Bioassay directed isolation of an antileukemic extract of Morinda parvifolia (Hong-Zhu-Teng) (Rubiaceae) has led to the characterization of morindaparvin-A (1), a new cytotoxic and antileukemic anthraquinone, and the known alizarin-1-methyl ether (2). The structure of 1 was identified as 1,2-methylenedioxyanthraquinone by synthesis from alizarin (3) and dibromomethane. The mono- and di-acetates (4 and 5), cinnamates (6 and 7) and senecioates (8 and 9) of alizarin were prepared and tested for their in vivo antileukemic activity against P-388 lymphocytic leukemia growth in BDF1 mice at 10 mg/kg/day and were found to be inactive, whereas 3 and its related derivatives 2, 10 (alizarin-2-methyl ether) and 11(1,2-ethylenedioxyanthraquinone) demonstrated marginal activity (T/C-126-136%) in the P-388 lymphocytic leukemia screen at 10 mg/kg/day.