An essential oil-free infusion of lemongrass was prepared and fractionated by column chromatography as previously de-scribed (Figueirinha et al., 2008). All the fractionation process was monitored by high-performance liquid chromatography (HPLC) and thin layer chromatography (TLC) for polyphenols. The flavonoid-rich fraction was used as the starting point to isolate luteolin 7-O-β-glucopyranoside, luteolin 6-C-β-glucopyranoside and luteolin 2″-O-rhamnosyl-C-(6-deoxy-ribo-hexos-3-ulosyl), commonly known as cassiaoccidentalin B. Freeze-dried flavonoid-rich fraction was dissolved in metha-nol and applied on chromatography cellulose paper sheets (46 × 57 cm)Whatman® 3MM (Maldstone, England), and eluted in a saturated chamber with 15% acetic acid. Each isolated spot was detected by UV (366 nm) observation and removed from the paper by 50% methanol extraction and purified on poly-amide. Structural elucidation of each isolated flavonoid was achieved by 1H NMR.