<jats:title>Abstract</jats:title><jats:p><jats:boxed-text content-type="graphic" position="anchor"><jats:graphic xmlns:xlink="http://www.w3.org/1999/xlink" mimetype="image/gif" position="anchor" specific-use="enlarged-web-image" xlink:href="graphic/mcontent.gif"><jats:alt-text>magnified image</jats:alt-text></jats:graphic></jats:boxed-text><jats:p>A dihydrobenzo[<jats:italic>c</jats:italic>]phenanthridine alkaloid, epizanthocadinanine A (<jats:bold>1</jats:bold>), together with 27 known compounds, including eight benzo[<jats:italic>c</jats:italic>]phenanthridines, <jats:italic>i.e.</jats:italic>, oxynitidine (<jats:bold>2</jats:bold>), oxyavicine (<jats:bold>3</jats:bold>), oxychelerythrine (<jats:bold>4</jats:bold>), dihydrochelerythrine (<jats:bold>5</jats:bold>), 6‐acetonyldihydrochelerythrine (<jats:bold>6</jats:bold>), norchelerythrine (<jats:bold>7</jats:bold>), decarine (<jats:bold>8</jats:bold>), and arnottianamide (<jats:bold>9</jats:bold>); two 2‐quinolones, <jats:italic>i.e.</jats:italic>, flindersine (<jats:bold>10</jats:bold>) and 4‐methoxy‐1‐methyl‐2‐quinolone (<jats:bold>11</jats:bold>); two furoquinolines, <jats:italic>i.e.</jats:italic>, skimmianine (<jats:bold>12</jats:bold>) and <jats:italic>γ</jats:italic>‐fagarine (<jats:bold>13</jats:bold>); three aporphines, <jats:italic>i.e.</jats:italic>, liriodenine (<jats:bold>14</jats:bold>), <jats:italic>N</jats:italic>‐acetyldehydroanonaine (<jats:bold>15</jats:bold>), and <jats:italic>N</jats:italic>‐acetylanonaine (<jats:bold>16</jats:bold>); six lignans, <jats:italic>i.e.</jats:italic>, sesamin (<jats:bold>17</jats:bold>), episesamin (<jats:bold>18</jats:bold>), piperitol‐3,3‐dimethylallyl ether (<jats:bold>19</jats:bold>), xanthoxylol‐3,3‐dimethylallyl ether (<jats:bold>20</jats:bold>), savinin (<jats:bold>21</jats:bold>), and 2,3‐bis(3,4‐methylenedioxybenzyl)but‐2‐en‐4‐olide (<jats:bold>22</jats:bold>); three terpenoids, <jats:italic>i.e.</jats:italic>, <jats:italic>α</jats:italic>‐cadinol (<jats:bold>23</jats:bold>), anticopalol (<jats:bold>24</jats:bold>), and spathulenol (<jats:bold>25</jats:bold>); one coumarin, <jats:italic>i.e.</jats:italic>, aesculetin dimethyl ether (<jats:bold>26</jats:bold>); and two steroids, <jats:italic>i.e.</jats:italic>, <jats:italic>β</jats:italic>‐sitosterol (<jats:bold>27</jats:bold>) and <jats:italic>β</jats:italic>‐sitostenone (<jats:bold>28</jats:bold>) were isolated from the stem bark of <jats:italic>Zanthoxylum nitidum.</jats:italic> Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR as well as MS analyses. Moreover, the recently reported structures <jats:bold>2′</jats:bold>–<jats:bold>4′</jats:bold> of rhoifolines B and A, and ‘8‐methoxynorchelerythrine’, resp., isolated as new compounds from <jats:italic>Z. rhoifolium</jats:italic> and <jats:italic>Z. nitidum</jats:italic>, resp., could be assigned the revised structures <jats:bold>2</jats:bold>–<jats:bold>4</jats:bold> 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 (<jats:bold>14</jats:bold>) was the most active compound against the MCF‐7, NCI‐H460, and SF‐268 cell lines with <jats:italic>IC</jats:italic><jats:sub>50</jats:sub> values of 2.19, 2.38, and 3.19 μg/ml, resp.