The new cytotoxic monotetrahydrofuran Annonaceous acetogenins, annocherin (1) and a mixture of (2,4)-cis- and trans-annocherinones (2 and 3), were isolated from the bioactive methanolic extract of Annonacherimolia seeds. Compounds 1-3 each possess an unusual 7-carbonyl group. Their structures were established on the basis of chemical and spectral evidence. Compounds 1-3 showed significant toxicity in the brine shrimp lethality test and cytotoxicity for six human solid tumor cell lines, with selectivity for the renal cell line (A-498) at potencies equivalent to Adriamycin.