigated for the first time. Six previously undescribed metabolites (1-6) with 23-norursane triterpenoids skeleton were isolated and their structures were unambiguously established by the analysis of spectroscopic data and single-crystal X-ray crystallographic experiments. Decarboxylation, oxidation, and hydroxylation reactions were observed on the triterpenoid skeleton. Especially, the decarboxylation of C-23 provided definite evidence to understand the biogenetic process of 23-norursane triterpenoids. Moreover, the qualitative analysis of the extract of I. pubescences showed metabolites 1, 3, 4, and 6 could be detected in the originated plant, indicating biotransformation by endophytic fungi is a practical strategy for the isolation of novel natural products. Finally, all isolates were evaluated for the protective activities against H2O2-induced HUVECs dysfunction in vitro. Compound 5 could improve the viability of endothelial cells and decrease the level of intracellular ROS.
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Affiliation(s)
- Wei-Qun Yang
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Qi-Ping Lu
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Cai-Xin Chen
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Li-Ping Zhu
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Xiao Zhang
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Wei Xu
- College of Pharmacy, Jinan University, Guangzhou 510632, China
| | - Le-Shi Hu
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Jie Chen
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Zhong-Xiang Zhao
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
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Dembitsky VM. Fascinating Furanosteroids and Their Pharmacological Profile. Molecules 2023; 28:5669. [PMID: 37570639 PMCID: PMC10419491 DOI: 10.3390/molecules28155669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/21/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023] Open
Abstract
This review article delves into the realm of furanosteroids and related isoprenoid lipids derived from diverse terrestrial and marine sources, exploring their wide array of biological activities and potential pharmacological applications. Fungi, fungal endophytes, plants, and various marine organisms, including sponges, corals, molluscs, and other invertebrates, have proven to be abundant reservoirs of these compounds. The biological activities exhibited by furanosteroids and related lipids encompass anticancer, cytotoxic effects against various cancer cell lines, antiviral, and antifungal effects. Notably, the discovery of exceptional compounds such as nakiterpiosin, malabaricol, dysideasterols, and cortistatins has revealed their potent anti-tuberculosis, antibacterial, and anti-hepatitis C attributes. These compounds also exhibit activity in inhibiting protein kinase C, phospholipase A2, and eliciting cytotoxicity against cancer cells. This comprehensive study emphasizes the significance of furanosteroids and related lipids as valuable natural products with promising therapeutic potential. The remarkable biodiversity found in both terrestrial and marine ecosystems offers an extensive resource for unearthing novel biologically active compounds, paving the way for future drug development and advancements in biomedical research. This review presents a compilation of data obtained from various studies conducted by different authors who employed the PASS software 9.1 to evaluate the biological activity of natural furanosteroids and compounds closely related to them. The utilization of the PASS software in this context offers valuable advantages, such as screening large chemical libraries, identifying compounds for subsequent experimental investigations, and gaining insights into potential biological activities based on their structural features. Nevertheless, it is crucial to emphasize that experimental validation remains indispensable for confirming the predicted activities.
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Affiliation(s)
- Valery M Dembitsky
- Centre for Applied Research, Innovation and Entrepreneurship, Lethbridge College, 3000 College Drive South, Lethbridge, AB T1K 1L6, Canada
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Küçüksolak M, Yılmaz S, Ballar-Kırmızıbayrak P, Bedir E. Potent telomerase activators from a novel sapogenin via biotransformation utilizing Camarosporium laburnicola, an endophytic fungus. Microb Cell Fact 2023; 22:66. [PMID: 37024895 PMCID: PMC10080871 DOI: 10.1186/s12934-023-02069-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 03/23/2023] [Indexed: 04/08/2023] Open
Abstract
BACKGROUND Cycloartane-type triterpenoids possess important biological activities, including immunostimulant, wound healing, and telomerase activation. Biotransformation is one of the derivatization strategies of natural products to improve their bioactivities. Endophytic fungi have attracted attention in biotransformation studies because of their ability to perform modifications in complex structures with a high degree of stereospecificity. RESULTS This study focuses on biotransformation studies on cyclocephagenol (1), a novel cycloartane-type sapogenin from Astragalus species, and its 12-hydroxy derivatives (2 and 3) to obtain new telomerase activators. Since the hTERT protein levels of cyclocephagenol (1) and its 12-hydroxy derivatives (2 and 3) on HEKn cells were found to be notable, biotransformation studies were carried out on cyclocephagenol and its 12-hydroxy derivatives using Camarosporium laburnicola, an endophytic fungus isolated from Astragalus angustifolius. Later, immunoblotting and PCR-based ELISA assay were used to screen starting compounds and biotransformation products for their effects on hTERT protein levels and telomerase activation. All compounds showed improved telomerase activation compared to the control group. CONCLUSIONS As a result of biotransformation studies, seven new metabolites were obtained and characterized, verifying the potential of C. laburnicola as a biocatalyst. Additionally, the bioactivity results showed that this endophytic biocatalyst is unique in transforming the metabolites of its host to afford potent telomerase activators.
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Affiliation(s)
- Melis Küçüksolak
- Department of Bioengineering, Izmir Institute of Technology, Urla, 35430, İzmir, Türkiye, Turkey
| | - Sinem Yılmaz
- Department of Biotechnology, Graduate School of Natural and Applied Sciences, Ege University, Bornova, İzmir, Türkiye, Turkey
- Department of Bioengineering, Faculty of Engineering, University of Alanya Aladdin Keykubat, Antalya, Türkiye, Turkey
| | | | - Erdal Bedir
- Department of Bioengineering, Izmir Institute of Technology, Urla, 35430, İzmir, Türkiye, Turkey.
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Neuroprotective metabolites via fungal biotransformation of a novel sapogenin, cyclocephagenol. Sci Rep 2022; 12:18481. [PMID: 36323752 PMCID: PMC9630500 DOI: 10.1038/s41598-022-22799-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 10/19/2022] [Indexed: 01/06/2023] Open
Abstract
Cyclocephagenol (1), a novel cycloartane-type sapogenin with tetrahydropyran unit, is only encountered in Astragalus species. This rare sapogenin has never been a topic of biological activity or modification studies. The objectives of this study were; (i) to perform microbial transformation studies on cyclocephagenol (1) using Astragalus endophyte, Alternaria eureka 1E1BL1, followed by isolation and structural characterization of the metabolites; (ii) to investigate neuroprotective activities of the metabolites; (iii) to understand structure-activity relationships towards neuroprotection. The microbial transformation of cyclocephagenol (1) using Alternaria eureka resulted in the production of twenty-one (2-22) previously undescribed metabolites. Oxidation, monooxygenation, dehydration, methyl migration, epoxidation, and ring expansion reactions were observed on the triterpenoid skeleton. Structures of the compounds were established by 1D-, 2D-NMR, and HR-MS analyses. The neuroprotective activities of metabolites and parent compound (1) were evaluated against H2O2-induced cell injury. The structure-activity relationship (SAR) was established, and the results revealed that 1 and several other metabolites had potent neuroprotective activity. Further studies revealed that selected compounds reduced the amount of ROS and preserved the integrity of the mitochondrial membrane. This is the first report of microbial transformation of cyclocephagenol (1).
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Ju M, Zhang Q, Wang R, Yan S, Li Z, Li P, Gu P. Correlation in endophytic fungi community diversity and bioactive compounds of Sophora alopecuroides. Front Microbiol 2022; 13:955647. [PMID: 36118208 PMCID: PMC9475766 DOI: 10.3389/fmicb.2022.955647] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 08/04/2022] [Indexed: 12/03/2022] Open
Abstract
Sophora alopecuroides L. is a traditional Chinese medicine used for the treatment of several different disease states including bacillary dysentery and enteritis. But importantly, it also plays a role as an anti-tumor agent. That said, little is known about the role endophytes play regarding the clinically bioactive metabolites in S. alopecuroides. In order to explore the effects of endophytic fungi on the accumulation, quality, and correlation in the content of the medicinal compounds, the structural diversity of endophytic fungi in S. alopecuroides was analyzed. The relationship between endophytes and quinolizidine alkaloids (QAs), housed within the seeds of S. alopecuroides, which were interpreted based on established methods of high-throughput sequencing and high-performance liquid chromatography. A total of 1,034,418 effective sequence reads and 257 operational taxonomic units (OTUs) were obtained from 33 samples which were sourced from 11 different sampling sites and further classified into 9 phyla, 20 classes, 45 orders, 85 families, and 118 genera. Ascomycota was found to be the dominant phylum of endophytic fungi in S. alopecuroides, with a relative abundance ranging from 60.85 to 98.30%. Alternaria, Cladosporium, Filobasidium, and an unidentified Ascomycota were the core-shared endophytes, accounting for 49.96, 27.12, 14.83, and 7.88%, respectively. Correlation analysis showed that the Simpson's diversity index of endophytic fungal community in S. alopecuroides was significantly positively correlated with the Oxymatrine (OMA) content in different areas, while the Chao and Shannoneven indexes were significantly negatively correlated with OMA. The endophytic fungi of Alternaria were positively correlated with the content of OMA, Oxysophocarpine (OSC), and total QAs. This study has mastered the endophytic fungi resources of S. alopecuroides, explored potential functional endophytic fungi, and provided a scientific basis for using biological fertilization strategies to improve the quality of S. alopecuroides.
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Affiliation(s)
- Mingxiu Ju
- School of Agriculture, Ningxia University, Yinchuan, China
| | - Qingchen Zhang
- Department of Pharmacotherapy and Translational Research, University of Florida, Gainesville, FL, United States
| | - Ruotong Wang
- School of Agriculture, Ningxia University, Yinchuan, China
| | - Siyuan Yan
- School of Agriculture, Ningxia University, Yinchuan, China
| | - Zhengnan Li
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot, China
| | - Peng Li
- State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, Yinchuan, China
| | - Peiwen Gu
- School of Agriculture, Ningxia University, Yinchuan, China
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Zhou ZY, Liu X, Cui JL, Wang JH, Wang ML, Zhang G. Endophytic fungi and their bioactive secondary metabolites in medicinal leguminosae plants: Nearly untapped medical resources. FEMS Microbiol Lett 2022; 369:6615458. [PMID: 35746878 DOI: 10.1093/femsle/fnac052] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 06/07/2022] [Indexed: 11/12/2022] Open
Abstract
There are many species of Chinese traditional leguminosae family plants that are well known for their medicinal applications, such as Astragalus membranaceus, Catsia tora, Glycyrrhiza uralensis, Sophora flavescens and Albacia acacia. Their unique bioactive composition and internal phenological environment contribute to the formation of specific and unique endophytic fungal communities, which are important resources for new compounds used in a variety of pharmacological activities. Nonetheless, they have not been systematically studied. In the last decade, nearly 64 genera and thousands of species of endophytic fungi have been discovered from leguminosae plants, as well as 138 secondary metabolites (with 34 new compounds) including flavonoid, alkaloids, phenol, anthraquinone, macrolide, terpenoid, phytohormone and many more. They were shown to have diverse applications and benefits, such as antibacterial, antitumor, antioxidative, immunoregulatory and neuroprotective properties. Here, we provide a summarized overview with the aim of raising awareness of endophytic fungi from medicinal leguminosae plants and providing a comprehensive review of the discoveries of new natural products that may be of medicinal and pharmaceutical importance.
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Affiliation(s)
- Zhong-Ya Zhou
- Institute of Applied Chemistry, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China.,Modern Research Center for Traditional Chinese Medicine, the Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China
| | - Xi Liu
- Institute of Applied Chemistry, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China.,Modern Research Center for Traditional Chinese Medicine, the Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China
| | - Jin-Long Cui
- Institute of Applied Chemistry, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China
| | - Jun-Hong Wang
- Institute of Applied Chemistry, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China
| | - Meng-Liang Wang
- Institute of Applied Chemistry, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China
| | - Gang Zhang
- College of Pharmacy, Shaanxi University of Chinese Medicine, Century Avenue, Xianyang 712046, China
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Zhang L, Li X, Song X, Bian C, Kang X, Zhao J, Qiao H, Gong Y. Assessment of the Endophytic Fungal Composition of Lactobacillus plantarum and Enterococcus faecalis-Fermented Astragalus membranaceus Using Single-Molecule, Real-Time Sequencing Technology. Front Vet Sci 2022; 9:880152. [PMID: 35573417 PMCID: PMC9096703 DOI: 10.3389/fvets.2022.880152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 03/03/2022] [Indexed: 11/13/2022] Open
Abstract
Endophytic fungus represents microorganisms existing within the healthy plant organs, which can significantly influence metabolic product production in plants, a process with great research value and broad prospects for development. To investigate the effect of fermentation with probiotic cultures on the endophytic fungal diversity and composition of Astragalus membranaceus, we used single-molecular, real-time sequencing (Pacific Biosciences) for 18S ribosomal RNA (rRNA) sequencing. The results showed that the endophytic fungi of A. membranaceus mainly belonged to Aspergillus, Penicillium, Cystofilobasidium, Candida, Guehomyces, and Wallemia. Furthermore, the endophytic fungal diversity and abundance of A. membranaceus were more variable after fermentation with Enterococcus faecium and/or Lactobacillus plantarum. Our data lays a solid and comprehensive foundation for further exploration of endophytic fungi from A. membranaceus as potential sources of functional compounds.
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Affiliation(s)
- Liheng Zhang
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
- College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou, China
| | - Xianghui Li
- College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou, China
| | - Xinghui Song
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Chuanzhou Bian
- College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou, China
| | - Xiangtao Kang
- College of Animal Science and Technology HAU, Henan Agricultural University, Zhengzhou, China
| | - Junqiang Zhao
- Henan Tianhao Hongfa Biotechnology Co., Ltd., Zhengzhou, China
| | - Hongxing Qiao
- College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou, China
- *Correspondence: Hongxing Qiao
| | - Yanzhang Gong
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, China
- Yanzhang Gong
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Liu X, Zhou ZY, Cui JL, Wang ML, Wang JH. Biotransformation ability of endophytic fungi: from species evolution to industrial applications. Appl Microbiol Biotechnol 2021; 105:7095-7113. [PMID: 34499202 PMCID: PMC8426592 DOI: 10.1007/s00253-021-11554-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 12/26/2022]
Abstract
Abstract Increased understanding of the interactions between endophytic fungi and plants has led to the discovery of a new generation of chemical compounds and processes between endophytic fungi and plants. Due to the long-term co-evolution between fungal endophytes and host plants, endophytes have evolved special biotransformation abilities, which can have critical consequences on plant metabolic processes and their composition. Biotransformation or bioconversion can impact the synthesis and decomposition of hormones, sugars, amino acids, vitamins, lipids, proteins, and various secondary metabolites, including flavonoids, polysaccharides, and terpenes. Endophytic fungi produce enzymes and various bioactive secondary metabolites with industrial value and can degrade or sequester inorganic and organic small molecules and macromolecules (e.g., toxins, pollutants, heavy metals). These fungi also have the ability to cause highly selective catalytic conversion of high-value compounds in an environmentally friendly manner, which can be important for the production/innovation of bioactive molecules, food and nutrition, agriculture, and environment. This work mainly summarized recent research progress in this field, providing a reference for further research and application of fungal endophytes. Key points •The industrial value of degradation of endophytes was summarized. • The commercial value for the pharmaceutical industry is reviewed. Graphical abstract ![]()
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Affiliation(s)
- Xi Liu
- Institute of Applied Chemistry, Shanxi University, Taiyuan, 030006, Shanxi, China.,Modern Research Center for Traditional Chinese Medicine, The Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan, 030006, Shanxi, China
| | - Zhong-Ya Zhou
- Institute of Applied Chemistry, Shanxi University, Taiyuan, 030006, Shanxi, China.,Modern Research Center for Traditional Chinese Medicine, The Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan, 030006, Shanxi, China
| | - Jin-Long Cui
- Institute of Applied Chemistry, Shanxi University, Taiyuan, 030006, Shanxi, China.
| | - Meng-Liang Wang
- Institute of Applied Chemistry, Shanxi University, Taiyuan, 030006, Shanxi, China
| | - Jun-Hong Wang
- Institute of Applied Chemistry, Shanxi University, Taiyuan, 030006, Shanxi, China
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Bedir E, Karakoyun Ç, Doğan G, Kuru G, Küçüksolak M, Yusufoğlu H. New Cardenolides from Biotransformation of Gitoxigenin by the Endophytic Fungus Alternaria eureka 1E1BL1: Characterization and Cytotoxic Activities. Molecules 2021; 26:molecules26103030. [PMID: 34069653 PMCID: PMC8161373 DOI: 10.3390/molecules26103030] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022] Open
Abstract
Microbial biotransformation is an important tool in drug discovery and for metabolism studies. To expand our bioactive natural product library via modification and to identify possible mammalian metabolites, a cytotoxic cardenolide (gitoxigenin) was biotransformed using the endophytic fungus Alternaria eureka 1E1BL1. Initially, oleandrin was isolated from the dried leaves of Nerium oleander L. and subjected to an acid-catalysed hydrolysis to obtain the substrate gitoxigenin (yield; ~25%). After 21 days of incubation, five new cardenolides 1, 3, 4, 6, and 8 and three previously- identified compounds 2, 5 and 7 were isolated using chromatographic methods. Structural elucidations were accomplished through 1D/2D NMR, HR-ESI-MS and FT-IR analysis. A. eureka catalyzed oxygenation, oxidation, epimerization and dimethyl acetal formation reactions on the substrate. Cytotoxicity of the metabolites were evaluated using MTT cell viability method, whereas doxorubicin and oleandrin were used as positive controls. Biotransformation products displayed less cytotoxicity than the substrate. The new metabolite 8 exhibited the highest activity with IC50 values of 8.25, 1.95 and 3.4 µM against A549, PANC-1 and MIA PaCa-2 cells, respectively, without causing toxicity on healthy cell lines (MRC-5 and HEK-293) up to concentration of 10 µM. Our results suggest that A. eureka is an effective biocatalyst for modifying cardenolide-type secondary metabolites.
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Affiliation(s)
- Erdal Bedir
- Department of Bioengineering, Faculty of Engineering, İzmir Institute of Technology, 35430 Urla-İzmir, Turkey; (G.D.); (G.K.); (M.K.)
- Correspondence: (E.B.); (Ç.K.); Tel.: +90-232-750-7389 (E.B.); +90-232-311-2598 (Ç.K.)
| | - Çiğdem Karakoyun
- Department of Pharmacognosy, Faculty of Pharmacy, Ege University, 35100 Bornova-İzmir, Turkey
- Correspondence: (E.B.); (Ç.K.); Tel.: +90-232-750-7389 (E.B.); +90-232-311-2598 (Ç.K.)
| | - Gamze Doğan
- Department of Bioengineering, Faculty of Engineering, İzmir Institute of Technology, 35430 Urla-İzmir, Turkey; (G.D.); (G.K.); (M.K.)
| | - Gülten Kuru
- Department of Bioengineering, Faculty of Engineering, İzmir Institute of Technology, 35430 Urla-İzmir, Turkey; (G.D.); (G.K.); (M.K.)
| | - Melis Küçüksolak
- Department of Bioengineering, Faculty of Engineering, İzmir Institute of Technology, 35430 Urla-İzmir, Turkey; (G.D.); (G.K.); (M.K.)
| | - Hasan Yusufoğlu
- Department of Pharmacognosy, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia;
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Telomerase activators from 20(27)-octanor-cycloastragenol via biotransformation by the fungal endophytes. Bioorg Chem 2021; 109:104708. [PMID: 33621779 DOI: 10.1016/j.bioorg.2021.104708] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/24/2020] [Accepted: 01/28/2021] [Indexed: 02/06/2023]
Abstract
Cycloastragenol [20(R),24(S)-epoxy-3β,6α,16β,25-tetrahydroxycycloartane] (CA), the principle sapogenol of many cycloartane-type glycosides found in Astragalus genus, is currently the only natural product in the anti-aging market as telomerase activator. Here, we report biotransformation of 20(27)-octanor-cycloastragenol (1), a thermal degradation product of CA, using Astragalus species originated endophytic fungi, viz. Penicillium roseopurpureum, Alternaria eureka, Neosartorya hiratsukae and Camarosporium laburnicola. Fifteen new biotransformation products (2-16) were isolated, and their structures were established by NMR and HRESIMS. Endophytic fungi were found to be capable of performing hydroxylation, oxidation, ring cleavage-methyl migration, dehydrogenation and Baeyer-Villiger type oxidation reactions on the starting compound (1), which would be difficult to achieve by conventional synthetic methods. In addition, the ability of the metabolites to increase telomerase activation in Hekn cells was evaluated, which showed from 1.08 to 12.4-fold activation compared to the control cells treated with DMSO. Among the compounds tested, 10, 11 and 12 were found to be the most potent in terms of telomerase activation with 12.40-, 7.89- and 5.43-fold increase, respectively (at 0.1, 2 and 10 nM concentrations, respectively).
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