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Sciacca C, Cardullo N, Pulvirenti L, Di Francesco A, Muccilli V. Evaluation of honokiol, magnolol and of a library of new nitrogenated neolignans as pancreatic lipase inhibitors. Bioorg Chem 2023; 134:106455. [PMID: 36913880 DOI: 10.1016/j.bioorg.2023.106455] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/16/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023]
Abstract
Obesity is a complex disease defined as an excessive amount of body fat. It is considered a risk factor for several pathologies; therefore, there is an increasing interest in its treatment. Pancreatic lipase (PL) plays a key role in fat digestion, and its inhibition is a preliminary step in the search for anti-obesity agents. For this reason, many natural compounds and their derivatives are studied as new PL inhibitors. This study reports the synthesis of a library of new compounds inspired by two natural neolignans, honokiol (1) and magnolol (2) and bearing amino or nitro groups linked to a biphenyl core. The synthesis of unsymmetrically substituted biphenyls was achieved through an optimisation of the Suzuki-Miyaura cross-coupling reaction followed by the insertion of allyl chains, thus furnishing the O- and/or N-allyl derivatives, and finally, a sigmatropic rearrangement yielding in some cases, the C-allyl analogues. Magnolol, honokiol and the twenty-one synthesised biphenyls were evaluated for their in vitro inhibitory activity toward PL. Three compounds (15b, 16 and 17b) were more effective inhibitors than the natural neolignans (magnolol IC50 = 158.7 µM and honokiol IC50 = 115.5 µM) with IC50 of 41-44 µM. Detailed studies through kinetics suggested better inhibitory activity of the synthetic analogues compared with the natural 1 and 2. Magnolol (Ki = 614.3 µM; K'i of 140.9 µM) and the synthetic biphenyls 15b (Ki = 286.4 µM; K'i = 36.6 µM) and 16 (Ki = 176.2 µM; K'i = 6.4 µM) are mixed-type inhibitors, whereas honokiol (Ki = 674.8 µM) and 17b (Ki = 249 µM) are competitive inhibitors. Docking studies corroborated these findings, showing the best fitting for intermolecular interaction between biphenyl neolignans and PL. The above outcomes highlighted how the proposed structures could be considered interesting candidates for future studies for the development of more effective PL inhibitors.
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Affiliation(s)
- Claudia Sciacca
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6. 95125, Catania, Italy
| | - Nunzio Cardullo
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6. 95125, Catania, Italy
| | - Luana Pulvirenti
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6. 95125, Catania, Italy
| | - Antonella Di Francesco
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6. 95125, Catania, Italy
| | - Vera Muccilli
- Department of Chemical Sciences, University of Catania, V.le A. Doria 6. 95125, Catania, Italy.
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Lichte D, Pirkl N, Heinrich G, Dutta S, Goebel JF, Koley D, Gooßen LJ. Palladium-Catalyzed para-C-H Arylation of Anilines with Aromatic Halides. Angew Chem Int Ed Engl 2022; 61:e202210009. [PMID: 36112053 PMCID: PMC9828783 DOI: 10.1002/anie.202210009] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [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: 07/08/2022] [Indexed: 01/12/2023]
Abstract
Controlling regioselectivity in C-H functionalizations is a key challenge in chemical method development. In arenes, functionalizations are most difficult to direct towards the C-H group furthest away from a substituent, in its para position. We herein demonstrate how the para-C-H arylation of anilines with non-activated aryl halides, elusive to date, is achieved by a base-assisted "metalla-tautomerism" approach. A proton is abstracted from the aniline substrate and replaced by an arylpalladium species, generated from the aryl halide coupling partner. In this step, the palladium is directed away from the N- to the tautomeric para-C-H position by a large phosphine ligand combined with a triphenylmethyl shielding group. The triphenylmethyl group is easily installed and removed, and can be recycled.
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Affiliation(s)
- Dominik Lichte
- Fakultät für Chemie und BiochemieRuhr-Universität BochumUniversitätsstraße 15044801BochumGermany
| | - Nico Pirkl
- Fakultät für Chemie und BiochemieRuhr-Universität BochumUniversitätsstraße 15044801BochumGermany
| | - Gregor Heinrich
- Fakultät für Chemie und BiochemieRuhr-Universität BochumUniversitätsstraße 15044801BochumGermany
| | - Sayan Dutta
- Department of Chemical SciencesIndian Institute of Science Education and Research (IISER)Kolkata, Mohanpur 741 246India
| | - Jonas F. Goebel
- Fakultät für Chemie und BiochemieRuhr-Universität BochumUniversitätsstraße 15044801BochumGermany
| | - Debasis Koley
- Department of Chemical SciencesIndian Institute of Science Education and Research (IISER)Kolkata, Mohanpur 741 246India
| | - Lukas J. Gooßen
- Fakultät für Chemie und BiochemieRuhr-Universität BochumUniversitätsstraße 15044801BochumGermany
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Kiani F, Naeimi H. Ultrasonic accelerated coupling reaction using magnetically recyclable bis (propyl molononitril) Ni complex nanocatalyst: A novel, green and efficient synthesis of biphenyl derivatives. Ultrason Sonochem 2018; 48:267-274. [PMID: 30080550 DOI: 10.1016/j.ultsonch.2018.06.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 05/30/2018] [Accepted: 06/01/2018] [Indexed: 06/08/2023]
Abstract
A novel, green and rapid sonochemical research to preparation of the biphenyls was carried out through the coupling reaction between various aryl halides and phenylboronic acid by using bis(propyl malononitrile) Ni (0) complex (NiFe2O4@SiO2-BPMN-Ni) as an efficient nano catalyst. The catalyst can be recycled via an external magnet and reused several times without considerable loss of its catalytic activity. Compare to the previous works, this procedure has advantages such as easy workup, high yields of products, environmentally benign and short reaction times. The novel nickel catalyst prepared and characterized by FT-IR, XRD, SEM, EDX, TGA and VSM techniques.
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Affiliation(s)
- Fatemeh Kiani
- Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan 87317, Islamic Republic of Iran
| | - Hossein Naeimi
- Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan 87317, Islamic Republic of Iran.
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Pailee P, Kuhakarn C, Sangsuwan C, Hongthong S, Piyachaturawat P, Suksen K, Jariyawat S, Akkarawongsapat R, Limthongkul J, Napaswad C, Kongsaeree P, Prabpai S, Jaipetch T, Pohmakotr M, Tuchinda P, Reutrakul V. Anti-HIV and cytotoxic biphenyls, benzophenones and xanthones from stems, leaves and twigs of Garcinia speciosa. Phytochemistry 2018; 147:68-79. [PMID: 29304383 DOI: 10.1016/j.phytochem.2017.12.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [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: 09/11/2017] [Revised: 12/18/2017] [Accepted: 12/19/2017] [Indexed: 06/07/2023]
Abstract
Eleven previously undescribed compounds, including four benzophenones (garciosones A-D), four xanthones (garciosones E-H) and three biphenyls (garciosines A-C), along with eighteen known compounds were isolated from the stems, leaves and twigs of Garcinia speciosa Wall. (Clusiaceae). Their structures were established by extensive spectroscopic analysis. For garciosines A-C, the structures were confirmed by single crystal X-ray diffraction analysis. Most of the isolated compounds were evaluated for their cytotoxic activity and anti-HIV-1 activity using the syncytium inhibition assay and HIV-1 reverse transcriptase (RT) assay. The known compounds, 4,6,3',4'-tetrahydroxy-2-methoxybenzophenone and macluraxanthone, displayed significant cytotoxic activity with the ED50 in the range of 1.85-11.76 μM. 1,5-Dihydroxyxanthone exhibited the most potent anti-HIV activity against syncytium formation with EC50 < 17.13 μM (SI > 25.28) and 2-(3,3-dimethylallyl)-1,3,7-trihydroxyxanthone was the most active compound in the HIV-1 reverse transcriptase assay with IC50 value of 58.24 μM. Structure-activity relationship of some isolated compounds were also discussed.
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Affiliation(s)
- Phanruethai Pailee
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Chutima Kuhakarn
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Chanyapat Sangsuwan
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Sakchai Hongthong
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Pawinee Piyachaturawat
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Kanoknetr Suksen
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Surawat Jariyawat
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Radeekorn Akkarawongsapat
- Department of Microbiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Jitra Limthongkul
- Department of Microbiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Chanita Napaswad
- Department of Microbiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Palangpon Kongsaeree
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Samran Prabpai
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Thaworn Jaipetch
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Manat Pohmakotr
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Patoomratana Tuchinda
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Vichai Reutrakul
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
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Chaturonrutsamee S, Kuhakarn C, Surawatanawong P, Prabpai S, Kongsaeree P, Jaipetch T, Piyachaturawat P, Jariyawat S, Akkarawongsapat R, Suksen K, Limthongkul J, Napaswad C, Nuntasaen N, Reutrakul V. Polycyclic polyprenylated acylphloroglucinols and biphenyl derivatives from the roots of Garcinia nuntasaenii Ngerns. & Suddee. Phytochemistry 2018; 146:63-74. [PMID: 29247893 DOI: 10.1016/j.phytochem.2017.12.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [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: 08/30/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 06/07/2023]
Abstract
Seven previously undescribed compounds, including three polycyclic polyprenylated acylphloroglucinols (garcinuntins A-C), three biphenyl derivatives (garcinuntabiphenyls A-C) and a lanostane triterpene (garcinuntine), along with thirteen known compounds were isolated from the root of Garcinia nuntasaenii Ngerns. & Suddee. Their structures were elucidated on the basis of spectroscopic techniques. For garcinuntins A-C, the absolute configurations were confirmed by the combination of single X-ray crystallography and ECD calculations. Anti-HIV activity using anti-HIV-1 reverse transcriptase and syncytium inhibition assays, and cytotoxic activity against a panel of cultured mammalian cancer cell lines of isolated compounds were investigated.
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Affiliation(s)
- Suppisak Chaturonrutsamee
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand; Research and Development Department, International Laboratories Corp., Ltd., Bang Phli, Samut Prakan 10540, Thailand
| | - Chutima Kuhakarn
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Panida Surawatanawong
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Samran Prabpai
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Palangpon Kongsaeree
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Thaworn Jaipetch
- Mahidol University, Center of Excellence for Innovation in Chemistry (PERCH-CIC), Kanchanaburi Campus, Saiyok, Kanchanaburi 71150, Thailand
| | - Pawinee Piyachaturawat
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Surawat Jariyawat
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Radeekorn Akkarawongsapat
- Department of Microbiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Kanoknetr Suksen
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Jitra Limthongkul
- Department of Microbiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Chanita Napaswad
- Department of Microbiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
| | - Narong Nuntasaen
- The Forest Herbarium, Department of National Parks, Wildlife and Plant Conservation, Ministry of Natural Resources and Environment, Bangkok 10900, Thailand
| | - Vichai Reutrakul
- Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
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6
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Ju L, Zhou Z, Jiang B, Lou Y, Zhang Z. miR-21 is involved in skeletal deficiencies of zebrafish embryos exposed to polychlorinated biphenyls. Environ Sci Pollut Res Int 2017; 24:886-891. [PMID: 27761858 DOI: 10.1007/s11356-016-7874-8] [Citation(s) in RCA: 6] [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: 02/01/2016] [Accepted: 10/10/2016] [Indexed: 06/06/2023]
Abstract
Polychlorinated biphenyl (PCB) exposure increases the incidence and severity of skeletal diseases, but little is known about the mechanisms that mediate this relationship. We exposed zebrafish embryos to PCB1254 and assessed the changes in bone morphology protein receptor II (BMPRII), which is involved in bone formation and embryonic development, miRNA-21, for which BMPRII is a known target, and calcium metabolism. PCB1254 upregulated the expression of miR-21 and suppressed BMPRII expression. The inhibition of miR-21 reversed the downregulation of BMPRII and alleviated the PCB1254-induced loss of calcium. These findings suggest new biomarkers of developmental defects of the skeleton caused by PCBs.
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MESH Headings
- Animals
- Bone Diseases, Developmental/chemically induced
- Bone Diseases, Developmental/embryology
- Bone Diseases, Developmental/metabolism
- Bone Diseases, Developmental/pathology
- Bone Morphogenetic Protein Receptors, Type II/genetics
- Calcium/metabolism
- Embryo, Nonmammalian/abnormalities
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/metabolism
- Embryo, Nonmammalian/pathology
- Embryonic Development/drug effects
- Embryonic Development/genetics
- MicroRNAs/genetics
- Polychlorinated Biphenyls/toxicity
- Water Pollutants, Chemical/toxicity
- Zebrafish/embryology
- Zebrafish Proteins/genetics
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Affiliation(s)
- Li Ju
- Department of Pediatric Orthopaedics, Children's Hospital of Nanjing Medical University, 72 Guang Zhou Road, Nanjing, 210008, People's Republic of China
| | - Zhiwen Zhou
- Department of Pediatric Orthopaedics, Children's Hospital of Nanjing Medical University, 72 Guang Zhou Road, Nanjing, 210008, People's Republic of China
| | - Bo Jiang
- Department of Pediatric Orthopaedics, Children's Hospital of Nanjing Medical University, 72 Guang Zhou Road, Nanjing, 210008, People's Republic of China
| | - Yue Lou
- Department of Pediatric Orthopaedics, Children's Hospital of Nanjing Medical University, 72 Guang Zhou Road, Nanjing, 210008, People's Republic of China
| | - Zhiqun Zhang
- Department of Pediatric Orthopaedics, Children's Hospital of Nanjing Medical University, 72 Guang Zhou Road, Nanjing, 210008, People's Republic of China.
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Shang SZ, Xu WX, Lei P, Zhao W, Tang JG, Miao MM, Sun HD, Pu JX, Chen YK, Yang GY. Biphenyls from Nicotiana tabacum and their anti-tobacco mosaic virus. Fitoterapia 2014; 99:35-9. [PMID: 25128901 DOI: 10.1016/j.fitote.2014.08.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 08/05/2014] [Accepted: 08/06/2014] [Indexed: 11/17/2022]
Abstract
Five new biphenyls, tababiphenyls A-E (1-5), together with five known ones (5-10), were isolated from the leaves of Nicotiana tabacum, of which compound 1 possessed a seldom reported 6-carbons unit in biphenyls. Their structures were established on the basis of extensive spectroscopic analyses. All compounds were tested for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compounds 3 and 5 exhibited high anti-TMV activities with inhibition rate of 48.4% and 32.1%, respectively, which were higher than that of positive control (ningnanmycin). The other compounds also showed potential anti-TMV activities with inhibition rates in the range of 18.6-28.7%, respectively.
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Affiliation(s)
- Shan-Zhai Shang
- Key Laboratory of Tobacco Chemistry of Yunnan Province, China Tobacco Yunnan Industrial Co., Ltd, Kunming 650231, PR China; State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, PR China
| | - Wen-Xiu Xu
- Key Laboratory of Tobacco Chemistry of Yunnan Province, China Tobacco Yunnan Industrial Co., Ltd, Kunming 650231, PR China; School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Nature Products, Kunming Medical University, Kunming Yunnan 650500, PR China
| | - Ping Lei
- Key Laboratory of Tobacco Chemistry of Yunnan Province, China Tobacco Yunnan Industrial Co., Ltd, Kunming 650231, PR China
| | - Wei Zhao
- Key Laboratory of Tobacco Chemistry of Yunnan Province, China Tobacco Yunnan Industrial Co., Ltd, Kunming 650231, PR China; State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, PR China
| | - Jian-Guo Tang
- Key Laboratory of Tobacco Chemistry of Yunnan Province, China Tobacco Yunnan Industrial Co., Ltd, Kunming 650231, PR China
| | - Ming-Ming Miao
- Key Laboratory of Tobacco Chemistry of Yunnan Province, China Tobacco Yunnan Industrial Co., Ltd, Kunming 650231, PR China
| | - Han-Dong Sun
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, PR China
| | - Jian-Xin Pu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, PR China
| | - Yong-Kuan Chen
- Key Laboratory of Tobacco Chemistry of Yunnan Province, China Tobacco Yunnan Industrial Co., Ltd, Kunming 650231, PR China.
| | - Guang-Yu Yang
- Key Laboratory of Tobacco Chemistry of Yunnan Province, China Tobacco Yunnan Industrial Co., Ltd, Kunming 650231, PR China.
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Khalil MNA, Beuerle T, Müller A, Ernst L, Bhavanam VBR, Liu B, Beerhues L. Biosynthesis of the biphenyl phytoalexin aucuparin in Sorbus aucuparia cell cultures treated with Venturia inaequalis. Phytochemistry 2013; 96:101-109. [PMID: 24074553 DOI: 10.1016/j.phytochem.2013.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [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: 06/12/2013] [Revised: 08/25/2013] [Accepted: 09/02/2013] [Indexed: 06/02/2023]
Abstract
Aucuparin is the most widely distributed biphenyl phytoalexin in the rosaceous subtribe Pyrinae, which includes the economically important fruit trees apple and pear. The biphenyl scaffold is formed by biphenyl synthase, which catalyzes biosynthesis of 3,5-dihydroxybiphenyl. Conversion of this precursor to aucuparin (3,5-dimethoxy-4-hydroxybiphenyl) was studied in cell cultures of Sorbus aucuparia after treatment with an elicitor preparation from the scab-causing fungus Venturia inaequalis. The sequence of the biosynthetic steps detected was O-methylation - 4-hydroxylation - O-methylation. The two alkylation reactions were catalyzed by distinct methyltransferases, which differed in pH and temperature optima as well as stability. Biphenyl 4-hydroxylase was a microsomal cytochrome P450 monooxygenase, whose activity was appreciably decreased by the addition of established P450 inhibitors. When fed to V. inaequalis-treated S. aucuparia cell cultures, radioactively labeled 3,5-dihydroxybiphenyl was not only incorporated into aucuparin but also into the dibenzofuran eriobofuran, the accumulation of which paralleled that of aucuparin. However, biphenyl 2'-hydroxylase activity proposed to be involved in dibenzofuran formation was detected in neither microsomes nor cell-free extracts in the presence of NADPH and 2-oxoglutarate, respectively. Nevertheless, a basis for studying biphenyl biosynthesis at the gene level is provided.
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Affiliation(s)
- Mohammed N A Khalil
- Institute of Pharmaceutical Biology, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106 Braunschweig, Germany
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