Iridoid and irido-alkaloids from the fruits of Mitragyna stipulosa, and the plausible biosynthetic route to the new ring formation

• Published in: Biochemical systematics and ecology Vol. 111; p. 104732
• Main Authors: Ndoumbe, Christian Martial Mileng, Nono, Raymond Ngansop, Zeutsop, Jean Francois, Bitchagno, Gabin Thierry Mbahbou, Lenta, Bruno Ndjakou, Nkeng-Efouet-Alango, Pépin, Sewald, Norbert, Chouna, Jean Rodolphe
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-12-2023
• Subjects: Artifacts alkaloid; Biosynthetic route; Iridoid-dimer; Mitragyna stipulosa; Rubiaceae; Biosynthetic route; Artifacts alkaloid; Mitragyna stipulosa; Rubiaceae; Iridoid-dimer
• ISSN: 0305-1978; 1873-2925
• DOI: 10.1016/j.bse.2023.104732

Mitragynoid (1), a new iridoid along with twelve known natural derivatives (2–13) were isolated from the fruits of Mitragyna stipulosa. In addition, three likely-artifact irido-alkaloids, mitrageines A-C (14–16) and gentianine (17) probably formed during the alkaloids extraction process were also isolated. The structures of compounds were established by means of spectroscopic method including IR, 1D and 2D NMR and mass spectrometric analysis. The biosynthetic route to the new ring formation was also proposed.
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•Iridoid and new iridoid dimer.•Artifact alkaloids.•Gentiopicral and gentianine as diene/dienophile in Diels-Alder reaction.•Impact of ammonia on plant extract containing iridoid (sweroside and/or swertiamarin).