Anti-inflammatory Constituents from Bupleurum chinense DC. Aerial Parts: Identification and Computational Mechanistic Insights

Abstract

Bupleurum chinense DC. is a medicinal plant used for inflammatory conditions. While the anti-inflammatory activity of its roots is well established and attributed to saikosaponins, its aerial parts are routinely discarded during processing, leaving their chemical composition and bioactivity largely unexplored. To address this, a systematic phytochemical and anti-inflammatory study were conducted on these abandoned aerial tissues. The 70% ethanol extract of aerial parts was fractionated through silica gel column chromatography, ODS reversed-phase chromatography and preparative HPLC, affording 16 compounds structurally characterized by NMR and HR-ESI-MS. These isolates were categorized into four major groups, including flavonoids (6, 7), organic acids (1-4, 10-14), terpenoids (15, 16), lignans and sterols (5, 8, 9). Subsequent anti-inflammatory assays on LPS-stimulated RAW264.7 macrophages at concentrations of 6.25-100 µM showed that methyl chlorogenate exhibited the most potent inhibitory effect on NO production, superior to all other isolated constituents. This research expands the chemical constituent library of B. chinense aerial parts and identifies methyl chlorogenate as a promising anti-inflammatory lead compound, providing solid chemical and pharmacological evidence for the sustainable high-value utilization of the aerial waste resources of this medicinal plant.