Flavonoid Compounds from the Leaves of Kalanchoe prolifera and Their Cytotoxic Activity against P-388 Murine Leukimia Cells

Seven flavonoid compounds, kaempferol (1), quercetin (2), quercetin-3-O-β-D-glucopyranoside (3), kaempferol-3-O-β-D-glucopyranoside (4), kaempferol-3-O-α-L-rhamnoside (5), quercetin-3-O-sophoroside (6) and quercetin-3-O-rutinoside (7), were isolated from the methanolic extract of leaves of Kalanchoe prolifera. Compounds 1-7 were isolated for first time from this plant. These compounds were evaluated their cytotoxic activity against P-388 murine leukimia cells in vitro. Among those compounds kaempferol (1) and quercetin (2) showed strongest cytotoxic activity with IC₅₀ values of 4.45 ± 0.05 and 6.28 ± 0.02 µg/mL, respectively.