Two new acridone alkaloids from the branch of Atalantia buxifolia and their biological activity.

Two new acridone alkaloids, 3-methoxy-1,4,5-trihydroxy-10-methylacridone (1) and 2,3-dimethoxy-1,4,5-trihydroxy-10-methylacridone (2), were isolated from the ethanol extract of the branch of Atalantia buxifolia. Their structures were elucidated by spectroscopic methods including 1D and 2D NMR. Compounds 1 and 2 exhibited significant antibacterial activity against Staphylococcus aureus and weak inhibitory effect on acetylcholinesterase.