Four new alkaloid glycosides, zanthonitisides A–D (1-4), together with five known compounds (5–9) were isolated from the aqueous fraction of stems and twigs of Zanthoxylum nitidum (Roxb.) DC. Their structures were determined on the basis of extensive spectroscopic methods, including 1D-, 2D-NMR, MS, and CD data. All isolated compounds were evaluated for their cytotoxic activity against three human cancer cell lines, CT-26, MCF-7, and MKN-45. As results, compound 4 showed significant cytotoxic activity on MKN-45 cancer cell line with IC50 value of 7.4 ± 1.0 μM. Compound 9 exhibited moderate cytotoxic activity on all tested cancer cell lines with an IC50 values ranging from 34.7 to 44.7 μM. © 2019 Phytochemical Society of Europe