JOURNAL OF NATURAL MEDICINES, vol.61, no.2, pp.164-169, 2007 (SCI-Expanded)
Reversed-phase HPLC analysis of the methanol extract of the aerial parts of Centaurea gigantea afforded chlorogenic acid and five flavonoids, 2"-(4"'-hydroxybenzoyl)-isoorientin, orientin, isoorientin, isoquercetrin and cirsiliol. The structures of the these phenolic compounds were established unequivocally by UV, MS, a series of 1D and 2D NMR analyses and by comparison of their spectroscopic data with literature data. The free radical scavenging properties of these compounds were assessed by the DPPH assay, and their toxicity towards brine shrimps, and cytotoxicity towards cancer cells were evaluated, respectively, by the brine shrimp lethality assay and the MTT assay using CaCo-2 colon cancer cell line. Among the compounds, chlorogenic acid exhibited considerable anti-colon cancer activity (IC50=79.0 mu M).