A dihydrobenzo[ c ]phenanthridine alkaloid, epizanthocadinanine A ( 1 ), together with 27 known compounds, including eight benzo[ c ]phenanthridines, i.e. , oxynitidine ( 2 ), oxyavicine ( 3 ), oxychelerythrine ( 4 ), dihydrochelerythrine ( 5 ), 6‐acetonyldihydrochelerythrine ( 6 ), norchelerythrine ( 7 ), decarine ( 8 ), and arnottianamide ( 9 ); two 2‐quinolones, i.e. , flindersine ( 10 ) and 4‐methoxy‐1‐methyl‐2‐quinolone ( 11 ); two furoquinolines, i.e. , skimmianine ( 12 ) and γ ‐fagarine ( 13 ); three aporphines, i.e. , liriodenine ( 14 ), N ‐acetyldehydroanonaine ( 15 ), and N ‐acetylanonaine ( 16 ); six lignans, i.e. , sesamin ( 17 ), episesamin ( 18 ), piperitol‐3,3‐dimethylallyl ether ( 19 ), xanthoxylol‐3,3‐dimethylallyl ether ( 20 ), savinin ( 21 ), and 2,3‐bis(3,4‐methylenedioxybenzyl)but‐2‐en‐4‐olide ( 22 ); three terpenoids, i.e. , α ‐cadinol ( 23 ), anticopalol ( 24 ), and spathulenol ( 25 ); one coumarin, i.e. , aesculetin dimethyl ether ( 26 ); and two steroids, i.e. , β ‐sitosterol ( 27 ) and β ‐sitostenone ( 28 ) were isolated from the stem bark of Zanthoxylum nitidum. Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR as well as MS analyses. Moreover, the recently reported structures 2′ – 4′ of rhoifolines B and A, and ‘8‐methoxynorchelerythrine’, resp., isolated as new compounds from Z. rhoifolium and Z. nitidum , resp., could be assigned the revised structures 2 – 4 by reinvestigation of the spectroscopic data. In addition, the cytotoxicity of the isolates was evaluated on the MCF‐7, NCI‐H460, and SF‐268 cell lines. Among these isolates, liriodenine ( 14 ) was the most active compound against the MCF‐7, NCI‐H460, and SF‐268 cell lines with IC 50 values of 2.19, 2.38, and 3.19 μg/ml, resp.