Studies on the differentiation inducers of myeloid leukemic cells from Citrus species.

An attempt was made to isolate differentiation inducers from Aurantii Nobilis Pericarpium and the fruit peel of Citrus reticulata Blanco (Rutaceae). Twenty-seven kinds of flavones, including five new flavones, were isolated after repeated chromatography from methanol extracts of these plants and their structures were established, from their physicochemical data, to be highly methoxylated flavones. Each compound, except for two flavone glucosides, showed the differentiation inducing activity toward mouse myeloid leukemia cells (M1), and the cells came to have phagocytic activity. Furthermore, differentiation inducing activity was tested using human acute promyelocytic leukemia cell line (HL-60).