Two flavonoids, quercetin-3-O-β-D-glucopyranoside (1) and quercetin-3, 7-di-O-β-D-glucopyranoside (2), were isolated from the leaves of Mours alba (Moraceae). These two flavonoids exerted a significant inhibitory effect on the growth of the human promyelocytic leukemia cell line (HL-60) at the concentration of 2×10^-4 M. Compound 2 also induced differentiation of the HL-60 cell line to express CD 66b and CD 14 antigens. These flavonoids exhibited significant free radical scavenging effects on 1, 1-diphenyl-2-picyl-hydrazyl radical.