Chemical constituents isolated from the aerial parts of Swertia pseudochinensis and their potential neuroprotective effects

Abstract

Abstract Objective: Swertia pseudochinensis, an annual herb of the genus Swertia in the family Gentianaceae. Some constituents and extracts from the Swertia genus have been recently reported to possess neuroprotective effects, suggesting their potential utility in the prevention and treatment of Parkinson disease (PD). The aim of this work is to identify the chemical constituents and evaluate the potential biological activists of Swertia pseudochinensis. Methods: The phytochemicals from the aerial parts of S. pseudochinensis were isolated and purified by silica gel, Sephadex LH-20 gel, semi-preparative high-performance liquid chromatography, and identified by the spectroscopic methods. All compounds were evaluated for their potential neuroprotective effects against 1-methyl-4-phenylpyridinium-induced apoptosis in the SH-SY5Y human neuroblastoma cell line using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay. Then, we performed an enrichment analysis using the Database for Annotation, Visualization, and Integrated Discovery and investigated the mechanisms by which bellidifolin regulates neurodegenerative disease. Results: Two new anthraquinone, 1,5,6-trimethoxy-2-hydroxy-3-methy-anthraquinone (1) and 1,5,6,8-tetramethoxy-2-hydroxy-3-methyanthraquinone (2), together with nine known including 7-O-β-d-glucopyranosyl-1,8-dihydroxy-3-methoxyxanthone (3), gentisin (4), swertianolin (5), bellidifolin (6), gentiacaulein (7), norswertianolin (8), 5-O-β-d-glucopyranosyl-1,3,8-trihydroxyapatone (9), 1-hydroxy-3,5,8-trimethoxyxanthone (10), and aurantio-obtusin (11), were isolated and compounds 6–8 and 10 exhibited neuroprotective effects at a concentration of 50 μmol/L. Among them, bellidifolin showed significant protective activity, and might have potential as a neuroprotective agent for the treatment of PD, possibly by acting on oxidative damage and reactive oxygen species. Conclusions: These findings indicate that further research on the genus Swertia and its bioactive constituents toward neurodegenerative disorders could be extremely rewarding.