Phytochemical study of Ligularia subspicata and valuation of its anti-inflammatory activity

This report illustrated isolation and identification of 42 compounds comprising five (spicatainoids A-E) undescribed eremophilanolide type sesquiterpenoids and one undescribed nor-eremophilane (spicatainoid F) from Ligularia subspicata.. Among all the isolated new compounds, 4 is reported as the first enantiomeric form of novel eremophilanolide type sesquiterpenoid. Comprehensive analysis of HRESIMS, 1D/2D NMR, experimental circular dichroism (CD), calculated ECD analysis, and X-ray crystallographic (XRD) analysis validated the complete configuration and confirmation of these isolated compounds. All the isolated compounds were tested for the anti-inflammatory potential by measuring the amount of nitric oxide production. Among the tested compounds, 4 was the most effective with 90% NO-inhibition activity. Compounds 1, 2, 3, 9, 10 18, 29, 34, 35 exhibited moderate inhibitory effects against the production of NO, while other compounds displayed no activity even at the concentration of 50 μM. Additionally, compounds 1, 3 and 4 presented moderate anti-inflammatory activity by inhibiting the release of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in LPS-stimulated N9 cells. The IC₅₀ values of compounds 1, 3 and 4 were calculated 39.6 ± 2.7, 42.5 ± 3.8 and 27.60 ± 1.9 μΜ.