Anti-inflammatory steroidal glycosides from Allium chinense G. don

Phytochemical investigation of the bulbs of Allium chinense G. Don led to the isolation of sixteen steroidal glycosides, including ten previously undescribed compounds (1-3, 8-14). Their chemical structures were determined through comprehensive spectroscopic analysis (1D and 2D NMR, HRESIMS), with their absolute configurations further established by quantum chemical NMR calculations and DP4+ statistical analysis. Biological evaluation demonstrated that the isolated steroids significantly inhibited nitric oxide (NO) production in LPS-induced RAW 264.7 macrophages. Notably, compounds 2 and 9 exhibited potent anti-inflammatory activity with IC₅₀ values of 44.27 ± 2.13 and 34.85 ± 4.03 μM, respectively. Mechanistic studies revealed that the most potent isolate, compound 9, exerts its anti-inflammatory effect by blocking NF-κB nuclear translocation and dose-dependently downregulating the expression of key pro-inflammatory mediators, including iNOS, COX-2, and IL-1β, at both mRNA and protein levels. These findings provide robust evidence that A. chinense-derived steroids are potential lead compounds for the development of previously unreported anti-inflammatory therapeutics.