Eight acridone alkaloids were isolated from Bosistoa transversa. Three of them are novel and have been identified as 1,3,5-trihydroxy-2-(2 xi-hydroxy-3-methylbut-3-enyl)-10-methylacridan-9-one (trivial name, bosistidine), 1,3,5-trihydroxy-2-(2 xi-hydroxy-3-methylbut-3-enyl)-4-(3-methylbut-2-enyl)-10-methylacridan-9-one (bosistine) and 1,3,5-trihydroxy-4-(25-hydroxy-3-methylbut-3-enyl)-yukocritine. The structures were elucidated on the basis of NMR spectral data, notably NOESY and HMBC experiments.