Isolation of new indole alkaloid triglucoside from the aqueous extract of Uncaria rhynchophylla

• Published in: Journal of natural medicines 2025, Vol.79 (1), p.28-35
• Main Authors: Koseki, Yuta, Nishimura, Hiroaki, Asano, Ryuji, Aoki, Katsuyuki, Shiyu, Li, Sugiyama, Ryosuke, Yamazaki, Mami
• Format: Article
• Language: English
• Subjects: Alkaloids; Biomedical and Life Sciences; Biomedicine; Complementary & Alternative Medicine; Crystallization; Crystals; Glucosides - chemistry; Glucosides - isolation & purification; Indole Alkaloids - chemistry; Indole Alkaloids - isolation & purification; Magnetic Resonance Spectroscopy; Mass spectroscopy; Medicinal Chemistry; Molecular Structure; Original Paper; Pharmacology/Toxicology; Pharmacy; Plant Extracts - chemistry; Plant Sciences; Spectrometry, Mass, Electrospray Ionization; Uncaria - chemistry; Uncaria rhynchophylla; X-ray diffraction
• ISSN: 1340-3443; 1861-0293; 1861-0293
• DOI: 10.1007/s11418-024-01836-9

Uncaria rhynchophylla (Miq.) Miq. (Rubiaceae) is widely used as a botanical raw material for traditional Japanese and Chinese medicines. However, not all of its potentially bioactive constituents have been isolated and characterized. Herein, one new indole alkaloid triglucoside ( 1 ), nine known alkaloids ( 2 – 10 ) and thirteen known non-alkaloids ( 11 – 23 ) were isolated from the aqueous extract of Uncaria rhynchophylla hook and structurally characterized 1 H and 13 C NMR and high-resolution electrospray ionization mass spectrometry. The absolute configurations of isolated compounds ( 1 , 2 and 3 ) were determined by the X-ray diffraction analysis of their single crystals obtained using a micro-drop crystallization technique. This technique allows single crystals to be obtained from samples as small as 50 µg, thus providing detailed structural information even on minor constituents and enabling the accurate quality monitoring of botanical raw materials more accurately. Graphical abstract