Molecular Networking-Guided Isolation of Cycloartane-type Triterpenoids from Curculigo orchioides and Their Inhibitory Effect on Nitric Oxide Production

The MolNetEnhancer workflow was applied to molecular
networking
analysis of the CH2Cl2-soluble fraction of the
rhizomes of Curculigo orchioides, which
showed a potent inhibitory effect on the lipopolysaccharide (LPS)-induced
nitric oxide production. Among the molecular network, clusters of
cycloartane-type triterpenoids were classified using the ClassyFire
module of MolNetEnhancer, and their structures were predicted by the
in silico fragment analysis tool, Network Annotation Propagation (NAP).
Using mass spectrometry (MS)-guided isolation methods, six cycloartane-type
triterpenoids (1–6) were isolated,
and their structures were elucidated based on the interpretation of
NMR, HRESIMS, and single-crystal X-ray diffraction. Among the isolates,
compounds 1 and 4, which have an α,β-unsaturated
carbonyl moiety on the A-ring, exhibited significant inhibitory effects
on LPS-induced nitric oxide production in RAW264.7 cells with IC50 values of 12.4 and 11.8 μM, respectively.