New phenolic acids from the whole herb of Elephantopus scaber Linn. and their anti-inflammatory activity

Two new phenolic acids, ethyl 3,3′,4,4′-tetrahydroxy-δ-truxinate (1), 3-O-p-coumaroyl-4-O-caffeoyl quinic acid methyl ester (2), together with three known compounds (3–5) were isolated from the whole plant of Elephantopus scaber Linn. The structures of the new compounds were elucidated using detailed spectroscopic analysis. Compound 3 was obtained and given its NMR data for the first time. All isolates were evaluated for their anti-inflammatory activity via inhibiting the production of nitric oxide (NO) in lipopolysaccharide (LPS)-stimulated murine macrophage RAW 264.7 cells, and 1, 4 and 5 showed a moderate inhibition with IC₅₀ values ranging from 11.85 to 20.62 μM.