A new indole alkaloid, 17-O-methyl-19-(Z)-naucline (1), together with seven known alkaloids (2–8), were isolated from the stems and leaves of Nauclea officinalis. The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons their data with those reported in the literature. 17-O-methyl-19-(Z)-naucline (1) showed significant inhibitory activity on nitric oxide production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells in vitro with an IC50 value of 3.6 μM. © 2017 Informa UK Limited, trading as Taylor & Francis Group.