Four new prenylated xanthones, cudratricusxanthones J-M (1-4), were isolated from the CH2Cl2-soluble extract of the root bark of Cudrania tricuspidata, along with four known prenylated xanthones, isocudraxanthone K (5), cudraxanthone C (6), cudratricusxanthone A (7), and cudraxanthone L (8), and three known prenylated flavonoids, cudraflavone A (9), cudraflavanone A (10), and cudraflavone B (11). The structures of compounds 1-4 were elucidated using spectroscopic methods. Cudratricusxanthone A (7), cudraflavanone A (10), and cudraflavone B (11) showed moderate inhibitory effects on mouse brain monoamine oxidase (MAO) with IC50 values of 88.3, 89.7, and 80.0 microM, respectively.