Cytotoxic monoterpenoid indole alkaloids from Tabernaemontana bovina

• Published in: Phytochemistry (Oxford) 2025-02, Vol.230, p.114336, Article 114336
• Main Authors: Tan, Bang-Yin, Lin, Hua, Zhang, Heng-Gang, Zhao, Jing-Zhi, Deng, Shi-Yu, Guo, Rui-Rong, Wei, Xin, Zhang, Lan-Chun, Zhang, Rong-Ping, Yu, Hao-Fei
• Format: Article
• Language: English
• Subjects: Alkaloids; Antineoplastic Agents, Phytogenic - chemistry; Antineoplastic Agents, Phytogenic - isolation & purification; Antineoplastic Agents, Phytogenic - pharmacology; Apocynaceae; Apoptosis - drug effects; Cell Proliferation - drug effects; Cytotoxicity; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Hep G2 Cells; Humans; Molecular Structure; Secologanin Tryptamine Alkaloids - chemistry; Secologanin Tryptamine Alkaloids - isolation & purification; Secologanin Tryptamine Alkaloids - pharmacology; Structure-Activity Relationship; Tabernaemontana - chemistry; Tabernaemontana bovina; Tabernovinaine A-E
• ISSN: 0031-9422; 1873-3700; 1873-3700
• DOI: 10.1016/j.phytochem.2024.114336

Chemical investigation of the native medicinal plant Tabernaemontana bovina led to the isolation of five previously unreported monoterpenoid indole alkaloids tabernovinaines A-E (1–5) together with twenty-seven known analogs (6–32), including a bisindole alkaloid 1 with the (E)-4-aminobut-3-en-2-one fragment, as well as a unique cage skeleton 2 containing 6/5/8/6/6 ring system. The chemical structures of these unreported compounds were elucidated using mass spectrometry, NMR spectroscopy, circular dichroism, density functional theory calculations, and derivatizations. The activity evaluation shows that the bisindole alkaloid 1 revealed a potential cytotoxic effect by inducing HepG2 cell apoptosis and damaging clonal sphere expansion. Five undescribed monoterpenoid indole alkaloids tabernovinaines A-E were isolated and characterized from the Tabernaemontana bovina, and tabernovinaine A had certain cytotoxic activities. [Display omitted] •Five previously unreported monoterpenoid indole alkaloids were isolated from Tabernaemontana bovina.•Compound 1 was the first reported bisindole alkaloid with the (E)-4-aminobut-3-en-2-one fragment.•Compound 2 was identified as a unique cage skeleton containing 6/5/8/6/6 ring system.•The bisindole alkaloid 1 with potential antitumor effection.