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Traxler F, Zhang H, Mahavorasirikul W, Krivanek K, Cai XH, Aiyakool W, Pfeiffer M, Brecker L, Schinnerl J. Two Novel Iboga-Type and an Oxindole Glucuronide Alkaloid from Tabernaemontana peduncularis Disclose Related Biosynthetic Pathways to Tabernaemontana divaricata. Molecules 2023; 28:6664. [PMID: 37764440 PMCID: PMC10535570 DOI: 10.3390/molecules28186664] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/12/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
Phytochemical investigation of the two Tabernaemontana species (Apocynaceae) T. peduncularis Wall. and T. divaricata (L.) R.Br. ex Roem. & Schult. indicated closely related biosynthetic pathways leading to lipophilic and hydrophilic alkaloids. In total, 18 specialized metabolites comprising indole-derived alkaloid aglycones, three oxindole-derived alkaloid glycosides, and two iridoid glucosides could be identified in the studied species. Among the alkaloids, the two Iboga-type alkaloids 3,7-coronaridine isoindolenine, coronaridine 3,4-iminium and a javaniside derivative bearing a glucuronic acid, named javanuronic acid, could be described by spectroscopic and spectrometric methods for the first time. A docking experiment using alpha-fold was performed to generate a protein model of the enzyme 7-deoxyloganetic acid glucosyl transferase. Performed bioassays exhibited a growth reduction of neonate Spodoptera littoralis larvae and reduced cell viability of HepG2 cells of the extracts containing Iboga alkaloids, whilst the javaniside derivatives containing hydrophilic fraction did not show any effects. These findings indicate a high flexibility in the formation of bioactive indole alkaloid aglycones by Tabernaemontana species and also evidence similar accumulation trends in both species as well as indicate that biosynthetic routes leading to oxindole alkaloids like javanisides are more widespread than reported. Furthermore, the incorporation of the three novel compounds into potential biosynthetic pathways is discussed.
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Affiliation(s)
- Florian Traxler
- Department of Organic Chemistry, University of Vienna, Währinger Strasse 38, A-1090 Vienna, Austria; (F.T.); (K.K.)
- Vienna Doctoral School in Chemistry, University of Vienna, Währinger Strasse 42, A-1090 Vienna, Austria
| | - Haoqi Zhang
- Department of Organic Chemistry, University of Vienna, Währinger Strasse 38, A-1090 Vienna, Austria; (F.T.); (K.K.)
- Vienna Doctoral School in Chemistry, University of Vienna, Währinger Strasse 42, A-1090 Vienna, Austria
| | - Wiratchanee Mahavorasirikul
- Drug Discovery and Development Center, Advanced Science and Technologies, Thammasat University (Rangsit Campus), Pathumthani 12121, Thailand;
- Thammasat University Research Unit in Cannabis and Herbal Products Innovation, Thammasat University (Rangsit Campus), Pathumthani 12121, Thailand
| | - Katharina Krivanek
- Department of Organic Chemistry, University of Vienna, Währinger Strasse 38, A-1090 Vienna, Austria; (F.T.); (K.K.)
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
| | - Xiang-Hai Cai
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China;
| | - Wichai Aiyakool
- Department of Botany, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand;
- Department of Agriculture, Ministry of Agriculture and Cooperatives, Bangkok 10900, Thailand
| | - Martin Pfeiffer
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, A-8010 Graz, Austria;
| | - Lothar Brecker
- Department of Organic Chemistry, University of Vienna, Währinger Strasse 38, A-1090 Vienna, Austria; (F.T.); (K.K.)
| | - Johann Schinnerl
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
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