Isolation of Three Lycorine Type Alkaloids from Rhodolirium speciosum (Herb.) Ravenna Using pH-Zone-Refinement Centrifugal Partition Chromatography and Their Acetylcholinesterase Inhibitory Activities

• Published in: Metabolites Vol. 10; no. 8; p. 309
• Main Authors: Correa, Diana Isabel, Pastene-Navarrete, Edgar, Bustamante, Luis, Baeza, Marcelo, Alarcón-Enos, Julio
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 28.07.2020; MDPI
• Subjects: Acetonitrile; Acetylcholinesterase; Alkaloids; amaryllidaceae alkaloids; Chromatography; Diacetyl; Gas chromatography; mass spectrometry; Mass spectroscopy; NMR; Nuclear magnetic resonance; pH effects; pH zone refining centrifugal partition chromatography; Solvents
• ISSN: 2218-1989; 2218-1989
• DOI: 10.3390/metabo10080309

Preparative separation of three lycorine type alkaloids from Rhodolirum speciosum (Amaryllidaceae) was successfully carried out using pH-zone-refinement centrifugal partition chromatography (CPC) using the solvent system methyl-tert-butyl ether/acetonitrile/water (4:1:5, v/v/v) in descending mode. Using this system, Alkaloid 1 (165.7 mg, 88.2%, purity), 2 (60.1 mg, 97.7% purity) and 3 (12.3 mg, 84.4% purity) were obtained in one step. For structure elucidation, the pure alkaloids were subjected to spectroscopy analysis using nuclear magnetic resonance experiments (1H-NMR, 13C-NMR) and gas chromatography coupled with mass spectrometry (GC-MS). Alkaloids 1, 2, and 3 were identified as 1-O-acetyl-5,6-dehydrolycorine, 1-O-acetyl-lycorine, and 1,2-O-diacetyl-5,6-dehydrolycorine, respectively. The acetylcholinesterase inhibitory activity of these alkaloids was IC50 151.1 μg/mL, IC50 203.5 μg/mL, IC50 470.0 μg/mL, and IC50 17.1 μg/mL, respectively.