New acylglycosides from the roots of Rheum palmatum L. (June 2022)

• Record Type: Journal Article
• Authors: Feng, Wei-Jiao; Yang, Hong-Ying; He, Yi-Lin; Li, Ya; Gao, Kun
• Is Part Of: Phytochemistry letters. Volume 49(2022)
• Page Start: 83
• Page End: 87
• Publication Date: 2022-06
• Subjects: Rheum palmatum L. -- Acylglycosides -- Anthraquinone -- LAG3/MHC II -- LAG3/FGL1; Botanical chemistry -- Periodicals; Chimie végétale -- Périodiques; 572.205
• DOI: 10.1016/j.phytol.2022.03.009
• Languages: English
• ISSNs: 1874-3900

Abstract

Abstract: A phytochemical investigation of the EtOH extract of the roots of Rheum palmatum L. was performed, leading to the isolation of 3 new acylglycosides (1 –3 ) and 19 previously reported compounds, including 4 cinnamoyl glucosides (4 –7 ) and 15 anthraquinones (8 –22 ). Their structures were elucidated using nuclear magnetic resonance, infrared, ultraviolet and high-resolution electrospray ionization mass spectra and X-ray diffraction data. The biological activities of compounds 2, 4 –9, and 11 –13, including their lymphocyte activation gene 3 (LAG3)/major histocompatibility complex class II (MHC II) and LAG3/fibrinogen-like protein 1 (FGL1) binding inhibition activities, were evaluated. Among the isolates, compound 7 exhibited clear inhibitory activity against the LAG3/FGL1 interaction with an IC50 of 7.89 μ M, meanwhile compound 6 inhibited the LAG3/MHC II interaction with an IC50 of 6.00 μ M. Graphical Abstract: ga1 Highlights: Three undescribed acylglycosides were isolated from roots of Rheum palmatum L. The absolute configuration of 1 was confirmed by single crystal X-ray diffraction. This is the first report of the crystal structure of a cinnamoyl glucoside. Their activities against the interaction of LAG3 with MHC II or FGL1 were evaluated.