Maesa lanceolata is an ethno-medicinal plant distributedin Central and East Africa, especially Ethiopia and Kenya. It hasbeen used as a traditional medicine against bacterial infections inthe small intestine and viral infections in the liver and throat, aswell as treatment for rheumatic arthritis. Even though the activityof M. lanceolata leaves has been studied in angiogenesis, whichis significantly related to cancer and tumorigenesis, tangibleevidence for cancer inhibiting activity of M. lanceolata seeds hasnot yet been obtained. To the best of our knowledge, this is thefirst study in which an anti-cancer compound has been identifiedfrom the seeds of M. lanceolata and its anti-tumor activityevaluated in HCT116 human colon cancer cells.