Partial purification of novel differentiation-inducing substances(s) from hot water extract of Japanese pine cone

The effects of hot-water extract of pine cone (PCE) of Pinus parviflora Sieb. et Zucc. on the growth and differentiation of ML-1 cells, derived from a patient with human myeloblastic leukemia, were investigated. Growth of ML-1 cells was slightly inhibited at 3% (v/v) PCE, and a cytotoxic effect appeared at greater than 10%. Growth inhibition was accompanied by conversion to morphologically macrophage-like cells with alpha-naphthyl acetate esterase activity. In contrast, PCE dose-dependently increased the Fc receptor and nitroblue tetrazolium (NBT)-reducing activity up to 3%; above 3% its effect declined. Most of the cytotoxic activity was extracted from PCE with ethanol, and separated from the insoluble pellet, which contained the differentiation-inducing activity. The differentiation-inducing activity was eluted near the void volume on Sephadex G-200 gel filtration, with a 260-fold increase in the specific activity.